1 /* $NetBSD: system.c,v 1.24 2012/06/25 22:32:45 abs 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 1.24 2012/06/25 22:32:45 abs 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 50 #include "env.h" 51 #include "reentrant.h" 52 53 int 54 system(const char *command) 55 { 56 pid_t pid; 57 struct sigaction intsa, quitsa, sa; 58 sigset_t nmask, omask; 59 int pstat; 60 const char *argp[] = {"sh", "-c", NULL, NULL}; 61 argp[2] = command; 62 63 /* 64 * ISO/IEC 9899:1999 in 7.20.4.6 describes this special case. 65 * We need to check availability of a command interpreter. 66 */ 67 if (command == NULL) { 68 if (access(_PATH_BSHELL, X_OK) == 0) 69 return 1; 70 return 0; 71 } 72 73 sa.sa_handler = SIG_IGN; 74 sigemptyset(&sa.sa_mask); 75 sa.sa_flags = 0; 76 77 if (sigaction(SIGINT, &sa, &intsa) == -1) 78 return -1; 79 if (sigaction(SIGQUIT, &sa, &quitsa) == -1) { 80 sigaction(SIGINT, &intsa, NULL); 81 return -1; 82 } 83 84 sigemptyset(&nmask); 85 sigaddset(&nmask, SIGCHLD); 86 if (sigprocmask(SIG_BLOCK, &nmask, &omask) == -1) { 87 sigaction(SIGINT, &intsa, NULL); 88 sigaction(SIGQUIT, &quitsa, NULL); 89 return -1; 90 } 91 92 (void)__readlockenv(); 93 switch(pid = vfork()) { 94 case -1: /* error */ 95 (void)__unlockenv(); 96 sigaction(SIGINT, &intsa, NULL); 97 sigaction(SIGQUIT, &quitsa, NULL); 98 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 99 return -1; 100 case 0: /* child */ 101 sigaction(SIGINT, &intsa, NULL); 102 sigaction(SIGQUIT, &quitsa, NULL); 103 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 104 execve(_PATH_BSHELL, __UNCONST(argp), environ); 105 _exit(127); 106 } 107 (void)__unlockenv(); 108 109 while (waitpid(pid, &pstat, 0) == -1) { 110 if (errno != EINTR) { 111 pstat = -1; 112 break; 113 } 114 } 115 116 sigaction(SIGINT, &intsa, NULL); 117 sigaction(SIGQUIT, &quitsa, NULL); 118 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 119 120 return (pstat); 121 } 122