popen.c revision 279813
1270096Strasz/* 2270096Strasz * Copyright (c) 1988, 1993 3270096Strasz * The Regents of the University of California. All rights reserved. 4270096Strasz * Copyright (c) 2014 The FreeBSD Foundation 5270096Strasz * All rights reserved. 6270096Strasz * 7270096Strasz * This code is derived from software written by Ken Arnold and 8270096Strasz * published in UNIX Review, Vol. 6, No. 8. 9270096Strasz * 10270096Strasz * Portions of this software were developed by Edward Tomasz Napierala 11270096Strasz * under sponsorship from the FreeBSD Foundation. 12270096Strasz * 13270096Strasz * Redistribution and use in source and binary forms, with or without 14270096Strasz * modification, are permitted provided that the following conditions 15270096Strasz * are met: 16270096Strasz * 1. Redistributions of source code must retain the above copyright 17270096Strasz * notice, this list of conditions and the following disclaimer. 18270096Strasz * 2. Redistributions in binary form must reproduce the above copyright 19270096Strasz * notice, this list of conditions and the following disclaimer in the 20270096Strasz * documentation and/or other materials provided with the distribution. 21270096Strasz * 4. Neither the name of the University nor the names of its contributors 22270096Strasz * may be used to endorse or promote products derived from this software 23270096Strasz * without specific prior written permission. 24270096Strasz * 25270096Strasz * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26270096Strasz * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27270096Strasz * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28270096Strasz * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29270096Strasz * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30270096Strasz * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31270096Strasz * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32270096Strasz * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33270096Strasz * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34270096Strasz * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35270096Strasz * SUCH DAMAGE. 36270096Strasz * 37270096Strasz */ 38270096Strasz 39270276Strasz#include <sys/cdefs.h> 40270276Strasz__FBSDID("$FreeBSD: head/usr.sbin/autofs/popen.c 279813 2015-03-09 15:31:33Z trasz $"); 41270276Strasz 42270096Strasz#include <sys/param.h> 43270096Strasz#include <sys/queue.h> 44270096Strasz#include <sys/wait.h> 45270096Strasz 46270096Strasz#include <errno.h> 47270096Strasz#include <fcntl.h> 48270096Strasz#include <unistd.h> 49270096Strasz#include <stdarg.h> 50270096Strasz#include <stdio.h> 51270096Strasz#include <stdlib.h> 52270096Strasz#include <string.h> 53270096Strasz#include <paths.h> 54270096Strasz 55270096Strasz#include "common.h" 56270096Strasz 57270096Straszextern char **environ; 58270096Strasz 59270096Straszstruct pid { 60270096Strasz SLIST_ENTRY(pid) next; 61270096Strasz FILE *outfp; 62270096Strasz pid_t pid; 63270096Strasz char *command; 64270096Strasz}; 65270096Straszstatic SLIST_HEAD(, pid) pidlist = SLIST_HEAD_INITIALIZER(pidlist); 66270096Strasz 67270096Strasz#define ARGV_LEN 42 68270096Strasz 69270096Strasz/* 70270096Strasz * Replacement for popen(3), without stdin (which we do not use), but with 71270096Strasz * stderr, proper logging, and improved command line arguments passing. 72270096Strasz * Error handling is built in - if it returns, then it succeeded. 73270096Strasz */ 74270096StraszFILE * 75270096Straszauto_popen(const char *argv0, ...) 