external/bsd/blacklist/port/popenve.c

   1 /*      $NetBSD: popenve.c,v 1.2 2015/01/22 03:10:50 christos Exp $     */
   2
   3 /*
   4  * Copyright (c) 1988, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This code is derived from software written by Ken Arnold and
   8  * published in UNIX Review, Vol. 6, No. 8.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #ifdef HAVE_CONFIG_H
  36 #include "config.h"
  37 #endif
  38
  39 #include <sys/cdefs.h>
  40 #if defined(LIBC_SCCS) && !defined(lint)
  41 #if 0
  42 static char sccsid[] = "@(#)popen.c     8.3 (Berkeley) 5/3/95";
  43 #else
  44 __RCSID("$NetBSD: popenve.c,v 1.2 2015/01/22 03:10:50 christos Exp $");
  45 #endif
  46 #endif /* LIBC_SCCS and not lint */
  47
  48 #include <sys/param.h>
  49 #include <sys/wait.h>
  50 #include <sys/socket.h>
  51
  52 #include <assert.h>
  53 #include <errno.h>
  54 #include <paths.h>
  55 #include <signal.h>
  56 #include <stdio.h>
  57 #include <stdlib.h>
  58 #include <string.h>
  59 #include <unistd.h>
  60 #include <fcntl.h>
  61
  62 #ifdef __weak_alias
  63 __weak_alias(popen,_popen)
  64 __weak_alias(pclose,_pclose)
  65 #endif
  66
  67 static struct pid {
  68         struct pid *next;
  69         FILE *fp;
  70 #ifdef _REENTRANT
  71         int fd;
  72 #endif
  73         pid_t pid;
  74 } *pidlist;
  75
  76 #ifdef _REENTRANT
  77 static rwlock_t pidlist_lock = RWLOCK_INITIALIZER;
  78 #endif
  79
  80 static struct pid *
  81 pdes_get(int *pdes, const char **type)
  82 {
  83         struct pid *cur;
  84         int flags = strchr(*type, 'e') ? O_CLOEXEC : 0;
  85         int serrno;
  86
  87         if (strchr(*type, '+')) {
  88 #ifndef SOCK_CLOEXEC
  89 #define SOCK_CLOEXEC 0
  90 #endif
  91                 int stype = flags ? (SOCK_STREAM | SOCK_CLOEXEC) : SOCK_STREAM;
  92                 *type = "r+";
  93                 if (socketpair(AF_LOCAL, stype, 0, pdes) < 0)
  94                         return NULL;
  95 #if SOCK_CLOEXEC == 0
  96                 fcntl(pdes[0], F_SETFD, FD_CLOEXEC);
  97                 fcntl(pdes[1], F_SETFD, FD_CLOEXEC);
  98 #endif
  99         } else  {
 100                 *type = strrchr(*type, 'r') ? "r" : "w";
 101 #if SOCK_CLOEXEC != 0
 102                 if (pipe2(pdes, flags) == -1)
 103                         return NULL;
 104 #else
 105                 if (pipe(pdes) == -1)
 106                         return NULL;
 107                 fcntl(pdes[0], F_SETFL, fcntl(pdes[0], F_GETFL) | flags);
 108                 fcntl(pdes[1], F_SETFL, fcntl(pdes[1], F_GETFL) | flags);
 109 #endif
 110         }
 111
 112         if ((cur = malloc(sizeof(*cur))) != NULL)
 113                 return cur;
 114         serrno = errno;
 115         (void)close(pdes[0]);
 116         (void)close(pdes[1]);
 117         errno = serrno;
 118         return NULL;
 119 }
 120
 121 static void
 122 pdes_child(int *pdes, const char *type)
 123 {
 124         struct pid *old;
 125
 126         /* POSIX.2 B.3.2.2 "popen() shall ensure that any streams
 127            from previous popen() calls that remain open in the
 128            parent process are closed in the new child process. */
 129         for (old = pidlist; old; old = old->next)
 130 #ifdef _REENTRANT
 131                 (void)close(old->fd); /* don't allow a flush */
 132 #else
 133                 (void)close(fileno(old->fp)); /* don't allow a flush */
 134 #endif
 135
 136         if (type[0] == 'r') {
 137                 (void)close(pdes[0]);
 138                 if (pdes[1] != STDOUT_FILENO) {
 139                         (void)dup2(pdes[1], STDOUT_FILENO);
 140                         (void)close(pdes[1]);
 141                 }
 142                 if (type[1] == '+')
 143                         (void)dup2(STDOUT_FILENO, STDIN_FILENO);
