1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1988, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #include "namespace.h" 33 #include <sys/types.h> 34 #include <sys/wait.h> 35 36 #include <errno.h> 37 #include <paths.h> 38 #include <signal.h> 39 #include <stddef.h> 40 #include <stdlib.h> 41 #include <string.h> 42 #include <unistd.h> 43 #include "un-namespace.h" 44 #include "libc_private.h" 45 #include "spinlock.h" 46 47 #pragma weak system 48 int 49 system(const char *command) 50 { 51 return (((int (*)(const char *)) 52 __libc_interposing[INTERPOS_system])(command)); 53 } 54 55 int 56 __libc_system(const char *command) 57 { 58 static spinlock_t lock = _SPINLOCK_INITIALIZER; 59 static volatile unsigned long concurrent; 60 static struct sigaction ointact, oquitact; 61 struct sigaction ign; 62 sigset_t sigblock, osigblock; 63 char *argv[] = { "sh", "-c", __DECONST(char *, command), NULL }; 64 extern char **environ; 65 int pstat = -1, serrno = 0; 66 pid_t pid; 67 68 if (command == NULL) /* just checking... */ 69 return (eaccess(_PATH_BSHELL, X_OK) == 0); 70 71 /* 72 * If we are the first concurrent instance, ignore SIGINT and 73 * SIGQUIT. Block SIGCHLD regardless of concurrency, since on 74 * FreeBSD, sigprocmask() is equivalent to pthread_sigmask(). 75 */ 76 if (__isthreaded) 77 _SPINLOCK(&lock); 78 if (concurrent++ == 0) { 79 memset(&ign, 0, sizeof(ign)); 80 ign.sa_handler = SIG_IGN; 81 sigemptyset(&ign.sa_mask); 82 (void)__libc_sigaction(SIGINT, &ign, &ointact); 83 (void)__libc_sigaction(SIGQUIT, &ign, &oquitact); 84 } 85 sigemptyset(&sigblock); 86 sigaddset(&sigblock, SIGCHLD); 87 (void)__libc_sigprocmask(SIG_BLOCK, &sigblock, &osigblock); 88 if (__isthreaded) 89 _SPINUNLOCK(&lock); 90 91 /* 92 * Fork the child process. 93 */ 94 if ((pid = fork()) < 0) { /* error */ 95 serrno = errno; 96 } else if (pid == 0) { /* child */ 97 /* 98 * Restore original signal dispositions. 99 */ 100 (void)__libc_sigaction(SIGINT, &ointact, NULL); 101 (void)__libc_sigaction(SIGQUIT, &oquitact, NULL); 102 (void)__sys_sigprocmask(SIG_SETMASK, &osigblock, NULL); 103 /* 104 * Exec the command. 105 */ 106 _execve(_PATH_BSHELL, argv, environ); 107 _exit(127); 108 } else { /* parent */ 109 /* 110 * Wait for the child to terminate. 111 */ 112 while (_wait4(pid, &pstat, 0, NULL) < 0) { 113 if (errno != EINTR) { 114 serrno = errno; 115 break; 116 } 117 } 118 } 119 120 /* 121 * If we are the last concurrent instance, restore original signal 122 * dispositions. Unblock SIGCHLD, unless it was already blocked. 123 */ 124 if (__isthreaded) 125 _SPINLOCK(&lock); 126 if (--concurrent == 0) { 127 (void)__libc_sigaction(SIGINT, &ointact, NULL); 128 (void)__libc_sigaction(SIGQUIT, &oquitact, NULL); 129 } 130 if (!sigismember(&osigblock, SIGCHLD)) 131 (void)__libc_sigprocmask(SIG_UNBLOCK, &sigblock, NULL); 132 if (__isthreaded) 133 _SPINUNLOCK(&lock); 134 if (serrno != 0) 135 errno = serrno; 136 return (pstat); 137 } 138 139 __weak_reference(__libc_system, __system); 140 __weak_reference(__libc_system, _system); 141