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posix: Remove spawni.c
Although it provide an alternate implementation that communicates using pipe() instead of shared memory, no port uses and it adds extra burden for posix_spawn() extensions. Reviewed-by: Florian Weimer <fweimer@redhat.com>
This commit is contained in:
Adhemerval Zanella
parent
b0a33dc967
commit
8f42a98654
@ -1,343 +0,0 @@
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/* Guts of POSIX spawn interface. Generic POSIX.1 version.
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Copyright (C) 2000-2021 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <spawn.h>
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#include <assert.h>
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#include <fcntl.h>
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#include <paths.h>
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#include <string.h>
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#include <sys/resource.h>
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#include <sys/wait.h>
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#include <sys/param.h>
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#include <sys/mman.h>
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#include <not-cancel.h>
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#include <local-setxid.h>
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#include <shlib-compat.h>
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#include <pthreadP.h>
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#include <dl-sysdep.h>
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#include <libc-pointer-arith.h>
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#include <ldsodefs.h>
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#include "spawn_int.h"
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/* The Unix standard contains a long explanation of the way to signal
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an error after the fork() was successful. Since no new wait status
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was wanted there is no way to signal an error using one of the
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available methods. The committee chose to signal an error by a
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normal program exit with the exit code 127. */
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#define SPAWN_ERROR 127
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struct posix_spawn_args
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{
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sigset_t oldmask;
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const char *file;
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int (*exec) (const char *, char *const *, char *const *);
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const posix_spawn_file_actions_t *fa;
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const posix_spawnattr_t *restrict attr;
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char *const *argv;
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ptrdiff_t argc;
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char *const *envp;
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int xflags;
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int pipe[2];
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};
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/* Older version requires that shell script without shebang definition
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to be called explicitly using /bin/sh (_PATH_BSHELL). */
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static void
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maybe_script_execute (struct posix_spawn_args *args)
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{
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if (SHLIB_COMPAT (libc, GLIBC_2_2, GLIBC_2_15)
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&& (args->xflags & SPAWN_XFLAGS_TRY_SHELL) && errno == ENOEXEC)
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{
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char *const *argv = args->argv;
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ptrdiff_t argc = args->argc;
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/* Construct an argument list for the shell. */
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char *new_argv[argc + 2];
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new_argv[0] = (char *) _PATH_BSHELL;
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new_argv[1] = (char *) args->file;
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if (argc > 1)
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memcpy (new_argv + 2, argv + 1, argc * sizeof (char *));
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else
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new_argv[2] = NULL;
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/* Execute the shell. */
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args->exec (new_argv[0], new_argv, args->envp);
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}
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}
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/* Function used in the clone call to setup the signals mask, posix_spawn
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attributes, and file actions. */
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static int
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__spawni_child (void *arguments)
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{
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struct posix_spawn_args *args = arguments;
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const posix_spawnattr_t *restrict attr = args->attr;
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const posix_spawn_file_actions_t *file_actions = args->fa;
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int ret;
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__close (args->pipe[0]);
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/* Set signal default action. */
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if ((attr->__flags & POSIX_SPAWN_SETSIGDEF) != 0)
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{
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/* We have to iterate over all signals. This could possibly be
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done better but it requires system specific solutions since
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the sigset_t data type can be very different on different
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architectures. */
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int sig;
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struct sigaction sa;
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memset (&sa, '\0', sizeof (sa));
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sa.sa_handler = SIG_DFL;
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for (sig = 1; sig <= _NSIG; ++sig)
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if (__sigismember (&attr->__sd, sig) != 0
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&& __sigaction (sig, &sa, NULL) != 0)
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goto fail;
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}
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#ifdef _POSIX_PRIORITY_SCHEDULING
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/* Set the scheduling algorithm and parameters. */
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if ((attr->__flags & (POSIX_SPAWN_SETSCHEDPARAM | POSIX_SPAWN_SETSCHEDULER))
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== POSIX_SPAWN_SETSCHEDPARAM)
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{
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if (__sched_setparam (0, &attr->__sp) == -1)
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goto fail;
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}
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else if ((attr->__flags & POSIX_SPAWN_SETSCHEDULER) != 0)
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{
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if (__sched_setscheduler (0, attr->__policy, &attr->__sp) == -1)
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goto fail;
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}
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#endif
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/* Set the process session ID. */
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if ((attr->__flags & POSIX_SPAWN_SETSID) != 0
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&& __setsid () < 0)
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goto fail;
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/* Set the process group ID. */
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if ((attr->__flags & POSIX_SPAWN_SETPGROUP) != 0
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&& __setpgid (0, attr->__pgrp) != 0)
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goto fail;
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/* Set the effective user and group IDs. */
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if ((attr->__flags & POSIX_SPAWN_RESETIDS) != 0
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&& (local_seteuid (__getuid ()) != 0
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|| local_setegid (__getgid ())) != 0)
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goto fail;
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/* Execute the file actions. */
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if (file_actions != NULL)
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{
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int cnt;
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struct rlimit64 fdlimit;
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bool have_fdlimit = false;
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for (cnt = 0; cnt < file_actions->__used; ++cnt)
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{
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struct __spawn_action *action = &file_actions->__actions[cnt];
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switch (action->tag)
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{
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case spawn_do_close:
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if (__close_nocancel (action->action.close_action.fd) != 0)
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{
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if (have_fdlimit == 0)
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{
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__getrlimit64 (RLIMIT_NOFILE, &fdlimit);
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have_fdlimit = true;
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}
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/* Only signal errors for file descriptors out of range. */
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if (action->action.close_action.fd < 0
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|| action->action.close_action.fd >= fdlimit.rlim_cur)
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goto fail;
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}
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break;
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case spawn_do_open:
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{
