diff options
Diffstat (limited to 'sys-utils')
| -rw-r--r-- | sys-utils/Makefile | 3 | ||||
| -rw-r--r-- | sys-utils/ipc.info | 140 | ||||
| -rw-r--r-- | sys-utils/ipc.texi | 246 | ||||
| -rw-r--r-- | sys-utils/readprofile.c | 37 |
4 files changed, 234 insertions, 192 deletions
diff --git a/sys-utils/Makefile b/sys-utils/Makefile index b1151742..4e67514e 100644 --- a/sys-utils/Makefile +++ b/sys-utils/Makefile @@ -77,6 +77,9 @@ renice: renice.o readprofile: readprofile.o setsid: setsid.o +ipc.info: ipc.texi + makeinfo ipc.texi + install: all $(INSTALLDIR) $(SBINDIR) $(BINDIR) $(USRBINDIR) $(USRSBINDIR) $(INSTALLBIN) $(SBIN) $(SBINDIR) diff --git a/sys-utils/ipc.info b/sys-utils/ipc.info index 5d34e18d..5bb1a538 100644 --- a/sys-utils/ipc.info +++ b/sys-utils/ipc.info @@ -1,5 +1,4 @@ -This is Info file ipc.info, produced by Makeinfo-1.47 from the input -file ipc.texi. +This is ipc.info, produced by makeinfo version 4.0 from ipc.texi. This file documents the System V style inter process communication primitives available under linux. @@ -9,8 +8,13 @@ primitives available under linux. Permission is granted to use this material and the accompanying programs within the terms of the GNU GPL. +INFO-DIR-SECTION Miscellaneous +START-INFO-DIR-ENTRY +* ipc: (ipc). System V style inter process communication +END-INFO-DIR-ENTRY + -File: ipc.info, Node: top, Next: Overview, Prev: Notes, Up: (dir) +File: ipc.info, Node: Top, Next: Overview, Prev: Notes, Up: (dir) System V IPC. ************* @@ -21,7 +25,7 @@ these system V mechanisms to accomplish inter process communication (IPC). The specifics described here are applicable to the Linux -implementation. Other implementations may do things slightly +implementation. Other implementations may do things slightly differently. * Menu: @@ -33,7 +37,7 @@ differently. * Notes:: Miscellaneous notes. -File: ipc.info, Node: Overview, Next: example, Prev: top, Up: top +File: ipc.info, Node: Overview, Next: example, Prev: Top, Up: Top Overview ======== @@ -75,9 +79,9 @@ implementation and others by the system administrator when configuring the kernel (*Note msglimits::, *Note semlimits::, *Note shmlimits::). There is an `msqid_ds', `semid_ds' or `shmid_ds' struct associated -with each message queue, semaphore array or shared segment. Each ipc +with each message queue, semaphore array or shared segment. Each ipc resource has an associated `ipc_perm' struct which defines the creator, -owner, access perms ..etc.., for the resource. These structures are +owner, access perms ..etc.., for the resource. These structures are detailed in the following sections. @@ -190,9 +194,9 @@ The "get" system calls ---------------------- The `get' call typically takes a KEY and returns a numeric ID that -is used for further access. The ID is an index into the resource table. -A sequence number is maintained and incremented when a resource is -destroyed so that acceses using an obselete ID is likely to fail. +is used for further access. The ID is an index into the resource +table. A sequence number is maintained and incremented when a resource +is destroyed so that access using an obsolete ID is likely to fail. The user also specifies the permissions and other behaviour charecteristics for the current access. The flags are or-ed with the @@ -247,8 +251,8 @@ Commands supported by all `ctl' calls: * IPC_RMID : remove resource. The user must be the owner, creator or super-user. -The IPC_RMID command results in immediate removal of a message queue or -semaphore array. Shared memory segments however, are only destroyed + The IPC_RMID command results in immediate removal of a message queue +or semaphore array. Shared memory segments however, are only destroyed upon the last detach after IPC_RMID is executed. The `semctl' call provides a number of command options that allow @@ -260,9 +264,9 @@ The "op" system calls --------------------- Used to send or receive messages, read or alter semaphore values, -attach or detach shared memory segments. The IPC_NOWAIT flag will cause -the operation to fail with error EAGAIN if the process has to wait on -the call. +attach or detach shared memory segments. The IPC_NOWAIT flag will +cause the operation to fail with error EAGAIN if the process has to +wait on the call. `flags' : IPC_NOWAIT => return with error if a wait is required. @@ -270,14 +274,14 @@ See Also: *Note msgsnd::,*Note msgrcv::,*Note semop::,*Note shmat::, *Note shmdt::. -File: ipc.info, Node: Messages, Next: msgget, Prev: syscalls, Up: top +File: ipc.info, Node: Messages, Next: msgget, Prev: syscalls, Up: Top Messages ======== A message resource is described by a struct `msqid_ds' which is allocated and initialized when the resource is created. Some fields in -`msqid_ds' can then be altered (if desired) by invoking `msgctl'. The +`msqid_ds' can then be altered (if desired) by invoking `msgctl'. The memory used by the resource is released when it is destroyed by a `msgctl' call. @@ -462,13 +466,13 @@ user supplied buffer. In the case of IPC_SET, the queue size (`msg_qbytes') and the `uid', `gid', `mode' (low 9 bits) fields of the `msg_perm' struct are set from -the user supplied values. `msg_ctime' is updated. +the user supplied values. `msg_ctime' is updated. Note that only the super user may increase the limit on