diff options
Diffstat (limited to 'src/pkg/syscall/exec_linux.go')
-rw-r--r-- | src/pkg/syscall/exec_linux.go | 262 |
1 files changed, 0 insertions, 262 deletions
diff --git a/src/pkg/syscall/exec_linux.go b/src/pkg/syscall/exec_linux.go deleted file mode 100644 index f27950f73..000000000 --- a/src/pkg/syscall/exec_linux.go +++ /dev/null @@ -1,262 +0,0 @@ -// Copyright 2011 The Go Authors. All rights reserved. -// Use of this source code is governed by a BSD-style -// license that can be found in the LICENSE file. - -// +build linux - -package syscall - -import ( - "unsafe" -) - -type SysProcAttr struct { - Chroot string // Chroot. - Credential *Credential // Credential. - Ptrace bool // Enable tracing. - Setsid bool // Create session. - Setpgid bool // Set process group ID to new pid (SYSV setpgrp) - Setctty bool // Set controlling terminal to fd Ctty (only meaningful if Setsid is set) - Noctty bool // Detach fd 0 from controlling terminal - Ctty int // Controlling TTY fd (Linux only) - Pdeathsig Signal // Signal that the process will get when its parent dies (Linux only) - Cloneflags uintptr // Flags for clone calls (Linux only) -} - -// Implemented in runtime package. -func runtime_BeforeFork() -func runtime_AfterFork() - -// Fork, dup fd onto 0..len(fd), and exec(argv0, argvv, envv) in child. -// If a dup or exec fails, write the errno error to pipe. -// (Pipe is close-on-exec so if exec succeeds, it will be closed.) -// In the child, this function must not acquire any locks, because -// they might have been locked at the time of the fork. This means -// no rescheduling, no malloc calls, and no new stack segments. -// For the same reason compiler does not race instrument it. -// The calls to RawSyscall are okay because they are assembly -// functions that do not grow the stack. -func forkAndExecInChild(argv0 *byte, argv, envv []*byte, chroot, dir *byte, attr *ProcAttr, sys *SysProcAttr, pipe int) (pid int, err Errno) { - // Declare all variables at top in case any - // declarations require heap allocation (e.g., err1). - var ( - r1 uintptr - err1 Errno - nextfd int - i int - ) - - // Guard against side effects of shuffling fds below. - // Make sure that nextfd is beyond any currently open files so - // that we can't run the risk of overwriting any of them. - fd := make([]int, len(attr.Files)) - nextfd = len(attr.Files) - for i, ufd := range attr.Files { - if nextfd < int(ufd) { - nextfd = int(ufd) - } - fd[i] = int(ufd) - } - nextfd++ - - // About to call fork. - // No more allocation or calls of non-assembly functions. - runtime_BeforeFork() - r1, _, err1 = RawSyscall6(SYS_CLONE, uintptr(SIGCHLD)|sys.Cloneflags, 0, 0, 0, 0, 0) - if err1 != 0 { - runtime_AfterFork() - return 0, err1 - } - - if r1 != 0 { - // parent; return PID - runtime_AfterFork() - return int(r1), 0 - } - - // Fork succeeded, now in child. - - // Parent death signal - if sys.Pdeathsig != 0 { - _, _, err1 = RawSyscall6(SYS_PRCTL, PR_SET_PDEATHSIG, uintptr(sys.Pdeathsig), 0, 0, 0, 0) - if err1 != 0 { - goto childerror - } - - // Signal self if parent is already dead. This might cause a - // duplicate signal in rare cases, but it won't matter when - // using SIGKILL. - r1, _, _ = RawSyscall(SYS_GETPPID, 0, 0, 0) - if r1 == 1 { - pid, _, _ := RawSyscall(SYS_GETPID, 0, 0, 0) - _, _, err1 := RawSyscall(SYS_KILL, pid, uintptr(sys.Pdeathsig), 0) - if err1 != 0 { - goto childerror - } - } - } - - // Enable tracing if requested. - if sys.Ptrace { - _, _, err1 = RawSyscall(SYS_PTRACE, uintptr(PTRACE_TRACEME), 0, 0) - if err1 != 0 { - goto childerror - } - } - - // Session ID - if sys.Setsid { - _, _, err1 = RawSyscall(SYS_SETSID, 0, 0, 0) - if err1 != 