gen/FreeBSD/popen.c

   1 /*
   2  * Copyright (c) 1988, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software written by Ken Arnold and
   6  * published in UNIX Review, Vol. 6, No. 8.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 4. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #ifdef VARIANT_DARWINEXTSN
  34 #define _DARWIN_UNLIMITED_STREAMS
  35 #endif /* VARIANT_DARWINEXTSN */
  36
  37 #if defined(LIBC_SCCS) && !defined(lint)
  38 static char sccsid[] = "@(#)popen.c     8.3 (Berkeley) 5/3/95";
  39 #endif /* LIBC_SCCS and not lint */
  40 #include <sys/cdefs.h>
  41 __FBSDID("$FreeBSD: src/lib/libc/gen/popen.c,v 1.21 2009/05/27 19:28:04 ed Exp $");
  42
  43 #include "namespace.h"
  44 #include <sys/param.h>
  45 #include <sys/queue.h>
  46 #include <sys/wait.h>
  47 #include <sys/socket.h>
  48 #include <wchar.h>              /* fwide() */
  49 #include <signal.h>
  50 #include <errno.h>
  51 #include <unistd.h>
  52 #include <stdio.h>
  53 #include <stdlib.h>
  54 #include <string.h>
  55 #include <paths.h>
  56 #include <pthread.h>
  57 #include <spawn.h>
  58 #include "un-namespace.h"
  59 #include "libc_private.h"
  60
  61 #include <crt_externs.h>
  62 #define environ (*_NSGetEnviron())
  63
  64 /* Our queue.h doesn't have SLIST_REMOVE_AFTER in it yet
  65  * <rdar://problem/7431558> API: Add SLIST_REMOVE_AFTER to sys/queue.h (from FreeBSD)
  66  */
  67 #ifndef SLIST_REMOVE_AFTER
  68 #define SLIST_REMOVE_AFTER(elm, field) do {                             \
  69         SLIST_NEXT(elm, field) =                                        \
  70             SLIST_NEXT(SLIST_NEXT(elm, field), field);                  \
  71 } while (0)
  72 #endif
  73
  74 /* 3516149 - store file descriptor and use that to close to prevent blocking */
  75 struct pid {
  76         SLIST_ENTRY(pid) next;
  77         FILE *fp;
  78         int fd;
  79         pid_t pid;
  80 };
  81 #define pidlist         __popen_pidlist
  82 #define pidlist_mutex   __popen_pidlist_mutex
  83 #ifndef BUILDING_VARIANT
  84 __private_extern__ SLIST_HEAD(, pid) pidlist = SLIST_HEAD_INITIALIZER(pidlist);
  85 __private_extern__ pthread_mutex_t pidlist_mutex = PTHREAD_MUTEX_INITIALIZER;
  86 #else /* BUILDING_VARIANT */
  87 extern SLIST_HEAD(, pid) pidlist;
  88 extern pthread_mutex_t pidlist_mutex;
  89 #endif /* !BUILDING_VARIANT */
  90
  91 #define THREAD_LOCK()   if (__isthreaded) _pthread_mutex_lock(&pidlist_mutex)
  92 #define THREAD_UNLOCK() if (__isthreaded) _pthread_mutex_unlock(&pidlist_mutex)
  93
  94 FILE *
  95 popen(command, type)
  96         const char *command, *type;
  97 {
  98         struct pid *cur;
  99         FILE *iop;
 100         int pdes[2], pid, twoway, other;
 101         char *argv[4];
 102         struct pid *p;
 103         posix_spawn_file_actions_t file_actions;
 104         int err;
 105
 106         if (type == NULL) {
 107                 errno = EINVAL;
 108                 return (NULL);
 109         }
 110         if (strcmp(type, "r+") == 0) {
 111                 twoway = 1;
 112                 type = "r+";
 113                 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pdes) < 0)
 114                         return (NULL);
 115         } else  {
 116                 twoway = 0;
 117                 if ((*type != 'r' && *type != 'w') || type[1]) {
 118                         errno = EINVAL;
 119                         return (NULL);
 120                 }
 121                 if (pipe(pdes) < 0)
 122                         return (NULL);
 123         }
 124
 125         /* fdopen can now fail */
 126         if (*type == 'r') {
 127                 iop = fdopen(pdes[0], type);
 128                 other = pdes[1];
 129         } else {
 130                 iop = fdopen(pdes[1], type);
 131                 other = pdes[0];
 132         }
 133         if (iop == NULL) {
 134                 (void)_close(pdes[0]);
 135                 (void)_close(pdes[1]);
 136                 return (NULL);
 137         }
 138
 139         if ((cur = malloc(sizeof(struct pid))) == NULL) {
 140                 (void)fclose(iop);
 141                 (void)_close(other);
 142                 return (NULL);
 143         }
 144
 145         if ((err = posix_spawn_file_actions_init(&file_actions)) != 0) {
 146                 (void)fclose(iop);
 147                 (void)_close(other);
 148                 free(cur);
 149                 errno = err;
 150                 return (NULL);
 151         }
 152         if (*type == 'r') {
 153                 /*
 154                  * The dup2() to STDIN_FILENO is repeated to avoid
 155                  * writing to pdes[1], which might corrupt the
 156                  * parent's copy.  This isn't good enough in
 157                  * general, since the _exit() is no return, so
 158                  * the compiler is free to corrupt all the local
 159                  * variables.