the size of a message queue beyond MSGMNB. When the queue is destroyed (IPC_RMID), the sequence number is -incremented and all waiting readers and writers are awakened. These +incremented and all waiting readers and writers are awakened. These processes will then return with `errno' set to EIDRM. Errors: @@ -496,11 +500,11 @@ Sizeof various structures: Limits * MSGMNI : number of message queue identifiers ... policy. - * MSGMAX : max size of message. Header and message space allocated - on one page. MSGMAX = (PAGE_SIZE - sizeof(struct msg)). + * MSGMAX : max size of message. Header and message space allocated + on one page. MSGMAX = (PAGE_SIZE - sizeof(struct msg)). Implementation maximum MSGMAX = 4080. - * MSGMNB : default max size of a message queue ... policy. The + * MSGMNB : default max size of a message queue ... policy. The super-user can increase the size of a queue beyond MSGMNB by a `msgctl' call. @@ -509,7 +513,7 @@ MSGTQL max number of message headers system-wide. MSGPOOL total size in bytes of msg pool. -File: ipc.info, Node: Semaphores, Next: semget, Prev: msglimits, Up: top +File: ipc.info, Node: Semaphores, Next: semget, Prev: msglimits, Up: Top Semaphores ========== @@ -573,8 +577,9 @@ A semaphore array is allocated by a semget system call: * `nsems' : # of semaphores in array (0 <= nsems <= SEMMSL <= SEMMNS) - 0 => dont care can be used when not creating the resource. If - successful you always get access to the entire array anyway. + 0 => dont care can be used when not creating the resource. + If successful you always get access to the entire array + anyway. * semflg : IPC_CREAT used to create a new resource @@ -743,9 +748,9 @@ Limits : * SEMMNI number of semaphore identifiers (or arrays) system wide...policy. - * SEMMSL maximum number of semaphores per id. 1 semid_ds per + * SEMMSL maximum number of semaphores per id. 1 semid_ds per array, 1 struct sem per semaphore => SEMMSL = (PAGE_SIZE - - sizeof(semid_ds)) / sizeof(sem). Implementation maximum SEMMSL = + sizeof(semid_ds)) / sizeof(sem). Implementation maximum SEMMSL = 500. * SEMMNS maximum number of semaphores system wide ... policy. @@ -760,7 +765,7 @@ SEMMNU number of undo structures system-wide. SEMUME maximum number of undo entries per process. -File: ipc.info, Node: Shared Memory, Next: shmget, Prev: semlimits, Up: top +File: ipc.info, Node: Shared Memory, Next: shmget, Prev: semlimits, Up: Top Shared Memory ============= @@ -860,7 +865,7 @@ Maps a shared segment into the process' address space. * shmaddr : requested attach address. If shmaddr is 0 the system finds an unmapped region. - If a non-zero value is indicated the value must be page + If a non-zero value is indicated the value must be page aligned or the user must specify the SHM_RND flag. * shmflg : @@ -877,18 +882,18 @@ encouraged to avoid non-specific attaches. Algorithm: Determine attach address as described above. Check region (shmaddr, shmaddr + size) is not mapped and allocate - page tables (undocumented SHM_REMAP flag!). + page tables (undocumented SHM_REMAP flag!). Map the region by setting up pointers into the internal page table. Add a descriptor for the attach to the task struct for the process. `shm_nattch', `shm_lpid', `shm_atime' are updated. Notes: -The `brk' value is not altered. The segment is automatically detached -when the process exits. The same segment may be attached as read-only -or read-write and more than once in the process' address space. A -shmat can succeed on a segment marked for destruction. The request for -a particular type of attach is made using the SHM_RDONLY flag. There is -no notion of a write-only attach. The requested attach permissions +The `brk' value is not altered. The segment is automatically detached +when the process exits. The same segment may be attached as read-only +or read-write and more than once in the process' address space. A +shmat can succeed on a segment marked for destruction. The request for +a particular type of attach is made using the SHM_RDONLY flag. There +is no notion of a write-only attach. The requested attach permissions must fall within those allowed by `shm_perm.mode'. Errors: @@ -911,7 +916,7 @@ shmdt An attached segment is detached and `shm_nattch' decremented. The occupied region in user space is unmapped. The segment is destroyed if -it is marked for destruction and `shm_nattch' is 0. `shm_lpid' and +it is marked for destruction and `shm_nattch' is 0. `shm_lpid' and `shm_dtime' are updated. Errors: @@ -965,24 +970,24 @@ Limits: * SHMMAX max shared memory segment size (bytes) ... 4M - * SHMMIN min shared memory segment size (bytes). 1 byte (though + * SHMMIN min shared memory segment size (bytes). 