0 { - goto childerror - } - } - - // Set process group - if sys.Setpgid { - _, _, err1 = RawSyscall(SYS_SETPGID, 0, 0, 0) - if err1 != 0 { - goto childerror - } - } - - // Chroot - if chroot != nil { - _, _, err1 = RawSyscall(SYS_CHROOT, uintptr(unsafe.Pointer(chroot)), 0, 0) - if err1 != 0 { - goto childerror - } - } - - // User and groups - if cred := sys.Credential; cred != nil { - ngroups := uintptr(len(cred.Groups)) - var groups unsafe.Pointer - if ngroups > 0 { - groups = unsafe.Pointer(&cred.Groups[0]) - } - _, _, err1 = RawSyscall(SYS_SETGROUPS, ngroups, uintptr(groups), 0) - if err1 != 0 { - goto childerror - } - _, _, err1 = RawSyscall(SYS_SETGID, uintptr(cred.Gid), 0, 0) - if err1 != 0 { - goto childerror - } - _, _, err1 = RawSyscall(SYS_SETUID, uintptr(cred.Uid), 0, 0) - if err1 != 0 { - goto childerror - } - } - - // Chdir - if dir != nil { - _, _, err1 = RawSyscall(SYS_CHDIR, uintptr(unsafe.Pointer(dir)), 0, 0) - if err1 != 0 { - goto childerror - } - } - - // Pass 1: look for fd[i] < i and move those up above len(fd) - // so that pass 2 won't stomp on an fd it needs later. - if pipe < nextfd { - _, _, err1 = RawSyscall(SYS_DUP2, uintptr(pipe), uintptr(nextfd), 0) - if err1 != 0 { - goto childerror - } - RawSyscall(SYS_FCNTL, uintptr(nextfd), F_SETFD, FD_CLOEXEC) - pipe = nextfd - nextfd++ - } - for i = 0; i < len(fd); i++ { - if fd[i] >= 0 && fd[i] < int(i) { - _, _, err1 = RawSyscall(SYS_DUP2, uintptr(fd[i]), uintptr(nextfd), 0) - if err1 != 0 { - goto childerror - } - RawSyscall(SYS_FCNTL, uintptr(nextfd), F_SETFD, FD_CLOEXEC) - fd[i] = nextfd - nextfd++ - if nextfd == pipe { // don't stomp on pipe - nextfd++ - } - } - } - - // Pass 2: dup fd[i] down onto i. - for i = 0; i < len(fd); i++ { - if fd[i] == -1 { - RawSyscall(SYS_CLOSE, uintptr(i), 0, 0) - continue - } - if fd[i] == int(i) { - // dup2(i, i) won't clear close-on-exec flag on Linux, - // probably not elsewhere either. - _, _, err1 = RawSyscall(SYS_FCNTL, uintptr(fd[i]), F_SETFD, 0) - if err1 != 0 { - goto childerror - } - continue - } - // The new fd is created NOT close-on-exec, - // which is exactly what we want. - _, _, err1 = RawSyscall(SYS_DUP2, uintptr(fd[i]), uintptr(i), 0) - if err1 != 0 { - goto childerror - } - } - - // By convention, we don't close-on-exec the fds we are - // started with, so if len(fd) < 3, close 0, 1, 2 as needed. - // Programs that know they inherit fds >= 3 will need - // to set them close-on-exec. - for i = len(fd); i < 3; i++ { - RawSyscall(SYS_CLOSE, uintptr(i), 0, 0) - } - - // Detach fd 0 from tty - if sys.Noctty { - _, _, err1 = RawSyscall(SYS_IOCTL, 0, uintptr(TIOCNOTTY), 0) - if err1 != 0 { - goto childerror - } - } - - // Set the controlling TTY to Ctty - if sys.Setctty && sys.Ctty >= 0 { - _, _, err1 = RawSyscall(SYS_IOCTL, uintptr(sys.Ctty), uintptr(TIOCSCTTY), 0) - if err1 != 0 { - goto childerror - } - } - - // Time to exec. - _, _, err1 = RawSyscall(SYS_EXECVE, - uintptr(unsafe.Pointer(argv0)), - uintptr(unsafe.Pointer(&argv[0])), - uintptr(unsafe.Pointer(&envv[0]))) - -childerror: - // send error code on pipe - RawSyscall(SYS_WRITE, uintptr(pipe), uintptr(unsafe.Pointer(&err1)), unsafe.Sizeof(err1)) - for { - RawSyscall(SYS_EXIT, 253, 0, 0) - } -} - -// Try to open a pipe with O_CLOEXEC set on both file descriptors. -func forkExecPipe(p []int) (err error) { - err = Pipe2(p, O_CLOEXEC) - // pipe2 was added in 2.6.27 and our minimum requirement is 2.6.23, so it - // might not be implemented. - if err == ENOSYS { - if err = Pipe(p); err != nil { - return - } - if _, err = fcntl(p[0], F_SETFD, FD_CLOEXEC); err != nil { - return - } - _, err = fcntl(p[1], F_SETFD, FD_CLOEXEC) - } - return -} |