gen/popen-fbsd.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  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  */
  36
  37 #ifdef VARIANT_DARWINEXTSN
  38 #define _DARWIN_UNLIMITED_STREAMS
  39 #endif /* VARIANT_DARWINEXTSN */
  40
  41 #if defined(LIBC_SCCS) && !defined(lint)
  42 static char sccsid[] = "@(#)popen.c     8.3 (Berkeley) 5/3/95";
  43 #endif /* LIBC_SCCS and not lint */
  44 #include <sys/cdefs.h>
  45 __FBSDID("$FreeBSD: src/lib/libc/gen/popen.c,v 1.18 2003/01/04 00:15:15 tjr Exp $");
  46
  47 #include "namespace.h"
  48 #include <sys/param.h>
  49 #include <sys/wait.h>
  50 #include <sys/socket.h>
  51 #include <wchar.h>              /* fwide() */
  52 #include <signal.h>
  53 #include <errno.h>
  54 #include <unistd.h>
  55 #include <stdio.h>
  56 #include <stdlib.h>
  57 #include <string.h>
  58 #include <paths.h>
  59 #include <pthread.h>
  60 #include <spawn.h>
  61 #include "un-namespace.h"
  62 #include "libc_private.h"
  63
  64 #include <crt_externs.h>
  65 #define environ (*_NSGetEnviron())
  66
  67 /* 3516149 - store file descriptor and use that to close to prevent blocking */
  68 struct pid {
  69         struct pid *next;
  70         FILE *fp;
  71         int fd;
  72         pid_t pid;
  73 };
  74 #define pidlist         __popen_pidlist
  75 #define pidlist_mutex   __popen_pidlist_mutex
  76 #ifndef BUILDING_VARIANT
  77 __private_extern__ struct pid *pidlist = NULL;
  78 __private_extern__ pthread_mutex_t pidlist_mutex = PTHREAD_MUTEX_INITIALIZER;
  79 #else /* BUILDING_VARIANT */
  80 extern struct pid *pidlist;
  81 extern pthread_mutex_t pidlist_mutex;
  82 #endif /* !BUILDING_VARIANT */
  83
  84 #define THREAD_LOCK()   if (__isthreaded) _pthread_mutex_lock(&pidlist_mutex)
  85 #define THREAD_UNLOCK() if (__isthreaded) _pthread_mutex_unlock(&pidlist_mutex)
  86
  87 FILE *
  88 popen(command, type)
  89         const char *command, *type;
  90 {
  91         struct pid *cur;
  92         FILE *iop;
  93         int pdes[2], pid, twoway, other;
  94         char *argv[4];
  95         struct pid *p;
  96         posix_spawn_file_actions_t file_actions;
  97         int err;
  98
  99         if (type == NULL) {
 100                 errno = EINVAL;
 101                 return (NULL);
 102         }
 103         if (strcmp(type, "r+") == 0) {
 104                 twoway = 1;
 105                 type = "r+";
 106                 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pdes) < 0)
 107                         return (NULL);
 108         } else  {
 109                 twoway = 0;
 110                 if ((*type != 'r' && *type != 'w') || type[1]) {
 111                         errno = EINVAL;
 112                         return (NULL);
 113                 }
 114                 if (pipe(pdes) < 0)
 115                         return (NULL);
 116         }
 117
 118         /* fdopen can now fail */
 119         if (*type == 'r') {
 120                 iop = fdopen(pdes[0], type);
 121                 other = pdes[1];
 122         } else {
 123                 iop = fdopen(pdes[1], type);
 124                 other = pdes[0];
 125         }
 126         if (iop == NULL) {
 127                 (void)_close(pdes[0]);
 128                 (void)_close(pdes[1]);
 129                 return (NULL);
 130         }
 131
 132         if ((cur = malloc(sizeof(struct pid))) == NULL) {
 133                 (void)fclose(iop);
 134                 (void)_close(other);
 135                 return (NULL);
 136         }
 137
 138         if ((err = posix_spawn_file_actions_init(&file_actions)) != 0) {
 139                 (void)fclose(iop);
 140                 (void)_close(other);
 141                 free(cur);
 142                 errno = err;
 143                 return (NULL);
 144         }
 145         if (*type == 'r') {
 146                 /*
 147                  * The dup2() to STDIN_FILENO is repeated to avoid
 148                  * writing to pdes[1], which might corrupt the
 149                  * parent's copy.  This isn't good enough in
 150                  * general, since the _exit() is no return, so
 151                  * the compiler is free to corrupt all the local
 152                  * variables.