76270096Strasz{ 77270096Strasz va_list ap; 78270096Strasz struct pid *cur, *p; 79270096Strasz pid_t pid; 80270096Strasz int error, i, nullfd, outfds[2]; 81270096Strasz char *arg, *argv[ARGV_LEN], *command; 82270096Strasz 83270096Strasz nullfd = open(_PATH_DEVNULL, O_RDWR, 0); 84270096Strasz if (nullfd < 0) 85270096Strasz log_err(1, "cannot open %s", _PATH_DEVNULL); 86270096Strasz 87270096Strasz error = pipe(outfds); 88270096Strasz if (error != 0) 89270096Strasz log_err(1, "pipe"); 90270096Strasz 91270096Strasz cur = malloc(sizeof(struct pid)); 92270096Strasz if (cur == NULL) 93270096Strasz log_err(1, "malloc"); 94270096Strasz 95270096Strasz argv[0] = checked_strdup(argv0); 96270096Strasz command = argv[0]; 97270096Strasz 98270096Strasz va_start(ap, argv0); 99270096Strasz for (i = 1;; i++) { 100270096Strasz if (i >= ARGV_LEN) 101270096Strasz log_errx(1, "too many arguments to auto_popen"); 102270096Strasz arg = va_arg(ap, char *); 103270096Strasz argv[i] = arg; 104270096Strasz if (arg == NULL) 105270096Strasz break; 106270096Strasz 107279813Strasz command = concat(command, ' ', arg); 108270096Strasz } 109270096Strasz va_end(ap); 110270096Strasz 111270096Strasz cur->command = checked_strdup(command); 112270096Strasz 113270096Strasz switch (pid = fork()) { 114270096Strasz case -1: /* Error. */ 115270096Strasz log_err(1, "fork"); 116270096Strasz /* NOTREACHED */ 117270096Strasz case 0: /* Child. */ 118270096Strasz dup2(nullfd, STDIN_FILENO); 119270096Strasz dup2(outfds[1], STDOUT_FILENO); 120270096Strasz 121270096Strasz close(nullfd); 122270096Strasz close(outfds[0]); 123270096Strasz close(outfds[1]); 124270096Strasz 125270096Strasz SLIST_FOREACH(p, &pidlist, next) 126270096Strasz close(fileno(p->outfp)); 127270096Strasz execvp(argv[0], argv); 128270096Strasz log_err(1, "failed to execute %s", argv[0]); 129270096Strasz /* NOTREACHED */ 130270096Strasz } 131270096Strasz 132270096Strasz log_debugx("executing \"%s\" as pid %d", command, pid); 133270096Strasz 134270096Strasz /* Parent; assume fdopen cannot fail. */ 135270096Strasz cur->outfp = fdopen(outfds[0], "r"); 136270096Strasz close(nullfd); 137270096Strasz close(outfds[1]); 138270096Strasz 139270096Strasz /* Link into list of file descriptors. */ 140270096Strasz cur->pid = pid; 141270096Strasz SLIST_INSERT_HEAD(&pidlist, cur, next); 142270096Strasz 143270096Strasz return (cur->outfp); 144270096Strasz} 145270096Strasz 146270096Straszint 147270096Straszauto_pclose(FILE *iop) 148270096Strasz{ 149270096Strasz struct pid *cur, *last = NULL; 150270096Strasz int status; 151270096Strasz pid_t pid; 152270096Strasz 153270096Strasz /* 154270096Strasz * Find the appropriate file pointer and remove it from the list. 155270096Strasz */ 156270096Strasz SLIST_FOREACH(cur, &pidlist, next) { 157270096Strasz if (cur->outfp == iop) 158270096Strasz break; 159270096Strasz last = cur; 160270096Strasz } 161270096Strasz if (cur == NULL) { 162270096Strasz return (-1); 163270096Strasz } 164270096Strasz if (last == NULL) 165270096Strasz SLIST_REMOVE_HEAD(&pidlist, next); 166270096Strasz else 167270096Strasz SLIST_REMOVE_AFTER(last, next); 168270096Strasz 169270096Strasz fclose(cur->outfp); 170270096Strasz 171270096Strasz do { 172270096Strasz pid = wait4(cur->pid, &status, 0, NULL); 173270096Strasz } while (pid == -1 && errno == EINTR); 174270096Strasz 175270096Strasz if (WIFSIGNALED(status)) { 176270096Strasz log_warnx("\"%s\", pid %d, terminated with signal %d", 177270096Strasz cur->command, pid, WTERMSIG(status)); 178270096Strasz return (status); 179270096Strasz } 180270096Strasz 181270096Strasz if (WEXITSTATUS(status) != 0) { 182270096Strasz log_warnx("\"%s\", pid %d, terminated with exit status %d", 183270096Strasz cur->command, pid, WEXITSTATUS(status)); 184270096Strasz return (status); 185270096Strasz } 186270096Strasz 187270096Strasz log_debugx("\"%s\", pid %d, terminated gracefully", cur->command, pid); 188270096Strasz 189270096Strasz free(cur->command); 190270096Strasz free(cur); 191270096Strasz 192270096Strasz return (pid == -1 ? -1 : status); 193270096Strasz} 194