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_reset();
19 info("Received signal %d to re-open the log files", signo);
20 reopen_all_log_files();
24 void sig_handler_save(int signo)
27 error_log_limit_reset();
28 info("Received signal %d to save the database...", signo);
33 void sig_handler_reload_health(int signo)
36 error_log_limit_reset();
37 info("Received signal %d to reload health configuration...", signo);
42 static void chown_open_file(int fd, uid_t uid, gid_t gid) {
47 if(fstat(fd, &buf) == -1) {
48 error("Cannot fstat() fd %d", fd);
52 if((buf.st_uid != uid || buf.st_gid != gid) && S_ISREG(buf.st_mode)) {
53 if(fchown(fd, uid, gid) == -1)
54 error("Cannot fchown() fd %d.", fd);
58 int become_user(const char *username, int pid_fd)
60 struct passwd *pw = getpwnam(username);
62 error("User %s is not present.", username);
66 uid_t uid = pw->pw_uid;
67 gid_t gid = pw->pw_gid;
69 int ngroups = (int)sysconf(_SC_NGROUPS_MAX);
70 gid_t *supplementary_groups = NULL;
72 supplementary_groups = mallocz(sizeof(gid_t) * ngroups);
73 if(getgrouplist(username, gid, supplementary_groups, &ngroups) == -1) {
74 error("Cannot get supplementary groups of user '%s'.", username);
75 freez(supplementary_groups);
76 supplementary_groups = NULL;
81 chown_open_file(STDOUT_FILENO, uid, gid);
82 chown_open_file(STDERR_FILENO, uid, gid);
83 chown_open_file(stdaccess_fd, uid, gid);
84 chown_open_file(pid_fd, uid, gid);
86 if(supplementary_groups && ngroups) {
87 if(setgroups(ngroups, supplementary_groups) == -1)
88 error("Cannot set supplementary groups for user '%s'", username);
90 freez(supplementary_groups);
91 supplementary_groups = NULL;
95 if(setresgid(gid, gid, gid) != 0) {
96 error("Cannot switch to user's %s group (gid: %u).", username, gid);
100 if(setresuid(uid, uid, uid) != 0) {
101 error("Cannot switch to user %s (uid: %u).", username, uid);
105 if(setgid(gid) != 0) {
106 error("Cannot switch to user's %s group (gid: %u).", username, gid);
109 if(setegid(gid) != 0) {
110 error("Cannot effectively switch to user's %s group (gid: %u).", username, gid);
113 if(setuid(uid) != 0) {
114 error("Cannot switch to user %s (uid: %u).", username, uid);
117 if(seteuid(uid) != 0) {
118 error("Cannot effectively switch to user %s (uid: %u).", username, uid);
125 void oom_score_adj(int score) {
127 int fd = open("/proc/self/oom_score_adj", O_WRONLY);
130 ssize_t len = snprintfz(buf, 10, "%d", score);
131 if(write(fd, buf, len) == len) done = 1;
136 error("Cannot adjust my Out-Of-Memory score to %d.", score);
138 info("Adjusted my Out-Of-Memory score to %d.", score);
141 int sched_setscheduler_idle(void) {
143 const struct sched_param param = {
147 int i = sched_setscheduler(0, SCHED_IDLE, ¶m);
149 error("Cannot adjust my scheduling priority to IDLE.");
151 info("Adjusted my scheduling priority to IDLE.");
159 int become_daemon(int dont_fork, const char *user)
164 perror("cannot fork");
168 exit(0); // the parent
171 // become session leader
173 perror("Cannot become session leader.");
180 perror("cannot fork");
184 exit(0); // the parent
188 // generate our pid file
191 pidfd = open(pidfile, O_WRONLY | O_CREAT, 0644);
193 if(ftruncate(pidfd, 0) != 0)
194 error("Cannot truncate pidfile '%s'.", pidfile);
197 sprintf(b, "%d\n", getpid());
198 ssize_t i = write(pidfd, b, strlen(b));
200 error("Cannot write pidfile '%s'.", pidfile);
202 else error("Failed to open pidfile '%s'.", pidfile);
205 // Set new file permissions
208 // adjust my Out-Of-Memory score
211 // never become a problem
212 if(sched_setscheduler_idle() != 0) {
213 if(nice(19) == -1) error("Cannot lower my CPU priority.");
214 else info("Set my nice value to 19.");
218 if(become_user(user, pidfd) != 0) {
219 error("Cannot become user '%s'. Continuing as we are.", user);
221 else info("Successfully became user '%s'.", user);