masqmail

view src/listen.c @ 214:ecd8d737d78e

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removed the old manual because it is really outdated now In masqmail's 0.3 branch, so much changed that the old manual causes more harm than it improves the distribution. Most content is covered by the man pages anyway. You'll still find the old manual on masqmail's homepage.
author meillo@marmaro.de
date Mon, 19 Jul 2010 14:06:08 +0200
parents 5745edd5b769
children fc1c6425c024
line source
1 /* MasqMail
2 Copyright (C) 1999/2000 Oliver Kurth
3
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2 of the License, or
7 (at your option) any later version.
8
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
13
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software
16 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17 */
18
19 #include <sys/wait.h>
20 #include <sys/types.h>
21
22 #include "masqmail.h"
23
24 static int volatile sighup_seen = 0;
25
26 static void
27 sighup_handler(int sig)
28 {
29 sighup_seen = 1;
30 signal(SIGHUP, sighup_handler);
31 }
32
33 static void
34 sigchld_handler(int sig)
35 {
36 pid_t pid;
37 int status;
38
39 pid = waitpid(0, &status, 0);
40 if (pid > 0) {
41 if (WEXITSTATUS(status) != EXIT_SUCCESS)
42 logwrite(LOG_WARNING, "process %d exited with %d\n", pid, WEXITSTATUS(status));
43 if (WIFSIGNALED(status))
44 logwrite(LOG_WARNING, "process with pid %d got signal: %d\n", pid, WTERMSIG(status));
45 }
46 signal(SIGCHLD, sigchld_handler);
47 }
48
49 void
50 accept_connect(int listen_sock, int sock, struct sockaddr_in *sock_addr)
51 {
52 pid_t pid;
53 int dup_sock = dup(sock);
54 FILE *out, *in;
55 gchar *rem_host;
56 gchar *ident = NULL;
57
58 rem_host = g_strdup(inet_ntoa(sock_addr->sin_addr));
59 #ifdef ENABLE_IDENT
60 {
61 gchar *id = NULL;
62 if ((id = (gchar *) ident_id(sock, 60))) {
63 ident = g_strdup(id);
64 }
65 logwrite(LOG_NOTICE, "connect from host %s, port %hd ident=%s\n", rem_host,
66 ntohs(sock_addr->sin_port), ident ? ident : "(unknown)");
67 }
68 #else
69 logwrite(LOG_NOTICE, "connect from host %s, port %hd\n", rem_host, ntohs(sock_addr->sin_port));
70 #endif
71
72 /* start child for connection: */
73 signal(SIGCHLD, sigchld_handler);
74 pid = fork();
75 if (pid == 0) {
76 close(listen_sock);
77 out = fdopen(sock, "w");
78 in = fdopen(dup_sock, "r");
79
80 smtp_in(in, out, rem_host, ident);
81
82 _exit(EXIT_SUCCESS);
83 } else if (pid < 0) {
84 logwrite(LOG_WARNING, "could not fork for incoming smtp connection: %s\n", strerror(errno));
85 }
86 #ifdef ENABLE_IDENT
87 if (ident != NULL)
88 g_free(ident);
89 #endif
90
91 close(sock);
92 close(dup_sock);
93 }
94
95 void
96 listen_port(GList * iface_list, gint qival, char *argv[])
97 {
98 int i;
99 fd_set active_fd_set, read_fd_set;
100 struct timeval tm;
101 time_t time_before, time_now;
102 struct sockaddr_in clientname;
103 size_t size;
104 GList *node, *node_next;
105 int sel_ret;
106
107 /* Create the sockets and set them up to accept connections. */
108 FD_ZERO(&active_fd_set);
109 for (node = g_list_first(iface_list); node; node = node_next) {
110 interface *iface = (interface *) (node->data);
111 int sock;
112
113 node_next = g_list_next(node);