1 byte (though PAGE_SIZE is the effective minimum size). * SHMALL max shared mem system wide (in pages) ... policy. - * SHMLBA segment low boundary address multiple. Must be page + * SHMLBA segment low boundary address multiple. Must be page aligned. SHMLBA = PAGE_SIZE. Unused or unimplemented: SHMSEG : maximum number of shared segments per process. -File: ipc.info, Node: Notes, Next: top, Prev: shmlimits, Up: top +File: ipc.info, Node: Notes, Next: Top, Prev: shmlimits, Up: Top Miscellaneous Notes =================== - The system calls are mapped into one -- `sys_ipc'. This should be + The system calls are mapped into one - `sys_ipc'. This should be transparent to the user. Semaphore `undo' requests @@ -999,7 +1004,7 @@ may have been accumulated over many `semop' calls. Thus use the undo mechanism with private semaphores only. Should the process sleep in `exit' or should all undo operations be -applied with the IPC_NOWAIT flag in effect? Currently those undo +applied with the IPC_NOWAIT flag in effect? Currently those undo operations which go through immediately are applied and those that require a wait are ignored silently. @@ -1052,7 +1057,7 @@ not the semaphore undo information. In the case of an exec, the attached shared segments are detached. The sem undo information however remains intact. - Upon exit, all attached shared memory segments are detached. The + Upon exit, all attached shared memory segments are detached. The adjust values in the undo structures are added to the relevant semvals if the operations are permitted. Disallowed operations are ignored. @@ -1072,6 +1077,9 @@ SEMINFO `ctl' calls are used by the `ipcs' program to provide information on allocated resources. These can be modified as needed or moved to a proc file system interface. + + + Thanks to Ove Ewerlid, Bruno Haible, Ulrich Pegelow and Linus Torvalds for ideas, tutorials, bug reports and fixes, and merriment. And more thanks to Bruno. @@ -1079,28 +1087,28 @@ And more thanks to Bruno. Tag Table: -Node: top349 -Node: Overview1049 -Node: example2881 -Node: perms4383 -Node: syscalls5943 -Node: Messages9392 -Node: msgget11426 -Node: msgsnd12810 -Node: msgrcv13778 -Node: msgctl15477 -Node: msglimits16684 -Node: Semaphores17558 -Node: semget19517 -Node: semop21060 -Node: semctl23624 -Node: semlimits25383 -Node: Shared Memory26523 -Node: shmget28008 -Node: shmat29803 -Node: shmdt31851 -Node: shmctl32383 -Node: shmlimits33514 -Node: Notes34161 +Node: Top469 +Node: Overview1170 +Node: example3004 +Node: perms4506 +Node: syscalls6066 +Node: Messages9519 +Node: msgget11554 +Node: msgsnd12938 +Node: msgrcv13906 +Node: msgctl15605 +Node: msglimits16814 +Node: Semaphores17691 +Node: semget19650 +Node: semop21203 +Node: semctl23767 +Node: semlimits25526 +Node: Shared Memory26668 +Node: shmget28153 +Node: shmat29948 +Node: shmdt31985 +Node: shmctl32518 +Node: shmlimits33649 +Node: Notes34298 End Tag Table diff --git a/sys-utils/ipc.texi b/sys-utils/ipc.texi index 53c4e4e5..672d8b84 100644 --- a/sys-utils/ipc.texi +++ b/sys-utils/ipc.texi @@ -4,28 +4,28 @@ @settitle Inter Process Communication. @setchapternewpage odd @comment %**end of header (This is for running Texinfo on a region.) - + @ifinfo This file documents the System V style inter process communication primitives available under linux. - + Copyright @copyright{} 1992 krishna balasubramanian - + Permission is granted to use this material and the accompanying programs within the terms of the GNU GPL. @end ifinfo - + @titlepage @sp 10 @center @titlefont{System V Inter Process Communication} @sp 2 @center krishna balasubramanian, - + @comment The following two commands start the copyright page. @page @vskip 0pt plus 1filll Copyright @copyright{} 1992 krishna balasubramanian - + Permission is granted to use this material and the accompanying programs within the terms of the GNU GPL. @end titlepage @@ -35,12 +35,12 @@ programs within the terms of the GNU GPL. * ipc: (ipc). System V style inter process communication @end direntry -@node top, Overview, Notes, (dir) +@node Top, Overview, Notes, (dir) @chapter System V IPC. These facilities are provided to maintain compatibility with -programs developed on system V unix systems and others -that rely on these system V mechanisms to accomplish inter +programs developed on system V unix systems and others +that rely on these system V mechanisms to accomplish inter process communication (IPC).@refill The specifics described here are applicable to the Linux implementation. @@ -54,17 +54,17 @@ Other implementations may do things slightly differently. * Notes:: Miscellaneous notes. @end menu -@node Overview, example, top, top +@node Overview, example, Top, Top @section Overview @noindent System V IPC consists of three mechanisms: @itemize @bullet -@item +@item Messages : exchange messages with any process or server. -@item +@item Semaphores : allow unrelated processes to synchronize execution. -@item +@item Shared memory : allow unrelated processes to share memory. @end itemize @@ -77,11 +77,11 @@ Shared memory : allow unrelated processes to share memory. Access to all resources is permitted on the basis of permissions set up when the resource was created.@refill -A resource here consists of message queue, a semaphore set (array) +A resource here consists of message queue, a semaphore set (array) or a shared memory segment.@refill A resource must first be allocated by a creator before it is used. -The creator can assign a different owner. After use the resource +The creator can assign a different owner. After use the resource must be explicitly destroyed by the creator or owner.@refill A resource is identified by a numeric @var{id}. Typically a creator @@ -93,14 +93,14 @@ pathnames or strings to numeric keys.