1 /* $NetBSD: mime_child.c,v 1.6 2007/10/29 23:20:38 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 2006 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Anon Ymous. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 40 #ifdef MIME_SUPPORT 41 42 #include <sys/cdefs.h> 43 #ifndef __lint__ 44 __RCSID("$NetBSD: mime_child.c,v 1.6 2007/10/29 23:20:38 christos Exp $"); 45 #endif /* not __lint__ */ 46 47 #include <assert.h> 48 #include <fcntl.h> 49 #include <signal.h> 50 #include <stdio.h> 51 #include <stdlib.h> 52 #include <unistd.h> 53 54 #include "def.h" 55 #include "extern.h" 56 57 #ifdef MIME_SUPPORT 58 #include "mime.h" 59 #include "mime_child.h" 60 #endif 61 62 /* 63 * This module contains the core routines used by mime modules that 64 * need to fork children. Nothing else in the mime modules should be 65 * doing a pipe(), fork(), or a call to any popen functions that do. 66 * These routines are tied to the file registry in popen.c and hence 67 * share much of popen code. 68 */ 69 70 #define READ 0 71 #define WRITE 1 72 73 static int 74 get_cmd_flags(const char *cmd, const char **cmd_start) 75 { 76 const char *cp; 77 int flags; 78 79 flags = 0; 80 for (cp = cmd; cp && *cp; cp++) 81 switch (*cp) { 82 case '+': 83 flags |= CMD_FLAG_ALTERNATIVE; 84 break; 85 case '-': 86 flags |= CMD_FLAG_NO_DECODE; 87 break; 88 case '!': 89 flags |= CMD_FLAG_SHELLCMD; 90 break; 91 default: 92 goto done; 93 } 94 done: 95 if (cmd_start) 96 *cmd_start = cp; 97 98 return flags; 99 } 100 101 102 static int 103 prepare_pipe(sigset_t *nset, int p[2]) 104 { 105 if (pipe(p) == -1) 106 return -1; 107 108 (void)fcntl(p[READ], F_SETFD, FD_CLOEXEC); 109 (void)fcntl(p[WRITE], F_SETFD, FD_CLOEXEC); 110 /* 111 * We _must_ ignore SIGINT and SIGPIPE or the child 112 * will end up in our earlier handlers. 113 */ 114 (void)sigemptyset(nset); 115 (void)sigaddset(nset, SIGINT); 116 (void)sigaddset(nset, SIGPIPE); 117 (void)sigaddset(nset, SIGHUP); 118 (void)sigaddset(nset, SIGTSTP); 119 (void)sigaddset(nset, SIGTTOU); 120 (void)sigaddset(nset, SIGTTIN); 121 122 return 0; 123 } 124 125 126 PUBLIC int 127 mime_run_command(const char *cmd, FILE *fo) 128 { 129 sigset_t nset; 130 FILE *nfo; 131 pid_t pid; 132 int p[2]; 133 int flags; 134 135 if (cmd == NULL) 136 return 0; 137 138 flags = get_cmd_flags(cmd, &cmd); 139 if (fo == NULL) /* no output file, just return the flags! */ 140 return flags; 141 142 if ((flags & CMD_FLAG_SHELLCMD) != 0) { /* run command under the shell */ 143 char *cp; 144 char *shellcmd; 145 if ((shellcmd = value(ENAME_SHELL)) == NULL) 146 shellcmd = __UNCONST(_PATH_CSHELL); 147 (void)sasprintf(&cp, "%s -c '%s'", shellcmd, cmd); 148 cmd = cp; 149 } 150 if (prepare_pipe(&nset, p) != 0) { 151 warn("mime_run_command: prepare_pipe"); 152 return flags; /* XXX - this or -1? */ 153 } 154 flush_files(fo, 0); /* flush fo, all registered files, and stdout */ 155 156 switch (pid = start_command(cmd, &nset, p[READ], fileno(fo), NULL)) { 157 case -1: /* error */ 158 /* start_command already did a warn(). */ 159 warnx("mime_run_command: %s", cmd); /* tell a bit more */ 160 (void)close(p[READ]); 161 (void)close(p[WRITE]); 162 return flags; /* XXX - this or -1? */ 163 164 case 0: /* child */ 165 assert(/*CONSTCOND*/ 0); /* a real coding error! */ 166 /* NOTREACHED */ 167 168 default: /* parent */ 169 (void)close(p[READ]); 170 171 nfo = fdopen(p[WRITE], "w"); 172 if (nfo == NULL) { 173 warn("mime_run_command: fdopen"); 174 (void)close(p[WRITE]); 175 warn("fdopen"); 176 return flags; 177 } 178 register_file(nfo, 1, pid); 179 return flags; 180 } 181 } 182 183 184 PUBLIC void 185 mime_run_function(void (*fn)(FILE *, FILE *, void *), FILE *fo, void *cookie) 186 { 187 sigset_t nset; 188 FILE *nfo; 189 pid_t pid; 190 int p[2]; 191 192 if (prepare_pipe(&nset, p) != 0) { 193 warn("mime_run_function: pipe"); 194 return; 195 } 196 flush_files(fo, 0); /* flush fo, all registered files, and stdout */ 197 198 switch (pid = fork()) { 199 case -1: /* error */ 200 warn("mime_run_function: fork"); 201 (void)close(p[READ]); 202 (void)close(p[WRITE]); 203 return; 204 205 case 0: /* child */ 206 (void)close(p[WRITE]); 207 prepare_child(&nset, p[READ], fileno(fo)); 208 fn(stdin, stdout, cookie); 209 (void)fflush(stdout); 210 _exit(0); 211 /* NOTREACHED */ 212 213 default: /* parent */ 214 (void)close(p[READ]); 215 nfo = fdopen(p[WRITE], "w"); 216 if (nfo == NULL) { 217 warn("run_function: fdopen"); 218 (void)close(p[WRITE]); 219 return; 220 } 221 register_file(nfo, 1, pid); 222 return; 223 } 224 } 225 226 #endif /* MIME_SUPPORT */ 227