path: root/usr/src/man/man4/proc.4

'\" te
.\" Copyright 1989 AT&T
.\" Copyright (c) 2006, Sun Microsystems, Inc. All Rights Reserved.
.\" Copyright (c) 2013, Joyent, Inc. All rights reserved.
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.TH PROC 4 "Jun 6, 2016"
.SH NAME
proc \- /proc, the process file system
.SH DESCRIPTION
.LP
\fB/proc\fR is a file system that provides access to the state of each process
and light-weight process (lwp) in the system. The name of each entry in the
\fB/proc\fR directory is a decimal number corresponding to a process-ID. These
entries are themselves subdirectories. Access to process state is provided by
additional files contained within each subdirectory; the hierarchy is described
more completely below. In this document, ``\fB/proc\fR file'' refers to a
non-directory file within the hierarchy rooted at \fB/proc\fR. The owner of
each \fB/proc\fR file and subdirectory is determined by the user-ID of the
process.
.sp
.LP
\fB/proc\fR can be mounted on any mount point, in addition to the standard
\fB/proc\fR mount point, and can be mounted several places at once. Such
additional mounts are allowed in order to facilitate the confinement of
processes to subtrees of the file system via \fBchroot\fR(1M) and yet allow
such processes access to commands like \fBps\fR(1).
.sp
.LP
Standard system calls are used to access \fB/proc\fR files: \fBopen\fR(2),
\fBclose\fR(2), \fBread\fR(2), and \fBwrite\fR(2) (including \fBreadv\fR(2),
\fBwritev\fR(2), \fBpread\fR(2), and \fBpwrite\fR(2)). Most files describe
process state and can only be opened for reading. \fBctl\fR and \fBlwpctl\fR
(control) files permit manipulation of process state and can only be opened for
writing. \fBas\fR (address space) files contain the image of the running
process and can be opened for both reading and writing. An open for writing
allows process control; a read-only open allows inspection but not control. In
this document, we refer to the process as open for reading or writing if any of
its associated \fB/proc\fR files is open for reading or writing.
.sp
.LP
In general, more than one process can open the same \fB/proc\fR file at the
same time. \fIExclusive\fR \fIopen\fR is an advisory mechanism provided to
allow controlling processes to avoid collisions with each other. A process can
obtain exclusive control of a target process, with respect to other cooperating
processes, if it successfully opens any \fB/proc\fR file in the target process
for writing (the \fBas\fR or \fBctl\fR files, or the \fBlwpctl\fR file of any
lwp) while specifying \fBO_EXCL\fR in the \fBopen\fR(2). Such an open will fail
if the target process is already open for writing (that is, if an \fBas\fR,
\fBctl\fR, or \fBlwpctl\fR file is already open for writing). There can be any
number of concurrent read-only opens; \fBO_EXCL\fR is ignored on opens for
reading. It is recommended that the first open for writing by a controlling
process use the \fBO_EXCL\fR flag; multiple controlling processes usually
result in chaos.
.sp
.LP
If a process opens one of its own \fB/proc\fR files for writing, the open
succeeds regardless of \fBO_EXCL\fR and regardless of whether some other
process has the process open for writing. Self-opens do not count when another
process attempts an exclusive open. (A process cannot exclude a debugger by
opening itself for writing and the application of a debugger cannot prevent a
process from opening itself.) All self-opens for writing are forced to be
close-on-exec (see the \fBF_SETFD\fR operation of \fBfcntl\fR(2)).
.sp
.LP
Data may be transferred from or to any locations in the address space of the
traced process by applying \fBlseek\fR(2) to position the \fBas\fR file at the
virtual address of interest followed by \fBread\fR(2) or \fBwrite\fR(2) (or by
using \fBpread\fR(2) or \fBpwrite\fR(2) for the combined operation). The
address-map files \fB/proc/\fR\fIpid\fR\fB/map\fR and
\fB/proc/\fR\fIpid\fR\fB/xmap\fR can be read to determine the accessible areas
(mappings) of the address space. \fBI/O\fR transfers may span contiguous
mappings. An \fBI/O\fR request extending into an unmapped area is truncated at
the boundary. A write request beginning at an unmapped virtual address fails
with \fBEIO\fR; a read request beginning at an unmapped virtual address returns
zero (an end-of-file indication).
.sp
.LP
Information and control operations are provided through additional files.
\fB<procfs.h>\fR contains definitions of data structures and message formats
used with these files. Some of these definitions involve the use of sets of
flags. The set types \fBsigset_t\fR, \fBfltset_t\fR, and \fBsysset_t\fR
correspond, respectively, to signal, fault, and system call enumerations
defined in \fB<sys/signal.h>\fR, \fB<sys/fault.h>\fR, and
\fB<sys/syscall.h>\fR\&. Each set type is large enough to hold flags for its
own enumeration. Although they are of different sizes, they have a common
structure and can be manipulated by these macros:
.sp
.in +2
.nf
prfillset(&set);             /* turn on all flags in set */
premptyset(&set);            /* turn off all flags in set */
praddset(&set, flag);        /* turn on the specified flag */
prdelset(&set, flag);        /* turn off the specified flag */
r = prismember(&set, flag);  /* != 0 iff flag is turned on */
.fi
.in -2

.sp
.LP
One of \fBprfillset()\fR or \fBpremptyset()\fR must be used to initialize
\fBset\fR before it is used in any other operation. \fBflag\fR must be a member
of the enumeration corresponding to \fBset\fR.
.sp
.LP
Every process contains at least one \fIlight-weight process\fR, or \fIlwp\fR.
Each lwp represents a flow of execution that is independently scheduled by the
operating system. All lwps in a process share its address space as well as many
other attributes. Through the use of \fBlwpctl\fR and \fBctl\fR files as
described below, it is possible to affect individual lwps in a process or to
affect all of them at once, depending on the operation.
.sp
.LP
When the process has more than one lwp, a representative lwp is chosen by the
system for certain process status files and control operations. The
representative lwp is a stopped lwp only if all of the process's lwps are
stopped; is stopped on an event of interest only if all of the lwps are so
stopped (excluding \fBPR_SUSPENDED\fR lwps); is in a \fBPR_REQUESTED\fR stop
only if there are no other events of interest to be found; or, failing
everything else, is in a \fBPR_SUSPENDED\fR stop (implying that the process is
deadlocked). See the description of the \fBstatus\fR file for definitions of
stopped states. See the \fBPCSTOP\fR control operation for the definition of
``event of interest''.
.sp
.LP
The representative lwp remains fixed (it will be chosen again on the next
operation) as long as all of the lwps are stopped on events of interest or are
in a \fBPR_SUSPENDED\fR stop and the \fBPCRUN\fR control operation is not
applied to any of them.
.sp
.LP
When applied to the process control file, every \fB/proc\fR control operation
that must act on an lwp uses the same algorithm to choose which lwp to act
upon. Together with synchronous stopping (see \fBPCSET\fR), this enables a
debugger to control a multiple-lwp process using only the process-level status
and control files if it so chooses. More fine-grained control can be achieved
using the lwp-specific files.
.sp
.LP
The system supports two process data models, the traditional 32-bit data model
in which ints, longs and pointers are all 32 bits wide (the ILP32 data model),
and on some platforms the 64-bit data model in which longs and pointers, but
not ints, are 64 bits in width (the LP64 data model). In the LP64 data model
some system data types, notably \fBsize_t\fR, \fBoff_t\fR, \fBtime_t\fR and
\fBdev_t\fR, grow from 32 bits to 64 bits as well.
.sp
.LP
The \fB/proc\fR interfaces described here are available to both 32-bit and
64-bit controlling processes. However, many operations attempted by a 32-bit
controlling process on a 64-bit target process will fail with \fBEOVERFLOW\fR
because the address space range of a 32-bit process cannot encompass a 64-bit
process or because the data in some 64-bit system data type cannot be
compressed to fit into the corresponding 32-bit type without loss of
information. Operations that fail in this circumstance include reading and
writing the address space, reading the address-map files, and setting the
target process's registers. There is no restriction on operations applied by a
64-bit process to either a 32-bit or a 64-bit target processes.
.sp
.LP
The format of the contents of any \fB/proc\fR file depends on the data model of
the observer (the controlling process), not on the data model of the target
process. A 64-bit debugger does not have to translate the information it reads
from a \fB/proc\fR file for a 32-bit process from 32-bit format to 64-bit
format. However, it usually has to be aware of the data model of the target
process. The \fBpr_dmodel\fR field of the \fBstatus\fR files indicates the
target process's data model.
.sp
.LP
To help deal with system data structures that are read from 32-bit processes, a
64-bit controlling program can be compiled with the C preprocessor symbol
\fB_SYSCALL32\fR defined before system header files are included. This makes
explicit 32-bit fixed-width data structures (like \fBcstruct stat32\fR) visible
to the 64-bit program. See \fBtypes32.h\fR(3HEAD).
.SH DIRECTORY STRUCTURE
.LP
At the top level, the directory \fB/proc\fR contains entries each of which
names an existing process in the system. These entries are themselves
directories. Except where otherwise noted, the files described below can be
opened for reading only. In addition, if a process becomes a \fIzombie\fR (one
that has exited but whose parent has not yet performed a \fBwait\fR(3C) upon
it), most of its associated \fB/proc\fR files disappear from the hierarchy;
subsequent attempts to open them, or to read or write files opened before the
process exited, will elicit the error \fBENOENT\fR.
.sp
.LP
Although process state and consequently the contents of \fB/proc\fR files can
change from instant to instant, a single \fBread\fR(2) of a \fB/proc\fR file is
guaranteed to return a sane representation of state; that is, the read will be
atomic with respect to the state of the process. No such guarantee applies to
successive reads applied to a \fB/proc\fR file for a running process. In
addition, atomicity is not guaranteed for \fBI/O\fR applied to the \fBas\fR
(address-space) file for a running process or for a process whose address space
contains memory shared by another running process.
.sp
.LP
A number of structure definitions are used to describe the files. These
structures may grow by the addition of elements at the end in future releases
of the system and it is not legitimate for a program to assume that they will
not.
.SH STRUCTURE OF \fB/proc/\fR\fIpid\fR
.LP
A given directory \fB/proc/\fR\fIpid\fR contains the following entries. A
process can use the invisible alias \fB/proc/self\fR if it wishes to open one
of its own \fB/proc\fR files (invisible in the sense that the name ``self''
does not appear in a directory listing of \fB/proc\fR obtained from
\fBls\fR(1), \fBgetdents\fR(2), or \fBreaddir\fR(3C)).
.SS "contracts"
.LP
A directory containing references to the contracts held by the process. Each
entry is a symlink to the contract's directory under \fB/system/contract\fR.
See \fBcontract\fR(4).
.SS "as"
.LP
Contains the address-space image of the process; it can be opened for both
reading and writing. \fBlseek\fR(2) is used to position the file at the virtual
address of interest and then the address space can be examined or changed
through \fBread\fR(2) or \fBwrite\fR(2) (or by using \fBpread\fR(2) or
\fBpwrite\fR(2) for the combined operation).
.SS "ctl"
.LP
A write-only file to which structured messages are written directing the system
to change some aspect of the process's state or control its behavior in some
way. The seek offset is not relevant when writing to this file. Individual lwps
also have associated \fBlwpctl\fR files in the lwp subdirectories. A control
message may be written either to the process's \fBctl\fR file or to a specific
\fBlwpctl\fR file with operation-specific effects. The effect of a control
message is immediately reflected in the state of the process visible through
appropriate status and information files. The types of control messages are
described in detail later. See \fBCONTROL MESSAGES\fR.
.SS "status"
.LP
Contains state information about the process and the representative lwp. The
file contains a \fBpstatus\fR structure which contains an embedded
\fBlwpstatus\fR structure for the representative lwp, as follows:
.sp
.in +2
.nf
typedef struct pstatus {
     int pr_flags;            /* flags (see below) */
     int pr_nlwp;             /* number of active lwps in the process */
     int pr_nzomb;            /* number of zombie lwps in the process */
     pid_tpr_pid;             /* process id */
     pid_tpr_ppid;            /* parent process id */
     pid_tpr_pgid;            /* process group id */
     pid_tpr_sid;             /* session id */
     id_t pr_aslwpid;         /* obsolete */
     id_t pr_agentid;         /* lwp-id of the agent lwp, if any */
     sigset_t pr_sigpend;     /* set of process pending signals */
     uintptr_t pr_brkbase;    /* virtual address of the process heap */
     size_t pr_brksize;       /* size of the process heap, in bytes */
     uintptr_t pr_stkbase;    /* virtual address of the process stack */
     size_tpr_stksize;        /* size of the process stack, in bytes */
     timestruc_t pr_utime;    /* process user cpu time */
     timestruc_t pr_stime;    /* process system cpu time */
     timestruc_t pr_cutime;   /* sum of children's user times */
     timestruc_t pr_cstime;   /* sum of children's system times */
     sigset_t pr_sigtrace;    /* set of traced signals */
     fltset_t pr_flttrace;    /* set of traced faults */
     sysset_t pr_sysentry;    /* set of system calls traced on entry */
     sysset_t pr_sysexit;     /* set of system calls traced on exit */
     char pr_dmodel;          /* data model of the process */
     taskid_t pr_taskid;      /* task id */
     projid_t pr_projid;      /* project id */
     zoneid_t pr_zoneid;      /* zone id */
     lwpstatus_t pr_lwp;      /* status of the representative lwp */
} pstatus_t;
.fi
.in -2