@refill There are system and implementation defined limits on the number and sizes of resources of any given type. Some of these are imposed by the -implementation and others by the system administrator +implementation and others by the system administrator when configuring the kernel (@xref{msglimits}, @xref{semlimits}, @xref{shmlimits}).@refill -There is an @code{msqid_ds}, @code{semid_ds} or @code{shmid_ds} struct -associated with each message queue, semaphore array or shared segment. -Each ipc resource has an associated @code{ipc_perm} struct which defines -the creator, owner, access perms ..etc.., for the resource. +There is an @code{msqid_ds}, @code{semid_ds} or @code{shmid_ds} struct +associated with each message queue, semaphore array or shared segment. +Each ipc resource has an associated @code{ipc_perm} struct which defines +the creator, owner, access perms ..etc.., for the resource. These structures are detailed in the following sections.@refill @@ -112,21 +112,21 @@ Here is a code fragment with pointers on how to use shared memory. The same methods are applicable to other resources.@refill In a typical access sequence the creator allocates a new instance -of the resource with the @code{get} system call using the IPC_CREAT +of the resource with the @code{get} system call using the IPC_CREAT flag.@refill @noindent creator process:@* @example #include <sys/shm.h> -int id; -key_t key; +int id; +key_t key; char proc_id = 'C'; int size = 0x5000; /* 20 K */ int flags = 0664 | IPC_CREAT; /* read-only for others */ key = ftok ("~creator/ipckey", proc_id); -id = shmget (key, size, flags); +id = shmget (key, size, flags); exit (0); /* quit leaving resource allocated */ @end example @@ -137,8 +137,8 @@ Client process: @example #include <sys/shm.h> char *shmaddr; -int id; -key_t key; +int id; +key_t key; char proc_id = 'C'; key = ftok ("~creator/ipckey", proc_id); @@ -170,7 +170,7 @@ shmctl (id, IPC_RMID, NULL); @node perms, syscalls, example, Overview @section Permissions -Each resource has an associated @code{ipc_perm} struct which defines the +Each resource has an associated @code{ipc_perm} struct which defines the creator, owner and access perms for the resource.@refill @example @@ -185,18 +185,18 @@ struct ipc_perm @end example The creating process is the default owner. The owner can be reassigned -by the creator and has creator perms. Only the owner, creator or super-user +by the creator and has creator perms. Only the owner, creator or super-user can delete the resource.@refill -The lowest nine bits of the flags parameter supplied by the user to the -system call are compared with the values stored in @code{ipc_perms.mode} +The lowest nine bits of the flags parameter supplied by the user to the +system call are compared with the values stored in @code{ipc_perms.mode} to determine if the requested access is allowed. In the case that the system call creates the resource, these bits are initialized from the user supplied value.@refill As for files, access permissions are specified as read, write and exec -for user, group or other (though the exec perms are unused). For example -0624 grants read-write to owner, write-only to group and read-only +for user, group or other (though the exec perms are unused). For example +0624 grants read-write to owner, write-only to group and read-only access to others.@refill For shared memory, note that read-write access for segments is determined @@ -214,23 +214,23 @@ cannot be changed by the user.@refill This section provides an overview of the IPC system calls. See the specific sections on each type of resource for details.@refill -Each type of mechanism provides a @dfn{get}, @dfn{ctl} and one or more +Each type of mechanism provides a @dfn{get}, @dfn{ctl} and one or more @dfn{op} system calls that allow the user to create or procure the -resource (get), define its behaviour or destroy it (ctl) and manipulate +resource (get), define its behaviour or destroy it (ctl) and manipulate the resources (op).@refill @subsection The @dfn{get} system calls -The @code{get} call typically takes a @var{key} and returns a numeric -@var{id} that is used for further access. +The @code{get} call typically takes a @var{key} and returns a numeric +@var{id} that is used for further access. The @var{id} is an index into the resource table. A sequence number is maintained and incremented when a resource is -destroyed so that acceses using an obselete @var{id} is likely to fail.@refill +destroyed so that access using an obsolete @var{id} is likely to fail.@refill The user also specifies the permissions and other behaviour -charecteristics for the current access. The flags are or-ed with the +charecteristics for the current access. The flags are or-ed with the permissions when invoking system calls as in:@refill @example msgflg = IPC_CREAT | IPC_EXCL | 0666; @@ -240,7 +240,7 @@ id = msgget (key, msgflg); @item @code{key} : IPC_PRIVATE => new instance of resource is initialized. @item -@code{flags} : +@code{flags} : @itemize @asis @item IPC_CREAT : resource created for @var{key} if it does not exist. @@ -252,14 +252,14 @@ returns : an identifier used for all further access to the resource. @end itemize Note that IPC_PRIVATE is not a flag but a special @code{key} -that ensures (when the call is successful) that a new resource is +that ensures (when the call is successful) that a new resource is created.