new codename, reset version to git
[paraslash.git] / daemon.c
1 /*
2 * Copyright (C) 1997-2006 Andre Noll <maan@systemlinux.org>
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, USA.
17 */
18
19 /** \file daemon.c some helpers for programs that detach from the console */
20 #include "para.h"
21 #include "daemon.h"
22 #include <pwd.h>
23
24 /* getgrnam() */
25 #include <sys/types.h>
26 #include <grp.h>
27
28 #include "string.h"
29
30 /**
31 * do the usual stuff to become a daemon
32 *
33 * Fork, become session leader, dup fd 0, 1, 2 to /dev/null.
34 *
35 * \sa fork(2), setsid(2), dup(2)
36 */
37 void daemon_init(void)
38 {
39 pid_t pid;
40 int null;
41
42 PARA_INFO_LOG("%s", "daemonizing\n");
43 if ((pid = fork()) < 0) {
44 PARA_EMERG_LOG("%s", "failed to init daemon\n");
45 exit(EXIT_FAILURE);
46 } else if (pid)
47 exit(EXIT_SUCCESS); /* parent exits */
48 /* child */
49 setsid(); /* become session leader */
50 chdir("/");
51 umask(0);
52
53 null = open("/dev/null", O_RDONLY);
54 if (null < 0)
55 exit(EXIT_FAILURE);
56 dup2(null, STDIN_FILENO);
57 dup2(null, STDOUT_FILENO);
58 dup2(null, STDERR_FILENO);
59 close(null);
60 }
61
62 /**
63 * fopen() a file in append mode
64 *
65 * \param logfile_name the name of the file to open
66 *
67 * Either calls exit() or returns a valid file handle.
68 */
69 FILE *open_log(const char *logfile_name)
70 {
71 FILE *logfile;
72
73 if (!logfile_name)
74 return NULL;
75 if (!(logfile = fopen(logfile_name, "a"))) {
76 PARA_EMERG_LOG("can not open %s, uid: %d\n", logfile_name,
77 getuid());
78 exit(EXIT_FAILURE);
79 }
80 setlinebuf(logfile);
81 return logfile;
82 }
83
84 /**
85 * close the log file of the daemon
86 *
87 * \param logfile the log file handle
88 *
89 * It's OK to call this with logfile == NULL
90 */
91 void close_log(FILE* logfile)
92 {
93 if (!logfile)
94 return;
95 PARA_INFO_LOG("%s", "closing logfile\n");
96 fclose(logfile);
97 }
98
99 /**
100 * log the startup message containing the paraslash version
101 */
102 void log_welcome(const char *whoami, int loglevel)
103 {
104 PARA_INFO_LOG("welcome to %s " PACKAGE_VERSION " ("BUILD_DATE")\n",
105 whoami);
106 PARA_DEBUG_LOG("using loglevel %d\n", loglevel);
107 }
108
109 /**
110 * give up superuser privileges
111 *
112 * \param username the user to switch to
113 * \param groupname the group to switch to
114 *
115 * This function returns immediately if not invoked with EUID zero. Otherwise,
116 * it tries to obtain the GID of \a groupname and the UID of \a username. On
117 * success, effective and real GID/UID and the saved set-group-ID/set-user-ID
118 * are all set accordingly. On errors, an appropriate message is logged and
119 * exit() is called to terminate the process.
120 *
121 * \sa getpwnam(3), getuid(2), setuid(2), getgrnam(2), setgid(2)
122 */
123 void para_drop_privileges(const char *username, const char *groupname)
124 {
125 struct passwd *p;
126 char *tmp;
127
128 if (geteuid())
129 return;
130 if (groupname) {
131 struct group *g = getgrnam(groupname);
132 if (!g) {
133 PARA_EMERG_LOG("failed to get group %s\n", groupname);
134 exit(EXIT_FAILURE);
135 }
136 if (setgid(g->gr_gid) < 0) {
137 PARA_EMERG_LOG("failed to set group id %d (%s)\n",
138 g->gr_gid, strerror(errno));
139 exit(EXIT_FAILURE);
140 }
141 }
142 if (!username) {
143 PARA_EMERG_LOG("%s", "root privileges, but no user option given\n");
144 exit(EXIT_FAILURE);
145 }
146 tmp = para_strdup(username);
147 p = getpwnam(tmp);
148 free(tmp);
149 if (!p) {
150 PARA_EMERG_LOG("%s", "no such user\n");
151 exit(EXIT_FAILURE);
152 }
153 PARA_INFO_LOG("%s", "dropping root privileges\n");
154 setuid(p->pw_uid);
155 PARA_DEBUG_LOG("uid: %d, euid: %d\n", getuid(), geteuid());
156 }
157
158 /**
159 * set/get the server uptime
160 *
161 * \param set_or_get chose one of the two modes
162 *
163 * This should be called at startup time with \a set_or_get equal to \p
164 * UPTIME_SET which sets the uptime to zero. Subsequent calls with \a
165 * set_or_get equal to \p UPTIME_GET return the number of seconds ellapsed
166 * since the last reset.
167 *
168 * \sa time(2), difftime(3)
169 */
170 time_t server_uptime(enum uptime set_or_get)
171 {
172 static time_t startuptime;
173 time_t now;
174
175 if (set_or_get == UPTIME_SET) {
176 time(&startuptime);
177 return 0;
178 }
179 time(&now);
180 return (time_t) difftime(now, startuptime);
181 }
182
183 /**
184 * construct string containing uptime
185 *
186 * The format of the returned string is "days:hours:minutes"
187 *
188 * \sa server_uptime
189 */
190 __malloc char *uptime_str(void)
191 {
192 time_t t = server_uptime(UPTIME_GET);
193 return make_message("%li:%02li:%02li", t / 86400,
194 (t / 3600) % 24, (t / 60) % 60);
195 }