114 if ((sock = make_server_socket(iface)) < 0) {
115 iface_list = g_list_remove_link(iface_list, node);
116 g_list_free_1(node);
117 continue;
118 }
119 if (listen(sock, 1) < 0) {
120 logwrite(LOG_ALERT, "listen: (terminating): %s\n", strerror(errno));
121 exit(EXIT_FAILURE);
122 }
123 logwrite(LOG_NOTICE, "listening on interface %s:%d\n", iface->address, iface->port);
124 DEBUG(5) debugf("sock = %d\n", sock);
125 FD_SET(sock, &active_fd_set);
126 }
127
128 /* setup handler for HUP signal: */
129 signal(SIGHUP, sighup_handler);
130 signal(SIGCHLD, sigchld_handler);
131
132 /* now that we have our socket(s), we can give up root privileges */
133 if (!conf.run_as_user) {
134 if (setegid(conf.mail_gid) != 0) {
135 logwrite(LOG_ALERT, "could not change gid to %d: %s\n", conf.mail_gid, strerror(errno));
136 exit(EXIT_FAILURE);
137 }
138 if (seteuid(conf.mail_uid) != 0) {
139 logwrite(LOG_ALERT, "could not change uid to %d: %s\n", conf.mail_uid, strerror(errno));
140 exit(EXIT_FAILURE);
141 }
142 }
143
144 /* sel_ret = 0; */
145 time(&time_before);
146 time_before -= qival;
147 sel_ret = -1;
148
149 while (1) {
150
151 /* if we were interrupted by an incoming connection (or a signal)
152 we have to recalculate the time until the next queue run should
153 occur. select may put a value into tm, but doc for select() says
154 we should not use it. */
155 if (qival > 0) {
156 time(&time_now);
157 if (sel_ret == 0) { /* we are either just starting or did a queue run */
158 tm.tv_sec = qival;
159 tm.tv_usec = 0;
160 time_before = time_now;
161 } else {
162 tm.tv_sec = qival - (time_now - time_before);
163 tm.tv_usec = 0;
164
165 /* race condition, very unlikely (but possible): */
166 if (tm.tv_sec < 0)
167 tm.tv_sec = 0;
168 }
169 }
170 /* Block until input arrives on one or more active sockets,
171 or signal arrives, or queuing interval time elapsed (if qival > 0) */
172 read_fd_set = active_fd_set;
173 if ((sel_ret = select(FD_SETSIZE, &read_fd_set, NULL, NULL, qival > 0 ? &tm : NULL)) < 0) {
174 if (errno != EINTR) {
175 logwrite(LOG_ALERT, "select: (terminating): %s\n", strerror(errno));
176 exit(EXIT_FAILURE);
177 } else {
178 if (sighup_seen) {
179 logwrite(LOG_NOTICE, "HUP signal received. Restarting daemon\n");
180
181 for (i = 0; i < FD_SETSIZE; i++)
182 if (FD_ISSET(i, &active_fd_set))
183 close(i);
184
185 execv(argv[0], &(argv[0]));
186 logwrite(LOG_ALERT, "restarting failed: %s\n", strerror(errno));
187 exit(EXIT_FAILURE);
188 }
189 }
190 } else if (sel_ret > 0) {
191 for (i = 0; i < FD_SETSIZE; i++) {
192 if (FD_ISSET(i, &read_fd_set)) {
193 int sock = i;
194 int new;
195 size = sizeof(clientname);
196 new = accept(sock, (struct sockaddr *) &clientname, &size);
197 if (new < 0) {
198 logwrite(LOG_ALERT, "accept: (ignoring): %s\n", strerror(errno));
199 } else
200 accept_connect(sock, new, &clientname);
201 }
202 }
203 } else {
204 /* If select returns 0, the interval time has elapsed.
205 We start a new queue runner process */
206 int pid;
207 signal(SIGCHLD, sigchld_handler);
208 if ((pid = fork()) == 0) {
209 queue_run();
210
211 _exit(EXIT_SUCCESS);
212 } else if (pid < 0) {
213 logwrite(LOG_ALERT, "could not fork for queue run");
214 }
215 }
216 }
217 }