@refill Use of IPC_PRIVATE does not make the resource inaccessible to other users. For this you must set the access permissions appropriately.@refill -There is currently no way for a process to ensure exclusive access to a -resource. IPC_CREAT | IPC_EXCL only ensures (on success) that a new +There is currently no way for a process to ensure exclusive access to a +resource. IPC_CREAT | IPC_EXCL only ensures (on success) that a new resource was initialized. It does not imply exclusive access.@refill @noindent @@ -267,7 +267,7 @@ See Also : @xref{msgget}, @xref{semget}, @xref{shmget}.@refill -@subsection The @dfn{ctl} system calls +@subsection The @dfn{ctl} system calls Provides or alters the information stored in the structure that describes the resource indexed by @var{id}.@refill @@ -288,9 +288,9 @@ Commands supported by all @code{ctl} calls:@* @itemize @bullet @item IPC_STAT : read info on resource specified by id into user allocated -buffer. The user must have read access to the resource.@refill +buffer. The user must have read access to the resource.@refill @item -IPC_SET : write info from buffer into resource data structure. The +IPC_SET : write info from buffer into resource data structure. The user must be owner creator or super-user.@refill @item IPC_RMID : remove resource. The user must be the owner, creator or @@ -301,7 +301,7 @@ The IPC_RMID command results in immediate removal of a message queue or semaphore array. Shared memory segments however, are only destroyed upon the last detach after IPC_RMID is executed.@refill -The @code{semctl} call provides a number of command options that allow +The @code{semctl} call provides a number of command options that allow the user to determine or set the values of the semaphores in an array.@refill @noindent @@ -324,7 +324,7 @@ See Also: @xref{msgsnd},@xref{msgrcv},@xref{semop},@xref{shmat}, -@node Messages, msgget, syscalls, top +@node Messages, msgget, syscalls, Top @section Messages A message resource is described by a struct @code{msqid_ds} which is @@ -334,7 +334,7 @@ The memory used by the resource is released when it is destroyed by a @code{msgctl} call.@refill @example -struct msqid_ds +struct msqid_ds struct ipc_perm msg_perm; struct msg *msg_first; /* first message on queue (internal) */ struct msg *msg_last; /* last message in queue (internal) */ @@ -350,14 +350,14 @@ struct msqid_ds ushort msg_lrpid; /* pid of last msgrcv */ @end example -To send or receive a message the user allocates a structure that looks -like a @code{msgbuf} but with an array @code{mtext} of the required size. -Messages have a type (positive integer) associated with them so that -(for example) a listener can choose to receive only messages of a +To send or receive a message the user allocates a structure that looks +like a @code{msgbuf} but with an array @code{mtext} of the required size. +Messages have a type (positive integer) associated with them so that +(for example) a listener can choose to receive only messages of a given type.@refill @example -struct msgbuf +struct msgbuf long mtype; type of message (@xref{msgrcv}). char mtext[1]; message text .. why is this not a ptr? @end example @@ -404,14 +404,14 @@ resource already exists.@refill rwxrwxrwx : access permissions. @end itemize @item -returns: msqid (an integer used for all further access) on success. +returns: msqid (an integer used for all further access) on success. -1 on failure.@refill @end itemize -A message queue is allocated if there is no resource corresponding -to the given key. The access permissions specified are then copied -into the @code{msg_perm} struct and the fields in @code{msqid_ds} -initialized. The user must use the IPC_CREAT flag or key = IPC_PRIVATE, +A message queue is allocated if there is no resource corresponding +to the given key. The access permissions specified are then copied +into the @code{msg_perm} struct and the fields in @code{msqid_ds} +initialized. The user must use the IPC_CREAT flag or key = IPC_PRIVATE, if a new instance is to be allocated. If a resource corresponding to @var{key} already exists, the access permissions are verified.@refill @@ -500,7 +500,7 @@ msgtyp : @item > 0 => get first message of matching type. @item -< 0 => get message with least type which is <= abs(msgtyp). +< 0 => get message with least type which is <= abs(msgtyp). @end itemize @item msgflg : @@ -518,11 +518,11 @@ returns : size of message if found. -1 on error. @end itemize The first message that meets the @code{msgtyp} specification is -identified. For msgtyp < 0, the entire queue is searched for the +identified. For msgtyp < 0, the entire queue is searched for the message with the smallest type.@refill -If its length is smaller than msgsz or if the user specified the -MSG_NOERROR flag, its text and type are copied to msgp->mtext and +If its length is smaller than msgsz or if the user specified the +MSG_NOERROR flag, its text and type are copied to msgp->mtext and msgp->mtype, and it is taken off the queue.@refill The @code{msg_cbytes}, @code{msg_qnum}, @code{msg_lrpid}, @@ -568,11 +568,11 @@ IPC_STAT results in the copy of the queue data structure into the user supplied buffer.@refill In the case of IPC_SET, the queue size (@code{msg_qbytes}) -and the @code{uid}, @code{gid}, @code{mode} (low 9 bits) fields +and the @code{uid}, @code{gid}, @code{mode} (low 9 bits) fields of the @code{msg_perm} struct are set from the user supplied values. @code{msg_ctime} is updated.