 160                  */
 161                 (void)posix_spawn_file_actions_addclose(&file_actions, pdes[0]);
 162                 if (pdes[1] != STDOUT_FILENO) {
 163                         (void)posix_spawn_file_actions_adddup2(&file_actions, pdes[1], STDOUT_FILENO);
 164                         (void)posix_spawn_file_actions_addclose(&file_actions, pdes[1]);
 165                         if (twoway)
 166                                 (void)posix_spawn_file_actions_adddup2(&file_actions, STDOUT_FILENO, STDIN_FILENO);
 167                 } else if (twoway && (pdes[1] != STDIN_FILENO))
 168                         (void)posix_spawn_file_actions_adddup2(&file_actions, pdes[1], STDIN_FILENO);
 169         } else {
 170                 if (pdes[0] != STDIN_FILENO) {
 171                         (void)posix_spawn_file_actions_adddup2(&file_actions, pdes[0], STDIN_FILENO);
 172                         (void)posix_spawn_file_actions_addclose(&file_actions, pdes[0]);
 173                 }
 174                 (void)posix_spawn_file_actions_addclose(&file_actions, pdes[1]);
 175         }
 176         SLIST_FOREACH(p, &pidlist, next)
 177                 (void)posix_spawn_file_actions_addclose(&file_actions, p->fd);
 178
 179         argv[0] = "sh";
 180         argv[1] = "-c";
 181         argv[2] = (char *)command;
 182         argv[3] = NULL;
 183
 184         err = posix_spawn(&pid, _PATH_BSHELL, &file_actions, NULL, argv, environ);
 185         posix_spawn_file_actions_destroy(&file_actions);
 186
 187         if (err == ENOMEM || err == EAGAIN) { /* as if fork failed */
 188                 (void)fclose(iop);
 189                 (void)_close(other);
 190                 free(cur);
 191                 errno = err;
 192                 return (NULL);
 193         } else if (err != 0) { /* couldn't exec the shell */
 194                 pid = -1;
 195         }
 196
 197         if (*type == 'r') {
 198                 cur->fd = pdes[0];
 199                 (void)_close(pdes[1]);
 200         } else {
 201                 cur->fd = pdes[1];
 202                 (void)_close(pdes[0]);
 203         }
 204
 205         /* Link into list of file descriptors. */
 206         cur->fp = iop;
 207         cur->pid = pid;
 208         THREAD_LOCK();
 209         SLIST_INSERT_HEAD(&pidlist, cur, next);
 210         THREAD_UNLOCK();
 211         fwide(iop, -1);         /* byte stream */
 212         return (iop);
 213 }
 214
 215 #ifndef BUILDING_VARIANT
 216 /*
 217  * pclose --
 218  *      Pclose returns -1 if stream is not associated with a `popened' command,
 219  *      if already `pclosed', or waitpid returns an error.
 220  */
 221 int
 222 pclose(iop)
 223         FILE *iop;
 224 {
 225         struct pid *cur, *last = NULL;
 226         int pstat;
 227         pid_t pid;
 228
 229         /*
 230          * Find the appropriate file pointer and remove it from the list.
 231          */
 232         THREAD_LOCK();
 233         SLIST_FOREACH(cur, &pidlist, next) {
 234                 if (cur->fp == iop)
 235                         break;
 236                 last = cur;
 237         }
 238         if (cur == NULL) {
 239                 THREAD_UNLOCK();
 240                 return (-1);
 241         }
 242         if (last == NULL)
 243                 SLIST_REMOVE_HEAD(&pidlist, next);
 244         else
 245                 SLIST_REMOVE_AFTER(last, next);
 246         THREAD_UNLOCK();
 247
 248         (void)fclose(iop);
 249
 250         if (cur->pid < 0) {
 251                 free(cur);
 252                 return W_EXITCODE(127, 0);
 253         }
 254         do {
 255                 pid = _wait4(cur->pid, &pstat, 0, (struct rusage *)0);
 256         } while (pid == -1 && errno == EINTR);
 257
 258         free(cur);
 259
 260         return (pid == -1 ? -1 : pstat);
 261 }
 262 #endif /* !BUILDING_VARIANT */