 144         } else {
 145                 (void)close(pdes[1]);
 146                 if (pdes[0] != STDIN_FILENO) {
 147                         (void)dup2(pdes[0], STDIN_FILENO);
 148                         (void)close(pdes[0]);
 149                 }
 150         }
 151 }
 152
 153 static void
 154 pdes_parent(int *pdes, struct pid *cur, pid_t pid, const char *type)
 155 {
 156         FILE *iop;
 157
 158         /* Parent; assume fdopen can't fail. */
 159         if (*type == 'r') {
 160                 iop = fdopen(pdes[0], type);
 161 #ifdef _REENTRANT
 162                 cur->fd = pdes[0];
 163 #endif
 164                 (void)close(pdes[1]);
 165         } else {
 166                 iop = fdopen(pdes[1], type);
 167 #ifdef _REENTRANT
 168                 cur->fd = pdes[1];
 169 #endif
 170                 (void)close(pdes[0]);
 171         }
 172
 173         /* Link into list of file descriptors. */
 174         cur->fp = iop;
 175         cur->pid =  pid;
 176         cur->next = pidlist;
 177         pidlist = cur;
 178 }
 179
 180 static void
 181 pdes_error(int *pdes, struct pid *cur)
 182 {
 183         free(cur);
 184         (void)close(pdes[0]);
 185         (void)close(pdes[1]);
 186 }
 187
 188 FILE *
 189 popenve(const char *cmd, char *const *argv, char *const *envp, const char *type)
 190 {
 191         struct pid *cur;
 192         int pdes[2], serrno;
 193         pid_t pid;
 194
 195         if ((cur = pdes_get(pdes, &type)) == NULL)
 196                 return NULL;
 197
 198 #ifdef _REENTRANT
 199         (void)rwlock_rdlock(&pidlist_lock);
 200 #endif
 201         switch (pid = vfork()) {
 202         case -1:                        /* Error. */
 203                 serrno = errno;
 204 #ifdef _REENTRANT
 205                 (void)rwlock_unlock(&pidlist_lock);
 206 #endif
 207                 pdes_error(pdes, cur);
 208                 errno = serrno;
 209                 return NULL;
 210                 /* NOTREACHED */
 211         case 0:                         /* Child. */
 212                 pdes_child(pdes, type);
 213                 execve(cmd, argv, envp);
 214                 _exit(127);
 215                 /* NOTREACHED */
 216         }
 217
 218         pdes_parent(pdes, cur, pid, type);
 219
 220 #ifdef _REENTRANT
 221         (void)rwlock_unlock(&pidlist_lock);
 222 #endif
 223
 224         return cur->fp;
 225 }
 226
 227 /*
 228  * pclose --
 229  *      Pclose returns -1 if stream is not associated with a `popened' command,
 230  *      if already `pclosed', or waitpid returns an error.
 231  */
 232 int
 233 pcloseve(FILE *iop)
 234 {
 235         struct pid *cur, *last;
 236         int pstat;
 237         pid_t pid;
 238
 239 #ifdef _REENTRANT
 240         rwlock_wrlock(&pidlist_lock);
 241 #endif
 242
 243         /* Find the appropriate file pointer. */
 244         for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next)
 245                 if (cur->fp == iop)
 246                         break;
 247         if (cur == NULL) {
 248 #ifdef _REENTRANT
 249                 (void)rwlock_unlock(&pidlist_lock);
 250 #endif
 251                 errno = ESRCH;
 252                 return -1;
 253         }
 254
 255         (void)fclose(iop);
 256
 257         /* Remove the entry from the linked list. */
 258         if (last == NULL)
 259                 pidlist = cur->next;
 260         else
 261                 last->next = cur->next;
 262
 263 #ifdef _REENTRANT
 264         (void)rwlock_unlock(&pidlist_lock);
 265 #endif
 266
 267         do {
 268                 pid = waitpid(cur->pid, &pstat, 0);
 269         } while (pid == -1 && errno == EINTR);
 270
 271         free(cur);
 272
 273         return pid == -1 ? -1 : pstat;
 274 }