usr.sbin/installer/libaura/popen.c

   1 /*
   2  * Copyright (c) 1988, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  * Copyright (c) 2004 The DragonFly Project.  All rights reserved.
   5  *
   6  * This code is derived from software written by Ken Arnold and
   7  * published in UNIX Review, Vol. 6, No. 8.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  * 3. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  * $FreeBSD: src/lib/libc/gen/popen.c,v 1.14 2000/01/27 23:06:19 jasone Exp $
  34  * $Id: popen.c,v 1.6 2005/02/06 06:57:30 cpressey Exp $
  35  *
  36  * @(#)popen.c  8.3 (Berkeley) 5/3/95
  37  *
  38  * A modified version of the standard popen()/pclose() functions
  39  * which adds a third function, pgetpid(), which allows the program
  40  * which used popen() to obtain the pid of the process on the other
  41  * end of the pipe.
  42  */
  43
  44 #include <sys/param.h>
  45 #include <sys/wait.h>
  46 #include <sys/types.h>
  47 #include <sys/time.h>
  48
  49 #include <errno.h>
  50 #include <signal.h>
  51 #include <stdarg.h>
  52 #include <paths.h>
  53 #include <stdio.h>
  54 #include <stdlib.h>
  55 #include <string.h>
  56 #include <unistd.h>
  57
  58 #include "popen.h"
  59
  60 extern char **environ;
  61
  62 static struct pid {
  63         struct pid      *next;
  64         FILE            *fp;
  65         pid_t           pid;
  66 } *pidlist;
  67
  68 FILE *
  69 aura_popen(const char *fmt, const char *type, ...)
  70 {
  71         FILE *iop;
  72         struct pid *cur;
  73         struct pid *p;
  74         va_list args;
  75         char *command;
  76         const char *argv[4];
  77         int pdes[2], pid;
  78         volatile enum { READ, WRITE, TWO_WAY } pipedir;
  79
  80         /*
  81          * Lite2 introduced two-way popen() pipes using socketpair().
  82          * FreeBSD's pipe() is bidirectional, so we use that.
  83          */
  84         if (strchr(type, '+')) {
  85                 pipedir = TWO_WAY;
  86         } else {
  87                 if (type[1] != '\0')
  88                         return(NULL);
  89                 if (*type == 'r')
  90                         pipedir = READ;
  91                 else if (*type == 'w')
  92                         pipedir = WRITE;
  93                 else
  94                         return(NULL);
  95         }
  96
  97         if (pipe(pdes) < 0)
  98                 return(NULL);
  99
 100         if ((cur = malloc(sizeof(struct pid))) == NULL) {
 101                 close(pdes[0]);
 102                 close(pdes[1]);
 103                 return(NULL);
 104         }
 105
 106         va_start(args, type);
 107         vasprintf(&command, fmt, args);
 108         va_end(args);
 109
 110         argv[0] = "sh";
 111         argv[1] = "-c";
 112         argv[2] = command;
 113         argv[3] = NULL;
 114
 115         switch (pid = vfork()) {
 116         case -1:                        /* Error. */
 117                 close(pdes[0]);
 118                 close(pdes[1]);
 119                 free(cur);
 120                 free(command);
 121                 return(NULL);
 122                 /* NOTREACHED */
 123         case 0:                         /* Child. */
 124                 if (pipedir == READ || pipedir == TWO_WAY) {
 125                         /*
 126                          * The dup2() to STDIN_FILENO is repeated to avoid
 127                          * writing to pdes[1], which might corrupt the
 128                          * parent's copy.  This isn't good enough in
 129                          * general, since the _exit() is no return, so
 130                          * the compiler is free to corrupt all the local
 131                          * variables.
