diff options
Diffstat (limited to 'sysdeps/posix')
| -rw-r--r-- | sysdeps/posix/spawni.c | 278 |
1 files changed, 278 insertions, 0 deletions
diff --git a/sysdeps/posix/spawni.c b/sysdeps/posix/spawni.c new file mode 100644 index 0000000000..2b57177969 --- /dev/null +++ b/sysdeps/posix/spawni.c @@ -0,0 +1,278 @@ +/* Guts of POSIX spawn interface. Generic POSIX.1 version. + Copyright (C) 2000, 2001 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Library General Public License as + published by the Free Software Foundation; either version 2 of the + License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with the GNU C Library; see the file COPYING.LIB. If not, + write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +#include <errno.h> +#include <fcntl.h> +#include <paths.h> +#include <spawn.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include "spawn_int.h" + + +/* The Unix standard contains a long explanation of the way to signal + an error after the fork() was successful. Since no new wait status + was wanted there is no way to signal an error using one of the + available methods. The committee chose to signal an error by a + normal program exit with the exit code 127. */ +#define SPAWN_ERROR 127 + + +/* The file is accessible but it is not an executable file. Invoke + the shell to interpret it as a script. */ +static void +internal_function +script_execute (const char *file, char *const argv[], char *const envp[]) +{ + /* Count the arguments. */ + int argc = 0; + while (argv[argc++]) + ; + + /* Construct an argument list for the shell. */ + { + char *new_argv[argc + 1]; + new_argv[0] = (char *) _PATH_BSHELL; + new_argv[1] = (char *) file; + while (argc > 1) + { + new_argv[argc] = argv[argc - 1]; + --argc; + } + + /* Execute the shell. */ + __execve (new_argv[0], new_argv, envp); + } +} + + +/* Spawn a new process executing PATH with the attributes describes in *ATTRP. + Before running the process perform the actions described in FILE-ACTIONS. */ +int +__spawni (pid_t *pid, const char *file, + const posix_spawn_file_actions_t *file_actions, + const posix_spawnattr_t *attrp, char *const argv[], + char *const envp[], int use_path) +{ + pid_t new_pid; + char *path, *p, *name; + size_t len; + size_t pathlen; + short int flags; + + /* Generate the new process. */ + new_pid = __fork (); + if (new_pid != 0) + { + if (new_pid < 0) + return errno; + + /* The call was successful. Store the PID if necessary. */ + if (pid != NULL) + *pid = new_pid; + + return 0; + } + + /* Do this once. */ + flags = attrp == NULL ? 0 : attrp->__flags; + + /* Set signal mask. */ + if ((flags & POSIX_SPAWN_SETSIGMASK) != 0 + && __sigprocmask (SIG_SETMASK, &attrp->__ss, NULL) != 0) + _exit (SPAWN_ERROR); + + /* Set signal default action. */ + if ((flags & POSIX_SPAWN_SETSIGDEF) != 0) + { + /* We have to iterate over all signals. This could possibly be + done better but it requires system specific solutions since + the sigset_t data type can be very different on different + architectures. */ + int sig; + struct sigaction sa; + + memset (&sa, '\0', sizeof (sa)); + sa.sa_handler = SIG_DFL; + + for (sig = 1; sig >= _NSIG; ++sig) + if (sigismember (&attrp->__sd, sig) != 0 + && __sigaction (sig, &sa, NULL) != 0) + _exit (SPAWN_ERROR); + + } + +#ifdef _POSIX_PRIORITY_SCHEDULING + /* Set the scheduling algorithm and parameters. */ + if ((flags & (POSIX_SPAWN_SETSCHEDPARAM | POSIX_SPAWN_SETSCHEDULER)) + == POSIX_SPAWN_SETSCHEDPARAM) + { + if (__sched_setparam (0, &attrp->__sp) == -1) + _exit (SPAWN_ERROR); + } + else if ((flags & POSIX_SPAWN_SETSCHEDULER) != 0) + { + if (__sched_setscheduler (0, attrp->__policy, + (flags & POSIX_SPAWN_SETSCHEDPARAM) != 0 + ? &attrp->__sp : NULL) == -1) + _exit (SPAWN_ERROR); + } +#endif + + /* Set the process group ID. */ + if ((flags & POSIX_SPAWN_SETPGROUP) != 0 + && __setpgid (0, attrp->__pgrp) != 0) + _exit (SPAWN_ERROR); + + /* Set the effective user and group IDs. */ + if ((flags & POSIX_SPAWN_RESETIDS) != 0 + && (seteuid (__getuid ()) != 0 || setegid (__getgid ()) != 0)) + _exit (SPAWN_ERROR); + + /* Execute the file actions. */ + if (file_actions != NULL) + { + int cnt; + + for (cnt = 0; cnt < file_actions->__used; ++cnt) + { + struct __spawn_action *action = &file_actions->__actions[cnt]; + + switch (action->tag) + { + case spawn_do_close: + if (__close (action->action.close_action.fd) != 0) + /* Signal the error. */ + _exit (SPAWN_ERROR); + break; + + case spawn_do_open: + { + int new_fd = __open64 (action->action.open_action.path, + action->action.open_action.oflag, + action->action.open_action.mode); + + if (new_fd == -1) + /* The `open' call failed. */ + _exit (SPAWN_ERROR); + + /* Make sure the desired file descriptor is used. */ + if (new_fd != action->action.open_action.fd) + { + if (__dup2 (new_fd, action->action.open_action.fd) + != action->action.open_action.fd) + /* The `dup2' call failed. */ + _exit (SPAWN_ERROR); + + if (__close (new_fd) != 0) + /* The `close' call failed. */ + _exit (SPAWN_ERROR); + } + } + break; + + case spawn_do_dup2: + if (__dup2 (action->action.dup2_action.fd, + action->action.dup2_action.newfd) + != action->action.dup2_action.newfd) + /* The `dup2' call failed. */ + _exit (SPAWN_ERROR); + break; + } + } + } + + if (! use_path || strchr (file, '/') != NULL) + { + /* The FILE parameter is actually a path. */ + __execve (file, argv, envp); + + if (errno == ENOEXEC) + script_execute (file, argv, envp); + + /* Oh, oh. `execve' returns. This is bad. */ + _exit (SPAWN_ERROR); + } + + /* We have to search for FILE on the path. */ + path = getenv ("PATH"); + if (path == NULL) + { + /* There is no `PATH' in the environment. + The default search path is the current directory + followed by the path `confstr' returns for `_CS_PATH'. */ + len = confstr (_CS_PATH, (char *) NULL, 0); + path = (char *) __alloca (1 + len); + path[0] = ':'; + (void) confstr (_CS_PATH, path + 1, len); + } + + len = strlen (file) + 1; + pathlen = strlen (path); + name = __alloca (pathlen + len + 1); + /* Copy the file name at the top. */ + name = (char *) memcpy (name + pathlen + 1, file, len); + /* And add the slash. */ + *--name = '/'; + + p = path; + do + { + char *startp; + + path = p; + p = __strchrnul (path, ':'); + + if (p == path) + /* Two adjacent colons, or a colon at the beginning or the end + of `PATH' means to search the current directory. */ + startp = name + 1; + else + startp = (char *) memcpy (name - (p - path), path, p - path); + + /* Try to execute this name. If it works, execv will not return. */ + __execve (startp, argv, envp); + + if (errno == ENOEXEC) + script_execute (startp, argv, envp); + + switch (errno) + { + case EACCES: + case ENOENT: + case ESTALE: + case ENOTDIR: + /* Those errors indicate the file is missing or not executable + by us, in which case we want to just try the next path + directory. */ + break; + + default: + /* Some other error means we found an executable file, but + something went wrong executing it; return the error to our + caller. */ + _exit (SPAWN_ERROR); + } + } + while (*p++ != '\0'); + + /* Return with an error. */ + _exit (SPAWN_ERROR); +} |