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Aram Hăvărneanu committed 1c75d65

hg diaf

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  • Parent commits 7fc6bc3

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File src/pkg/syscall/exec_solaris.go

-// 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.
-
-package syscall
-
-import (
-	"unsafe"
-)
-
-type SysProcAttr struct {
-	Chroot     string      // Chroot.
-	Credential *Credential // Credential.
-	Setsid     bool        // Create session.
-	Setpgid    bool        // Set process group ID to new pid (SYSV setpgrp)
-	Setctty    bool        // Set controlling terminal to fd 0
-	Noctty     bool        // Detach fd 0 from controlling terminal
-}
-
-// Implemented in runtime package.
-func runtime_BeforeFork()
-func runtime_AfterFork()
-
-func chdir(path uintptr) (err Errno)
-func chroot1(path uintptr) (err Errno)
-func close(fd uintptr) (err Errno)
-func execve(path uintptr, argv uintptr, envp uintptr) (err Errno)
-func exit(code uintptr)
-func fcntl1(fd uintptr, cmd uintptr, arg uintptr) (val uintptr, err Errno)
-func forkx(flags uintptr) (pid uintptr, err Errno)
-func ioctl(fd uintptr, req uintptr, arg uintptr) (err Errno)
-func setgid(gid uintptr) (err Errno)
-func setgroups1(ngid uintptr, gid uintptr) (err Errno)
-func setsid() (pid uintptr, err Errno)
-func setuid(uid uintptr) (err Errno)
-func setpgid(pid uintptr, pgid uintptr) (err Errno)
-func write1(fd uintptr, buf uintptr, nbyte uintptr) (n uintptr, err Errno)
-
-// 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.
-//
-// We call hand-crafted syscalls, implemented in
-// ../runtime/syscall_solaris.goc, rather than generated libc wrappers
-// because we need to avoid lazy-loading the functions (might malloc,
-// split the stack, or acquire mutexes). We can't call RawSyscall
-// because it's not safe even for BSD-subsystem calls.
-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 = forkx(0x1) // FORK_NOSIGCHLD
-	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.
-
-	// Session ID
-	if sys.Setsid {
-		_, err1 = setsid()
-		if err1 != 0 {
-			goto childerror
-		}
-	}
-
-	// Set process group
-	if sys.Setpgid {
-		err1 = setpgid(0, 0)
-		if err1 != 0 {
-			goto childerror
-		}
-	}
-
-	// Chroot
-	if chroot != nil {
-		err1 = chroot1(uintptr(unsafe.Pointer(chroot)))
-		if err1 != 0 {
-			goto childerror
-		}
-	}
-
-	// User and groups
-	if cred := sys.Credential; cred != nil {
-		ngroups := uintptr(len(cred.Groups))
-		groups := uintptr(0)
-		if ngroups > 0 {
-			groups = uintptr(unsafe.Pointer(&cred.Groups[0]))
-		}
-		err1 = setgroups1(ngroups, groups)
-		if err1 != 0 {
-			goto childerror
-		}
-		err1 = setgid(uintptr(cred.Gid))
-		if err1 != 0 {
-			goto childerror
-		}
-		err1 = setuid(uintptr(cred.Uid))
-		if err1 != 0 {
-			goto childerror
-		}
-	}
-
-	// Chdir
-	if dir != nil {
-		err1 = chdir(uintptr(unsafe.Pointer(dir)))
-		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 = fcntl1(uintptr(pipe), F_DUP2FD, uintptr(nextfd))
-		if err1 != 0 {
-			goto childerror
-		}
-		fcntl1(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 = fcntl1(uintptr(fd[i]), F_DUP2FD, uintptr(nextfd))
-			if err1 != 0 {
-				goto childerror
-			}
-			fcntl1(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 {
-			close(uintptr(i))
-			continue
-		}
-		if fd[i] == int(i) {
-			// dup2(i, i) won't clear close-on-exec flag on Linux,
-			// probably not elsewhere either.
-			_, err1 = fcntl1(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 = fcntl1(uintptr(fd[i]), F_DUP2FD, uintptr(i))
-		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++ {
-		close(uintptr(i))
-	}
-
-	// Detach fd 0 from tty
-	if sys.Noctty {
-		err1 = ioctl(0, uintptr(TIOCNOTTY), 0)
-		if err1 != 0 {
-			goto childerror
-		}
-	}
-
-	// Make fd 0 the tty
-	if sys.Setctty {
-		err1 = ioctl(0, uintptr(TIOCSCTTY), 0)
-		if err1 != 0 {
-			goto childerror
-		}
-	}
-
-	// Time to exec.
-	err1 = execve(
-		uintptr(unsafe.Pointer(argv0)),
-		uintptr(unsafe.Pointer(&argv[0])),
-		uintptr(unsafe.Pointer(&envv[0])))
-
-childerror:
-	// send error code on pipe
-	write1(uintptr(pipe), uintptr(unsafe.Pointer(&err1)), unsafe.Sizeof(err1))
-	for {
-		exit(253)
-	}
-}
-
-// Try to open a pipe with O_CLOEXEC set on both file descriptors.
-func forkExecPipe(p []int) error {
-	err := Pipe(p)
-	if err != nil {
-		return err
-	}
-	_, err = fcntl(p[0], F_SETFD, FD_CLOEXEC)
-	if err != nil {
-		return err
-	}
-	_, err = fcntl(p[1], F_SETFD, FD_CLOEXEC)
-	return err
-}