.sp
.LP
\fBpr_flags\fR is a bit-mask holding the following process flags. For
convenience, it also contains the lwp flags for the representative lwp,
described later.
.sp
.ne 2
.na
\fB\fBPR_ISSYS\fR\fR
.ad
.RS 13n
process is a system process (see \fBPCSTOP\fR).
.RE

.sp
.ne 2
.na
\fB\fBPR_VFORKP\fR\fR
.ad
.RS 13n
process is the parent of a vforked child (see \fBPCWATCH\fR).
.RE

.sp
.ne 2
.na
\fB\fBPR_FORK\fR\fR
.ad
.RS 13n
process has its inherit-on-fork mode set (see \fBPCSET\fR).
.RE

.sp
.ne 2
.na
\fB\fBPR_RLC\fR\fR
.ad
.RS 13n
process has its run-on-last-close mode set (see \fBPCSET\fR).
.RE

.sp
.ne 2
.na
\fB\fBPR_KLC\fR\fR
.ad
.RS 13n
process has its kill-on-last-close mode set (see \fBPCSET\fR).
.RE

.sp
.ne 2
.na
\fB\fBPR_ASYNC\fR\fR
.ad
.RS 13n
process has its asynchronous-stop mode set (see \fBPCSET\fR).
.RE

.sp
.ne 2
.na
\fB\fBPR_MSACCT\fR\fR
.ad
.RS 13n
Set by default in all processes to indicate that microstate accounting is
enabled. However, this flag has been deprecated and no longer has any effect.
Microstate accounting may not be disabled; however, it is still possible to
toggle the flag.
.RE

.sp
.ne 2
.na
\fB\fBPR_MSFORK\fR\fR
.ad
.RS 13n
Set by default in all processes to indicate that microstate accounting will be
enabled for processes that this parent forks(). However, this flag has been
deprecated and no longer has any effect. It is possible to toggle this flag;
however, it is not possible to disable microstate accounting.
.RE

.sp
.ne 2
.na
\fB\fBPR_BPTADJ\fR\fR
.ad
.RS 13n
process has its breakpoint adjustment mode set (see \fBPCSET\fR).
.RE

.sp
.ne 2
.na
\fB\fBPR_PTRACE\fR\fR
.ad
.RS 13n
process has its ptrace-compatibility mode set (see \fBPCSET\fR).
.RE

.sp
.LP
\fBpr_nlwp\fR is the total number of active lwps in the process. pr_nzomb is
the total number of zombie lwps in the process. A zombie lwp is a non-detached
lwp that has terminated but has not been reaped with \fBthr_join\fR(3C) or
\fBpthread_join\fR(3C).
.sp
.LP
\fBpr_pid\fR, \fBpr_ppid\fR, \fBpr_pgid\fR, and \fBpr_sid\fR are, respectively,
the process ID, the ID of the process's parent, the process's process group ID,
and the process's session ID.
.sp
.LP
\fBpr_aslwpid\fR is obsolete and is always zero.
.sp
.LP
\fBpr_agentid\fR is the lwp-ID for the \fB/proc\fR agent lwp (see the
\fBPCAGENT\fR control operation). It is zero if there is no agent lwp in the
process.
.sp
.LP
\fBpr_sigpend\fR identifies asynchronous signals pending for the process.
.sp
.LP
\fBpr_brkbase\fR is the virtual address of the process heap and
\fBpr_brksize\fR is its size in bytes. The address formed by the sum of these
values is the process \fBbreak\fR (see \fBbrk\fR(2)). \fBpr_stkbase\fR and
\fBpr_stksize\fR are, respectively, the virtual address of the process stack
and its size in bytes. (Each lwp runs on a separate stack; the distinguishing
characteristic of the process stack is that the operating system will grow it
when necessary.)
.sp
.LP
\fBpr_utime\fR, \fBpr_stime\fR, \fBpr_cutime\fR, and \fBpr_cstime\fR are,
respectively, the user \fBCPU\fR and system \fBCPU\fR time consumed by the
process, and the cumulative user \fBCPU\fR and system \fBCPU\fR time consumed
by the process's children, in seconds and nanoseconds.
.sp
.LP
\fBpr_sigtrace\fR and \fBpr_flttrace\fR contain, respectively, the set of
signals and the set of hardware faults that are being traced (see
\fBPCSTRACE\fR and \fBPCSFAULT\fR).
.sp
.LP
\fBpr_sysentry\fR and \fBpr_sysexit\fR contain, respectively, the sets of
system calls being traced on entry and exit (see \fBPCSENTRY\fR and
\fBPCSEXIT\fR).
.sp
.LP
\fBpr_dmodel\fR indicates the data model of the process. Possible values are:
.sp
.ne 2
.na
\fB\fBPR_MODEL_ILP32\fR\fR
.ad
.RS 19n
process data model is ILP32.
.RE

.sp
.ne 2
.na
\fB\fBPR_MODEL_LP64\fR\fR
.ad
.RS 19n
process data model is LP64.
.RE

.sp
.ne 2
.na
\fB\fBPR_MODEL_NATIVE\fR\fR
.ad
.RS 19n
process data model is native.
.RE

.sp
.LP
The \fBpr_taskid\fR, \fBpr_projid\fR, and \fBpr_zoneid\fR fields contain
respectively, the numeric \fBID\fRs of the task, project, and zone in which the
process was running.
.sp
.LP
The constant \fBPR_MODEL_NATIVE\fR reflects the data model of the controlling
process, \fIthat is\fR, its value is \fBPR_MODEL_ILP32\fR or
\fBPR_MODEL_LP64\fR according to whether the controlling process has been
compiled as a 32-bit program or a 64-bit program, respectively.
.sp
.LP
\fBpr_lwp\fR contains the status information for the representative lwp:
.sp
.in +2
.nf
typedef struct lwpstatus {
  int pr_flags;              /* flags (see below) */
  id_t pr_lwpid;             /* specific lwp identifier */
  short pr_why;              /* reason for lwp stop, if stopped */
  short pr_what;             /* more detailed reason */
  short pr_cursig;           /* current signal, if any */
  siginfo_t pr_info;         /* info associated with signal or fault */
  sigset_t pr_lwppend;       /* set of signals pending to the lwp */
  sigset_t pr_lwphold;       /* set of signals blocked by the lwp */
  struct sigaction pr_action;/* signal action for current signal */
  stack_t pr_altstack;       /* alternate signal stack info */
  uintptr_t pr_oldcontext;   /* address of previous ucontext */
  short pr_syscall;          /* system call number (if in syscall) */
  short pr_nsysarg;          /* number of arguments to this syscall */
  int pr_errno;              /* errno for failed syscall */
  long pr_sysarg[PRSYSARGS]; /* arguments to this syscall */
  long pr_rval1;             /* primary syscall return value */
  long pr_rval2;             /* second syscall return value, if any */
  char pr_clname[PRCLSZ];    /* scheduling class name */
  timestruc_t pr_tstamp;     /* real-time time stamp of stop */
  timestruc_t pr_utime;      /* lwp user cpu time */
  timestruc_t pr_stime;      /* lwp system cpu time */
  uintptr_t pr_ustack;       /* stack boundary data (stack_t) address */
  ulong_t pr_instr;          /* current instruction */
  prgregset_t pr_reg;        /* general registers */
  prfpregset_t pr_fpreg;     /* floating-point registers */
} lwpstatus_t;
.fi
.in -2

.sp
.LP
\fBpr_flags\fR is a bit-mask holding the following lwp flags. For convenience,
it also contains the process flags, described previously.
.sp
.ne 2
.na
\fB\fBPR_STOPPED\fR\fR
.ad
.RS 14n
The lwp is stopped.
.RE

.sp
.ne 2
.na
\fB\fBPR_ISTOP\fR\fR
.ad
.RS 14n
The lwp is stopped on an event of interest (see \fBPCSTOP\fR).
.RE

.sp
.ne 2
.na
\fB\fBPR_DSTOP\fR\fR
.ad
.RS 14n
The lwp has a stop directive in effect (see \fBPCSTOP\fR).
.RE

.sp
.ne 2
.na
\fB\fBPR_STEP\fR\fR
.ad
.RS 14n
The lwp has a single-step directive in effect (see \fBPCRUN\fR).
.RE

.sp
.ne 2
.na
\fB\fBPR_ASLEEP\fR\fR
.ad
.RS 14n
The lwp is in an interruptible sleep within a system call.
.RE

.sp
.ne 2
.na
\fB\fBPR_PCINVAL\fR\fR
.ad
.RS 14n
The lwp's current instruction (\fBpr_instr\fR) is undefined.
.RE

.sp
.ne 2
.na
\fB\fBPR_DETACH\fR\fR
.ad
.RS 14n
This is a detached lwp (see \fBpthread_create\fR(3C) and
\fBpthread_join\fR(3C)).
.RE

.sp
.ne 2
.na
\fB\fBPR_DAEMON\fR\fR
.ad
.RS 14n
This is a daemon lwp (see \fBpthread_create\fR(3C)).
.RE

.sp
.ne 2
.na
\fB\fBPR_ASLWP\fR\fR
.ad
.RS 14n
This flag is obsolete and is never set.
.RE

.sp
.ne 2
.na
\fB\fBPR_AGENT\fR\fR
.ad
.RS 14n
This is the \fB/proc\fR agent lwp for the process.
.RE

.sp
.LP
\fBpr_lwpid\fR names the specific lwp.
.sp
.LP
\fBpr_why\fR and \fBpr_what\fR together describe, for a stopped lwp, the reason
for the stop. Possible values of \fBpr_why\fR and the associated \fBpr_what\fR
are:
.sp
.ne 2
.na
\fB\fBPR_REQUESTED\fR\fR
.ad
.RS 17n
indicates that the stop occurred in response to a stop directive, normally
because \fBPCSTOP\fR was applied or because another lwp stopped on an event of
interest and the asynchronous-stop flag (see \fBPCSET\fR) was not set for the
process. \fBpr_what\fR is unused in this case.
.RE

.sp
.ne 2
.na
\fB\fBPR_SIGNALLED\fR\fR
.ad
.RS 17n
indicates that the lwp stopped on receipt of a signal (see \fBPCSTRACE\fR);
\fBpr_what\fR holds the signal number that caused the stop (for a newly-stopped
lwp, the same value is in \fBpr_cursig\fR).
.RE

.sp
.ne 2
.na
\fB\fBPR_FAULTED\fR\fR
.ad
.RS 17n
indicates that the lwp stopped on incurring a hardware fault (see
\fBPCSFAULT\fR); \fBpr_what\fR holds the fault number that caused the stop.
.RE

.sp
.ne 2
.na
\fB\fBPR_SYSENTRY\fR\fR
.ad
.br
.na
\fB\fBPR_SYSEXIT\fR\fR
.ad
.RS 17n
indicate a stop on entry to or exit from a system call (see \fBPCSENTRY\fR and
\fBPCSEXIT\fR); \fBpr_what\fR holds the system call number.
.RE

.sp
.ne 2
.na
\fB\fBPR_JOBCONTROL\fR\fR
.ad
.RS 17n
indicates that the lwp stopped due to the default action of a job control stop
signal (see \fBsigaction\fR(2)); \fBpr_what\fR holds the stopping signal
number.
.RE

.sp
.ne 2
.na
\fB\fBPR_SUSPENDED\fR\fR
.ad
.RS 17n
indicates that the lwp stopped due to internal synchronization of lwps within
the process. \fBpr_what\fR is unused in this case.
.RE

