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 static void chown_open_file(int fd, uid_t uid, gid_t gid) {
38 if(fstat(fd, &buf) == -1) {
39 error("Cannot fstat() fd %d", fd);
43 if((buf.st_uid != uid || buf.st_gid != gid) && S_ISREG(buf.st_mode)) {
44 if(fchown(fd, uid, gid) == -1)
45 error("Cannot fchown() fd %d.", fd);
49 int become_user(const char *username, int pid_fd)
51 struct passwd *pw = getpwnam(username);
53 error("User %s is not present.", username);
57 uid_t uid = pw->pw_uid;
58 gid_t gid = pw->pw_gid;
60 int ngroups = (int)sysconf(_SC_NGROUPS_MAX);
61 gid_t *supplementary_groups = NULL;
63 supplementary_groups = mallocz(sizeof(gid_t) * ngroups);
64 if(getgrouplist(username, gid, supplementary_groups, &ngroups) == -1) {
65 error("Cannot get supplementary groups of user '%s'.", username);
66 freez(supplementary_groups);
67 supplementary_groups = NULL;
72 chown_open_file(STDOUT_FILENO, uid, gid);
73 chown_open_file(STDERR_FILENO, uid, gid);
74 chown_open_file(stdaccess_fd, uid, gid);
75 chown_open_file(pid_fd, uid, gid);
77 if(supplementary_groups && ngroups) {
78 if(setgroups(ngroups, supplementary_groups) == -1)
79 error("Cannot set supplementary groups for user '%s'", username);
81 freez(supplementary_groups);
82 supplementary_groups = NULL;
86 if(setresgid(gid, gid, gid) != 0) {
87 error("Cannot switch to user's %s group (gid: %u).", username, gid);
91 if(setresuid(uid, uid, uid) != 0) {
92 error("Cannot switch to user %s (uid: %u).", username, uid);
96 if(setgid(gid) != 0) {
97 error("Cannot switch to user's %s group (gid: %u).", username, gid);
100 if(setegid(gid) != 0) {
101 error("Cannot effectively switch to user's %s group (gid: %u).", username, gid);
104 if(setuid(uid) != 0) {
105 error("Cannot switch to user %s (uid: %u).", username, uid);
108 if(seteuid(uid) != 0) {
109 error("Cannot effectively switch to user %s (uid: %u).", username, uid);
116 void oom_score_adj(int score) {
118 int fd = open("/proc/self/oom_score_adj", O_WRONLY);
121 ssize_t len = snprintfz(buf, 10, "%d", score);
122 if(write(fd, buf, len) == len) done = 1;
127 error("Cannot adjust my Out-Of-Memory score to %d.", score);
129 info("Adjusted my Out-Of-Memory score to %d.", score);
132 int sched_setscheduler_idle(void) {
133 const struct sched_param param = {
137 int i = sched_setscheduler(0, SCHED_IDLE, ¶m);
139 error("Cannot adjust my scheduling priority to IDLE.");
141 info("Adjusted my scheduling priority to IDLE.");
146 int become_daemon(int dont_fork, const char *user)
151 perror("cannot fork");
155 exit(0); // the parent
158 // become session leader
160 perror("Cannot become session leader.");
167 perror("cannot fork");
171 exit(0); // the parent
175 // generate our pid file
178 pidfd = open(pidfile, O_WRONLY | O_CREAT, 0644);
180 if(ftruncate(pidfd, 0) != 0)
181 error("Cannot truncate pidfile '%s'.", pidfile);
184 sprintf(b, "%d\n", getpid());
185 ssize_t i = write(pidfd, b, strlen(b));
187 error("Cannot write pidfile '%s'.", pidfile);
189 else error("Failed to open pidfile '%s'.", pidfile);
192 // Set new file permissions
195 // adjust my Out-Of-Memory score
198 // never become a problem
199 if(sched_setscheduler_idle() != 0) {
200 if(nice(19) == -1) error("Cannot lower my CPU priority.");
201 else info("Set my nice value to 19.");
205 if(become_user(user, pidfd) != 0) {
206 error("Cannot become user '%s'. Continuing as we are.", user);
208 else info("Successfully became user '%s'.", user);