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. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by the University of 20 * California, Berkeley and its contributors. 21 * 4. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * $FreeBSD: src/lib/libc/gen/popen.c,v 1.14 2000/01/27 23:06:19 jasone Exp $ 38 * $DragonFly: src/contrib/bsdinstaller-1.1.6/src/lib/libaura/popen.c,v 1.1.1.1 2008/03/12 22:15:54 dave Exp $ 39 * $Id: popen.c,v 1.6 2005/02/06 06:57:30 cpressey Exp $ 40 * 41 * @(#)popen.c 8.3 (Berkeley) 5/3/95 42 * 43 * A modified version of the standard popen()/pclose() functions 44 * which adds a third function, pgetpid(), which allows the program 45 * which used popen() to obtain the pid of the process on the other 46 * end of the pipe. 47 */ 48 49 #include <sys/param.h> 50 #include <sys/wait.h> 51 #include <sys/types.h> 52 #include <sys/time.h> 53 54 #include <errno.h> 55 #include <signal.h> 56 #include <stdarg.h> 57 #include <paths.h> 58 #include <stdio.h> 59 #include <stdlib.h> 60 #include <string.h> 61 #include <unistd.h> 62 63 #include "popen.h" 64 65 extern char **environ; 66 67 static struct pid { 68 struct pid *next; 69 FILE *fp; 70 pid_t pid; 71 } *pidlist; 72 73 FILE * 74 aura_popen(const char *fmt, const char *type, ...) 75 { 76 FILE *iop; 77 struct pid *cur; 78 struct pid *p; 79 va_list args; 80 char *command; 81 const char *argv[4]; 82 int pdes[2], pid; 83 volatile enum { READ, WRITE, TWO_WAY } pipedir; 84 85 /* 86 * Lite2 introduced two-way popen() pipes using socketpair(). 87 * FreeBSD's pipe() is bidirectional, so we use that. 88 */ 89 if (strchr(type, '+')) { 90 pipedir = TWO_WAY; 91 } else { 92 if (type[1] != '\0') 93 return(NULL); 94 if (*type == 'r') 95 pipedir = READ; 96 else if (*type == 'w') 97 pipedir = WRITE; 98 else 99 return(NULL); 100 } 101 102 if (pipe(pdes) < 0) 103 return(NULL); 104 105 if ((cur = malloc(sizeof(struct pid))) == NULL) { 106 close(pdes[0]); 107 close(pdes[1]); 108 return(NULL); 109 } 110 111 va_start(args, type); 112 vasprintf(&command, fmt, args); 113 va_end(args); 114 115 argv[0] = "sh"; 116 argv[1] = "-c"; 117 argv[2] = command; 118 argv[3] = NULL; 119 120 switch (pid = vfork()) { 121 case -1: /* Error. */ 122 close(pdes[0]); 123 close(pdes[1]); 124 free(cur); 125 free(command); 126 return(NULL); 127 /* NOTREACHED */ 128 case 0: /* Child. */ 129 if (pipedir == READ || pipedir == TWO_WAY) { 130 /* 131 * The dup2() to STDIN_FILENO is repeated to avoid 132 * writing to pdes[1], which might corrupt the 133 * parent's copy. This isn't good enough in 134 * general, since the _exit() is no return, so 135 * the compiler is free to corrupt all the local 136 * variables. 