.sp
.LP
\fBpr_cursig\fR names the current signal, that is, the next signal to be
delivered to the lwp, if any. \fBpr_info\fR, when the lwp is in a
\fBPR_SIGNALLED\fR or \fBPR_FAULTED\fR stop, contains additional information
pertinent to the particular signal or fault (see \fB<sys/siginfo.h>\fR).
.sp
.LP
\fBpr_lwppend\fR identifies any synchronous or directed signals pending for the
lwp. \fBpr_lwphold\fR identifies those signals whose delivery is being blocked
by the lwp (the signal mask).
.sp
.LP
\fBpr_action\fR contains the signal action information pertaining to the
current signal (see \fBsigaction\fR(2)); it is undefined if \fBpr_cursig\fR is
zero. \fBpr_altstack\fR contains the alternate signal stack information for the
lwp (see \fBsigaltstack\fR(2)).
.sp
.LP
\fBpr_oldcontext\fR, if not zero, contains the address on the lwp stack of a
\fBucontext\fR structure describing the previous user-level context (see
\fBucontext.h\fR(3HEAD)). It is non-zero only if the lwp is executing in the
context of a signal handler.
.sp
.LP
\fBpr_syscall\fR is the number of the system call, if any, being executed by
the lwp; it is non-zero if and only if the lwp is stopped on \fBPR_SYSENTRY\fR
or \fBPR_SYSEXIT\fR, or is asleep within a system call ( \fBPR_ASLEEP\fR is
set). If \fBpr_syscall\fR is non-zero, \fBpr_nsysarg\fR is the number of
arguments to the system call and \fBpr_sysarg\fR contains the actual arguments.
.sp
.LP
\fBpr_rval1\fR, \fBpr_rval2\fR, and \fBpr_errno\fR are defined only if the lwp
is stopped on \fBPR_SYSEXIT\fR or if the \fBPR_VFORKP\fR flag is set. If
\fBpr_errno\fR is zero, \fBpr_rval1\fR and \fBpr_rval2\fR contain the return
values from the system call. Otherwise, \fBpr_errno\fR contains the error
number for the failing system call (see \fB<sys/errno.h>\fR).
.sp
.LP
\fBpr_clname\fR contains the name of the lwp's scheduling class.
.sp
.LP
\fBpr_tstamp\fR, if the lwp is stopped, contains a time stamp marking when the
lwp stopped, in real time seconds and nanoseconds since an arbitrary time in
the past.
.sp
.LP
\fBpr_utime\fR is the amount of user level CPU time used by this LWP.
.sp
.LP
\fBpr_stime\fR is the amount of system level CPU time used by this LWP.
.sp
.LP
\fBpr_ustack\fR is the virtual address of the \fBstack_t\fR that contains the
stack boundaries for this LWP. See \fBgetustack\fR(2) and
\fB_stack_grow\fR(3C).
.sp
.LP
\fBpr_instr\fR contains the machine instruction to which the lwp's program
counter refers. The amount of data retrieved from the process is
machine-dependent. On SPARC based machines, it is a 32-bit word. On x86-based
machines, it is a single byte. In general, the size is that of the machine's
smallest instruction. If \fBPR_PCINVAL\fR is set, \fBpr_instr\fR is undefined;
this occurs whenever the lwp is not stopped or when the program counter refers
to an invalid virtual address.
.sp
.LP
\fBpr_reg\fR is an array holding the contents of a stopped lwp's general
registers.
.sp
.ne 2
.na
\fBSPARC\fR
.ad
.RS 21n
On SPARC-based machines, the predefined constants \fBR_G0\fR ... \fBR_G7\fR,
\fBR_O0\fR ... \fBR_O7\fR, \fBR_L0\fR ... \fBR_L7\fR, \fBR_I0\fR ...
\fBR_I7\fR, \fBR_PC\fR, \fBR_nPC\fR, and \fBR_Y\fR can be used as indices to
refer to the corresponding registers; previous register windows can be read
from their overflow locations on the stack (however, see the \fBgwindows\fR
file in the \fB/proc/\fR\fIpid\fR\fB/lwp/\fR\fIlwpid\fR subdirectory).
.RE

.sp
.ne 2
.na
\fBSPARC V8 (32-bit)\fR
.ad
.RS 21n
For SPARC V8 (32-bit) controlling processes, the predefined constants
\fBR_PSR\fR, \fBR_WIM\fR, and \fBR_TBR\fR can be used as indices to refer to
the corresponding special registers. For SPARC V9 (64-bit) controlling
processes, the predefined constants \fBR_CCR\fR, \fBR_ASI\fR, and \fBR_FPRS\fR
can be used as indices to refer to the corresponding special registers.
.RE

.sp
.ne 2
.na
\fBx86 (32-bit)\fR
.ad
.RS 21n
For 32-bit x86 processes, the predefined constants listed belowcan be used as
indices to refer to the corresponding registers.
.sp
.in +2
.nf
SS
UESP
EFL
CS
EIP
ERR
TRAPNO
EAX
ECX
EDX
EBX
ESP
EBP
ESI
EDI
DS
ES
GS
.fi
.in -2

The preceding constants are listed in \fB<sys/regset.h>\fR\&.
.sp
Note that a 32-bit process can run on an x86 64-bit system, using the constants
listed above.
.RE

.sp
.ne 2
.na
\fBx86 (64-bit)\fR
.ad
.RS 21n
To read the registers of a 32- \fBor\fR a 64-bit process, a 64-bit x86 process
should use the predefined constants listed below.
.sp
.in +2
.nf
REG_GSBASE
REG_FSBASE
REG_DS
REG_ES
REG_GS
REG_FS
REG_SS
REG_RSP
REG_RFL
REG_CS
REG_RIP
REG_ERR
REG_TRAPNO
REG_RAX
REG_RCX
REG_RDX
REG_RBX
REG_RBP
REG_RSI
REG_RDI
REG_R8
REG_R9
REG_R10
REG_R11
REG_R12
REG_R13
REG_R14
REG_R15
.fi
.in -2

The preceding constants are listed in \fB<sys/regset.h>\fR\&.
.RE

.sp
.LP
\fBpr_fpreg\fR is a structure holding the contents of the floating-point
registers.
.sp
.LP
SPARC registers, both general and floating-point, as seen by a 64-bit
controlling process are the V9 versions of the registers, even if the target
process is a 32-bit (V8) process. V8 registers are a subset of the V9
registers.
.sp
.LP
If the lwp is not stopped, all register values are undefined.
.SS "psinfo"
.LP
Contains miscellaneous information about the process and the representative lwp
needed by the \fBps\fR(1) command. \fBpsinfo\fR remains accessible after a
process becomes a \fIzombie\fR. The file contains a \fBpsinfo\fR structure
which contains an embedded \fBlwpsinfo\fR structure for the representative lwp,
as follows:
.sp
.in +2
.nf
typedef struct psinfo {
    int pr_flag;             /* process flags (DEPRECATED: see below) */
    int pr_nlwp;             /* number of active lwps in the process */
    int pr_nzomb;            /* number of zombie lwps in the process */
    pid_t pr_pid;            /* process id */
    pid_t pr_ppid;           /* process id of parent */
    pid_t pr_pgid;           /* process id of process group leader */
    pid_t pr_sid;            /* session id */
    uid_t pr_uid;            /* real user id */
    uid_t pr_euid;           /* effective user id */
    gid_t pr_gid;            /* real group id */
    gid_t pr_egid;           /* effective group id */
    uintptr_t pr_addr;       /* address of process */
    size_t pr_size;          /* size of process image in Kbytes */
    size_t pr_rssize;        /* resident set size in Kbytes */
    dev_t pr_ttydev;         /* controlling tty device (or PRNODEV) */
    ushort_t pr_pctcpu;      /* % of recent cpu time used by all lwps */
    ushort_t pr_pctmem;      /* % of system memory used by process */
    timestruc_t pr_start;    /* process start time, from the epoch */
    timestruc_t pr_time;     /* cpu time for this process */
    timestruc_t pr_ctime;    /* cpu time for reaped children */
    char pr_fname[PRFNSZ];   /* name of exec'ed file */
    char pr_psargs[PRARGSZ]; /* initial characters of arg list */
    int pr_wstat;            /* if zombie, the wait() status */
    int pr_argc;             /* initial argument count */
    uintptr_t pr_argv;       /* address of initial argument vector */
    uintptr_t pr_envp;       /* address of initial environment vector */
    char pr_dmodel;          /* data model of the process */
    lwpsinfo_t pr_lwp;       /* information for representative lwp */
    taskid_t pr_taskid;      /* task id */
    projid_t pr_projid;      /* project id */
    poolid_t pr_poolid;      /* pool id */
    zoneid_t pr_zoneid;      /* zone id */
    ctid_t pr_contract;      /* process contract id */
} psinfo_t;
.fi
.in -2

.sp
.LP
Some of the entries in \fBpsinfo\fR, such as \fBpr_addr\fR, refer to internal
kernel data structures and should not be expected to retain their meanings
across different versions of the operating system.
.sp
.LP
\fBpsinfo_t.pr_flag\fR is a deprecated interface that should no longer be used.
Applications currently relying on the \fBSSYS\fR bit in \fBpr_flag\fR should
migrate to checking \fBPR_ISSYS\fR in the \fBpstatus\fR structure's
\fBpr_flags\fR field.
.sp
.LP
\fBpr_pctcpu\fR and \fBpr_pctmem\fR are 16-bit binary fractions in the range
0.0 to 1.0 with the binary point to the right of the high-order bit (1.0 ==
0x8000). \fBpr_pctcpu\fR is the summation over all lwps in the process.
.sp
.LP
\fBpr_lwp\fR contains the \fBps\fR(1) information for the representative lwp.
If the process is a \fIzombie\fR, \fBpr_nlwp\fR, \fBpr_nzomb\fR, and
\fBpr_lwp.pr_lwpid\fR are zero and the other fields of \fBpr_lwp\fR are
undefined:
.sp
.in +2
.nf
typedef struct lwpsinfo {
    int pr_flag;             /* lwp flags (DEPRECATED: see below) */
    id_t pr_lwpid;           /* lwp id */
    uintptr_t pr_addr;       /* internal address of lwp */
    uintptr_t pr_wchan;      /* wait addr for sleeping lwp */
    char pr_stype;           /* synchronization event type */
    char pr_state;           /* numeric lwp state */
    char pr_sname;           /* printable character for pr_state */
    char pr_nice;            /* nice for cpu usage */
    short pr_syscall;        /* system call number (if in syscall) */
    char pr_oldpri;          /* pre-SVR4, low value is high priority */
    char pr_cpu;             /* pre-SVR4, cpu usage for scheduling */
    int pr_pri;              /* priority, high value = high priority */
    ushort_t pr_pctcpu;      /* % of recent cpu time used by this lwp */
    timestruc_t pr_start;    /* lwp start time, from the epoch */
    timestruc_t pr_time;     /* cpu time for this lwp */
    char pr_clname[PRCLSZ];  /* scheduling class name */
    char pr_name[PRFNSZ];    /* name of system lwp */
    processorid_t pr_onpro;  /* processor which last ran this lwp */
    processorid_t pr_bindpro;/* processor to which lwp is bound */
    psetid_t pr_bindpset;    /* processor set to which lwp is bound */
    lgrp_id_t pr_lgrp	      /* home lgroup */
} lwpsinfo_t;
.fi
.in -2

.sp
.LP
Some of the entries in \fBlwpsinfo\fR, such as \fBpr_addr\fR, \fBpr_wchan\fR,
\fBpr_stype\fR, \fBpr_state\fR, and \fBpr_name\fR, refer to internal kernel
data structures and should not be expected to retain their meanings across
different versions of the operating system.
.sp
.LP
\fBlwpsinfo_t.pr_flag\fR is a deprecated interface that should no longer be
used.
.sp
.LP
\fBpr_pctcpu\fR is a 16-bit binary fraction, as described above. It represents
the \fBCPU\fR time used by the specific lwp. On a multi-processor machine, the
maximum value is 1/N, where N is the number of \fBCPU\fRs.
.sp
.LP
\fBpr_contract\fR is the id of the process contract of which the process is a
member. See \fBcontract\fR(4) and \fBprocess\fR(4).
.SS "cred"
.LP
Contains a description of the credentials associated with the process:
.sp
.in +2
.nf
typedef struct prcred {
	uid_t pr_euid;      /* effective user id */
	uid_t pr_ruid;      /* real user id */
	uid_t pr_suid;      /* saved user id (from exec) */
	gid_t pr_egid;      /* effective group id */
	gid_t pr_rgid;      /* real group id */
	gid_t pr_sgid;      /* saved group id (from exec) */
	int pr_ngroups;     /* number of supplementary groups */
	gid_t pr_groups[1]; /* array of supplementary groups */
} prcred_t;
.fi
.in -2
.sp

.sp
.LP
The array of associated supplementary groups in \fBpr_groups\fR is of variable
length; the \fBcred\fR file contains all of the supplementary groups.
\fBpr_ngroups\fR indicates the number of supplementary groups. (See also the
\fBPCSCRED\fR and \fBPCSCREDX\fR control operations.)
.SS "priv"
.LP
Contains a description of the privileges associated with the process:
.sp
.in +2
.nf
typedef struct prpriv {
     uint32_t        pr_nsets;      /* number of privilege set */
     uint32_t        pr_setsize;    /* size of privilege set */
     uint32_t        pr_infosize;   /* size of supplementary data */
     priv_chunk_t    pr_sets[1];    /* array of sets */
} prpriv_t;
.fi
.in -2

.sp
.LP
The actual dimension of the \fBpr_sets\fR[] field is
.sp
.in +2
.nf
pr_sets[pr_nsets][pr_setsize]
.fi
.in -2

.sp
.LP
which is followed by additional information about the process state
\fBpr_infosize\fR bytes in size.
.sp
.LP
The full size of the structure can be computed using
\fBPRIV_PRPRIV_SIZE\fR(\fBprpriv_t *\fR).
.SS "secflags"
.LP
This file contains the security-flags of the process.  It contains a
description of the security flags associated with the process.
.sp
.in +2
.nf
typedef struct prsecflags {
	uint32_t pr_version;		/* ABI Versioning of this structure */
	secflagset_t pr_effective;	/* Effective flags */
	secflagset_t pr_inherit;	/* Inheritable flags */
	secflagset_t pr_lower;		/* Lower flags */
	secflagset_t pr_upper;		/* Upper flags */
} prsecflags_t;
.in -2