 153                  */
 154                 (void)posix_spawn_file_actions_addclose(&file_actions, pdes[0]);
 155                 if (pdes[1] != STDOUT_FILENO) {
 156                         (void)posix_spawn_file_actions_adddup2(&file_actions, pdes[1], STDOUT_FILENO);
 157                         (void)posix_spawn_file_actions_addclose(&file_actions, pdes[1]);
 158                         if (twoway)
 159                                 (void)posix_spawn_file_actions_adddup2(&file_actions, STDOUT_FILENO, STDIN_FILENO);
 160                 } else if (twoway && (pdes[1] != STDIN_FILENO))
 161                         (void)posix_spawn_file_actions_adddup2(&file_actions, pdes[1], STDIN_FILENO);
 162         } else {
 163                 if (pdes[0] != STDIN_FILENO) {
 164                         (void)posix_spawn_file_actions_adddup2(&file_actions, pdes[0], STDIN_FILENO);
 165                         (void)posix_spawn_file_actions_addclose(&file_actions, pdes[0]);
 166                 }
 167                 (void)posix_spawn_file_actions_addclose(&file_actions, pdes[1]);
 168         }
 169         for (p = pidlist; p; p = p->next) {
 170                 (void)posix_spawn_file_actions_addclose(&file_actions, p->fd);
 171         }
 172
 173         argv[0] = "sh";
 174         argv[1] = "-c";
 175         argv[2] = (char *)command;
 176         argv[3] = NULL;
 177
 178         err = posix_spawn(&pid, _PATH_BSHELL, &file_actions, NULL, argv, environ);
 179         posix_spawn_file_actions_destroy(&file_actions);
 180
 181         if (err == ENOMEM || err == EAGAIN) { /* as if fork failed */
 182                 (void)fclose(iop);
 183                 (void)_close(other);
 184                 free(cur);
 185                 errno = err;
 186                 return (NULL);
 187         } else if (err != 0) { /* couldn't exec the shell */
 188                 pid = -1;
 189         }
 190
 191         if (*type == 'r') {
 192                 cur->fd = pdes[0];
 193                 (void)_close(pdes[1]);
 194         } else {
 195                 cur->fd = pdes[1];
 196                 (void)_close(pdes[0]);
 197         }
 198
 199         /* Link into list of file descriptors. */
 200         cur->fp = iop;
 201         cur->pid = pid;
 202         THREAD_LOCK();
 203         cur->next = pidlist;
 204         pidlist = cur;
 205         THREAD_UNLOCK();
 206         fwide(iop, -1);         /* byte stream */
 207         return (iop);
 208 }
 209
 210 #ifndef BUILDING_VARIANT
 211 /*
 212  * pclose --
 213  *      Pclose returns -1 if stream is not associated with a `popened' command,
 214  *      if already `pclosed', or waitpid returns an error.
 215  */
 216 int
 217 pclose(iop)
 218         FILE *iop;
 219 {
 220         struct pid *cur, *last;
 221         int pstat;
 222         pid_t pid;
 223
 224         /*
 225          * Find the appropriate file pointer and remove it from the list.
 226          */
 227         THREAD_LOCK();
 228         for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next)
 229                 if (cur->fp == iop)
 230                         break;
 231         if (cur == NULL) {
 232                 THREAD_UNLOCK();
 233                 return (-1);
 234         }
 235         if (last == NULL)
 236                 pidlist = cur->next;
 237         else
 238                 last->next = cur->next;
 239         THREAD_UNLOCK();
 240
 241         (void)fclose(iop);
 242
 243         if (cur->pid < 0) {
 244                 free(cur);
 245                 return W_EXITCODE(127, 0);
 246         }
 247         do {
 248                 pid = _wait4(cur->pid, &pstat, 0, (struct rusage *)0);
 249         } while (pid == -1 && errno == EINTR);
 250
 251         free(cur);
 252
 253         return (pid == -1 ? -1 : pstat);
 254 }
 255 #endif /* !BUILDING_VARIANT */