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314 lines
8.7 KiB
C
314 lines
8.7 KiB
C
/* Guts of POSIX spawn interface. Generic POSIX.1 version.
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Copyright (C) 2000-2005, 2006, 2011, 2012 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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<http://www.gnu.org/licenses/>. */
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#include <errno.h>
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#include <fcntl.h>
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#include <paths.h>
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#include <spawn.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <signal.h>
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#include <sys/resource.h>
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#include "spawn_int.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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/* 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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/* The file is accessible but it is not an executable file. Invoke
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the shell to interpret it as a script. */
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static void
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internal_function
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script_execute (const char *file, char *const argv[], char *const envp[])
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{
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/* Count the arguments. */
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int argc = 0;
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while (argv[argc++])
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;
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/* Construct an argument list for the shell. */
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{
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char *new_argv[argc + 1];
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new_argv[0] = (char *) _PATH_BSHELL;
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new_argv[1] = (char *) file;
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while (argc > 1)
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{
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new_argv[argc] = argv[argc - 1];
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--argc;
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}
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/* Execute the shell. */
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__execve (new_argv[0], new_argv, envp);
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}
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}
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static inline void
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maybe_script_execute (const char *file, char *const argv[], char *const envp[],
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int xflags)
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{
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if (SHLIB_COMPAT (libc, GLIBC_2_2, GLIBC_2_15)
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&& (xflags & SPAWN_XFLAGS_TRY_SHELL)
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&& errno == ENOEXEC)
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script_execute (file, argv, envp);
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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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__spawni (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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{
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pid_t new_pid;
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char *path, *p, *name;
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size_t len;
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size_t pathlen;
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/* Do this once. */
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short int flags = attrp == NULL ? 0 : attrp->__flags;
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/* Generate the new process. */
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if ((flags & POSIX_SPAWN_USEVFORK) != 0
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/* If no major work is done, allow using vfork. Note that we
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might perform the path searching. But this would be done by
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a call to execvp(), too, and such a call must be OK according
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to POSIX. */
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|| ((flags & (POSIX_SPAWN_SETSIGMASK | POSIX_SPAWN_SETSIGDEF
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| POSIX_SPAWN_SETSCHEDPARAM | POSIX_SPAWN_SETSCHEDULER
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| POSIX_SPAWN_SETPGROUP | POSIX_SPAWN_RESETIDS)) == 0
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&& file_actions == NULL))
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new_pid = __vfork ();
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else
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new_pid = __fork ();
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if (new_pid != 0)
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{
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if (new_pid < 0)
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return errno;
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/* The call was successful. Store the PID if necessary. */
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if (pid != NULL)
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*pid = new_pid;
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return 0;
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}
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/* Set signal mask. */
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if ((flags & POSIX_SPAWN_SETSIGMASK) != 0
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&& __sigprocmask (SIG_SETMASK, &attrp->__ss, NULL) != 0)
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_exit (SPAWN_ERROR);
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/* Set signal default action. */
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if ((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 (&attrp->__sd, sig) != 0
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&& __sigaction (sig, &sa, NULL) != 0)
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_exit (SPAWN_ERROR);
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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 ((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, &attrp->__sp) == -1)
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_exit (SPAWN_ERROR);
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}
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else if ((flags & POSIX_SPAWN_SETSCHEDULER) != 0)
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{
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if (__sched_setscheduler (0, attrp->__policy, &attrp->__sp) == -1)
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_exit (SPAWN_ERROR);
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}
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#endif
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/* Set the process group ID. */
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if ((flags & POSIX_SPAWN_SETPGROUP) != 0
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&& __setpgid (0, attrp->__pgrp) != 0)
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_exit (SPAWN_ERROR);
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/* Set the effective user and group IDs. */
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if ((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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_exit (SPAWN_ERROR);
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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_not_cancel (action->action.close_action.fd) != 0)
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{
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if (! have_fdlimit)
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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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/* Signal the error. */
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_exit (SPAWN_ERROR);
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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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int new_fd = open_not_cancel (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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/* The `open' call failed. */
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_exit (SPAWN_ERROR);
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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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/* The `dup2' call failed. */
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_exit (SPAWN_ERROR);
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if (close_not_cancel (new_fd) != 0)
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/* The `close' call failed. */
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_exit (SPAWN_ERROR);
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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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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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/* The `dup2' call failed. */
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_exit (SPAWN_ERROR);
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break;
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}
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}
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}
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if ((xflags & SPAWN_XFLAGS_USE_PATH) == 0 || strchr (file, '/') != NULL)
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{
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/* The FILE parameter is actually a path. */
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__execve (file, argv, envp);
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maybe_script_execute (file, argv, envp, xflags);
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/* Oh, oh. `execve' returns. This is bad. */
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_exit (SPAWN_ERROR);
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}
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/* We have to search for FILE on the path. */
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path = getenv ("PATH");
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if (path == NULL)
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{
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/* There is no `PATH' in the environment.
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The default search path is the current directory
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followed by the path `confstr' returns for `_CS_PATH'. */
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len = confstr (_CS_PATH, (char *) NULL, 0);
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path = (char *) __alloca (1 + len);
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path[0] = ':';
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(void) confstr (_CS_PATH, path + 1, len);
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}
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len = strlen (file) + 1;
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pathlen = strlen (path);
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name = __alloca (pathlen + len + 1);
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/* Copy the file name at the top. */
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name = (char *) memcpy (name + pathlen + 1, file, len);
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/* And add the slash. */
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*--name = '/';
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p = path;
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do
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{
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char *startp;
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path = p;
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p = __strchrnul (path, ':');
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if (p == path)
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/* Two adjacent colons, or a colon at the beginning or the end
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of `PATH' means to search the current directory. */
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startp = name + 1;
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else
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startp = (char *) memcpy (name - (p - path), path, p - path);
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/* Try to execute this name. If it works, execv will not return. */
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__execve (startp, argv, envp);
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maybe_script_execute (startp, argv, envp, xflags);
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switch (errno)
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{
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case EACCES:
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case ENOENT:
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case ESTALE:
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case ENOTDIR:
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/* Those errors indicate the file is missing or not executable
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by us, in which case we want to just try the next path
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directory. */
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break;
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default:
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/* Some other error means we found an executable file, but
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something went wrong executing it; return the error to our
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caller. */
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_exit (SPAWN_ERROR);
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}
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}
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while (*p++ != '\0');
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/* Return with an error. */
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_exit (SPAWN_ERROR);
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}
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