.sp
.LP
The \fBpr_version\fR field is a version number for the structure, currently
\fBPRSECFLAGS_VERSION_1\fR.
.SS "sigact"
.LP
Contains an array of \fBsigaction structures\fR describing the current
dispositions of all signals associated with the traced process (see
\fBsigaction\fR(2)). Signal numbers are displaced by 1 from array indices, so
that the action for signal number \fIn\fR appears in position \fIn\fR-1 of the
array.
.SS "auxv"
.LP
Contains the initial values of the process's aux vector in an array of
\fBauxv_t\fR structures (see \fB<sys/auxv.h>\fR). The values are those that
were passed by the operating system as startup information to the dynamic
linker.
.SS "ldt"
.LP
This file exists only on x86-based machines. It is non-empty only if the
process has established a local descriptor table (\fBLDT\fR). If non-empty, the
file contains the array of currently active \fBLDT\fR entries in an array of
elements of type \fBstruct ssd\fR, defined in \fB<sys/sysi86.h>\fR, one element
for each active \fBLDT\fR entry.
.SS "map, xmap"
.LP
Contain information about the virtual address map of the process. The map file
contains an array of \fBprmap\fR structures while the xmap file contains an
array of \fBprxmap\fR structures. Each structure describes a contiguous virtual
address region in the address space of the traced process:
.sp
.in +2
.nf
typedef struct prmap {
	uintptr_tpr_vaddr;         /* virtual address of mapping */
	size_t pr_size;            /* size of mapping in bytes */
	char pr_mapname[PRMAPSZ];  /* name in /proc/pid/object */
	offset_t pr_offset;        /* offset into mapped object, if any */
	int pr_mflags;             /* protection and attribute flags */
	int pr_pagesize;           /* pagesize for this mapping in bytes */
	int pr_shmid;              /* SysV shared memory identifier */
} prmap_t;
.fi
.in -2
.sp

.sp
.in +2
.nf
typedef struct prxmap {
	uintptr_t pr_vaddr;        /* virtual address of mapping */
	size_t pr_size;            /* size of mapping in bytes */
	char pr_mapname[PRMAPSZ];  /* name in /proc/pid/object */
	offset_t pr_offset;        /* offset into mapped object, if any */
	int pr_mflags;             /* protection and attribute flags */
	int pr_pagesize;           /* pagesize for this mapping in bytes */
	int pr_shmid;              /* SysV shared memory identifier */
	dev_t pr_dev;              /* device of mapped object, if any */
	uint64_t pr_ino;           /* inode of mapped object, if any */
	size_t pr_rss;             /* pages of resident memory */
	size_t pr_anon;            /* pages of resident anonymous memory */
	size_t pr_locked;          /* pages of locked memory */
	uint64_t pr_hatpagesize;   /* pagesize of mapping */
} prxmap_t;
.fi
.in -2
.sp

.sp
.LP
\fBpr_vaddr\fR is the virtual address of the mapping within the traced process
and \fBpr_size\fR is its size in bytes. \fBpr_mapname\fR, if it does not
contain a null string, contains the name of a file in the \fBobject\fR
directory (see below) that can be opened read-only to obtain a file descriptor
for the mapped file associated with the mapping. This enables a debugger to
find object file symbol tables without having to know the real path names of
the executable file and shared libraries of the process. \fBpr_offset\fR is the
64-bit offset within the mapped file (if any) to which the virtual address is
mapped.
.sp
.LP
\fBpr_mflags\fR is a bit-mask of protection and attribute flags:
.sp
.ne 2
.na
\fB\fBMA_READ\fR\fR
.ad
.RS 17n
mapping is readable by the traced process.
.RE

.sp
.ne 2
.na
\fB\fBMA_WRITE\fR\fR
.ad
.RS 17n
mapping is writable by the traced process.
.RE

.sp
.ne 2
.na
\fB\fBMA_EXEC\fR\fR
.ad
.RS 17n
mapping is executable by the traced process.
.RE

.sp
.ne 2
.na
\fB\fBMA_SHARED\fR\fR
.ad
.RS 17n
mapping changes are shared by the mapped object.
.RE

.sp
.ne 2
.na
\fB\fBMA_ISM\fR\fR
.ad
.RS 17n
mapping is intimate shared memory (shared MMU resources)
.RE

.sp
.ne 2
.na
\fB\fBMAP_NORESERVE\fR\fR
.ad
.RS 17n
mapping does not have swap space reserved (mapped with MAP_NORESERVE)
.RE

.sp
.ne 2
.na
\fB\fBMA_SHM\fR\fR
.ad
.RS 17n
mapping System V shared memory
.RE

.sp
.LP
A contiguous area of the address space having the same underlying mapped object
may appear as multiple mappings due to varying read, write, and execute
attributes. The underlying mapped object does not change over the range of a
single mapping. An \fBI/O\fR operation to a mapping marked \fBMA_SHARED\fR
fails if applied at a virtual address not corresponding to a valid page in the
underlying mapped object. A write to a \fBMA_SHARED\fR mapping that is not
marked \fBMA_WRITE\fR fails. Reads and writes to private mappings always
succeed. Reads and writes to unmapped addresses fail.
.sp
.LP
\fBpr_pagesize\fR is the page size for the mapping, currently always the system
pagesize.
.sp
.LP
\fBpr_shmid\fR is the shared memory identifier, if any, for the mapping. Its
value is \fB\(mi1\fR if the mapping is not System V shared memory. See
\fBshmget\fR(2).
.sp
.LP
\fBpr_dev\fR is the device of the mapped object, if any, for the mapping. Its
value is \fBPRNODEV\fR (-1) if the mapping does not have a device.
.sp
.LP
\fBpr_ino\fR is the inode of the mapped object, if any, for the mapping. Its
contents are only valid if \fBpr_dev\fR is not \fBPRNODEV.\fR
.sp
.LP
\fBpr_rss\fR is the number of resident pages of memory for the mapping. The
number of resident bytes for the mapping may be determined by multiplying
\fBpr_rss\fR by the page size given by \fBpr_pagesize.\fR
.sp
.LP
\fBpr_anon\fR is the number of resident anonymous memory pages (pages which are
private to this process) for the mapping.
.sp
.LP
\fBpr_locked\fR is the number of locked pages for the mapping. Pages which are
locked are always resident in memory.
.sp
.LP
\fBpr_hatpagesize\fR is the size, in bytes, of the \fBHAT\fR (\fBMMU\fR)
translation for the mapping. \fBpr_hatpagesize\fR may be different than
\fBpr_pagesize.\fR The possible values are hardware architecture specific, and
may change over a mapping's lifetime.
.SS "rmap"
.LP
Contains information about the reserved address ranges of the process. The file
contains an array of \fBprmap\fR structures, as defined above for the \fBmap\fR
file. Each structure describes a contiguous virtual address region in the
address space of the traced process that is reserved by the system in the sense
that an \fBmmap\fR(2) system call that does not specify \fBMAP_FIXED\fR will
not use any part of it for the new mapping. Examples of such reservations
include the address ranges reserved for the process stack and the individual
thread stacks of a multi-threaded process.
.SS "cwd"
.LP
A symbolic link to the process's current working directory. See \fBchdir\fR(2).
A \fBreadlink\fR(2) of \fB/proc/\fIpid\fR/cwd\fR yields a null string. However,
it can be opened, listed, and searched as a directory, and can be the target of
\fBchdir\fR(2).
.SS "root"
.LP
A symbolic link to the process's root directory.
\fB/proc/\fR\fIpid\fR\fB/root\fR can differ from the system root directory if
the process or one of its ancestors executed \fBchroot\fR(2) as super user. It
has the same semantics as \fB/proc/\fR\fIpid\fR\fB/cwd\fR.
.SS "fd"
.LP
A directory containing references to the open files of the process. Each entry
is a decimal number corresponding to an open file descriptor in the process.
.sp
.LP
If an entry refers to a regular file, it can be opened with normal file system
semantics but, to ensure that the controlling process cannot gain greater
access than the controlled process, with no file access modes other than its
read/write open modes in the controlled process. If an entry refers to a
directory, it can be accessed with the same semantics as
\fB/proc/\fIpid\fR/cwd\fR. An attempt to open any other type of entry fails
with \fBEACCES\fR.
.SS "object"
.LP
A directory containing read-only files with names corresponding to the
\fBpr_mapname\fR entries in the \fBmap\fR and \fBpagedata\fR files. Opening
such a file yields a file descriptor for the underlying mapped file associated
with an address-space mapping in the process. The file name \fBa.out\fR appears
in the directory as an alias for the process's executable file.
.sp
.LP
The \fBobject\fR directory makes it possible for a controlling process to gain
access to the object file and any shared libraries (and consequently the symbol
tables) without having to know the actual path names of the executable files.
.SS "path"
.LP
A directory containing symbolic links to files opened by the process. The
directory includes one entry for \fBcwd\fR and \fBroot\fR. The directory also
contains a numerical entry for each file descriptor in the \fBfd\fR directory,
and entries matching those in the \fBobject\fR directory. If this information
is not available, any attempt to read the contents of the symbolic link will
fail. This is most common for files that do not exist in the filesystem
namespace (such as \fBFIFO\fRs and sockets), but can also happen for regular
files. For the file descriptor entries, the path may be different from the one
used by the process to open the file.
.SS "pagedata"
.LP
Opening the page data file enables tracking of address space references and
modifications on a per-page basis.
.sp
.LP
A \fBread\fR(2) of the page data file descriptor returns structured page data
and atomically clears the page data maintained for the file by the system. That
is to say, each read returns data collected since the last read; the first read
returns data collected since the file was opened. When the call completes, the
read buffer contains the following structure as its header and thereafter
contains a number of section header structures and associated byte arrays that
must be accessed by walking linearly through the buffer.
.sp
.in +2
.nf
typedef struct prpageheader {
    timestruc_t pr_tstamp; /* real time stamp, time of read() */
    ulong_t pr_nmap;       /* number of address space mappings */
    ulong_t pr_npage;      /* total number of pages */
} prpageheader_t;
.fi
.in -2

.sp
.LP
The header is followed by \fBpr_nmap prasmap\fR structures and associated data
arrays. The \fBprasmap\fR structure contains the following elements:
.sp
.in +2
.nf
typedef struct prasmap {
    uintptr_t pr_vaddr;        /* virtual address of mapping */
    ulong_t pr_npage;          /* number of pages in mapping */
    char pr_mapname[PRMAPSZ];  /* name in /proc/pid/object */
    offset_t pr_offset;        /* offset into mapped object, if any */
    int pr_mflags;             /* protection and attribute flags */
    int pr_pagesize;           /* pagesize for this mapping in bytes */
    int pr_shmid;              /* SysV shared memory identifier */
} prasmap_t;
.fi
.in -2

.sp
.LP
Each section header is followed by \fBpr_npage\fR bytes, one byte for each page
in the mapping, plus 0-7 null bytes at the end so that the next \fBprasmap\fR
structure begins on an eight-byte aligned boundary. Each data byte may contain
these flags:
.sp
.ne 2
.na
\fB\fBPG_REFERENCED\fR\fR
.ad
.RS 17n
page has been referenced.
.RE

.sp
.ne 2
.na
\fB\fBPG_MODIFIED\fR\fR
.ad
.RS 17n
page has been modified.
.RE

.sp
.LP
If the read buffer is not large enough to contain all of the page data, the
read fails with \fBE2BIG\fR and the page data is not cleared. The required size
of the read buffer can be determined through \fBfstat\fR(2). Application of
\fBlseek\fR(2) to the page data file descriptor is ineffective; every read
starts from the beginning of the file. Closing the page data file descriptor
terminates the system overhead associated with collecting the data.
.sp
.LP
More than one page data file descriptor for the same process can be opened, up
to a system-imposed limit per traced process. A read of one does not affect the
data being collected by the system for the others. An open of the page data
file will fail with \fBENOMEM\fR if the system-imposed limit would be exceeded.
.SS "watch"
.LP
Contains an array of \fBprwatch\fR structures, one for each watched area
established by the \fBPCWATCH\fR control operation. See \fBPCWATCH\fR for
details.
.SS "usage"
.LP
Contains process usage information described by a \fBprusage\fR structure which
contains at least the following fields:
.sp
.in +2
.nf
typedef struct prusage {
    id_t pr_lwpid;           /* lwp id.  0: process or defunct */
    int pr_count;            /* number of contributing lwps */
    timestruc_t pr_tstamp;   /* real time stamp, time of read() */
    timestruc_t pr_create;   /* process/lwp creation time stamp */
    timestruc_t pr_term;     /* process/lwp termination time stamp */
    timestruc_t pr_rtime;    /* total lwp real (elapsed) time */
    timestruc_t pr_utime;    /* user level CPU time */
    timestruc_t pr_stime;    /* system call CPU time */
    timestruc_t pr_ttime;    /* other system trap CPU time */
    timestruc_t pr_tftime;   /* text page fault sleep time */
    timestruc_t pr_dftime;   /* data page fault sleep time */
    timestruc_t pr_kftime;   /* kernel page fault sleep time */
    timestruc_t pr_ltime;    /* user lock wait sleep time */
    timestruc_t pr_slptime;  /* all other sleep time */
    timestruc_t pr_wtime;    /* wait-cpu (latency) time */
    timestruc_t pr_stoptime; /* stopped time */
    ulong_t pr_minf;         /* minor page faults */
    ulong_t pr_majf;         /* major page faults */
    ulong_t pr_nswap;        /* swaps */
    ulong_t pr_inblk;        /* input blocks */
    ulong_t pr_oublk;        /* output blocks */
    ulong_t pr_msnd;         /* messages sent */
    ulong_t pr_mrcv;         /* messages received */
    ulong_t pr_sigs;         /* signals received */
    ulong_t pr_vctx;         /* voluntary context switches */
    ulong_t pr_ictx;         /* involuntary context switches */
    ulong_t pr_sysc;         /* system calls */
    ulong_t pr_ioch;         /* chars read and written */
} prusage_t;
.fi
.in -2

