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 int pstat = -1, serrno = 0; 64 pid_t pid; 65 66 if (command == NULL) /* just checking... */ 67 return (eaccess(_PATH_BSHELL, X_OK) == 0); 68 69 /* 70 * If we are the first concurrent instance, ignore SIGINT and 71 * SIGQUIT. Block SIGCHLD regardless of concurrency, since on 72 * FreeBSD, sigprocmask() is equivalent to pthread_sigmask(). 73 */ 74 if (__isthreaded) 75 _SPINLOCK(&lock); 76 if (concurrent++ == 0) { 77 memset(&ign, 0, sizeof(ign)); 78 ign.sa_handler = SIG_IGN; 79 sigemptyset(&ign.sa_mask); 80 (void)__libc_sigaction(SIGINT, &ign, &ointact); 81 (void)__libc_sigaction(SIGQUIT, &ign, &oquitact); 82 } 83 sigemptyset(&sigblock); 84 sigaddset(&sigblock, SIGCHLD); 85 (void)__libc_sigprocmask(SIG_BLOCK, &sigblock, &osigblock); 86 if (__isthreaded) 87 _SPINUNLOCK(&lock); 88 89 /* 90 * Fork the child process. 91 */ 92 if ((pid = fork()) < 0) { /* error */ 93 serrno = errno; 94 } else if (pid == 0) { /* child */ 95 /* 96 * Restore original signal dispositions. 97 */ 98 (void)__libc_sigaction(SIGINT, &ointact, NULL); 99 (void)__libc_sigaction(SIGQUIT, &oquitact, NULL); 100 (void)__sys_sigprocmask(SIG_SETMASK, &osigblock, NULL); 101 /* 102 * Exec the command. 103 */ 104 execl(_PATH_BSHELL, "sh", "-c", command, NULL); 105 _exit(127); 106 } else { /* parent */ 107 /* 108 * Wait for the child to terminate. 109 */ 110 while (_wait4(pid, &pstat, 0, NULL) < 0) { 111 if (errno != EINTR) { 112 serrno = errno; 113 break; 114 } 115 } 116 } 117 118 /* 119 * If we are the last concurrent instance, restore original signal 120 * dispositions. Unblock SIGCHLD, unless it was already blocked. 121 */ 122 if (__isthreaded) 123 _SPINLOCK(&lock); 124 if (--concurrent == 0) { 125 (void)__libc_sigaction(SIGINT, &ointact, NULL); 126 (void)__libc_sigaction(SIGQUIT, &oquitact, NULL); 127 } 128 if (!sigismember(&osigblock, SIGCHLD)) 129 (void)__libc_sigprocmask(SIG_UNBLOCK, &sigblock, NULL); 130 if (__isthreaded) 131 _SPINUNLOCK(&lock); 132 if (serrno != 0) 133 errno = serrno; 134 return (pstat); 135 } 136 137 __weak_reference(__libc_system, __system); 138 __weak_reference(__libc_system, _system); 139