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/* POSIX states that if fildes was already an open file descriptor,
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it shall be closed before the new file is opened. This avoid
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pontential issues when posix_spawn plus addopen action is called
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with the process already at maximum number of file descriptor
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opened and also for multiple actions on single-open special
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paths (like /dev/watchdog). */
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__close_nocancel (action->action.open_action.fd);
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int new_fd = __open_nocancel (action->action.open_action.path,
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action->action.open_action.oflag
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| O_LARGEFILE,
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action->action.open_action.mode);
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if (new_fd == -1)
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goto fail;
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/* Make sure the desired file descriptor is used. */
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if (new_fd != action->action.open_action.fd)
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{
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if (__dup2 (new_fd, action->action.open_action.fd)
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!= action->action.open_action.fd)
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goto fail;
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if (__close_nocancel (new_fd) != 0)
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goto fail;
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}
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}
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break;
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case spawn_do_dup2:
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/* Austin Group issue #411 requires adddup2 action with source
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and destination being equal to remove close-on-exec flag. */
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if (action->action.dup2_action.fd
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== action->action.dup2_action.newfd)
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{
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int fd = action->action.dup2_action.newfd;
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int flags = __fcntl (fd, F_GETFD, 0);
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if (flags == -1)
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goto fail;
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if (__fcntl (fd, F_SETFD, flags & ~FD_CLOEXEC) == -1)
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goto fail;
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}
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else if (__dup2 (action->action.dup2_action.fd,
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action->action.dup2_action.newfd)
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!= action->action.dup2_action.newfd)
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goto fail;
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break;
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case spawn_do_chdir:
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if (__chdir (action->action.chdir_action.path) != 0)
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goto fail;
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break;
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case spawn_do_fchdir:
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if (__fchdir (action->action.fchdir_action.fd) != 0)
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goto fail;
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break;
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case spawn_do_closefrom:
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__set_errno (EINVAL);
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goto fail;
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}
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}
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}
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/* Set the initial signal mask of the child if POSIX_SPAWN_SETSIGMASK
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is set, otherwise restore the previous one. */
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__sigprocmask (SIG_SETMASK, (attr->__flags & POSIX_SPAWN_SETSIGMASK)
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? &attr->__ss : &args->oldmask, 0);
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args->exec (args->file, args->argv, args->envp);
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/* This is compatibility function required to enable posix_spawn run
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script without shebang definition for older posix_spawn versions
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(2.15). */
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maybe_script_execute (args);
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fail:
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/* errno should have an appropriate non-zero value; otherwise,
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there's a bug in glibc or the kernel. For lack of an error code
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(EINTERNALBUG) describing that, use ECHILD. Another option would
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be to set args->err to some negative sentinel and have the parent
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abort(), but that seems needlessly harsh. */
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ret = errno ? : ECHILD;
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if (ret)
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/* Since sizeof errno < PIPE_BUF, the write is atomic. */
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while (__write_nocancel (args->pipe[1], &ret, sizeof (ret)) < 0);
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_exit (SPAWN_ERROR);
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}
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/* Spawn a new process executing PATH with the attributes describes in *ATTRP.
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Before running the process perform the actions described in FILE-ACTIONS. */
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int
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__spawnix (pid_t *pid, const char *file,
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const posix_spawn_file_actions_t *file_actions,
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const posix_spawnattr_t *attrp, char *const argv[],
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char *const envp[], int xflags,
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int (*exec) (const char *, char *const *, char *const *))
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{
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struct posix_spawn_args args;
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int ec;
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if (__pipe2 (args.pipe, O_CLOEXEC))
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return errno;
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/* Disable asynchronous cancellation. */
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int state;
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__libc_ptf_call (__pthread_setcancelstate,
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(PTHREAD_CANCEL_DISABLE, &state), 0);
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ptrdiff_t argc = 0;
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ptrdiff_t limit = INT_MAX - 1;
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while (argv[argc++] != NULL)
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if (argc == limit)
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{
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errno = E2BIG;
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return errno;
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}
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args.file = file;
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args.exec = exec;
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args.fa = file_actions;
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args.attr = attrp ? attrp : &(const posix_spawnattr_t) { 0 };
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args.argv = argv;
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args.argc = argc;
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args.envp = envp;
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args.xflags = xflags;
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/* Generate the new process. */
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pid_t new_pid = __fork ();
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if (new_pid == 0)
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__spawni_child (&args);
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else if (new_pid > 0)
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{
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__close (args.pipe[1]);
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if (__read (args.pipe[0], &ec, sizeof ec) != sizeof ec)
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ec = 0;
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else
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__waitpid (new_pid, &(int) { 0 }, 0);
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}
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else
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ec = errno;
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__close (args.pipe[0]);
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if ((ec == 0) && (pid != NULL))
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*pid = new_pid;
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__libc_ptf_call (__pthread_setcancelstate, (state, NULL), 0);
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return ec;
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}
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int
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__spawni (pid_t * pid, const char *file,
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const posix_spawn_file_actions_t * acts,
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const posix_spawnattr_t * attrp, char *const argv[],
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char *const envp[], int xflags)
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{
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/* It uses __execvpex to avoid run ENOEXEC in non compatibility mode (it
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will be handled by maybe_script_execute). */
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return __spawnix (pid, file, acts, attrp, argv, envp, xflags,
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xflags & SPAWN_XFLAGS_USE_PATH ? __execvpex : __execve);
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}
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