.sp
.LP
Microstate accounting is now continuously enabled. While this information was
previously an estimate, if microstate accounting were not enabled, the current
information is now never an estimate represents time the process has spent in
various states.
.SS "lstatus"
.LP
Contains a \fBprheader\fR structure followed by an array of \fBlwpstatus\fR
structures, one for each active lwp in the process (see also
\fB/proc/\fR\fIpid\fR\fB/lwp/\fR\fIlwpid\fR/\fBlwpstatus\fR, below). The
\fBprheader\fR structure describes the number and size of the array entries
that follow.
.sp
.in +2
.nf
typedef struct prheader {
    long pr_nent;        /* number of entries */
    size_t pr_entsize;   /* size of each entry, in bytes */
} prheader_t;
.fi
.in -2

.sp
.LP
The \fBlwpstatus\fR structure may grow by the addition of elements at the end
in future releases of the system. Programs must use \fBpr_entsize\fR in the
file header to index through the array. These comments apply to all \fB/proc\fR
files that include a \fBprheader\fR structure (\fBlpsinfo\fR and \fBlusage\fR,
below).
.SS "lpsinfo"
.LP
Contains a \fBprheader\fR structure followed by an array of \fBlwpsinfo\fR
structures, one for eachactive and zombie lwp in the process. See also
\fB/proc/\fR\fIpid\fR\fB/lwp/\fR\fIlwpid\fR/\fBlwpsinfo\fR, below.
.SS "lusage"
.LP
Contains a \fBprheader\fR structure followed by an array of \fBprusage\fR
structures, one for each active lwp in the process, plus an additional element
at the beginning that contains the summation over all defunct lwps (lwps that
once existed but no longer exist in the process). Excluding the \fBpr_lwpid\fR,
\fBpr_tstamp\fR, \fBpr_create\fR, and \fBpr_term\fR entries, the entry-by-entry
summation over all these structures is the definition of the process usage
information obtained from the \fBusage\fR file. (See also
\fB/proc/\fR\fIpid\fR\fB/lwp/\fR\fIlwpid\fR/\fBlwpusage\fR, below.)
.SS "lwp"
.LP
A directory containing entries each of which names an active or zombie lwp
within the process. These entries are themselves directories containing
additional files as described below. Only the \fBlwpsinfo\fR file exists in the
directory of a zombie lwp.
.SH STRUCTURE OF \fB/proc/\fR\fIpid\fR\fB/lwp/\fR\fIlwpid\fR
.LP
A given directory \fB/proc/\fR\fIpid\fR\fB/lwp/\fR\fIlwpid\fR contains the
following entries:
.SS "lwpctl"
.LP
Write-only control file. The messages written to this file affect the specific
lwp rather than the representative lwp, as is the case for the process's
\fBctl\fR file.
.SS "lwpstatus"
.LP
lwp-specific state information. This file contains the \fBlwpstatus\fR
structure for the specific lwp as described above for the representative lwp in
the process's \fBstatus\fR file.
.SS "lwpsinfo"
.LP
lwp-specific \fBps\fR(1) information. This file contains the \fBlwpsinfo\fR
structure for the specific lwp as described above for the representative lwp in
the process's \fBpsinfo\fR file. The \fBlwpsinfo\fR file remains accessible
after an lwp becomes a zombie.
.SS "lwpusage"
.LP
This file contains the \fBprusage\fR structure for the specific lwp as
described above for the process's \fBusage\fR file.
.SS "gwindows"
.LP
This file exists only on SPARC based machines. If it is non-empty, it contains
a \fBgwindows_t\fR structure, defined in \fB<sys/regset.h>\fR, with the values
of those SPARC register windows that could not be stored on the stack when the
lwp stopped. Conditions under which register windows are not stored on the
stack are: the stack pointer refers to nonexistent process memory or the stack
pointer is improperly aligned. If the lwp is not stopped or if there are no
register windows that could not be stored on the stack, the file is empty (the
usual case).
.SS "xregs"
.LP
Extra state registers. The extra state register set is architecture dependent;
this file is empty if the system does not support extra state registers. If the
file is non-empty, it contains an architecture dependent structure of type
\fBprxregset_t\fR, defined in \fB<procfs.h>\fR, with the values of the lwp's
extra state registers. If the lwp is not stopped, all register values are
undefined. See also the \fBPCSXREG\fR control operation, below.
.SS "asrs"
.LP
This file exists only for 64-bit SPARC V9 processes. It contains an
\fBasrset_t\fR structure, defined in <\fBsys/regset.h\fR>, containing the
values of the lwp's platform-dependent ancillary state registers. If the lwp is
not stopped, all register values are undefined. See also the \fBPCSASRS\fR
control operation, below.
.SS "spymaster"
.LP
For an agent lwp (see \fBPCAGENT\fR), this file contains a \fBpsinfo_t\fR
structure that corresponds to the process that created the agent lwp at the
time the agent was created. This structure is identical to that retrieved via
the \fBpsinfo\fR file, with one modification: the \fBpr_time\fR field does not
correspond to the CPU time for the process, but rather to the creation time of
the agent lwp.
.SS "templates"
.LP
A directory which contains references to the active templates for the lwp,
named by the contract type. Changes made to an active template descriptor do
not affect the original template which was activated, though they do affect the
active template. It is not possible to activate an active template descriptor.
See \fBcontract\fR(4).
.SH CONTROL MESSAGES
.LP
Process state changes are effected through messages written to a process's
\fBctl\fR file or to an individual lwp's \fBlwpctl\fR file. All control
messages consist of a \fBlong\fR that names the specific operation followed by
additional data containing the operand, if any.
.sp
.LP
Multiple control messages may be combined in a single \fBwrite\fR(2) (or
\fBwritev\fR(2)) to a control file, but no partial writes are permitted. That
is, each control message, operation code plus operand, if any, must be
presented in its entirety to the \fBwrite\fR(2) and not in pieces over several
system calls. If a control operation fails, no subsequent operations contained
in the same \fBwrite\fR(2) are attempted.
.sp
.LP
Descriptions of the allowable control messages follow. In all cases, writing a
message to a control file for a process or lwp that has terminated elicits the
error \fBENOENT\fR.
.SS "PCSTOP PCDSTOP PCWSTOP PCTWSTOP"
.LP
When applied to the process control file, \fBPCSTOP\fR directs all lwps to stop
and waits for them to stop, \fBPCDSTOP\fR directs all lwps to stop without
waiting for them to stop, and \fBPCWSTOP\fR simply waits for all lwps to stop.
When applied to an lwp control file, \fBPCSTOP\fR directs the specific lwp to
stop and waits until it has stopped, \fBPCDSTOP\fR directs the specific lwp to
stop without waiting for it to stop, and \fBPCWSTOP\fR simply waits for the
specific lwp to stop. When applied to an lwp control file, \fBPCSTOP\fR and
\fBPCWSTOP\fR complete when the lwp stops on an event of interest, immediately
if already so stopped; when applied to the process control file, they complete
when every lwp has stopped either on an event of interest or on a
\fBPR_SUSPENDED\fR stop.
.sp
.LP
\fBPCTWSTOP\fR is identical to \fBPCWSTOP\fR except that it enables the
operation to time out, to avoid waiting forever for a process or lwp that may
never stop on an event of interest. \fBPCTWSTOP\fR takes a \fBlong\fR operand
specifying a number of milliseconds; the wait will terminate successfully after
the specified number of milliseconds even if the process or lwp has not
stopped; a timeout value of zero makes the operation identical to
\fBPCWSTOP\fR.
.sp
.LP
An ``event of interest'' is either a \fBPR_REQUESTED\fR stop or a stop that has
been specified in the process's tracing flags (set by \fBPCSTRACE\fR,
\fBPCSFAULT\fR, \fBPCSENTRY\fR, and \fBPCSEXIT\fR). \fBPR_JOBCONTROL\fR and
\fBPR_SUSPENDED\fR stops are specifically not events of interest. (An lwp may
stop twice due to a stop signal, first showing \fBPR_SIGNALLED\fR if the signal
is traced and again showing \fBPR_JOBCONTROL\fR if the lwp is set running
without clearing the signal.) If \fBPCSTOP\fR or \fBPCDSTOP\fR is applied to an
lwp that is stopped, but not on an event of interest, the stop directive takes
effect when the lwp is restarted by the competing mechanism. At that time, the
lwp enters a \fBPR_REQUESTED\fR stop before executing any user-level code.
.sp
.LP
A write of a control message that blocks is interruptible by a signal so that,
for example, an \fBalarm\fR(2) can be set to avoid waiting forever for a
process or lwp that may never stop on an event of interest. If \fBPCSTOP\fR is
interrupted, the lwp stop directives remain in effect even though the
\fBwrite\fR(2) returns an error. (Use of \fBPCTWSTOP\fR with a non-zero timeout
is recommended over \fBPCWSTOP\fR with an \fBalarm\fR(2).)
.sp
.LP
A system process (indicated by the \fBPR_ISSYS\fR flag) never executes at user
level, has no user-level address space visible through \fB/proc\fR, and cannot
be stopped. Applying one of these operations to a system process or any of its
lwps elicits the error \fBEBUSY\fR.
.SS "PCRUN"
.LP
Make an lwp runnable again after a stop. This operation takes a \fBlong\fR
operand containing zero or more of the following flags:
.sp
.ne 2
.na
\fB\fBPRCSIG\fR\fR
.ad
.RS 12n
clears the current signal, if any (see \fBPCCSIG\fR).
.RE

.sp
.ne 2
.na
\fB\fBPRCFAULT\fR\fR
.ad
.RS 12n
clears the current fault, if any (see \fBPCCFAULT\fR).
.RE

.sp
.ne 2
.na
\fB\fBPRSTEP\fR\fR
.ad
.RS 12n
directs the lwp to execute a single machine instruction. On completion of the
instruction, a trace trap occurs. If \fBFLTTRACE\fR is being traced, the lwp
stops; otherwise, it is sent \fBSIGTRAP\fR. If \fBSIGTRAP\fR is being traced
and is not blocked, the lwp stops. When the lwp stops on an event of interest,
the single-step directive is cancelled, even if the stop occurs before the
instruction is executed. This operation requires hardware and operating system
support and may not be implemented on all processors. It is implemented on
SPARC and x86-based machines.
.RE

.sp
.ne 2
.na
\fB\fBPRSABORT\fR\fR
.ad
.RS 12n
is meaningful only if the lwp is in a \fBPR_SYSENTRY\fR stop or is marked
\fBPR_ASLEEP\fR; it instructs the lwp to abort execution of the system call
(see \fBPCSENTRY\fR and \fBPCSEXIT\fR).
.RE

.sp
.ne 2
.na
\fB\fBPRSTOP\fR\fR
.ad
.RS 12n
directs the lwp to stop again as soon as possible after resuming execution (see
\fBPCDSTOP\fR). In particular, if the lwp is stopped on \fBPR_SIGNALLED\fR or
\fBPR_FAULTED\fR, the next stop will show \fBPR_REQUESTED\fR, no other stop
will have intervened, and the lwp will not have executed any user-level code.
.RE

