gen.subproj/popen.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * Copyright (c) 1988, 1993
  24  *      The Regents of the University of California.  All rights reserved.
  25  *
  26  * This code is derived from software written by Ken Arnold and
  27  * published in UNIX Review, Vol. 6, No. 8.
  28  *
  29  * Redistribution and use in source and binary forms, with or without
  30  * modification, are permitted provided that the following conditions
  31  * are met:
  32  * 1. Redistributions of source code must retain the above copyright
  33  *    notice, this list of conditions and the following disclaimer.
  34  * 2. Redistributions in binary form must reproduce the above copyright
  35  *    notice, this list of conditions and the following disclaimer in the
  36  *    documentation and/or other materials provided with the distribution.
  37  * 3. All advertising materials mentioning features or use of this software
  38  *    must display the following acknowledgement:
  39  *      This product includes software developed by the University of
  40  *      California, Berkeley and its contributors.
  41  * 4. Neither the name of the University nor the names of its contributors
  42  *    may be used to endorse or promote products derived from this software
  43  *    without specific prior written permission.
  44  *
  45  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  46  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  47  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  48  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  49  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  50  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  51  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  52  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  53  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  54  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  55  * SUCH DAMAGE.
  56  */
  57
  58 #include <sys/param.h>
  59 #include <sys/wait.h>
  60 #include <sys/socket.h>
  61
  62 #include <signal.h>
  63 #include <errno.h>
  64 #include <unistd.h>
  65 #include <stdio.h>
  66 #include <stdlib.h>
  67 #include <string.h>
  68 #include <paths.h>
  69 #include <crt_externs.h>
  70
  71 #define environ *(_NSGetEnviron())
  72
  73 static struct pid {
  74         struct pid *next;
  75         FILE *fp;
  76         pid_t pid;
  77 } *pidlist;
  78
  79 FILE *
  80 popen(command, type)
  81         const char *command, *type;
  82 {
  83         struct pid *cur;
  84         FILE *iop;
  85         int pdes[2], pid, twoway;
  86         char *argv[4];
  87         struct pid *p;
  88
  89         if (strchr(type, '+')) {
  90                 twoway = 1;
  91                 type = "r+";
  92                 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pdes) < 0)
  93                         return (NULL);
  94         } else  {
  95                 twoway = 0;
  96                 if ((*type != 'r' && *type != 'w') || type[1])
  97                         return (NULL);
  98         }
  99         if (pipe(pdes) < 0)
 100                 return (NULL);
 101
 102         if ((cur = malloc(sizeof(struct pid))) == NULL) {
 103                 (void)close(pdes[0]);
 104                 (void)close(pdes[1]);
 105                 return (NULL);
 106         }
 107
 108         argv[0] = "sh";
 109         argv[1] = "-c";
 110         argv[2] = (char *)command;
 111         argv[3] = NULL;
 112
 113         switch (pid = vfork()) {
 114         case -1:                        /* Error. */
 115                 (void)close(pdes[0]);
 116                 (void)close(pdes[1]);
 117                 free(cur);
 118                 return (NULL);
 119                 /* NOTREACHED */
 120         case 0:                         /* Child. */
 121                 if (*type == 'r') {
 122                         /*
 123                          * The _dup2() to STDIN_FILENO is repeated to avoid
 124                          * writing to pdes[1], which might corrupt the
 125                          * parent's copy.  This isn't good enough in
 126                          * general, since the _exit() is no return, so
 127                          * the compiler is free to corrupt all the local
 128                          * variables.
 129                          */
 130                         (void)close(pdes[0]);
 131                         if (pdes[1] != STDOUT_FILENO) {
 132                                 (void)dup2(pdes[1], STDOUT_FILENO);
 133                                 (void)close(pdes[1]);
 134                                 if (twoway)
 135                                         (void)dup2(STDOUT_FILENO, STDIN_FILENO);
 136                         } else if (twoway && (pdes[1] != STDIN_FILENO))
 137                                 (void)dup2(pdes[1], STDIN_FILENO);
 138                 } else {
 139                         if (pdes[0] != STDIN_FILENO) {
 140                                 (void)dup2(pdes[0], STDIN_FILENO);
 141                                 (void)close(pdes[0]);
 142                         }
 143                         (void)close(pdes[1]);
 144                         }
 145                 for (p = pidlist; p; p = p->next) {
 146                         (void)close(fileno(p->fp));
 147                 }
 148                 execve(_PATH_BSHELL, argv, environ);
 149                 _exit(127);
 150                 /* NOTREACHED */
 151         }
 152
 153         /* Parent; assume fdopen can't fail. */
 154         if (*type == 'r') {
 155                 iop = fdopen(pdes[0], type);
 156                 (void)close(pdes[1]);
 157         } else {
 158                 iop = fdopen(pdes[1], type);
 159                 (void)close(pdes[0]);
 160         }
 161
 162         /* Link into list of file descriptors. */
 163         cur->fp = iop;
 164         cur->pid =  pid;
 165         cur->next = pidlist;
 166         pidlist = cur;
 167
 168         return (iop);
 169 }
 170
 171 /*
 172  * pclose --
 173  *      Pclose returns -1 if stream is not associated with a `popened' command,
 174  *      if already `pclosed', or waitpid returns an error.
 175  */
 176 int
 177 pclose(iop)
 178         FILE *iop;
 179 {
 180         register struct pid *cur, *last;
 181         int pstat;
 182         pid_t pid;
 183
 184         /* Find the appropriate file pointer. */
 185         for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next)
 186                 if (cur->fp == iop)
 187                         break;
 188         if (cur == NULL)
 189                 return (-1);
 190
 191         (void)fclose(iop);
 192
 193         do {
 194                 pid = wait4(cur->pid, &pstat, 0, (struct rusage *)0);
 195         } while (pid == -1 && errno == EINTR);
 196
 197         /* Remove the entry from the linked list. */
 198         if (last == NULL)
 199                 pidlist = cur->next;
 200         else
 201                 last->next = cur->next;
 202         free(cur);
 203
 204         return (pid == -1 ? -1 : pstat);
 205 }