1*0Sstevel@tonic-gate /* 2*0Sstevel@tonic-gate * Copyright 2004 Sun Microsystems, Inc. All rights reserved. 3*0Sstevel@tonic-gate * Use is subject to license terms. 4*0Sstevel@tonic-gate */ 5*0Sstevel@tonic-gate 6*0Sstevel@tonic-gate #pragma ident "%Z%%M% %I% %E% SMI" 7*0Sstevel@tonic-gate 8*0Sstevel@tonic-gate /* 9*0Sstevel@tonic-gate * shell_cmd() takes a shell command after %<character> substitutions. The 10*0Sstevel@tonic-gate * command is executed by a /bin/sh child process, with standard input, 11*0Sstevel@tonic-gate * standard output and standard error connected to /dev/null. 12*0Sstevel@tonic-gate * 13*0Sstevel@tonic-gate * Diagnostics are reported through syslog(3). 14*0Sstevel@tonic-gate * 15*0Sstevel@tonic-gate * Author: Wietse Venema, Eindhoven University of Technology, The Netherlands. 16*0Sstevel@tonic-gate */ 17*0Sstevel@tonic-gate 18*0Sstevel@tonic-gate #ifndef lint 19*0Sstevel@tonic-gate static char sccsid[] = "@(#) shell_cmd.c 1.5 94/12/28 17:42:44"; 20*0Sstevel@tonic-gate #endif 21*0Sstevel@tonic-gate 22*0Sstevel@tonic-gate /* System libraries. */ 23*0Sstevel@tonic-gate 24*0Sstevel@tonic-gate #include <sys/types.h> 25*0Sstevel@tonic-gate #include <sys/param.h> 26*0Sstevel@tonic-gate #include <signal.h> 27*0Sstevel@tonic-gate #include <stdio.h> 28*0Sstevel@tonic-gate #include <stdlib.h> 29*0Sstevel@tonic-gate #include <unistd.h> 30*0Sstevel@tonic-gate #include <wait.h> 31*0Sstevel@tonic-gate #include <fcntl.h> 32*0Sstevel@tonic-gate #include <syslog.h> 33*0Sstevel@tonic-gate #include <string.h> 34*0Sstevel@tonic-gate 35*0Sstevel@tonic-gate extern void exit(); 36*0Sstevel@tonic-gate 37*0Sstevel@tonic-gate /* Local stuff. */ 38*0Sstevel@tonic-gate 39*0Sstevel@tonic-gate #include "tcpd.h" 40*0Sstevel@tonic-gate 41*0Sstevel@tonic-gate /* Forward declarations. */ 42*0Sstevel@tonic-gate 43*0Sstevel@tonic-gate static void do_child(); 44*0Sstevel@tonic-gate 45*0Sstevel@tonic-gate /* shell_cmd - execute shell command */ 46*0Sstevel@tonic-gate 47*0Sstevel@tonic-gate void shell_cmd(command) 48*0Sstevel@tonic-gate char *command; 49*0Sstevel@tonic-gate { 50*0Sstevel@tonic-gate int child_pid; 51*0Sstevel@tonic-gate int wait_pid; 52*0Sstevel@tonic-gate 53*0Sstevel@tonic-gate /* 54*0Sstevel@tonic-gate * Most of the work is done within the child process, to minimize the 55*0Sstevel@tonic-gate * risk of damage to the parent. 56*0Sstevel@tonic-gate */ 57*0Sstevel@tonic-gate 58*0Sstevel@tonic-gate switch (child_pid = fork()) { 59*0Sstevel@tonic-gate case -1: /* error */ 60*0Sstevel@tonic-gate tcpd_warn("cannot fork: %m"); 61*0Sstevel@tonic-gate break; 62*0Sstevel@tonic-gate case 00: /* child */ 63*0Sstevel@tonic-gate do_child(command); 64*0Sstevel@tonic-gate /* NOTREACHED */ 65*0Sstevel@tonic-gate default: /* parent */ 66*0Sstevel@tonic-gate while ((wait_pid = wait((int *) 0)) != -1 && wait_pid != child_pid) 67*0Sstevel@tonic-gate /* void */ ; 68*0Sstevel@tonic-gate } 69*0Sstevel@tonic-gate } 70*0Sstevel@tonic-gate 71*0Sstevel@tonic-gate /* do_child - exec command with { stdin, stdout, stderr } to /dev/null */ 72*0Sstevel@tonic-gate 73*0Sstevel@tonic-gate static void do_child(command) 74*0Sstevel@tonic-gate char *command; 75*0Sstevel@tonic-gate { 76*0Sstevel@tonic-gate char *error; 77*0Sstevel@tonic-gate int tmp_fd; 78*0Sstevel@tonic-gate 79*0Sstevel@tonic-gate /* 80*0Sstevel@tonic-gate * Systems with POSIX sessions may send a SIGHUP to grandchildren if the 81*0Sstevel@tonic-gate * child exits first. This is sick, sessions were invented for terminals. 82*0Sstevel@tonic-gate */ 83*0Sstevel@tonic-gate 84*0Sstevel@tonic-gate signal(SIGHUP, SIG_IGN); 85*0Sstevel@tonic-gate 86*0Sstevel@tonic-gate /* Set up new stdin, stdout, stderr, and exec the shell command. */ 87*0Sstevel@tonic-gate 88*0Sstevel@tonic-gate for (tmp_fd = 0; tmp_fd < 3; tmp_fd++) 89*0Sstevel@tonic-gate (void) close(tmp_fd); 90*0Sstevel@tonic-gate if (open("/dev/null", 2) != 0) { 91*0Sstevel@tonic-gate error = "open /dev/null: %m"; 92*0Sstevel@tonic-gate } else if (dup(0) != 1 || dup(0) != 2) { 93*0Sstevel@tonic-gate error = "dup: %m"; 94*0Sstevel@tonic-gate } else { 95*0Sstevel@tonic-gate (void) execl("/bin/sh", "sh", "-c", command, (char *) 0); 96*0Sstevel@tonic-gate error = "execl /bin/sh: %m"; 97*0Sstevel@tonic-gate } 98*0Sstevel@tonic-gate 99*0Sstevel@tonic-gate /* Something went wrong. We MUST terminate the child process. */ 100*0Sstevel@tonic-gate 101*0Sstevel@tonic-gate tcpd_warn(error); 102*0Sstevel@tonic-gate _exit(0); 103*0Sstevel@tonic-gate } 104