From 82539ad8d59729fb45b0bb0edda8f2bddb719eb1 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 28 Apr 2024 15:15:26 +0200 Subject: Adding upstream version 1.17.13. Signed-off-by: Daniel Baumann --- src/syscall/exec_libc.go | 290 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 290 insertions(+) create mode 100644 src/syscall/exec_libc.go (limited to 'src/syscall/exec_libc.go') diff --git a/src/syscall/exec_libc.go b/src/syscall/exec_libc.go new file mode 100644 index 0000000..8a84954 --- /dev/null +++ b/src/syscall/exec_libc.go @@ -0,0 +1,290 @@ +// 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. + +//go:build aix || solaris +// +build aix solaris + +// This file handles forkAndExecInChild function for OS using libc syscall like AIX or Solaris. + +package syscall + +import ( + "unsafe" +) + +type SysProcAttr struct { + Chroot string // Chroot. + Credential *Credential // Credential. + Setsid bool // Create session. + // Setpgid sets the process group ID of the child to Pgid, + // or, if Pgid == 0, to the new child's process ID. + Setpgid bool + // Setctty sets the controlling terminal of the child to + // file descriptor Ctty. Ctty must be a descriptor number + // in the child process: an index into ProcAttr.Files. + // This is only meaningful if Setsid is true. + Setctty bool + Noctty bool // Detach fd 0 from controlling terminal + Ctty int // Controlling TTY fd + // Foreground places the child process group in the foreground. + // This implies Setpgid. The Ctty field must be set to + // the descriptor of the controlling TTY. + // Unlike Setctty, in this case Ctty must be a descriptor + // number in the parent process. + Foreground bool + Pgid int // Child's process group ID if Setpgid. +} + +// Implemented in runtime package. +func runtime_BeforeFork() +func runtime_AfterFork() +func runtime_AfterForkInChild() + +func chdir(path uintptr) (err Errno) +func chroot1(path uintptr) (err Errno) +func close(fd uintptr) (err Errno) +func dup2child(old uintptr, new uintptr) (val 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 getpid() (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) + +// syscall defines this global on our behalf to avoid a build dependency on other platforms +func init() { + execveLibc = execve +} + +// 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.go, 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. +//go:norace +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 || sys.Foreground { + // Place child in process group. + err1 = setpgid(0, uintptr(sys.Pgid)) + if err1 != 0 { + goto childerror + } + } + + if sys.Foreground { + pgrp := _Pid_t(sys.Pgid) + if pgrp == 0 { + r1, err1 = getpid() + if err1 != 0 { + goto childerror + } + + pgrp = _Pid_t(r1) + } + + // Place process group in foreground. + err1 = ioctl(uintptr(sys.Ctty), uintptr(TIOCSPGRP), uintptr(unsafe.Pointer(&pgrp))) + if err1 != 0 { + goto childerror + } + } + + // Restore the signal mask. We do this after TIOCSPGRP to avoid + // having the kernel send a SIGTTOU signal to the process group. + runtime_AfterForkInChild() + + // 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])) + } + if !cred.NoSetGroups { + 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 = dup2child(uintptr(pipe), 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) { + if nextfd == pipe { // don't stomp on pipe + nextfd++ + } + _, err1 = dup2child(uintptr(fd[i]), uintptr(nextfd)) + if err1 != 0 { + goto childerror + } + _, err1 = fcntl1(uintptr(nextfd), F_SETFD, FD_CLOEXEC) + if err1 != 0 { + goto childerror + } + fd[i] = nextfd + 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 = dup2child(uintptr(fd[i]), 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 + } + } + + // Set the controlling TTY to Ctty + if sys.Setctty { + // On AIX, TIOCSCTTY is undefined + if TIOCSCTTY == 0 { + err1 = ENOSYS + goto childerror + } + err1 = ioctl(uintptr(sys.Ctty), 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) + } +} -- cgit v1.2.3