usr/src/tools/cscope-fast/mypopen.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License, Version 1.0 only
   6  * (the "License").  You may not use this file except in compliance
   7  * with the License.
   8  *
   9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10  * or http://www.opensolaris.org/os/licensing.
  11  * See the License for the specific language governing permissions
  12  * and limitations under the License.
  13  *
  14  * When distributing Covered Code, include this CDDL HEADER in each
  15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16  * If applicable, add the following below this CDDL HEADER, with the
  17  * fields enclosed by brackets "[]" replaced with your own identifying
  18  * information: Portions Copyright [yyyy] [name of copyright owner]
  19  *
  20  * CDDL HEADER END
  21  */
  22 /*      Copyright (c) 1988 AT&T */
  23 /*        All Rights Reserved   */
  24
  25
  26 /*
  27  * Copyright (c) 1999 by Sun Microsystems, Inc.
  28  * All rights reserved.
  29  */
  30
  31 #pragma ident   "%Z%%M% %I%     %E% SMI"
  32
  33 #include <fcntl.h>
  34 #include <sys/types.h>
  35 #include <sys/wait.h>
  36 #include <unistd.h>
  37 #include <stdlib.h>
  38 #include <stdio.h>
  39 #include <libgen.h>
  40 #include "global.h"     /* pid_t, SIGTYPE, shell, and basename() */
  41
  42 #define tst(a, b) (*mode == 'r'? (b) : (a))
  43 #define RDR     0
  44 #define WTR     1
  45
  46 static pid_t popen_pid[20];
  47 static SIGTYPE (*tstat)();
  48
  49 FILE *
  50 mypopen(char *cmd, char *mode)
  51 {
  52         int     p[2];
  53         pid_t *poptr;
  54         int myside, yourside;
  55         pid_t pid;
  56
  57         if (pipe(p) < 0)
  58                 return (NULL);
  59         myside = tst(p[WTR], p[RDR]);
  60         yourside = tst(p[RDR], p[WTR]);
  61         if ((pid = fork()) > 0) {
  62                 tstat = signal(SIGTSTP, SIG_DFL);
  63         } else if (pid == 0) {
  64                 /* myside and yourside reverse roles in child */
  65                 int     stdio;
  66
  67                 /* close all pipes from other popen's */
  68                 for (poptr = popen_pid; poptr < popen_pid+20; poptr++) {
  69                         if (*poptr)
  70                                 (void) close(poptr - popen_pid);
  71                 }
  72                 stdio = tst(0, 1);
  73                 (void) close(myside);
  74                 (void) close(stdio);
  75                 (void) fcntl(yourside, F_DUPFD, stdio);
  76                 (void) close(yourside);
  77                 (void) execlp(shell, basename(shell), "-c", cmd, 0);
  78                 _exit(1);
  79         }
  80         if (pid == -1)
  81                 return (NULL);
  82         popen_pid[myside] = pid;
  83         (void) close(yourside);
  84         return (fdopen(myside, mode));
  85 }
  86
  87 int
  88 mypclose(FILE *ptr)
  89 {
  90         int f;
  91         pid_t r;
  92         int status;
  93         SIGTYPE (*hstat)(), (*istat)(), (*qstat)();
  94
  95         f = fileno(ptr);
  96         (void) fclose(ptr);
  97         istat = signal(SIGINT, SIG_IGN);
  98         qstat = signal(SIGQUIT, SIG_IGN);
  99         hstat = signal(SIGHUP, SIG_IGN);
 100         while ((r = wait(&status)) != popen_pid[f] && r != -1) {
 101         }
 102         if (r == -1)
 103                 status = -1;
 104         (void) signal(SIGINT, istat);
 105         (void) signal(SIGQUIT, qstat);
 106         (void) signal(SIGHUP, hstat);
 107         (void) signal(SIGTSTP, tstat);
 108         /* mark this pipe closed */
 109         popen_pid[f] = 0;
 110         return (status);
 111 }