.sp
.LP
When applied to an lwp control file, \fBPCRUN\fR clears any outstanding
directed-stop request and makes the specific lwp runnable. The operation fails
with \fBEBUSY\fR if the specific lwp is not stopped on an event of interest or
has not been directed to stop or if the agent lwp exists and this is not the
agent lwp (see \fBPCAGENT\fR).
.sp
.LP
When applied to the process control file, a representative lwp is chosen for
the operation as described for \fB/proc/\fR\fIpid\fR\fB/status\fR. The
operation fails with \fBEBUSY\fR if the representative lwp is not stopped on an
event of interest or has not been directed to stop or if the agent lwp exists.
If \fBPRSTEP\fR or \fBPRSTOP\fR was requested, the representative lwp is made
runnable and its outstanding directed-stop request is cleared; otherwise all
outstanding directed-stop requests are cleared and, if it was stopped on an
event of interest, the representative lwp is marked \fBPR_REQUESTED\fR. If, as
a consequence, all lwps are in the \fBPR_REQUESTED\fR or \fBPR_SUSPENDED\fR
stop state, all lwps showing \fBPR_REQUESTED\fR are made runnable.
.SS "PCSTRACE"
.LP
Define a set of signals to be traced in the process. The receipt of one of
these signals by an lwp causes the lwp to stop. The set of signals is defined
using an operand \fBsigset_t\fR contained in the control message. Receipt of
\fBSIGKILL\fR cannot be traced; if specified, it is silently ignored.
.sp
.LP
If a signal that is included in an lwp's held signal set (the signal mask) is
sent to the lwp, the signal is not received and does not cause a stop until it
is removed from the held signal set, either by the lwp itself or by setting the
held signal set with \fBPCSHOLD\fR.
.SS "PCCSIG"
.LP
The current signal, if any, is cleared from the specific or representative lwp.
.SS "PCSSIG"
.LP
The current signal and its associated signal information for the specific or
representative lwp are set according to the contents of the operand
\fBsiginfo\fR structure (see \fB<sys/siginfo.h>\fR). If the specified signal
number is zero, the current signal is cleared. The semantics of this operation
are different from those of \fBkill\fR(2) in that the signal is delivered to
the lwp immediately after execution is resumed (even if it is being blocked)
and an additional \fBPR_SIGNALLED\fR stop does not intervene even if the signal
is traced. Setting the current signal to \fBSIGKILL\fR terminates the process
immediately.
.SS "PCKILL"
.LP
If applied to the process control file, a signal is sent to the process with
semantics identical to those of \fBkill\fR(2). If applied to an lwp control
file, a directed signal is sent to the specific lwp. The signal is named in a
\fBlong\fR operand contained in the message. Sending \fBSIGKILL\fR terminates
the process immediately.
.SS "PCUNKILL"
.LP
A signal is deleted, that is, it is removed from the set of pending signals. If
applied to the process control file, the signal is deleted from the process's
pending signals. If applied to an lwp control file, the signal is deleted from
the lwp's pending signals. The current signal (if any) is unaffected. The
signal is named in a \fBlong\fR operand in the control message. It is an error
(\fBEINVAL\fR) to attempt to delete \fBSIGKILL\fR.
.SS "PCSHOLD"
.LP
Set the set of held signals for the specific or representative lwp (signals
whose delivery will be blocked if sent to the lwp). The set of signals is
specified with a \fBsigset_t\fR operand. \fBSIGKILL\fR and \fBSIGSTOP\fR cannot
be held; if specified, they are silently ignored.
.SS "PCSFAULT"
.LP
Define a set of hardware faults to be traced in the process. On incurring one
of these faults, an lwp stops. The set is defined via the operand
\fBfltset_t\fR structure. Fault names are defined in \fB<sys/fault.h>\fR and
include the following. Some of these may not occur on all processors; there may
be processor-specific faults in addition to these.
.sp
.ne 2
.na
\fB\fBFLTILL\fR\fR
.ad
.RS 13n
illegal instruction
.RE

.sp
.ne 2
.na
\fB\fBFLTPRIV\fR\fR
.ad
.RS 13n
privileged instruction
.RE

.sp
.ne 2
.na
\fB\fBFLTBPT\fR\fR
.ad
.RS 13n
breakpoint trap
.RE

.sp
.ne 2
.na
\fB\fBFLTTRACE\fR\fR
.ad
.RS 13n
trace trap (single-step)
.RE

.sp
.ne 2
.na
\fB\fBFLTWATCH\fR\fR
.ad
.RS 13n
watchpoint trap
.RE

.sp
.ne 2
.na
\fB\fBFLTACCESS\fR\fR
.ad
.RS 13n
memory access fault (bus error)
.RE

.sp
.ne 2
.na
\fB\fBFLTBOUNDS\fR\fR
.ad
.RS 13n
memory bounds violation
.RE

.sp
.ne 2
.na
\fB\fBFLTIOVF\fR\fR
.ad
.RS 13n
integer overflow
.RE

.sp
.ne 2
.na
\fB\fBFLTIZDIV\fR\fR
.ad
.RS 13n
integer zero divide
.RE

.sp
.ne 2
.na
\fB\fBFLTFPE\fR\fR
.ad
.RS 13n
floating-point exception
.RE

.sp
.ne 2
.na
\fB\fBFLTSTACK\fR\fR
.ad
.RS 13n
unrecoverable stack fault
.RE

.sp
.ne 2
.na
\fB\fBFLTPAGE\fR\fR
.ad
.RS 13n
recoverable page fault
.RE

.sp
.LP
When not traced, a fault normally results in the posting of a signal to the lwp
that incurred the fault. If an lwp stops on a fault, the signal is posted to
the lwp when execution is resumed unless the fault is cleared by \fBPCCFAULT\fR
or by the \fBPRCFAULT\fR option of \fBPCRUN\fR. \fBFLTPAGE\fR is an exception;
no signal is posted. The \fBpr_info\fR field in the \fBlwpstatus\fR structure
identifies the signal to be sent and contains machine-specific information
about the fault.
.SS "PCCFAULT"
.LP
The current fault, if any, is cleared; the associated signal will not be sent
to the specific or representative lwp.
.SS "PCSENTRY PCSEXIT"
.LP
These control operations instruct the process's lwps to stop on entry to or
exit from specified system calls. The set of system calls to be traced is
defined via an operand \fBsysset_t\fR structure.
.sp
.LP
When entry to a system call is being traced, an lwp stops after having begun
the call to the system but before the system call arguments have been fetched
from the lwp. When exit from a system call is being traced, an lwp stops on
completion of the system call just prior to checking for signals and returning
to user level. At this point, all return values have been stored into the lwp's
registers.
.sp
.LP
If an lwp is stopped on entry to a system call (\fBPR_SYSENTRY\fR) or when
sleeping in an interruptible system call (\fBPR_ASLEEP\fR is set), it may be
instructed to go directly to system call exit by specifying the \fBPRSABORT\fR
flag in a \fBPCRUN\fR control message. Unless exit from the system call is
being traced, the lwp returns to user level showing \fBEINTR\fR.
.SS "PCWATCH"
.LP
Set or clear a watched area in the controlled process from a \fBprwatch\fR
structure operand:
.sp
.in +2
.nf
typedef struct prwatch {
    uintptr_t pr_vaddr;  /* virtual address of watched area */
    size_t pr_size;      /* size of watched area in bytes */
    int pr_wflags;       /* watch type flags */
} prwatch_t;
.fi
.in -2

.sp
.LP
\fBpr_vaddr\fR specifies the virtual address of an area of memory to be watched
in the controlled process. \fBpr_size\fR specifies the size of the area, in
bytes. \fBpr_wflags\fR specifies the type of memory access to be monitored as a
bit-mask of the following flags:
.sp
.ne 2
.na
\fB\fBWA_READ\fR\fR
.ad
.RS 16n
read access
.RE

.sp
.ne 2
.na
\fB\fBWA_WRITE\fR\fR
.ad
.RS 16n
write access
.RE

.sp
.ne 2
.na
\fB\fBWA_EXEC\fR\fR
.ad
.RS 16n
execution access
.RE

.sp
.ne 2
.na
\fB\fBWA_TRAPAFTER\fR\fR
.ad
.RS 16n
trap after the instruction completes
.RE

.sp
.LP
If \fBpr_wflags\fR is non-empty, a watched area is established for the virtual
address range specified by \fBpr_vaddr\fR and \fBpr_size\fR. If \fBpr_wflags\fR
is empty, any previously-established watched area starting at the specified
virtual address is cleared; \fBpr_size\fR is ignored.
.sp
.LP
A watchpoint is triggered when an lwp in the traced process makes a memory
reference that covers at least one byte of a watched area and the memory
reference is as specified in \fBpr_wflags\fR. When an lwp triggers a
watchpoint, it incurs a watchpoint trap. If \fBFLTWATCH\fR is being traced, the
lwp stops; otherwise, it is sent a \fBSIGTRAP\fR signal; if \fBSIGTRAP\fR is
being traced and is not blocked, the lwp stops.
.sp
.LP
The watchpoint trap occurs before the instruction completes unless
\fBWA_TRAPAFTER\fR was specified, in which case it occurs after the instruction
completes. If it occurs before completion, the memory is not modified. If it
occurs after completion, the memory is modified (if the access is a write
access).
.sp
.LP
Physical i/o is an exception for watchpoint traps. In this instance, there is
no guarantee that memory before the watched area has already been modified (or
in the case of \fBWA_TRAPAFTER\fR, that the memory following the watched area
has not been modified) when the watchpoint trap occurs and the lwp stops.
.sp
.LP
\fBpr_info\fR in the \fBlwpstatus\fR structure contains information pertinent
to the watchpoint trap. In particular, the \fBsi_addr\fR field contains the
virtual address of the memory reference that triggered the watchpoint, and the
\fBsi_code\fR field contains one of \fBTRAP_RWATCH\fR, \fBTRAP_WWATCH\fR, or
\fBTRAP_XWATCH\fR, indicating read, write, or execute access, respectively. The
\fBsi_trapafter\fR field is zero unless \fBWA_TRAPAFTER\fR is in effect for
this watched area; non-zero indicates that the current instruction is not the
instruction that incurred the watchpoint trap. The \fBsi_pc\fR field contains
the virtual address of the instruction that incurred the trap.
.sp
.LP
A watchpoint trap may be triggered while executing a system call that makes
reference to the traced process's memory. The lwp that is executing the system
call incurs the watchpoint trap while still in the system call. If it stops as
a result, the \fBlwpstatus\fR structure contains the system call number and its
arguments. If the lwp does not stop, or if it is set running again without
clearing the signal or fault, the system call fails with \fBEFAULT\fR. If
\fBWA_TRAPAFTER\fR was specified, the memory reference will have completed and
the memory will have been modified (if the access was a write access) when the
watchpoint trap occurs.
.sp
.LP
If more than one of \fBWA_READ\fR, \fBWA_WRITE\fR, and \fBWA_EXEC\fR is
specified for a watched area, and a single instruction incurs more than one of
the specified types, only one is reported when the watchpoint trap occurs. The
precedence is \fBWA_EXEC\fR, \fBWA_READ\fR, \fBWA_WRITE\fR (\fBWA_EXEC\fR and
\fBWA_READ\fR take precedence over \fBWA_WRITE\fR), unless \fBWA_TRAPAFTER\fR
was specified, in which case it is \fBWA_WRITE\fR, \fBWA_READ\fR, \fBWA_EXEC\fR
(\fBWA_WRITE\fR takes precedence).
.sp
.LP
\fBPCWATCH\fR fails with \fBEINVAL\fR if an attempt is made to specify
overlapping watched areas or if \fBpr_wflags\fR contains flags other than those
specified above. It fails with \fBENOMEM\fR if an attempt is made to establish
more watched areas than the system can support (the system can support
thousands).
.sp
.LP
The child of a \fBvfork\fR(2) borrows the parent's address space. When a
\fBvfork\fR(2) is executed by a traced process, all watched areas established
for the parent are suspended until the child terminates or performs an
\fBexec\fR(2). Any watched areas established independently in the child are
cancelled when the parent resumes after the child's termination or
\fBexec\fR(2). \fBPCWATCH\fR fails with \fBEBUSY\fR if applied to the parent of
a \fBvfork\fR(2) before the child has terminated or performed an \fBexec\fR(2).
The \fBPR_VFORKP\fR flag is set in the \fBpstatus\fR structure for such a
parent process.
.sp
.LP
Certain accesses of the traced process's address space by the operating system
are immune to watchpoints. The initial construction of a signal stack frame
when a signal is delivered to an lwp will not trigger a watchpoint trap even if
the new frame covers watched areas of the stack. Once the signal handler is
entered, watchpoint traps occur normally. On SPARC based machines, register
window overflow and underflow will not trigger watchpoint traps, even if the
register window save areas cover watched areas of the stack.
.sp
.LP
Watched areas are not inherited by child processes, even if the traced
process's inherit-on-fork mode, \fBPR_FORK\fR, is set (see \fBPCSET\fR, below).
All watched areas are cancelled when the traced process performs a successful
\fBexec\fR(2).
.SS "PCSET PCUNSET"
.LP
\fBPCSET\fR sets one or more modes of operation for the traced process.
\fBPCUNSET\fR unsets these modes. The modes to be set or unset are specified by
flags in an operand \fBlong\fR in the control message:
.sp
.ne 2
.na
\fB\fBPR_FORK\fR\fR
.ad
.RS 13n
(inherit-on-fork): When set, the process's tracing flags and its
inherit-on-fork mode are inherited by the child of a \fBfork\fR(2),
\fBfork1\fR(2), or \fBvfork\fR(2). When unset, child processes start with all
tracing flags cleared.
.RE

.sp
.ne 2
.na
\fB\fBPR_RLC\fR\fR
.ad
.RS 13n
(run-on-last-close): When set and the last writable \fB/proc\fR file descriptor
referring to the traced process or any of its lwps is closed, all of the
process's tracing flags and watched areas are cleared, any outstanding stop
directives are canceled, and if any lwps are stopped on events of interest,
they are set running as though \fBPCRUN\fR had been applied to them. When
unset, the process's tracing flags and watched areas are retained and lwps are
not set running on last close.
.RE

.sp
.ne 2
.na
\fB\fBPR_KLC\fR\fR
.ad
.RS 13n
(kill-on-last-close): When set and the last writable \fB/proc\fR file
descriptor referring to the traced process or any of its lwps is closed, the
process is terminated with \fBSIGKILL\fR.
.RE