 132                          */
 133                         close(pdes[0]);
 134                         if (pdes[1] != STDOUT_FILENO) {
 135                                 dup2(pdes[1], STDOUT_FILENO);
 136                                 close(pdes[1]);
 137                                 if (pipedir == TWO_WAY)
 138                                         dup2(STDOUT_FILENO, STDIN_FILENO);
 139                         } else if (pipedir == TWO_WAY &&
 140                                    (pdes[1] != STDIN_FILENO)) {
 141                                 dup2(pdes[1], STDIN_FILENO);
 142                         }
 143                 } else {
 144                         if (pdes[0] != STDIN_FILENO) {
 145                                 dup2(pdes[0], STDIN_FILENO);
 146                                 close(pdes[0]);
 147                         }
 148                         close(pdes[1]);
 149                 }
 150                 for (p = pidlist; p; p = p->next) {
 151                         close(fileno(p->fp));
 152                 }
 153                 execve(_PATH_BSHELL, __DECONST(char **, argv), environ);
 154                 _exit(127);
 155                 /* NOTREACHED */
 156         }
 157
 158         /* Parent; assume fdopen can't fail. */
 159         if (pipedir == READ || pipedir == TWO_WAY) {
 160                 iop = fdopen(pdes[0], type);
 161                 close(pdes[1]);
 162         } else {
 163                 iop = fdopen(pdes[1], type);
 164                 close(pdes[0]);
 165         }
 166
 167         /* Link into list of file descriptors. */
 168         cur->fp = iop;
 169         cur->pid =  pid;
 170         cur->next = pidlist;
 171         pidlist = cur;
 172
 173         free(command);
 174         return(iop);
 175 }
 176
 177 /*
 178  * pclose --
 179  *      Pclose returns -1 if stream is not associated with a `popened' command,
 180  *      if already `pclosed', or waitpid returns an error.
 181  */
 182 int
 183 aura_pclose(FILE *iop)
 184 {
 185         struct pid *cur, *last;
 186         int pstat;
 187         pid_t pid;
 188
 189         /* Find the appropriate file pointer. */
 190         for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next) {
 191                 if (cur->fp == iop)
 192                         break;
 193         }
 194
 195         if (cur == NULL)
 196                 return (-1);
 197
 198         fclose(iop);
 199
 200         do {
 201                 pid = wait4(cur->pid, &pstat, 0, (struct rusage *)0);
 202         } while (pid == -1 && errno == EINTR);
 203
 204         /* Remove the entry from the linked list. */
 205         if (last == NULL)
 206                 pidlist = cur->next;
 207         else
 208                 last->next = cur->next;
 209         free(cur);
 210
 211         return (pid == -1 ? -1 : pstat);
 212 }
 213
 214 pid_t
 215 aura_pgetpid(FILE *iop)
 216 {
 217         struct pid *cur;
 218
 219         /* Find the appropriate file pointer. */
 220         for (cur = pidlist; cur; cur = cur->next)
 221                 if (cur->fp == iop)
 222                         break;
 223         if (cur == NULL)
 224                 return (-1);
 225         return(cur->pid);
 226 }
 227
 228 /*
 229  * Returns:
 230  *      1 if all went well.
 231  *      0 if an error occurred, in which case err is set to:
 232  *              AURA_PGETS_TIMEOUT:     select() timed out.
 233  *              AURA_PGETS_SELECT_ERR:  a select() error occurred.
 234  *              AURA_PGETS_EOF:         end of file condition on pipe.
 235  *              AURA_PGETS_FGETS_ERR:   a fgets() error occurred.
 236  */
 237 int
 238 aura_pgets(FILE *p, char *buf, size_t len, long msec, int *err)
 239 {
 240         struct timeval tv;
 241         struct timeval *tvp;
 242         fd_set r;
 243         int n;
 244
 245         tv.tv_sec = msec / 1000;
 246         tv.tv_usec = (msec % 1000) * 1000;
 247         tvp = (msec < 0 ? NULL : &tv);
 248
 249         FD_ZERO(&r);
 250         FD_SET(fileno(p), &r);
 251
 252         *err = 0;
 253         buf[0] = '\0';
 254
 255         if (feof(p)) {
 256                 *err = AURA_PGETS_EOF;
 257                 return(0);
 258         }
 259         if (ferror(p)) {
 260                 *err = AURA_PGETS_FGETS_ERR;
 261                 return(0);
 262         }
 263
 264         n = select(fileno(p) + 1, &r, NULL, NULL, tvp);
 265
 266         if (n == 0) {
 267                 *err = AURA_PGETS_TIMEOUT;
 268                 return(0);
 269         } else if (n < 0) {
 270                 *err = AURA_PGETS_SELECT_ERR;
 271                 return(0);
 272         } else {
 273                 /* Data came in; read it. */
 274                 if (fgets(buf, len, p) == NULL) {
 275                         if (feof(p)) {
 276                                 *err = AURA_PGETS_EOF;
 277                         } else {
 278                                 *err = AURA_PGETS_FGETS_ERR;
 279                         }
 280                         return(0);
 281                 } else {
 282                         return(1);
 283                 }
 284         }
 285 }