1 /* $NetBSD: popen.c,v 1.1 2018/01/09 03:31:15 christos Exp $ */ 2 3 /* 4 * Copyright (c) 1988, 1993 5 * The Regents of the University of California. All rights reserved. 6 * Copyright (c) 2017 The NetBSD Foundation, Inc. 7 * Copyright (c) 2016 The DragonFly Project 8 * Copyright (c) 2014 The FreeBSD Foundation 9 * All rights reserved. 10 * 11 * This code is derived from software contributed to The NetBSD Foundation 12 * by Tomohiro Kusumi <kusumi.tomohiro (at) gmail.com>. 13 * 14 * This code is derived from software written by Ken Arnold and 15 * published in UNIX Review, Vol. 6, No. 8. 16 * 17 * Portions of this software were developed by Edward Tomasz Napierala 18 * under sponsorship from the FreeBSD Foundation. 19 * 20 * Redistribution and use in source and binary forms, with or without 21 * modification, are permitted provided that the following conditions 22 * are met: 23 * 1. Redistributions of source code must retain the above copyright 24 * notice, this list of conditions and the following disclaimer. 25 * 2. Redistributions in binary form must reproduce the above copyright 26 * notice, this list of conditions and the following disclaimer in the 27 * documentation and/or other materials provided with the distribution. 28 * 3. Neither the name of the University nor the names of its contributors 29 * may be used to endorse or promote products derived from this software 30 * without specific prior written permission. 31 * 32 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 33 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 34 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 35 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 36 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 37 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 38 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 39 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 40 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 41 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 42 * SUCH DAMAGE. 43 * 44 */ 45 #include <sys/cdefs.h> 46 __RCSID("$NetBSD: popen.c,v 1.1 2018/01/09 03:31:15 christos Exp $"); 47 48 #include <sys/types.h> 49 #include <sys/queue.h> 50 #include <sys/wait.h> 51 #include <errno.h> 52 #include <fcntl.h> 53 #include <paths.h> 54 #include <stdarg.h> 55 #include <stdio.h> 56 #include <stdlib.h> 57 #include <string.h> 58 #include <unistd.h> 59 60 #include "common.h" 61 62 extern char **environ; 63 64 struct pid { 65 SLIST_ENTRY(pid) next; 66 FILE *outfp; 67 pid_t pid; 68 char *command; 69 }; 70 static SLIST_HEAD(, pid) pidlist = SLIST_HEAD_INITIALIZER(pidlist); 71 72 #define ARGV_LEN 42 73 74 /* 75 * Replacement for popen(3), without stdin (which we do not use), but with 76 * stderr, proper logging, and improved command line arguments passing. 77 * Error handling is built in - if it returns, then it succeeded. 78 */ 79 FILE * 80 auto_popen(const char *argv0, ...) 81 { 82 va_list ap; 83 struct pid *cur, *p; 84 pid_t pid; 85 int error, i, nullfd, outfds[2]; 86 char *arg, *argv[ARGV_LEN], *command; 87 88 nullfd = open(_PATH_DEVNULL, O_RDWR, 0); 89 if (nullfd < 0) 90 log_err(1, "cannot open %s", _PATH_DEVNULL); 91 92 error = pipe(outfds); 93 if (error != 0) 94 log_err(1, "pipe"); 95 96 cur = malloc(sizeof(struct pid)); 97 if (cur == NULL) 98 log_err(1, "malloc"); 99 100 argv[0] = checked_strdup(argv0); 101 command = argv[0]; 102 103 va_start(ap, argv0); 104 for (i = 1;; i++) { 105 if (i >= ARGV_LEN) 106 log_errx(1, "too many arguments to auto_popen"); 107 arg = va_arg(ap, char *); 108 argv[i] = arg; 109 if (arg == NULL) 110 break; 111 112 command = concat(command, ' ', arg); 113 } 114 va_end(ap); 115 116 cur->command = checked_strdup(command); 117 118 switch (pid = fork()) { 119 case -1: /* Error. */ 120 log_err(1, "fork"); 121 /* NOTREACHED */ 122 case 0: /* Child. */ 123 dup2(nullfd, STDIN_FILENO); 124 dup2(outfds[1], STDOUT_FILENO); 125 126 close(nullfd); 127 close(outfds[0]); 128 close(outfds[1]); 129 130 SLIST_FOREACH(p, &pidlist, next) 131 close(fileno(p->outfp)); 132 execvp(argv[0], argv); 133 log_err(1, "failed to execute %s", argv[0]); 134 /* NOTREACHED */ 135 } 136 137 log_debugx("executing \"%s\" as pid %d", command, pid); 138 139 /* Parent; assume fdopen cannot fail. */ 140 cur->outfp = fdopen(outfds[0], "r"); 141 close(nullfd); 142 close(outfds[1]); 143 144 /* Link into list of file descriptors. */ 145 cur->pid = pid; 146 SLIST_INSERT_HEAD(&pidlist, cur, next); 147 148 return cur->outfp; 149 } 150 151 int 152 auto_pclose(FILE *iop) 153 { 154 struct pid *cur, *last = NULL; 155 int status; 156 pid_t pid; 157 158 /* 159 * Find the appropriate file pointer and remove it from the list. 160 */ 161 SLIST_FOREACH(cur, &pidlist, next) { 162 if (cur->outfp == iop) 163 break; 164 last = cur; 165 } 166 if (cur == NULL) { 167 return -1; 168 } 169 if (last == NULL) 170 SLIST_REMOVE_HEAD(&pidlist, next); 171 else 172 SLIST_REMOVE_AFTER(last, next); 173 174 fclose(cur->outfp); 175 176 do { 177 pid = wait4(cur->pid, &status, 0, NULL); 178 } while (pid == -1 && errno == EINTR); 179 180 if (WIFSIGNALED(status)) { 181 log_warnx("\"%s\", pid %d, terminated with signal %d", 182 cur->command, pid, WTERMSIG(status)); 183 return status; 184 } 185 186 if (WEXITSTATUS(status) != 0) { 187 log_warnx("\"%s\", pid %d, terminated with exit status %d", 188 cur->command, pid, WEXITSTATUS(status)); 189 return status; 190 } 191 192 log_debugx("\"%s\", pid %d, terminated gracefully", cur->command, pid); 193 194 free(cur->command); 195 free(cur); 196 197 return pid == -1 ? -1 : status; 198 } 199
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