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
get_cmd_flags(const char * cmd,const char ** cmd_start)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
prepare_pipe(sigset_t * nset,int p[2])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
mime_run_command(const char * cmd,FILE * fo)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
mime_run_function(void (* fn)(FILE *,FILE *,void *),FILE * fo,void * cookie)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