@refill - -Note that only the super user may increase the limit on the size of a + +Note that only the super user may increase the limit on the size of a message queue beyond MSGMNB.@refill When the queue is destroyed (IPC_RMID), the sequence number is @@ -616,11 +616,11 @@ MSGMNI : number of message queue identifiers ... policy. @item MSGMAX : max size of message. Header and message space allocated on one page. -MSGMAX = (PAGE_SIZE - sizeof(struct msg)). +MSGMAX = (PAGE_SIZE - sizeof(struct msg)). Implementation maximum MSGMAX = 4080.@refill @item MSGMNB : default max size of a message queue ... policy. -The super-user can increase the size of a +The super-user can increase the size of a queue beyond MSGMNB by a @code{msgctl} call.@refill @end itemize @@ -630,8 +630,8 @@ MSGTQL max number of message headers system-wide.@* MSGPOOL total size in bytes of msg pool. - -@node Semaphores, semget, msglimits, top + +@node Semaphores, semget, msglimits, Top @section Semaphores Each semaphore has a value >= 0. An id provides access to an array @@ -641,9 +641,9 @@ semaphores in a set are performed by the @code{semop} call which processes @code{sembuf} described below. The operations are applied only if all of them succeed.@refill -If you do not have a need for such arrays, you are probably better off using +If you do not have a need for such arrays, you are probably better off using the @code{test_bit}, @code{set_bit} and @code{clear_bit} bit-operations -defined in <asm/bitops.h>.@refill +defined in <asm/bitops.h>.@refill Semaphore operations may also be qualified by a SEM_UNDO flag which results in the operation being undone when the process exits.@refill @@ -652,13 +652,13 @@ If a decrement cannot go through, a process will be put to sleep on a queue waiting for the @code{semval} to increase unless it specifies IPC_NOWAIT. A read operation can similarly result in a sleep on a queue waiting for @code{semval} to become 0. (Actually there are -two queues per semaphore array).@refill +two queues per semaphore array).@refill @noindent A semaphore array is described by: @example -struct semid_ds - struct ipc_perm sem_perm; +struct semid_ds + struct ipc_perm sem_perm; time_t sem_otime; /* last semop time */ time_t sem_ctime; /* last change time */ struct wait_queue *eventn; /* wait for a semval to increase */ @@ -670,7 +670,7 @@ struct semid_ds @noindent Each semaphore is described internally by : @example -struct sem +struct sem short sempid; /* pid of last semop() */ ushort semval; /* current value */ ushort semncnt; /* num procs awaiting increase in semval */ @@ -698,7 +698,7 @@ semid = semget (key_t key, int nsems, int semflg); @item @code{key} : an integer usually got from @code{ftok} or IPC_PRIVATE @item -@code{nsems} : +@code{nsems} : @itemize @asis @item # of semaphores in array (0 <= nsems <= SEMMSL <= SEMMNS) @@ -710,18 +710,18 @@ If successful you always get access to the entire array anyway.@refill semflg : @itemize @asis @item -IPC_CREAT used to create a new resource +IPC_CREAT used to create a new resource @item IPC_EXCL used with IPC_CREAT to ensure failure if the resource exists. @item rwxrwxrwx access permissions. @end itemize @item -returns : semid on success. -1 on failure. +returns : semid on success. -1 on failure. @end itemize An array of nsems semaphores is allocated if there is no resource -corresponding to the given key. The access permissions specified are +corresponding to the given key. The access permissions specified are then copied into the @code{sem_perm} struct for the array along with the user-id etc. The user must use the IPC_CREAT flag or key = IPC_PRIVATE if a new resource is to be created.@refill @@ -762,13 +762,13 @@ sops : array of semaphore operations. @item nsops : number of operations in array (0 < nsops < SEMOPM). @item -returns : semval for last operation. -1 on failure. +returns : semval for last operation. -1 on failure. @end itemize @noindent Operations are described by a structure sembuf: @example -struct sembuf +struct sembuf ushort sem_num; /* semaphore index in array */ short sem_op; /* semaphore operation */ short sem_flg; /* operation flags */ @@ -783,25 +783,25 @@ Two kinds of operations can result in wait: @enumerate @item If sem_op is 0 (read operation) and semval is non-zero, the process -sleeps on a queue waiting for semval to become zero or returns with +sleeps on a queue waiting for semval to become zero or returns with error EAGAIN if (IPC_NOWAIT | sem_flg) is true.@refill @item -If (sem_op < 0) and (semval + sem_op < 0), the process either sleeps +If (sem_op < 0) and (semval + sem_op < 0), the process either sleeps on a queue waiting for semval to increase or returns with error EAGAIN if (sem_flg & IPC_NOWAIT) is true.@refill @end enumerate - + The array sops is first read in and preliminary checks performed on the arguments. The operations are parsed to determine if any of them needs write permissions or requests an undo operation.