.sp
.ne 2
.na
\fB\fBPR_ASYNC\fR\fR
.ad
.RS 13n
(asynchronous-stop): When set, a stop on an event of interest by one lwp does
not directly affect any other lwp in the process. When unset and an lwp stops
on an event of interest other than \fBPR_REQUESTED\fR, all other lwps in the
process are directed to stop.
.RE

.sp
.ne 2
.na
\fB\fBPR_MSACCT\fR\fR
.ad
.RS 13n
(microstate accounting): Microstate accounting is now continuously enabled.
This flag is deprecated and no longer has any effect upon microstate
accounting. Applications may toggle this flag; however, microstate accounting
will remain enabled regardless.
.RE

.sp
.ne 2
.na
\fB\fBPR_MSFORK\fR\fR
.ad
.RS 13n
(inherit microstate accounting): All processes now inherit microstate
accounting, as it is continuously enabled. This flag has been deprecated and
its use no longer has any effect upon the behavior of microstate accounting.
.RE

.sp
.ne 2
.na
\fB\fBPR_BPTADJ\fR\fR
.ad
.RS 13n
(breakpoint trap pc adjustment): On x86-based machines, a breakpoint trap
leaves the program counter (the \fBEIP\fR) referring to the breakpointed
instruction plus one byte. When \fBPR_BPTADJ\fR is set, the system will adjust
the program counter back to the location of the breakpointed instruction when
the lwp stops on a breakpoint. This flag has no effect on SPARC based machines,
where breakpoint traps leave the program counter referring to the breakpointed
instruction.
.RE

.sp
.ne 2
.na
\fB\fBPR_PTRACE\fR\fR
.ad
.RS 13n
(ptrace-compatibility): When set, a stop on an event of interest by the traced
process is reported to the parent of the traced process by \fBwait\fR(3C),
\fBSIGTRAP\fR is sent to the traced process when it executes a successful
\fBexec\fR(2), setuid/setgid flags are not honored for execs performed by the
traced process, any exec of an object file that the traced process cannot read
fails, and the process dies when its parent dies. This mode is deprecated; it
is provided only to allow \fBptrace\fR(3C) to be implemented as a library
function using \fB/proc\fR.
.RE

.sp
.LP
It is an error (\fBEINVAL\fR) to specify flags other than those described above
or to apply these operations to a system process. The current modes are
reported in the \fBpr_flags\fR field of \fB/proc/\fR\fIpid\fR\fB/status\fR and
\fB/proc/\fR\fIpid\fR\fB/lwp/\fR\fIlwp\fR\fB/lwpstatus\fR.
.SS "PCSREG"
.LP
Set the general registers for the specific or representative lwp according to
the operand \fBprgregset_t\fR structure.
.sp
.LP
On SPARC based systems, only the condition-code bits of the processor-status
register (R_PSR) of SPARC V8 (32-bit) processes can be modified by
\fBPCSREG\fR. Other privileged registers cannot be modified at all.
.sp
.LP
On x86-based systems, only certain bits of the flags register (EFL) can be
modified by \fBPCSREG\fR: these include the condition codes, direction-bit, and
overflow-bit.
.sp
.LP
\fBPCSREG\fR fails with \fBEBUSY\fR if the lwp is not stopped on an event of
interest.
.SS "PCSVADDR"
.LP
Set the address at which execution will resume for the specific or
representative lwp from the operand \fBlong\fR. On SPARC based systems, both
%pc and %npc are set, with %npc set to the instruction following the virtual
address. On x86-based systems, only %eip is set. \fBPCSVADDR\fR fails with
\fBEBUSY\fR if the lwp is not stopped on an event of interest.
.SS "PCSFPREG"
.LP
Set the floating-point registers for the specific or representative lwp
according to the operand \fBprfpregset_t\fR structure. An error (\fBEINVAL\fR)
is returned if the system does not support floating-point operations (no
floating-point hardware and the system does not emulate floating-point machine
instructions). \fBPCSFPREG\fR fails with \fBEBUSY\fR if the lwp is not stopped
on an event of interest.
.SS "PCSXREG"
.LP
Set the extra state registers for the specific or representative lwp according
to the architecture-dependent operand \fBprxregset_t\fR structure. An error
(\fBEINVAL\fR) is returned if the system does not support extra state
registers. \fBPCSXREG\fR fails with \fBEBUSY\fR if the lwp is not stopped on an
event of interest.
.SS "PCSASRS"
.LP
Set the ancillary state registers for the specific or representative lwp
according to the SPARC V9 platform-dependent operand \fBasrset_t\fR structure.
An error (\fBEINVAL\fR) is returned if either the target process or the
controlling process is not a 64-bit SPARC V9 process. Most of the ancillary
state registers are privileged registers that cannot be modified. Only those
that can be modified are set; all others are silently ignored. \fBPCSASRS\fR
fails with \fBEBUSY\fR if the lwp is not stopped on an event of interest.
.SS "PCAGENT"
.LP
Create an agent lwp in the controlled process with register values from the
operand \fBprgregset_t\fR structure (see \fBPCSREG\fR, above). The agent lwp is
created in the stopped state showing \fBPR_REQUESTED\fR and with its held
signal set (the signal mask) having all signals except \fBSIGKILL\fR and
\fBSIGSTOP\fR blocked.
.sp
.LP
The \fBPCAGENT\fR operation fails with \fBEBUSY\fR unless the process is fully
stopped via \fB/proc\fR, that is, unless all of the lwps in the process are
stopped either on events of interest or on \fBPR_SUSPENDED\fR, or are stopped
on \fBPR_JOBCONTROL\fR and have been directed to stop via \fBPCDSTOP\fR.  It
fails with \fBEBUSY\fR if an agent lwp already exists. It fails with
\fBENOMEM\fR if system resources for creating new lwps have been exhausted.
.sp
.LP
Any \fBPCRUN\fR operation applied to the process control file or to the control
file of an lwp other than the agent lwp fails with \fBEBUSY\fR as long as the
agent lwp exists. The agent lwp must be caused to terminate by executing the
\fBSYS_lwp_exit\fR system call trap before the process can be restarted.
.sp
.LP
Once the agent lwp is created, its lwp-ID can be found by reading the process
status file. To facilitate opening the agent lwp's control and status files,
the directory name \fB/propc/\fR\fIpid\fR\fB/lwp/agent\fR is accepted for
lookup operations as an invisible alias for
\fB/proc/\fR\fIpid\fR\fB/lwp/\fR\fIlwpid,\fR \fIlwpid\fR being the lwp-ID of
the agent lwp (invisible in the sense that the name ``agent'' does not appear
in a directory listing of \fB/proc/\fR\fIpid\fR\fB/lwp\fR obtained from
\fBls\fR(1), \fBgetdents\fR(2), or \fBreaddir\fR(3C)).
.sp
.LP
The purpose of the agent lwp is to perform operations in the controlled process
on behalf of the controlling process: to gather information not directly
available via \fB/proc\fR files, or in general to make the process change state
in ways not directly available via \fB/proc\fR control operations. To make use
of an agent lwp, the controlling process must be capable of making it execute
system calls (specifically, the \fBSYS_lwp_exit\fR system call trap). The
register values given to the agent lwp on creation are typically the registers
of the representative lwp, so that the agent lwp can use its stack.
.sp
.LP
If the controlling process neglects to force the agent lwp to execute the
\fBSYS_lwp_exit\fR system call (due to either logic error or fatal failure on
the part of the controlling process), the agent lwp will remain in the target
process.  For purposes of being able to debug these otherwise rogue agents,
information as to the creator of the agent lwp is reflected in that lwp's
\fBspymaster\fR file in \fB/proc\fR. Should the target process generate a core
dump with the agent lwp in place, this information will be available via the
\fBNT_SPYMASTER\fR note in the core file (see \fBcore\fR(4)).
.sp
.LP
The agent lwp is not allowed to execute any variation of the \fBSYS_fork\fR or
\fBSYS_exec\fR system call traps. Attempts to do so yield \fBENOTSUP\fR to the
agent lwp.
.sp
.LP
Symbolic constants for system call trap numbers like \fBSYS_lwp_exit\fR and
\fBSYS_lwp_create\fR can be found in the header file <\fBsys/syscall.h\fR>.
.SS "PCREAD PCWRITE"
.LP
Read or write the target process's address space via a \fBpriovec\fR structure
operand:
.sp
.in +2
.nf
typedef struct priovec {
    void *pio_base;      /* buffer in controlling process */
    size_t pio_len;      /* size of read/write request in bytes */
    off_t pio_offset;    /* virtual address in target process */
} priovec_t;
.fi
.in -2

.sp
.LP
These operations have the same effect as \fBpread\fR(2) and \fBpwrite\fR(2),
respectively, of the target process's address space file. The difference is
that more than one \fBPCREAD\fR or \fBPCWRITE\fR control operation can be
written to the control file at once, and they can be interspersed with other
control operations in a single write to the control file. This is useful, for
example, when planting many breakpoint instructions in the process's address
space, or when stepping over a breakpointed instruction. Unlike \fBpread\fR(2)
and \fBpwrite\fR(2), no provision is made for partial reads or writes; if the
operation cannot be performed completely, it fails with \fBEIO\fR.
.SS "PCNICE"
.LP
The traced process's \fBnice\fR(2) value is incremented by the amount in the
operand \fBlong\fR. Only a process with the {\fBPRIV_PROC_PRIOCNTL\fR}
privilege asserted in its effective set can better a process's priority in this
way, but any user may lower the priority. This operation is not meaningful for
all scheduling classes.
.SS "PCSCRED"
.LP
Set the target process credentials to the values contained in the
\fBprcred_t\fR structure operand (see \fB/proc/\fR\fIpid\fR\fB/cred\fR). The
effective, real, and saved user-IDs and group-IDs of the target process are
set. The target process's supplementary groups are not changed; the
\fBpr_ngroups\fR and \fBpr_groups\fR members of the structure operand are
ignored. Only the privileged processes can perform this operation; for all
others it fails with \fBEPERM\fR.
.SS "PCSCREDX"
.LP
Operates like \fBPCSCRED\fR but also sets the supplementary groups; the length
of the data written with this control operation should be "sizeof
(\fBprcred_t\fR) + sizeof (\fBgid_t)\fR * (#groups - 1)".
.SS "PCSPRIV"
.LP
Set the target process privilege to the values contained in the \fBprpriv_t\fR
operand (see \fB/proc/pid/priv\fR). The effective, permitted, inheritable, and
limit sets are all changed. Privilege flags can also be set. The process is
made privilege aware unless it can relinquish privilege awareness. See
\fBprivileges\fR(5).
.sp
.LP
The limit set of the target process cannot be grown. The other privilege sets
must be subsets of the intersection of the effective set of the calling process
with the new limit set of the target process or subsets of the original values
of the sets in the target process.
.sp
.LP
If any of the above restrictions are not met, \fBEPERM\fR is returned. If the
structure written is improperly formatted, \fBEINVAL\fR is returned.
.SH PROGRAMMING NOTES
.LP
For security reasons, except for the \fBpsinfo\fR, \fBusage\fR, \fBlpsinfo\fR,
\fBlusage\fR, \fBlwpsinfo\fR, and \fBlwpusage\fR files, which are
world-readable, and except for privileged processes, an open of a \fB/proc\fR
file fails unless both the user-ID and group-ID of the caller match those of
the traced process and the process's object file is readable by the caller. The
effective set of the caller is a superset of both the inheritable and the
permitted set of the target process. The limit set of the caller is a superset
of the limit set of the target process. Except for the world-readable files
just mentioned, files corresponding to setuid and setgid processes can be
opened only by the appropriately privileged process.
.sp
.LP
A process that is missing the basic privilege {\fBPRIV_PROC_INFO\fR} cannot see
any processes under \fB/proc\fR that it cannot send a signal to.
.sp
.LP
A process that has {\fBPRIV_PROC_OWNER\fR} asserted in its effective set can
open any file for reading. To manipulate or control a process, the controlling
process must have at least as many privileges in its effective set as the
target process has in its effective, inheritable, and permitted sets. The limit
set of the controlling process must be a superset of the limit set of the
target process. Additional restrictions apply if any of the uids of the target
process are 0. See \fBprivileges\fR(5).
.sp
.LP
Even if held by a privileged process, an open process or lwp file descriptor
(other than file descriptors for the world-readable files) becomes invalid if
the traced process performs an \fBexec\fR(2) of a setuid/setgid object file or
an object file that the traced process cannot read. Any operation performed on
an invalid file descriptor, except \fBclose\fR(2), fails with \fBEAGAIN\fR. In
this situation, if any tracing flags are set and the process or any lwp file
descriptor is open for writing, the process will have been directed to stop and
its run-on-last-close flag will have been set (see \fBPCSET\fR). This enables a
controlling process (if it has permission) to reopen the \fB/proc\fR files to
get new valid file descriptors, close the invalid file descriptors, unset the
run-on-last-close flag (if desired), and proceed. Just closing the invalid file
descriptors causes the traced process to resume execution with all tracing
flags cleared. Any process not currently open for writing via \fB/proc\fR, but
that has left-over tracing flags from a previous open, and that executes a
setuid/setgid or unreadable object file, will not be stopped but will have all
its tracing flags cleared.
.sp
.LP
To wait for one or more of a set of processes or lwps to stop or terminate,
\fB/proc\fR file descriptors (other than those obtained by opening the
\fBcwd\fR or \fBroot\fR directories or by opening files in the \fBfd\fR or
\fBobject\fR directories) can be used in a \fBpoll\fR(2) system call. When
requested and returned, either of the polling events \fBPOLLPRI\fR or
\fBPOLLWRNORM\fR indicates that the process or lwp stopped on an event of
interest. Although they cannot be requested, the polling events \fBPOLLHUP\fR,
\fBPOLLERR\fR, and \fBPOLLNVAL\fR may be returned. \fBPOLLHUP\fR indicates that
the process or lwp has terminated. \fBPOLLERR\fR indicates that the file
descriptor has become invalid. \fBPOLLNVAL\fR is returned immediately if
\fBPOLLPRI\fR or \fBPOLLWRNORM\fR is requested on a file descriptor referring
to a system process (see \fBPCSTOP\fR). The requested events may be empty to
wait simply for termination.
.SH FILES
.ne 2
.na
\fB\fB/proc\fR\fR
.ad
.sp .6
.RS 4n
directory (list of processes)
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR\fR\fR
.ad
.sp .6
.RS 4n
specific process directory
.RE

