4 char pidfile[FILENAME_MAX + 1] = "";
6 void sig_handler_exit(int signo)
9 error_log_limit_unlimited();
10 error("Received signal %d. Exiting...", signo);
15 void sig_handler_logrotate(int signo)
18 error_log_limit_unlimited();
19 info("Received signal %d to re-open the log files", signo);
20 reopen_all_log_files();
21 error_log_limit_reset();
25 void sig_handler_save(int signo)
28 error_log_limit_unlimited();
29 info("Received signal %d to save the database...", signo);
31 error_log_limit_reset();
35 void sig_handler_reload_health(int signo)
38 error_log_limit_unlimited();
39 info("Received signal %d to reload health configuration...", signo);
41 error_log_limit_reset();
45 static void chown_open_file(int fd, uid_t uid, gid_t gid) {
50 if(fstat(fd, &buf) == -1) {
51 error("Cannot fstat() fd %d", fd);
55 if((buf.st_uid != uid || buf.st_gid != gid) && S_ISREG(buf.st_mode)) {
56 if(fchown(fd, uid, gid) == -1)
57 error("Cannot fchown() fd %d.", fd);
61 void create_needed_dir(const char *dir, uid_t uid, gid_t gid)
63 // attempt to create the directory
64 if(mkdir(dir, 0755) == 0) {
67 // chown it to match the required user
68 if(chown(dir, uid, gid) == -1)
69 error("Cannot chown directory '%s' to %u:%u", dir, (unsigned int)uid, (unsigned int)gid);
71 else if(errno != EEXIST)
72 // log an error only if the directory does not exist
73 error("Cannot create directory '%s'", dir);
76 int become_user(const char *username, int pid_fd)
78 struct passwd *pw = getpwnam(username);
80 error("User %s is not present.", username);
84 uid_t uid = pw->pw_uid;
85 gid_t gid = pw->pw_gid;
87 create_needed_dir(CACHE_DIR, uid, gid);
88 create_needed_dir(VARLIB_DIR, uid, gid);
91 if(chown(pidfile, uid, gid) == -1)
92 error("Cannot chown '%s' to %u:%u", pidfile, (unsigned int)uid, (unsigned int)gid);
95 int ngroups = (int)sysconf(_SC_NGROUPS_MAX);
96 gid_t *supplementary_groups = NULL;
98 supplementary_groups = mallocz(sizeof(gid_t) * ngroups);
99 if(getgrouplist(username, gid, supplementary_groups, &ngroups) == -1) {
100 error("Cannot get supplementary groups of user '%s'.", username);
101 freez(supplementary_groups);
102 supplementary_groups = NULL;
107 chown_open_file(STDOUT_FILENO, uid, gid);
108 chown_open_file(STDERR_FILENO, uid, gid);
109 chown_open_file(stdaccess_fd, uid, gid);
110 chown_open_file(pid_fd, uid, gid);
112 if(supplementary_groups && ngroups) {
113 if(setgroups(ngroups, supplementary_groups) == -1)
114 error("Cannot set supplementary groups for user '%s'", username);
116 freez(supplementary_groups);
117 supplementary_groups = NULL;
121 if(setresgid(gid, gid, gid) != 0) {
122 error("Cannot switch to user's %s group (gid: %u).", username, gid);
126 if(setresuid(uid, uid, uid) != 0) {
127 error("Cannot switch to user %s (uid: %u).", username, uid);
131 if(setgid(gid) != 0) {
132 error("Cannot switch to user's %s group (gid: %u).", username, gid);
135 if(setegid(gid) != 0) {
136 error("Cannot effectively switch to user's %s group (gid: %u).", username, gid);
139 if(setuid(uid) != 0) {
140 error("Cannot switch to user %s (uid: %u).", username, uid);
143 if(seteuid(uid) != 0) {
144 error("Cannot effectively switch to user %s (uid: %u).", username, uid);
151 void oom_score_adj(int score) {
153 int fd = open("/proc/self/oom_score_adj", O_WRONLY);
156 ssize_t len = snprintfz(buf, 10, "%d", score);
157 if(write(fd, buf, len) == len) done = 1;
162 error("Cannot adjust my Out-Of-Memory score to %d.", score);
164 debug(D_SYSTEM, "Adjusted my Out-Of-Memory score to %d.", score);
167 int sched_setscheduler_idle(void) {
169 const struct sched_param param = {
173 int i = sched_setscheduler(0, SCHED_IDLE, ¶m);
175 error("Cannot adjust my scheduling priority to IDLE.");
177 debug(D_SYSTEM, "Adjusted my scheduling priority to IDLE.");
185 int become_daemon(int dont_fork, const char *user)
190 perror("cannot fork");
194 exit(0); // the parent
197 // become session leader
199 perror("Cannot become session leader.");
206 perror("cannot fork");
210 exit(0); // the parent
214 // generate our pid file
217 pidfd = open(pidfile, O_WRONLY | O_CREAT, 0644);
219 if(ftruncate(pidfd, 0) != 0)
220 error("Cannot truncate pidfile '%s'.", pidfile);
223 sprintf(b, "%d\n", getpid());
224 ssize_t i = write(pidfd, b, strlen(b));
226 error("Cannot write pidfile '%s'.", pidfile);
228 else error("Failed to open pidfile '%s'.", pidfile);
231 // Set new file permissions
234 // adjust my Out-Of-Memory score
237 // never become a problem
238 if(sched_setscheduler_idle() != 0) {
239 if(nice(19) == -1) error("Cannot lower my CPU priority.");
240 else debug(D_SYSTEM, "Set my nice value to 19.");
244 if(become_user(user, pidfd) != 0) {
245 error("Cannot become user '%s'. Continuing as we are.", user);
247 else debug(D_SYSTEM, "Successfully became user '%s'.", user);
250 create_needed_dir(CACHE_DIR, getuid(), getgid());
251 create_needed_dir(VARLIB_DIR, getuid(), getgid());