@refill -The operations are then tried and the process sleeps if any operation +The operations are then tried and the process sleeps if any operation that does not specify IPC_NOWAIT cannot go through. If a process sleeps -it repeats these checks on waking up. If any operation that requests -IPC_NOWAIT, cannot go through at any stage, the call returns with errno +it repeats these checks on waking up. If any operation that requests +IPC_NOWAIT, cannot go through at any stage, the call returns with errno set to EAGAIN.@refill -Finally, operations are committed when all go through without an intervening +Finally, operations are committed when all go through without an intervening sleep. Processes waiting on the zero_queue or increment_queue are awakened if any of the semval's becomes zero or is incremented respectively.@refill @@ -842,19 +842,19 @@ semid : id obtained by a call to semget. @item cmd : @itemize @asis -@item +@item GETPID return pid for the process that executed the last semop. -@item +@item GETVAL return semval of semaphore with index semnum. -@item +@item GETNCNT return number of processes waiting for semval to increase. -@item +@item GETZCNT return number of processes waiting for semval to become 0 -@item +@item SETVAL set semval = arg.val. -@item -GETALL read all semval's into arg.array. -@item +@item +GETALL read all semval's into arg.array. +@item SETALL set all semval's with values given in arg.array. @end itemize @item @@ -866,17 +866,17 @@ The last two operate on all semaphores in the set.@refill @code{arg} is a union : @example -union semun - int val; value for SETVAL. +union semun + int val; value for SETVAL. struct semid_ds *buf; buffer for IPC_STAT and IPC_SET. - ushort *array; array for GETALL and SETALL + ushort *array; array for GETALL and SETALL @end example @itemize @bullet @item IPC_SET, SETVAL, SETALL : sem_ctime is updated. @item -SETVAL, SETALL : Undo entries are cleared for altered semaphores in +SETVAL, SETALL : Undo entries are cleared for altered semaphores in all processes. Processes sleeping on the wait queues are awakened if a semval becomes 0 or increases.@refill @item @@ -944,10 +944,10 @@ SEMUME maximum number of undo entries per process. -@node Shared Memory, shmget, semlimits, top +@node Shared Memory, shmget, semlimits, Top @section Shared Memory -Shared memory is distinct from the sharing of read-only code pages or +Shared memory is distinct from the sharing of read-only code pages or the sharing of unaltered data pages that is available due to the copy-on-write mechanism. The essential difference is that the shared pages are dirty (in the case of Shared memory) and can be @@ -956,7 +956,7 @@ made to appear at a convenient location in the process' address space.@refill @noindent A shared segment is described by : @example -struct shmid_ds +struct shmid_ds struct ipc_perm shm_perm; int shm_segsz; /* size of segment (bytes) */ time_t shm_atime; /* last attach time */ @@ -970,7 +970,7 @@ struct shmid_ds A shmget allocates a shmid_ds and an internal page table. A shmat maps the segment into the process' address space with pointers -into the internal page table and the actual pages are faulted in +into the internal page table and the actual pages are faulted in as needed. The memory associated with the segment must be explicitly destroyed by calling shmctl with IPC_RMID.@refill @@ -1009,13 +1009,13 @@ IPC_EXCL used with IPC_CREAT to ensure failure if the resource exists. rwxrwxrwx access permissions. @end itemize @item -returns : shmid on success. -1 on failure. +returns : shmid on success. -1 on failure. @end itemize A descriptor for a shared memory segment is allocated if there isn't one -corresponding to the given key. The access permissions specified are +corresponding to the given key. The access permissions specified are then copied into the @code{shm_perm} struct for the segment along with the -user-id etc. The user must use the IPC_CREAT flag or key = IPC_PRIVATE +user-id etc. The user must use the IPC_CREAT flag or key = IPC_PRIVATE to allocate a new segment.@refill If the segment already exists, the access permissions are verified, @@ -1083,8 +1083,8 @@ are encouraged to avoid non-specific attaches. Algorithm: @display Determine attach address as described above. -Check region (shmaddr, shmaddr + size) is not mapped and allocate - page tables (undocumented SHM_REMAP flag!). +Check region (shmaddr, shmaddr + size) is not mapped and allocate +page tables (undocumented SHM_REMAP flag!). Map the region by setting up pointers into the internal page table. Add a descriptor for the attach to the task struct for the process. @code{shm_nattch}, @code{shm_lpid}, @code{shm_atime} are updated. @@ -1094,12 +1094,12 @@ Add a descriptor for the attach to the task struct for the process. Notes:@* The @code{brk} value is not altered. The segment is automatically detached when the process exits. -The same segment may be attached as read-only or read-write and - more than once in the process' address space. +The same segment may be attached as read-only or read-write and +more than once in the process' address space. A shmat can succeed on a segment marked for destruction. The request for a particular type of attach is made using the SHM_RDONLY flag. There is no notion of a write-only attach. The requested attach - permissions must fall within those allowed by @code{shm_perm.mode}. +permissions must fall within those allowed by @code{shm_perm.mode}. @noindent Errors:@* @@ -1211,7 +1211,7 @@ SHMSEG : maximum number of shared segments per process. -@node Notes, top, shmlimits, top +@node Notes, Top, shmlimits, Top @section Miscellaneous Notes The system calls are mapped into one -- @code{sys_ipc}. This should be @@ -1226,10 +1226,10 @@ each semaphore which was altered (with an undo request) by the process. One major cause for unhappiness with the undo mechanism is that it does not fit in with the notion of having an atomic set of operations on an array. The undo requests for an array and each -semaphore therein may have been accumulated over many @code{semop} -calls. Thus use the undo mechanism with private semaphores only.