.sp
.ne 2
.na
\fB\fB/proc/self\fR\fR
.ad
.sp .6
.RS 4n
alias for a process's own directory
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/as\fR\fR
.ad
.sp .6
.RS 4n
address space file
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/ctl\fR\fR
.ad
.sp .6
.RS 4n
process control file
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/status\fR\fR
.ad
.sp .6
.RS 4n
process status
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/lstatus\fR\fR
.ad
.sp .6
.RS 4n
array of lwp status structs
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/psinfo\fR\fR
.ad
.sp .6
.RS 4n
process \fBps\fR(1) info
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/lpsinfo\fR\fR
.ad
.sp .6
.RS 4n
array of lwp \fBps\fR(1) info structs
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/map\fR\fR
.ad
.sp .6
.RS 4n
address space map
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/xmap\fR\fR
.ad
.sp .6
.RS 4n
extended address space map
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/rmap\fR\fR
.ad
.sp .6
.RS 4n
reserved address map
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/cred\fR\fR
.ad
.sp .6
.RS 4n
process credentials
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/priv\fR\fR
.ad
.sp .6
.RS 4n
process privileges
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/sigact\fR\fR
.ad
.sp .6
.RS 4n
process signal actions
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/auxv\fR\fR
.ad
.sp .6
.RS 4n
process aux vector
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/ldt\fR\fR
.ad
.sp .6
.RS 4n
process \fBLDT\fR (x86 only)
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/usage\fR\fR
.ad
.sp .6
.RS 4n
process usage
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/lusage\fR\fR
.ad
.sp .6
.RS 4n
array of lwp usage structs
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/path\fR\fR
.ad
.sp .6
.RS 4n
symbolic links to process open files
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/pagedata\fR\fR
.ad
.sp .6
.RS 4n
process page data
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/watch\fR\fR
.ad
.sp .6
.RS 4n
active watchpoints
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/cwd\fR\fR
.ad
.sp .6
.RS 4n
alias for the current working directory
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/root\fR\fR
.ad
.sp .6
.RS 4n
alias for the root directory
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/fd\fR\fR
.ad
.sp .6
.RS 4n
directory (list of open files)
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/fd/*\fR\fR
.ad
.sp .6
.RS 4n
aliases for process's open files
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/object\fR\fR
.ad
.sp .6
.RS 4n
directory (list of mapped files)
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/object/a.out\fR\fR
.ad
.sp .6
.RS 4n
alias for process's executable file
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/object/*\fR\fR
.ad
.sp .6
.RS 4n
aliases for other mapped files
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/lwp\fR\fR
.ad
.sp .6
.RS 4n
directory (list of lwps)
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/lwp/\fIlwpid\fR\fR\fR
.ad
.sp .6
.RS 4n
specific lwp directory
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/lwp/agent\fR\fR
.ad
.sp .6
.RS 4n
alias for the agent lwp directory
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/lwp/\fIlwpid\fR/lwpctl\fR\fR
.ad
.sp .6
.RS 4n
lwp control file
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/lwp/\fIlwpid\fR/lwpstatus\fR\fR
.ad
.sp .6
.RS 4n
lwp status
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/lwp/\fIlwpid\fR/lwpsinfo\fR\fR
.ad
.sp .6
.RS 4n
lwp \fBps\fR(1) info
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/lwp/\fIlwpid\fR/lwpusage\fR\fR
.ad
.sp .6
.RS 4n
lwp usage
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/lwp/\fIlwpid\fR/gwindows\fR\fR
.ad
.sp .6
.RS 4n
register windows (SPARC only)
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/lwp/\fIlwpid\fR/xregs\fR\fR
.ad
.sp .6
.RS 4n
extra state registers
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/lwp/\fIlwpid\fR/asrs\fR\fR
.ad
.sp .6
.RS 4n
ancillary state registers (SPARC V9 only)
.RE

.sp
.ne 2
.na
\fB\fB/proc/\fIpid\fR/lwp/\fIlwpid\fR/spymaster\fR\fR
.ad
.sp .6
.RS 4n
For an agent LWP, the controlling process
.RE

.SH SEE ALSO
.LP
\fBls\fR(1), \fBps\fR(1), \fBchroot\fR(1M), \fBalarm\fR(2), \fBbrk\fR(2),
\fBchdir\fR(2), \fBchroot\fR(2), \fBclose\fR(2), \fBcreat\fR(2), \fBdup\fR(2),
\fBexec\fR(2), \fBfcntl\fR(2), \fBfork\fR(2), \fBfork1\fR(2), \fBfstat\fR(2),
\fBgetdents\fR(2), \fBgetustack\fR(2), \fBkill\fR(2), \fBlseek\fR(2),
\fBmmap\fR(2), \fBnice\fR(2), \fBopen\fR(2), \fBpoll\fR(2), \fBpread\fR(2),
\fBptrace\fR(3C), \fBpwrite\fR(2), \fBread\fR(2), \fBreadlink\fR(2),
\fBreadv\fR(2), \fBshmget\fR(2), \fBsigaction\fR(2), \fBsigaltstack\fR(2),
\fBvfork\fR(2), \fBwrite\fR(2), \fBwritev\fR(2), \fB_stack_grow\fR(3C),
\fBreaddir\fR(3C), \fBpthread_create\fR(3C), \fBpthread_join\fR(3C),
\fBsiginfo.h\fR(3HEAD), \fBsignal.h\fR(3HEAD), \fBthr_create\fR(3C),
\fBthr_join\fR(3C), \fBtypes32.h\fR(3HEAD), \fBucontext.h\fR(3HEAD),
\fBwait\fR(3C), \fBcontract\fR(4), \fBcore\fR(4), \fBprocess\fR(4),
\fBlfcompile\fR(5), \fBprivileges\fR(5), \fBsecurity-flags\fR(5)
.SH DIAGNOSTICS
.LP
Errors that can occur in addition to the errors normally associated with file
system access:
.sp
.ne 2
.na
\fB\fBE2BIG\fR\fR
.ad
.RS 13n
Data to be returned in a \fBread\fR(2) of the page data file exceeds the size
of the read buffer provided by the caller.
.RE

.sp
.ne 2
.na
\fB\fBEACCES\fR\fR
.ad
.RS 13n
An attempt was made to examine a process that ran under a different uid than
the controlling process and {\fBPRIV_PROC_OWNER\fR} was not asserted in the
effective set.
.RE

.sp
.ne 2
.na
\fB\fBEAGAIN\fR\fR
.ad
.RS 13n
The traced process has performed an \fBexec\fR(2) of a setuid/setgid object
file or of an object file that it cannot read; all further operations on the
process or lwp file descriptor (except \fBclose\fR(2)) elicit this error.
.RE

.sp
.ne 2
.na
\fB\fBEBUSY\fR\fR
.ad
.RS 13n
\fBPCSTOP\fR, \fBPCDSTOP\fR, \fBPCWSTOP\fR, or \fBPCTWSTOP\fR was applied to a
system process; an exclusive \fBopen\fR(2) was attempted on a \fB/proc\fR file
for a process already open for writing; \fBPCRUN\fR, \fBPCSREG\fR,
\fBPCSVADDR\fR, \fBPCSFPREG\fR, or \fBPCSXREG\fR was applied to a process or
lwp not stopped on an event of interest; an attempt was made to mount
\fB/proc\fR when it was already mounted; \fBPCAGENT\fR was applied to a process
that was not fully stopped or that already had an agent lwp.
.RE

.sp
.ne 2
.na
\fB\fBEINVAL\fR\fR
.ad
.RS 13n
In general, this means that some invalid argument was supplied to a system
call. A non-exhaustive list of conditions eliciting this error includes: a
control message operation code is undefined; an out-of-range signal number was
specified with \fBPCSSIG\fR, \fBPCKILL\fR, or \fBPCUNKILL\fR; \fBSIGKILL\fR was
specified with \fBPCUNKILL\fR; \fBPCSFPREG\fR was applied on a system that does
not support floating-point operations; \fBPCSXREG\fR was applied on a system
that does not support extra state registers.
.RE

.sp
.ne 2
.na
\fB\fBEINTR\fR\fR
.ad
.RS 13n
A signal was received by the controlling process while waiting for the traced
process or lwp to stop via \fBPCSTOP\fR, \fBPCWSTOP\fR, or \fBPCTWSTOP\fR.
.RE

.sp
.ne 2
.na
\fB\fBEIO\fR\fR
.ad
.RS 13n
A \fBwrite\fR(2) was attempted at an illegal address in the traced process.
.RE

.sp
.ne 2
.na
\fB\fBENOENT\fR\fR
.ad
.RS 13n
The traced process or lwp has terminated after being opened. The basic
privilege {\fBPRIV_PROC_INFO\fR} is not asserted in the effective set of the
calling process and the calling process cannot send a signal to the target
process.
.RE

.sp
.ne 2
.na
\fB\fBENOMEM\fR\fR
.ad
.RS 13n
The system-imposed limit on the number of page data file descriptors was
reached on an open of \fB/proc/\fR\fIpid\fR\fB/pagedata\fR; an attempt was made
with \fBPCWATCH\fR to establish more watched areas than the system can support;
the \fBPCAGENT\fR operation was issued when the system was out of resources for
creating lwps.
.RE

.sp
.ne 2
.na
\fB\fBENOSYS\fR\fR
.ad
.RS 13n
An attempt was made to perform an unsupported operation (such as
\fBcreat\fR(2), \fBlink\fR(2), or \fBunlink\fR(2)) on an entry in \fB/proc\fR.
.RE

.sp
.ne 2
.na
\fB\fBEOVERFLOW\fR\fR
.ad
.RS 13n
A 32-bit controlling process attempted to read or write the \fBas\fR file or
attempted to read the \fBmap\fR, \fBrmap\fR, or \fBpagedata\fR file of a 64-bit
target process. A 32-bit controlling process attempted to apply one of the
control operations \fBPCSREG\fR, \fBPCSXREG\fR, \fBPCSVADDR\fR, \fBPCWATCH\fR,
\fBPCAGENT\fR, \fBPCREAD\fR, \fBPCWRITE\fR to a 64-bit target process.
.RE

.sp
.ne 2
.na
\fB\fBEPERM\fR\fR
.ad
.RS 13n
The process that issued the \fBPCSCRED\fR or \fBPCSCREDX\fR operation did not
have the {\fBPRIV_PROC_SETID\fR} privilege asserted in its effective set, or
the process that issued the \fBPCNICE\fR operation did not have the
{\fBPRIV_PROC_PRIOCNTL\fR} in its effective set.
.sp
An attempt was made to control a process of which the E, P, and I privilege
sets were not a subset of the effective set of the controlling process or the
limit set of the controlling process is not a superset of limit set of the
controlled process.
.sp
Any of the uids of the target process are 0 or an attempt was made to change
any of the uids to 0 using PCSCRED and the security policy imposed additional
restrictions. See \fBprivileges\fR(5).
.RE

.SH NOTES
.LP
Descriptions of structures in this document include only interesting structure
elements, not filler and padding fields, and may show elements out of order for
descriptive clarity. The actual structure definitions are contained in
\fB<procfs.h>\fR\&.
.SH BUGS
.LP
Because the old \fBioctl\fR(2)-based version of \fB/proc\fR is currently
supported for binary compatibility with old applications, the top-level
directory for a process, \fB/proc/\fR\fIpid\fR, is not world-readable, but it
is world-searchable. Thus, anyone can open \fB/proc/\fR\fIpid\fR\fB/psinfo\fR
even though \fBls\fR(1) applied to \fB/proc/\fR\fIpid\fR will fail for anyone
but the owner or an appropriately privileged process. Support for the old
\fBioctl\fR(2)-based version of \fB/proc\fR will be dropped in a future
release, at which time the top-level directory for a process will be made
world-readable.
.sp
.LP
On SPARC based machines, the types \fBgregset_t\fR and \fBfpregset_t\fR defined
in <\fBsys/regset.h\fR> are similar to but not the same as the types
\fBprgregset_t\fR and \fBprfpregset_t\fR defined in <\fBprocfs.h\fR>.