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#include "common.h"
#include <sched.h>
char pidfile[FILENAME_MAX + 1] = "";
void sig_handler_exit(int signo)
{
if(signo) {
error_log_limit_unlimited();
error("Received signal %d. Exiting...", signo);
netdata_exit = 1;
}
}
void sig_handler_logrotate(int signo)
{
if(signo) {
error_log_limit_reset();
info("Received signal %d to re-open the log files", signo);
reopen_all_log_files();
}
}
void sig_handler_save(int signo)
{
if(signo) {
error_log_limit_reset();
info("Received signal %d to save the database...", signo);
rrdset_save_all();
}
}
void sig_handler_reload_health(int signo)
{
if(signo) {
error_log_limit_reset();
info("Received signal %d to reload health configuration...", signo);
health_reload();
}
}
static void chown_open_file(int fd, uid_t uid, gid_t gid) {
if(fd == -1) return;
struct stat buf;
if(fstat(fd, &buf) == -1) {
error("Cannot fstat() fd %d", fd);
return;
}
if((buf.st_uid != uid || buf.st_gid != gid) && S_ISREG(buf.st_mode)) {
if(fchown(fd, uid, gid) == -1)
error("Cannot fchown() fd %d.", fd);
}
}
int become_user(const char *username, int pid_fd)
{
struct passwd *pw = getpwnam(username);
if(!pw) {
error("User %s is not present.", username);
return -1;
}
uid_t uid = pw->pw_uid;
gid_t gid = pw->pw_gid;
int ngroups = (int)sysconf(_SC_NGROUPS_MAX);
gid_t *supplementary_groups = NULL;
if(ngroups) {
supplementary_groups = mallocz(sizeof(gid_t) * ngroups);
if(getgrouplist(username, gid, supplementary_groups, &ngroups) == -1) {
error("Cannot get supplementary groups of user '%s'.", username);
freez(supplementary_groups);
supplementary_groups = NULL;
ngroups = 0;
}
}
chown_open_file(STDOUT_FILENO, uid, gid);
chown_open_file(STDERR_FILENO, uid, gid);
chown_open_file(stdaccess_fd, uid, gid);
chown_open_file(pid_fd, uid, gid);
if(supplementary_groups && ngroups) {
if(setgroups(ngroups, supplementary_groups) == -1)
error("Cannot set supplementary groups for user '%s'", username);
freez(supplementary_groups);
supplementary_groups = NULL;
ngroups = 0;
}
if(setresgid(gid, gid, gid) != 0) {
error("Cannot switch to user's %s group (gid: %u).", username, gid);
return -1;
}
if(setresuid(uid, uid, uid) != 0) {
error("Cannot switch to user %s (uid: %u).", username, uid);
return -1;
}
if(setgid(gid) != 0) {
error("Cannot switch to user's %s group (gid: %u).", username, gid);
return -1;
}
if(setegid(gid) != 0) {
error("Cannot effectively switch to user's %s group (gid: %u).", username, gid);
return -1;
}
if(setuid(uid) != 0) {
error("Cannot switch to user %s (uid: %u).", username, uid);
return -1;
}
if(seteuid(uid) != 0) {
error("Cannot effectively switch to user %s (uid: %u).", username, uid);
return -1;
}
return(0);
}
void oom_score_adj(int score) {
int done = 0;
int fd = open("/proc/self/oom_score_adj", O_WRONLY);
if(fd != -1) {
char buf[10 + 1];
ssize_t len = snprintfz(buf, 10, "%d", score);
if(write(fd, buf, len) == len) done = 1;
close(fd);
}
if(!done)
error("Cannot adjust my Out-Of-Memory score to %d.", score);
else
info("Adjusted my Out-Of-Memory score to %d.", score);
}
int sched_setscheduler_idle(void) {
#ifdef SCHED_IDLE
const struct sched_param param = {
.sched_priority = 0
};
int i = sched_setscheduler(0, SCHED_IDLE, ¶m);
if(i != 0)
error("Cannot adjust my scheduling priority to IDLE.");
else
info("Adjusted my scheduling priority to IDLE.");
return i;
#else
return -1;
#endif
}
int become_daemon(int dont_fork, const char *user)
{
if(!dont_fork) {
int i = fork();
if(i == -1) {
perror("cannot fork");
exit(1);
}
if(i != 0) {
exit(0); // the parent
}
// become session leader
if (setsid() < 0) {
perror("Cannot become session leader.");
exit(2);
}
// fork() again
i = fork();
if(i == -1) {
perror("cannot fork");
exit(1);
}
if(i != 0) {
exit(0); // the parent
}
}
// generate our pid file
int pidfd = -1;
if(pidfile[0]) {
pidfd = open(pidfile, O_WRONLY | O_CREAT, 0644);
if(pidfd >= 0) {
if(ftruncate(pidfd, 0) != 0)
error("Cannot truncate pidfile '%s'.", pidfile);
char b[100];
sprintf(b, "%d\n", getpid());
ssize_t i = write(pidfd, b, strlen(b));
if(i <= 0)
error("Cannot write pidfile '%s'.", pidfile);
}
else error("Failed to open pidfile '%s'.", pidfile);
}
// Set new file permissions
umask(0002);
// adjust my Out-Of-Memory score
oom_score_adj(1000);
// never become a problem
if(sched_setscheduler_idle() != 0) {
if(nice(19) == -1) error("Cannot lower my CPU priority.");
else info("Set my nice value to 19.");
}
if(user && *user) {
if(become_user(user, pidfd) != 0) {
error("Cannot become user '%s'. Continuing as we are.", user);
}
else info("Successfully became user '%s'.", user);
}
if(pidfd != -1) {
close(pidfd);
pidfd = -1;
}
return(0);
}
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