@refill +semaphore therein may have been accumulated over many @code{semop} +calls. Thus use the undo mechanism with private semaphores only.@refill -Should the process sleep in @code{exit} or should all undo +Should the process sleep in @code{exit} or should all undo operations be applied with the IPC_NOWAIT flag in effect? Currently those undo operations which go through immediately are applied and those that require a wait are ignored silently.@refill @@ -1255,21 +1255,21 @@ in the reverse sequence as attaches.@refill Taking control of the matter is probably best. The rule applied is that attaches are allowed in unmapped regions other than -in the text space (see <a.out.h>). Also remember that attach addresses +in the text space (see <a.out.h>). Also remember that attach addresses and segment sizes are multiples of PAGE_SIZE.@refill One more trap (I quote Bruno on this). If you use malloc() to get space -for your shared memory (ie. to fix the @code{brk}), you must ensure you -get an unmapped address range. This means you must mallocate more memory +for your shared memory (ie. to fix the @code{brk}), you must ensure you +get an unmapped address range. This means you must mallocate more memory than you had ever allocated before. Memory returned by malloc(), used, then freed by free() and then again returned by malloc is no good. Neither is calloced memory.@refill Note that a shared memory region remains a shared memory region until -you unmap it. Attaching a segment at the @code{brk} and calling malloc -after that will result in an overlap of what malloc thinks is its -space with what is really a shared memory region. For example in the case -of a read-only attach, you will not be able to write to the overlapped +you unmap it. Attaching a segment at the @code{brk} and calling malloc +after that will result in an overlap of what malloc thinks is its +space with what is really a shared memory region. For example in the case +of a read-only attach, you will not be able to write to the overlapped portion.@refill diff --git a/sys-utils/readprofile.c b/sys-utils/readprofile.c index 117a5307..a0dd3ac7 100644 --- a/sys-utils/readprofile.c +++ b/sys-utils/readprofile.c @@ -25,6 +25,10 @@ * - 64bit clean patch * 3Feb2001 Andrew Morton <andrewm@uow.edu.au> * - -M option to write profile multiplier. + * 2001-11-07 Werner Almesberger <wa@almesberger.net> + * - byte order auto-detection and -n option + * 2001-11-09 Werner Almesberger <wa@almesberger.net> + * - skip step size (index 0) */ #include <errno.h> @@ -46,7 +50,7 @@ static char *prgname; /* These are the defaults */ static char defaultmap[]="/usr/src/linux/System.map"; static char defaultpro[]="/proc/profile"; -static char optstring[]="M:m:p:itvarV"; +static char optstring[]="M:m:np:itvarV"; static void usage(void) { @@ -59,6 +63,7 @@ usage(void) { "\t -v print verbose data\n" "\t -a print all symbols, even if count is 0\n" "\t -r reset all the counters (root only)\n" + "\t -n disable byte order auto-detection\n" "\t -V print version and exit\n") ,prgname,prgname,defaultmap,defaultpro); exit(1); @@ -102,14 +107,14 @@ main (int argc, char **argv) { FILE *map; int proFd; char *mapFile, *proFile, *mult=0; - unsigned long len=0, add0=0, indx=0; + unsigned long len=0, add0=0, indx=1; unsigned int step; unsigned int *buf, total, fn_len; unsigned long fn_add, next_add; /* current and next address */ char fn_name[S_LEN], next_name[S_LEN]; /* current and next name */ char mode[8]; int c; - int optAll=0, optInfo=0, optReset=0, optVerbose=0; + int optAll=0, optInfo=0, optReset=0, optVerbose=0, optNative=0; char mapline[S_LEN]; int maplineno=1; int popenMap; /* flag to tell if popen() has been used */ @@ -127,6 +132,7 @@ main (int argc, char **argv) { while ((c=getopt(argc,argv,optstring))!=-1) { switch(c) { case 'm': mapFile=optarg; break; + case 'n': optNative++; break; case 'p': proFile=optarg; break; case 'a': optAll++; break; case 'i': optInfo++; break; @@ -190,6 +196,31 @@ main (int argc, char **argv) { } close(proFd); + if (!optNative) { + int entries = len/sizeof(*buf); + int big = 0,small = 0,i; + unsigned *p; + + for (p = buf+1; p < buf+entries; p++) + if (*p) { + if (*p >= 1 << (sizeof(*buf)/2)) big++; + else small++; + } + if (big > small) { + fprintf(stderr,"Assuming reversed byte order. " + "Use -n to force native byte order.\n"); + for (p = buf; p < buf+entries; p++) + for (i = 0; i < sizeof(*buf)/2; i++) { + unsigned char *b = (unsigned char *) p; + unsigned char tmp; + + tmp = b[i]; + b[i] = b[sizeof(*buf)-i-1]; + b[sizeof(*buf)-i-1] = tmp; + } + } + } + step=buf[0]; if (optInfo) { printf(_("Sampling_step: %i\n"),step); |