137 */ 138 close(pdes[0]); 139 if (pdes[1] != STDOUT_FILENO) { 140 dup2(pdes[1], STDOUT_FILENO); 141 close(pdes[1]); 142 if (pipedir == TWO_WAY) 143 dup2(STDOUT_FILENO, STDIN_FILENO); 144 } else if (pipedir == TWO_WAY && 145 (pdes[1] != STDIN_FILENO)) { 146 dup2(pdes[1], STDIN_FILENO); 147 } 148 } else { 149 if (pdes[0] != STDIN_FILENO) { 150 dup2(pdes[0], STDIN_FILENO); 151 close(pdes[0]); 152 } 153 close(pdes[1]); 154 } 155 for (p = pidlist; p; p = p->next) { 156 close(fileno(p->fp)); 157 } 158 execve(_PATH_BSHELL, __DECONST(char **, argv), environ); 159 _exit(127); 160 /* NOTREACHED */ 161 } 162 163 /* Parent; assume fdopen can't fail. */ 164 if (pipedir == READ || pipedir == TWO_WAY) { 165 iop = fdopen(pdes[0], type); 166 close(pdes[1]); 167 } else { 168 iop = fdopen(pdes[1], type); 169 close(pdes[0]); 170 } 171 172 /* Link into list of file descriptors. */ 173 cur->fp = iop; 174 cur->pid = pid; 175 cur->next = pidlist; 176 pidlist = cur; 177 178 free(command); 179 return(iop); 180 } 181 182 /* 183 * pclose -- 184 * Pclose returns -1 if stream is not associated with a `popened' command, 185 * if already `pclosed', or waitpid returns an error. 186 */ 187 int 188 aura_pclose(FILE *iop) 189 { 190 struct pid *cur, *last; 191 int pstat; 192 pid_t pid; 193 194 /* Find the appropriate file pointer. */ 195 for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next) { 196 if (cur->fp == iop) 197 break; 198 } 199 200 if (cur == NULL) 201 return (-1); 202 203 fclose(iop); 204 205 do { 206 pid = wait4(cur->pid, &pstat, 0, (struct rusage *)0); 207 } while (pid == -1 && errno == EINTR); 208 209 /* Remove the entry from the linked list. */ 210 if (last == NULL) 211 pidlist = cur->next; 212 else 213 last->next = cur->next; 214 free(cur); 215 216 return (pid == -1 ? -1 : pstat); 217 } 218 219 pid_t 220 aura_pgetpid(FILE *iop) 221 { 222 struct pid *cur, *last; 223 224 /* Find the appropriate file pointer. */ 225 for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next) 226 if (cur->fp == iop) 227 break; 228 if (cur == NULL) 229 return (-1); 230 return(cur->pid); 231 } 232 233 /* 234 * Returns: 235 * 1 if all went well. 236 * 0 if an error occurred, in which case err is set to: 237 * AURA_PGETS_TIMEOUT: select() timed out. 238 * AURA_PGETS_SELECT_ERR: a select() error occurred. 239 * AURA_PGETS_EOF: end of file condition on pipe. 240 * AURA_PGETS_FGETS_ERR: a fgets() error occurred. 241 */ 242 int 243 aura_pgets(FILE *p, char *buf, size_t len, long msec, int *err) 244 { 245 struct timeval tv; 246 struct timeval *tvp; 247 fd_set r; 248 int n; 249 250 tv.tv_sec = msec / 1000; 251 tv.tv_usec = (msec % 1000) * 1000; 252 tvp = (msec < 0 ? NULL : &tv); 253 254 FD_ZERO(&r); 255 FD_SET(fileno(p), &r); 256 257 *err = 0; 258 buf[0] = '\0'; 259 260 if (feof(p)) { 261 *err = AURA_PGETS_EOF; 262 return(0); 263 } 264 if (ferror(p)) { 265 *err = AURA_PGETS_FGETS_ERR; 266 return(0); 267 } 268 269 n = select(fileno(p) + 1, &r, NULL, NULL, tvp); 270 271 if (n == 0) { 272 *err = AURA_PGETS_TIMEOUT; 273 return(0); 274 } else if (n < 0) { 275 *err = AURA_PGETS_SELECT_ERR; 276 return(0); 277 } else { 278 /* Data came in; read it. */ 279 if (fgets(buf, len, p) == NULL) { 280 if (feof(p)) { 281 *err = AURA_PGETS_EOF; 282 } else { 283 *err = AURA_PGETS_FGETS_ERR; 284 } 285 return(0); 286 } else { 287 return(1); 288 } 289 } 290 } 291