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
  59 #include <sys/param.h>
  60 #include <sys/wait.h>
  61 #include <sys/socket.h>
  62
  63 #include <signal.h>
  64 #include <errno.h>
  65 #include <unistd.h>
  66 #include <stdio.h>
  67 #include <stdlib.h>
  68 #include <string.h>
  69 #include <paths.h>
  70
  71 static struct pid {
  72         struct pid *next;
  73         FILE *fp;
  74         pid_t pid;
  75 } *pidlist;
  76
  77 FILE *
  78 popen(command, type)
  79         const char *command, *type;
  80 {
  81         struct pid *cur;
  82         FILE *iop;
  83         int pdes[2], pid, twoway;
  84
  85         if (strchr(type, '+')) {
  86                 twoway = 1;
  87                 type = "r+";
  88                 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pdes) < 0)
  89                         return (NULL);
  90         } else  {
  91                 twoway = 0;
  92                 if (*type != 'r' && *type != 'w' || type[1] ||
  93                     (pipe(pdes) < 0))
  94                         return (NULL);
  95         }
  96
  97         if ((cur = malloc(sizeof(struct pid))) == NULL)
  98                 return (NULL);
  99
 100         switch (pid = vfork()) {
 101         case -1:                        /* Error. */
 102                 (void)close(pdes[0]);
 103                 (void)close(pdes[1]);
 104                 (void)free(cur);
 105                 return (NULL);
 106                 /* NOTREACHED */
 107         case 0:                         /* Child. */
 108                 if (*type == 'r') {
 109                         if (pdes[1] != STDOUT_FILENO) {
 110                                 (void)dup2(pdes[1], STDOUT_FILENO);
 111                                 (void)close(pdes[1]);
 112                                 pdes[1] = STDOUT_FILENO;
 113                         }
 114                         (void) close(pdes[0]);
 115                         if (twoway && (pdes[1] != STDIN_FILENO))
 116                                 (void)dup2(pdes[1], STDIN_FILENO);
 117                 } else {
 118                         if (pdes[0] != STDIN_FILENO) {
 119                                 (void)dup2(pdes[0], STDIN_FILENO);
 120                                 (void)close(pdes[0]);
 121                         }
 122                         (void)close(pdes[1]);
 123                 }
 124                 execl(_PATH_BSHELL, "sh", "-c", command, NULL);
 125                 _exit(127);
 126                 /* NOTREACHED */
 127         }
 128
 129         /* Parent; assume fdopen can't fail. */
 130         if (*type == 'r') {
 131                 iop = fdopen(pdes[0], type);
 132                 (void)close(pdes[1]);
 133         } else {
 134                 iop = fdopen(pdes[1], type);
 135                 (void)close(pdes[0]);
 136         }
 137
 138         /* Link into list of file descriptors. */
 139         cur->fp = iop;
 140         cur->pid =  pid;
 141         cur->next = pidlist;
 142         pidlist = cur;
 143
 144         return (iop);
 145 }
 146
 147 /*
 148  * pclose --
 149  *      Pclose returns -1 if stream is not associated with a `popened' command,
 150  *      if already `pclosed', or waitpid returns an error.
 151  */
 152 int
 153 pclose(iop)
 154         FILE *iop;
 155 {
 156         register struct pid *cur, *last;
 157         int omask;
 158         int pstat;
 159         pid_t pid;
 160
 161         /* Find the appropriate file pointer. */
 162         for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next)
 163                 if (cur->fp == iop)
 164                         break;
 165         if (cur == NULL)
 166                 return (-1);
 167
 168         (void)fclose(iop);
 169
 170         do {
 171                 pid = waitpid(cur->pid, &pstat, 0);
 172         } while (pid == -1 && errno == EINTR);
 173
 174         /* Remove the entry from the linked list. */
 175         if (last == NULL)
 176                 pidlist = cur->next;
 177         else
 178                 last->next = cur->next;
 179         free(cur);
 180
 181         return (pid == -1 ? -1 : pstat);
 182 }