masqmail

view src/listen.c @ 56:f6a6f55b7b9e

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added old manual from the old website it is dated May/July 2000
author meillo@marmaro.de
date Sat, 29 May 2010 21:51:13 +0200
parents 26e34ae9a3e3
children 5745edd5b769
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 #ifdef ENABLE_SMTP_SERVER
50 void
51 accept_connect(int listen_sock, int sock, struct sockaddr_in *sock_addr)
52 {
53 pid_t pid;
54 int dup_sock = dup(sock);
55 FILE *out, *in;
56 gchar *rem_host;
57 gchar *ident = NULL;
58
59 rem_host = g_strdup(inet_ntoa(sock_addr->sin_addr));
60 #ifdef ENABLE_IDENT
61 {
62 gchar *id = NULL;
63 if ((id = (gchar *) ident_id(sock, 60))) {
64 ident = g_strdup(id);
65 }
66 logwrite(LOG_NOTICE, "connect from host %s, port %hd ident=%s\n", rem_host,
67 ntohs(sock_addr->sin_port), ident ? ident : "(unknown)");
68 }
69 #else
70 logwrite(LOG_NOTICE, "connect from host %s, port %hd\n", rem_host, ntohs(sock_addr->sin_port));
71 #endif
72
73 // start child for connection:
74 signal(SIGCHLD, sigchld_handler);
75 pid = fork();
76 if (pid == 0) {
77 close(listen_sock);
78 out = fdopen(sock, "w");
79 in = fdopen(dup_sock, "r");
80
81 smtp_in(in, out, rem_host, ident);
82
83 _exit(EXIT_SUCCESS);
84 } else if (pid < 0) {
85 logwrite(LOG_WARNING, "could not fork for incoming smtp connection: %s\n", strerror(errno));
86 }
87 #ifdef ENABLE_IDENT
88 if (ident != NULL)
89 g_free(ident);
90 #endif
91
92 close(sock);
93 close(dup_sock);
94 }
95 #endif /*ifdef ENABLE_SMTP_SERVER */
96
97 void
98 listen_port(GList * iface_list, gint qival, char *argv[])
99 {
100 int i;
101 fd_set active_fd_set, read_fd_set;
102 struct timeval tm;
103 time_t time_before, time_now;
104 struct sockaddr_in clientname;
105 size_t size;
106 GList *node, *node_next;
107 int sel_ret;
108
109 /* Create the sockets and set them up to accept connections. */
110 FD_ZERO(&active_fd_set);
111 #ifdef ENABLE_SMTP_SERVER
112 for (node = g_list_first(iface_list); node; node = node_next) {
113 interface *iface = (interface *) (node->data);
114 int sock;
115
116 node_next = g_list_next(node);
117 if ((sock = make_server_socket(iface)) < 0) {
118 iface_list = g_list_remove_link(iface_list, node);
119 g_list_free_1(node);
120 continue;
121 }
122 if (listen(sock, 1) < 0) {
123 logwrite(LOG_ALERT, "listen: (terminating): %s\n", strerror(errno));
124 exit(EXIT_FAILURE);
125 }
126 logwrite(LOG_NOTICE, "listening on interface %s:%d\n", iface->address, iface->port);
127 DEBUG(5) debugf("sock = %d\n", sock);
128 FD_SET(sock, &active_fd_set);
129 }
130 #endif
131
132 /* setup handler for HUP signal: */
133 signal(SIGHUP, sighup_handler);
134 signal(SIGCHLD, sigchld_handler);
135
136 /* now that we have our socket(s), we can give up root privileges */
137 if (!conf.run_as_user) {
138 if (setegid(conf.mail_gid) != 0) {
139 logwrite(LOG_ALERT, "could not change gid to %d: %s\n", conf.mail_gid, strerror(errno));
140 exit(EXIT_FAILURE);
141 }
142 if (seteuid(conf.mail_uid) != 0) {
143 logwrite(LOG_ALERT, "could not change uid to %d: %s\n", conf.mail_uid, strerror(errno));
144 exit(EXIT_FAILURE);
145 }
146 }
147
148 /* sel_ret = 0; */
149 time(&time_before);
150 time_before -= qival;
151 sel_ret = -1;
152
153 while (1) {
154
155 /* if we were interrupted by an incoming connection (or a signal)
156 we have to recalculate the time until the next queue run should
157 occur. select may put a value into tm, but doc for select() says
158 we should not use it. */
159 if (qival > 0) {
160 time(&time_now);
161 if (sel_ret == 0) { /* we are either just starting or did a queue run */
162 tm.tv_sec = qival;
163 tm.tv_usec = 0;
164 time_before = time_now;
165 } else {
166 tm.tv_sec = qival - (time_now - time_before);
167 tm.tv_usec = 0;
168
169 /* race condition, very unlikely (but possible): */
170 if (tm.tv_sec < 0)
171 tm.tv_sec = 0;
172 }
173 }
174 /* Block until input arrives on one or more active sockets,
175 or signal arrives, or queuing interval time elapsed (if qival > 0) */
176 read_fd_set = active_fd_set;
177 if ((sel_ret = select(FD_SETSIZE, &read_fd_set, NULL, NULL, qival > 0 ? &tm : NULL)) < 0) {
178 if (errno != EINTR) {
179 logwrite(LOG_ALERT, "select: (terminating): %s\n", strerror(errno));
180 exit(EXIT_FAILURE);
181 } else {
182 if (sighup_seen) {
183 logwrite(LOG_NOTICE, "HUP signal received. Restarting daemon\n");
184
185 for (i = 0; i < FD_SETSIZE; i++)
186 if (FD_ISSET(i, &active_fd_set))
187 close(i);
188
189 execv(argv[0], &(argv[0]));
190 logwrite(LOG_ALERT, "restarting failed: %s\n", strerror(errno));
191 exit(EXIT_FAILURE);
192 }
193 }
194 } else if (sel_ret > 0) {
195 #ifdef ENABLE_SMTP_SERVER
196 for (i = 0; i < FD_SETSIZE; i++) {
197 if (FD_ISSET(i, &read_fd_set)) {
198 int sock = i;
199 int new;
200 size = sizeof(clientname);
201 new = accept(sock, (struct sockaddr *) &clientname, &size);
202 if (new < 0) {
203 logwrite(LOG_ALERT, "accept: (ignoring): %s\n", strerror(errno));
204 } else
205 accept_connect(sock, new, &clientname);
206 }
207 }
208 #else
209 ;
210 #endif
211 } else {
212 /* If select returns 0, the interval time has elapsed.
213 We start a new queue runner process */
214 int pid;
215 signal(SIGCHLD, sigchld_handler);
216 if ((pid = fork()) == 0) {
217 queue_run();
218
219 _exit(EXIT_SUCCESS);
220 } else if (pid < 0) {
221 logwrite(LOG_ALERT, "could not fork for queue run");
222 }
223 }
224 }
225 }