1 /* $NetBSD: mime_child.c,v 1.10 2019/12/14 20:21:43 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 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 33 #ifdef MIME_SUPPORT 34 35 #include <sys/cdefs.h> 36 #ifndef __lint__ 37 __RCSID("$NetBSD: mime_child.c,v 1.10 2019/12/14 20:21:43 christos Exp $"); 38 #endif /* not __lint__ */ 39 40 #include <assert.h> 41 #include <fcntl.h> 42 #include <signal.h> 43 #include <stdio.h> 44 #include <stdlib.h> 45 #include <unistd.h> 46 47 #include "def.h" 48 #include "extern.h" 49 50 #ifdef MIME_SUPPORT 51 #include "mime.h" 52 #include "mime_child.h" 53 #endif 54 55 /* 56 * This module contains the core routines used by mime modules that 57 * need to fork children. Nothing else in the mime modules should be 58 * doing a pipe(), fork(), or a call to any popen functions that do. 59 * These routines are tied to the file registry in popen.c and hence 60 * share much of popen code. 61 */ 62 63 #define READ 0 64 #define WRITE 1 65 66 static int 67 get_cmd_flags(const char *cmd, const char **cmd_start) 68 { 69 const char *cp; 70 int flags; 71 72 flags = 0; 73 for (cp = cmd; cp && *cp; cp++) 74 switch (*cp) { 75 case '+': 76 flags |= CMD_FLAG_ALTERNATIVE; 77 break; 78 case '-': 79 flags |= CMD_FLAG_NO_DECODE; 80 break; 81 case '!': 82 flags |= CMD_FLAG_SHELLCMD; 83 break; 84 default: 85 goto done; 86 } 87 done: 88 if (cmd_start) 89 *cmd_start = cp; 90 91 return flags; 92 } 93 94 95 static int 96 prepare_pipe(sigset_t *nset, int p[2]) 97 { 98 if (pipe2(p, O_CLOEXEC) == -1) 99 return -1; 100 101 /* 102 * We _must_ ignore SIGINT and SIGPIPE or the child 103 * will end up in our earlier handlers. 104 */ 105 (void)sigemptyset(nset); 106 (void)sigaddset(nset, SIGINT); 107 (void)sigaddset(nset, SIGPIPE); 108 (void)sigaddset(nset, SIGHUP); 109 (void)sigaddset(nset, SIGTSTP); 110 (void)sigaddset(nset, SIGTTOU); 111 (void)sigaddset(nset, SIGTTIN); 112 113 return 0; 114 } 115 116 117 PUBLIC int 118 mime_run_command(const char *cmd, FILE *fo) 119 { 120 sigset_t nset; 121 FILE *nfo; 122 pid_t pid; 123 int p[2]; 124 int flags; 125 126 if (cmd == NULL) 127 return 0; 128 129 flags = get_cmd_flags(cmd, &cmd); 130 if (fo == NULL) /* no output file, just return the flags! */ 131 return flags; 132 133 if ((flags & CMD_FLAG_SHELLCMD) != 0) { /* run command under the shell */ 134 char *cp; 135 char *shellcmd; 136 if ((shellcmd = value(ENAME_SHELL)) == NULL) 137 shellcmd = __UNCONST(_PATH_CSHELL); 138 (void)sasprintf(&cp, "%s -c '%s'", shellcmd, cmd); 139 cmd = cp; 140 } 141 if (prepare_pipe(&nset, p) != 0) { 142 warn("mime_run_command: prepare_pipe"); 143 return flags; /* XXX - this or -1? */ 144 } 145 flush_files(fo, 0); /* flush fo, all registered files, and stdout */ 146 147 switch (pid = start_command(cmd, &nset, p[READ], fileno(fo), NULL)) { 148 case -1: /* error */ 149 /* start_command already did a warn(). */ 150 warnx("mime_run_command: %s", cmd); /* tell a bit more */ 151 (void)close(p[READ]); 152 (void)close(p[WRITE]); 153 return flags; /* XXX - this or -1? */ 154 155 case 0: /* child */ 156 assert(/*CONSTCOND*/ 0); /* a real coding error! */ 157 /* NOTREACHED */ 158 159 default: /* parent */ 160 (void)close(p[READ]); 161 162 nfo = fdopen(p[WRITE], "we"); 163 if (nfo == NULL) { 164 warn("mime_run_command: fdopen"); 165 (void)close(p[WRITE]); 166 warn("fdopen"); 167 return flags; 168 } 169 register_file(nfo, 1, pid); 170 return flags; 171 } 172 } 173 174 175 PUBLIC void 176 mime_run_function(void (*fn)(FILE *, FILE *, void *), FILE *fo, void *cookie) 177 { 178 sigset_t nset; 179 FILE *nfo; 180 pid_t pid; 181 int p[2]; 182 183 if (prepare_pipe(&nset, p) != 0) { 184 warn("mime_run_function: pipe"); 185 return; 186 } 187 flush_files(fo, 0); /* flush fo, all registered files, and stdout */ 188 189 switch (pid = fork()) { 190 case -1: /* error */ 191 warn("mime_run_function: fork"); 192 (void)close(p[READ]); 193 (void)close(p[WRITE]); 194 return; 195 196 case 0: /* child */ 197 (void)close(p[WRITE]); 198 prepare_child(&nset, p[READ], fileno(fo)); 199 fn(stdin, stdout, cookie); 200 (void)fflush(stdout); 201 _exit(0); 202 /* NOTREACHED */ 203 204 default: /* parent */ 205 (void)close(p[READ]); 206 nfo = fdopen(p[WRITE], "we"); 207 if (nfo == NULL) { 208 warn("run_function: fdopen"); 209 (void)close(p[WRITE]); 210 return; 211 } 212 register_file(nfo, 1, pid); 213 return; 214 } 215 } 216 217 #endif /* MIME_SUPPORT */ 218
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