1 /* $NetBSD: system.c,v 1.22 2008/08/27 06:45:02 christos Exp $ */ 2 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 <sys/cdefs.h> 33 #if defined(LIBC_SCCS) && !defined(lint) 34 #if 0 35 static char sccsid[] = "@(#)system.c 8.1 (Berkeley) 6/4/93"; 36 #else 37 __RCSID("$NetBSD: system.c,v 1.22 2008/08/27 06:45:02 christos Exp $"); 38 #endif 39 #endif /* LIBC_SCCS and not lint */ 40 41 #include "namespace.h" 42 #include <sys/types.h> 43 #include <sys/wait.h> 44 #include <errno.h> 45 #include <signal.h> 46 #include <stdlib.h> 47 #include <unistd.h> 48 #include <paths.h> 49 #include "reentrant.h" 50 51 #ifdef _REENTRANT 52 extern rwlock_t __environ_lock; 53 #endif 54 extern char **environ; 55 56 int 57 system(command) 58 const char *command; 59 { 60 pid_t pid; 61 struct sigaction intsa, quitsa, sa; 62 sigset_t nmask, omask; 63 int pstat; 64 const char *argp[] = {"sh", "-c", NULL, NULL}; 65 argp[2] = command; 66 67 /* 68 * ISO/IEC 9899:1999 in 7.20.4.6 describes this special case. 69 * We need to check availability of a command interpreter. 70 */ 71 if (command == NULL) { 72 if (access(_PATH_BSHELL, X_OK) == 0) 73 return 1; 74 return 0; 75 } 76 77 sa.sa_handler = SIG_IGN; 78 sigemptyset(&sa.sa_mask); 79 sa.sa_flags = 0; 80 81 if (sigaction(SIGINT, &sa, &intsa) == -1) 82 return -1; 83 if (sigaction(SIGQUIT, &sa, &quitsa) == -1) { 84 sigaction(SIGINT, &intsa, NULL); 85 return -1; 86 } 87 88 sigemptyset(&nmask); 89 sigaddset(&nmask, SIGCHLD); 90 if (sigprocmask(SIG_BLOCK, &nmask, &omask) == -1) { 91 sigaction(SIGINT, &intsa, NULL); 92 sigaction(SIGQUIT, &quitsa, NULL); 93 return -1; 94 } 95 96 rwlock_rdlock(&__environ_lock); 97 switch(pid = vfork()) { 98 case -1: /* error */ 99 rwlock_unlock(&__environ_lock); 100 sigaction(SIGINT, &intsa, NULL); 101 sigaction(SIGQUIT, &quitsa, NULL); 102 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 103 return -1; 104 case 0: /* child */ 105 sigaction(SIGINT, &intsa, NULL); 106 sigaction(SIGQUIT, &quitsa, NULL); 107 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 108 execve(_PATH_BSHELL, __UNCONST(argp), environ); 109 _exit(127); 110 } 111 rwlock_unlock(&__environ_lock); 112 113 while (waitpid(pid, &pstat, 0) == -1) { 114 if (errno != EINTR) { 115 pstat = -1; 116 break; 117 } 118 } 119 120 sigaction(SIGINT, &intsa, NULL); 121 sigaction(SIGQUIT, &quitsa, NULL); 122 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 123 124 return (pstat); 125 } 126