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 #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 1.18 2003/01/04 00:15:15 tjr Exp $");
  42
  43 #include "namespace.h"
  44 #include <sys/param.h>
  45 #include <sys/wait.h>
  46 #include <sys/socket.h>
  47 #include <wchar.h>              /* fwide() */
  48 #include <signal.h>
  49 #include <errno.h>
  50 #include <unistd.h>
  51 #include <stdio.h>
  52 #include <stdlib.h>
  53 #include <string.h>
  54 #include <paths.h>
  55 #include <pthread.h>
  56 #include "un-namespace.h"
  57 #include "libc_private.h"
  58
  59 #include <crt_externs.h>
  60 #define environ (*_NSGetEnviron())
  61
  62 /* 3516149 - store file descriptor and use that to close to prevent blocking */
  63 static struct pid {
  64         struct pid *next;
  65         FILE *fp;
  66         int fd;
  67         pid_t pid;
  68 } *pidlist;
  69 static pthread_mutex_t pidlist_mutex = PTHREAD_MUTEX_INITIALIZER;
  70
  71 #define THREAD_LOCK()   if (__isthreaded) _pthread_mutex_lock(&pidlist_mutex)
  72 #define THREAD_UNLOCK() if (__isthreaded) _pthread_mutex_unlock(&pidlist_mutex)
  73
  74 FILE *
  75 popen(command, type)
  76         const char *command, *type;
  77 {
  78         struct pid *cur;
  79         FILE *iop;
  80         int pdes[2], pid, twoway;
  81         char *argv[4];
  82         struct pid *p;
  83
  84         if (type == NULL) {
  85                 errno = EINVAL;
  86                 return (NULL);
  87         }
  88         if (strcmp(type, "r+") == 0) {
  89                 twoway = 1;
  90                 type = "r+";
  91                 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pdes) < 0)
  92                         return (NULL);
  93         } else  {
  94                 twoway = 0;
  95                 if ((*type != 'r' && *type != 'w') || type[1]) {
  96                         errno = EINVAL;
  97                         return (NULL);
  98         }
  99         if (pipe(pdes) < 0)
 100                 return (NULL);
 101         }
 102
 103         if ((cur = malloc(sizeof(struct pid))) == NULL) {
 104                 (void)_close(pdes[0]);
 105                 (void)_close(pdes[1]);
 106                 return (NULL);
 107         }
 108
 109         argv[0] = "sh";
 110         argv[1] = "-c";
 111         argv[2] = (char *)command;
 112         argv[3] = NULL;
 113
 114         THREAD_LOCK();
 115         switch (pid = fork()) {
 116         case -1:                        /* Error. */
 117                 THREAD_UNLOCK();
 118                 (void)_close(pdes[0]);
 119                 (void)_close(pdes[1]);
 120                 free(cur);
 121                 return (NULL);
 122                 /* NOTREACHED */
 123         case 0:                         /* Child. */
 124                 if (*type == 'r') {
 125                         /*
 126                          * The _dup2() to STDIN_FILENO is repeated to avoid
 127                          * writing to pdes[1], which might corrupt the
 128                          * parent's copy.  This isn't good enough in
 129                          * general, since the _exit() is no return, so
 130                          * the compiler is free to corrupt all the local
 131                          * variables.
 132                          */
 133                         (void)_close(pdes[0]);
 134                         if (pdes[1] != STDOUT_FILENO) {
 135                                 (void)_dup2(pdes[1], STDOUT_FILENO);
 136                                 (void)_close(pdes[1]);
 137                                 if (twoway)
 138                                         (void)_dup2(STDOUT_FILENO, STDIN_FILENO);
 139                         } else if (twoway && (pdes[1] != STDIN_FILENO))
 140                                 (void)_dup2(pdes[1], STDIN_FILENO);
 141                 } else {
 142                         if (pdes[0] != STDIN_FILENO) {
 143                                 (void)_dup2(pdes[0], STDIN_FILENO);
 144                                 (void)_close(pdes[0]);
 145                         }
 146                         (void)_close(pdes[1]);
 147                 }
 148                 for (p = pidlist; p; p = p->next) {
 149                         (void)_close(p->fd);
 150                 }
 151                 _execve(_PATH_BSHELL, argv, environ);
 152                 _exit(127);
 153                 /* NOTREACHED */
 154         }
 155         THREAD_UNLOCK();
 156
 157         /* Parent; assume fdopen can't fail. */
 158         if (*type == 'r') {
 159                 iop = fdopen(pdes[0], type);
 160                 cur->fd = pdes[0];
 161                 (void)_close(pdes[1]);
 162         } else {
 163                 iop = fdopen(pdes[1], type);
 164                 cur->fd = pdes[1];
 165                 (void)_close(pdes[0]);
 166         }
 167
 168         /* Link into list of file descriptors. */
 169         cur->fp = iop;
 170         cur->pid = pid;
 171         THREAD_LOCK();
 172         cur->next = pidlist;
 173         pidlist = cur;
 174         THREAD_UNLOCK();
 175         fwide(iop, -1);         /* byte stream */
 176         return (iop);
 177 }
 178
 179 /*
 180  * pclose --
 181  *      Pclose returns -1 if stream is not associated with a `popened' command,
 182  *      if already `pclosed', or waitpid returns an error.
 183  */
 184 int
 185 pclose(iop)
 186         FILE *iop;
 187 {
 188         struct pid *cur, *last;
 189         int pstat;
 190         pid_t pid;
 191
 192         /*
 193          * Find the appropriate file pointer and remove it from the list.
 194          */
 195         THREAD_LOCK();
 196         for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next)
 197                 if (cur->fp == iop)
 198                         break;
 199         if (cur == NULL) {
 200                 THREAD_UNLOCK();
 201                 return (-1);
 202         }
 203         if (last == NULL)
 204                 pidlist = cur->next;
 205         else
 206                 last->next = cur->next;
 207         THREAD_UNLOCK();
 208
 209         (void)fclose(iop);
 210
 211         do {
 212                 pid = _wait4(cur->pid, &pstat, 0, (struct rusage *)0);
 213         } while (pid == -1 && errno == EINTR);
 214
 215         free(cur);
 216
 217         return (pid == -1 ? -1 : pstat);
 218 }