gnu/lib/libdialog/raw_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  * 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  * $FreeBSD: src/gnu/lib/libdialog/raw_popen.c,v 1.2.12.1 2002/06/18 07:57:40 dougb Exp $
  37  * $DragonFly: src/gnu/lib/libdialog/raw_popen.c,v 1.2 2003/06/17 04:25:43 dillon Exp $
  38  *
  39  * @(#)popen.c  8.1 (Berkeley) 6/4/93
  40  */
  41
  42 #include <sys/param.h>
  43 #include <sys/wait.h>
  44
  45 #include <signal.h>
  46 #include <errno.h>
  47 #include <unistd.h>
  48 #include <stdio.h>
  49 #include <stdlib.h>
  50 #include <string.h>
  51 #include <paths.h>
  52
  53 static struct pid {
  54         struct pid *next;
  55         FILE *fp;
  56         pid_t pid;
  57 } *pidlist;
  58
  59 FILE *
  60 raw_popen(const char *program, char * const *argv, const char *type)
  61 {
  62         struct pid *cur;
  63         FILE *iop;
  64         int pdes[2], pid;
  65
  66         if ((*type != 'r' && *type != 'w') || type[1])
  67                 return (NULL);
  68
  69         if ((cur = malloc(sizeof(struct pid))) == NULL)
  70                 return (NULL);
  71
  72         if (pipe(pdes) < 0) {
  73                 (void)free(cur);
  74                 return (NULL);
  75         }
  76
  77         switch (pid = vfork()) {
  78         case -1:                        /* Error. */
  79                 (void)close(pdes[0]);
  80                 (void)close(pdes[1]);
  81                 (void)free(cur);
  82                 return (NULL);
  83                 /* NOTREACHED */
  84         case 0:                         /* Child. */
  85                 if (*type == 'r') {
  86                         if (pdes[1] != STDOUT_FILENO) {
  87                                 (void)dup2(pdes[1], STDOUT_FILENO);
  88                                 (void)close(pdes[1]);
  89                         }
  90                         (void) close(pdes[0]);
  91                 } else {
  92                         if (pdes[0] != STDIN_FILENO) {
  93                                 (void)dup2(pdes[0], STDIN_FILENO);
  94                                 (void)close(pdes[0]);
  95                         }
  96                         (void)close(pdes[1]);
  97                 }
  98                 if (argv == NULL)
  99                         execl(_PATH_BSHELL, "sh", "-c", program, (char *)NULL);
 100                 else
 101                         execvp(program, argv);
 102                 _exit(127);
 103                 /* NOTREACHED */
 104         }
 105
 106         /* Parent; assume fdopen can't fail. */
 107         if (*type == 'r') {
 108                 iop = fdopen(pdes[0], type);
 109                 (void)close(pdes[1]);
 110         } else {
 111                 iop = fdopen(pdes[1], type);
 112                 (void)close(pdes[0]);
 113         }
 114
 115         /* Link into list of file descriptors. */
 116         cur->fp = iop;
 117         cur->pid =  pid;
 118         cur->next = pidlist;
 119         pidlist = cur;
 120
 121         return (iop);
 122 }
 123
 124 /*
 125  * pclose --
 126  *      Pclose returns -1 if stream is not associated with a `popened' command,
 127  *      if already `pclosed', or waitpid returns an error.
 128  */
 129 int
 130 raw_pclose(FILE *iop)
 131 {
 132         register struct pid *cur, *last;
 133         int omask, pstat;
 134         pid_t pid;
 135
 136         (void)fclose(iop);
 137
 138         /* Find the appropriate file pointer. */
 139         for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next)
 140                 if (cur->fp == iop)
 141                         break;
 142         if (cur == NULL)
 143                 return (-1);
 144
 145         /* Get the status of the process. */
 146         omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGHUP));
 147         do {
 148                 pid = waitpid(cur->pid, (int *) &pstat, 0);
 149         } while (pid == -1 && errno == EINTR);
 150         (void)sigsetmask(omask);
 151
 152         /* Remove the entry from the linked list. */
 153         if (last == NULL)
 154                 pidlist = cur->next;
 155         else
 156                 last->next = cur->next;
 157         free(cur);
 158
 159         return (pid == -1 ? -1 : pstat);
 160 }