From 49be65eeba37a3d29a8a33379794e7a84df6cca1 Mon Sep 17 00:00:00 2001 From: Clément Chigot Date: Fri, 28 Sep 2018 15:24:32 +0200 Subject: syscall: change solaris files to libc files AIX and Solaris both requires libc to make any syscalls and their implementation is really similar. Therefore, Solaris files reused by AIX have their name changed to *_libc. exec_libc.go is also adapted to AIX. Updates: #25893 Change-Id: I50d1d7b964831637013d5e64799187cd9565c42b Reviewed-on: https://go-review.googlesource.com/c/138719 Run-TryBot: Ian Lance Taylor TryBot-Result: Gobot Gobot Reviewed-by: Ian Lance Taylor --- src/syscall/exec_libc.go | 276 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 276 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 0000000000..d6d34c04c3 --- /dev/null +++ b/src/syscall/exec_libc.go @@ -0,0 +1,276 @@ +// 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 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 bool // Set process group ID to Pgid, or, if Pgid == 0, to new pid. + Setctty bool // Set controlling terminal to fd Ctty + Noctty bool // Detach fd 0 from controlling terminal + Ctty int // Controlling TTY fd + Foreground bool // Place child's process group in foreground. (Implies Setpgid. Uses Ctty as fd of controlling TTY) + 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. + + runtime_AfterForkInChild() + + // 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 := sys.Pgid + if pgrp == 0 { + r1, err1 = getpid() + if err1 != 0 { + goto childerror + } + + pgrp = int(r1) + } + + // Place process group in foreground. + err1 = ioctl(uintptr(sys.Ctty), uintptr(TIOCSPGRP), uintptr(unsafe.Pointer(&pgrp))) + 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])) + } + 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 v1.3