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-rw-r--r--daemon/daemon.c502
1 files changed, 502 insertions, 0 deletions
diff --git a/daemon/daemon.c b/daemon/daemon.c
new file mode 100644
index 0000000..2b8a655
--- /dev/null
+++ b/daemon/daemon.c
@@ -0,0 +1,502 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "common.h"
+#include <sched.h>
+
+char pidfile[FILENAME_MAX + 1] = "";
+char claimingdirectory[FILENAME_MAX + 1];
+char exepath[FILENAME_MAX + 1];
+
+void get_netdata_execution_path(void)
+{
+ int ret;
+ size_t exepath_size = 0;
+ struct passwd *passwd = NULL;
+ char *user = NULL;
+
+ passwd = getpwuid(getuid());
+ user = (passwd && passwd->pw_name) ? passwd->pw_name : "";
+
+ exepath_size = sizeof(exepath) - 1;
+ ret = uv_exepath(exepath, &exepath_size);
+ if (0 != ret) {
+ error("uv_exepath(\"%s\", %u) (user: %s) failed (%s).", exepath, (unsigned)exepath_size, user,
+ uv_strerror(ret));
+ fatal("Cannot start netdata without getting execution path.");
+ }
+ exepath[exepath_size] = '\0';
+}
+
+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);
+ }
+}
+
+void create_needed_dir(const char *dir, uid_t uid, gid_t gid)
+{
+ // attempt to create the directory
+ if(mkdir(dir, 0755) == 0) {
+ // we created it
+
+ // chown it to match the required user
+ if(chown(dir, uid, gid) == -1)
+ error("Cannot chown directory '%s' to %u:%u", dir, (unsigned int)uid, (unsigned int)gid);
+ }
+ else if(errno != EEXIST)
+ // log an error only if the directory does not exist
+ error("Cannot create directory '%s'", dir);
+}
+
+void clean_directory(char *dirname)
+{
+ DIR *dir = opendir(dirname);
+ if(!dir) return;
+
+ int dir_fd = dirfd(dir);
+ struct dirent *de = NULL;
+
+ while((de = readdir(dir)))
+ if(de->d_type == DT_REG)
+ if (unlinkat(dir_fd, de->d_name, 0))
+ error("Cannot delete %s/%s", dirname, de->d_name);
+
+ closedir(dir);
+}
+
+int become_user(const char *username, int pid_fd) {
+ int am_i_root = (getuid() == 0)?1:0;
+
+ 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;
+
+ create_needed_dir(netdata_configured_cache_dir, uid, gid);
+ create_needed_dir(netdata_configured_varlib_dir, uid, gid);
+ create_needed_dir(netdata_configured_lock_dir, uid, gid);
+ create_needed_dir(claimingdirectory, uid, gid);
+
+ clean_directory(netdata_configured_lock_dir);
+
+ if(pidfile[0]) {
+ if(chown(pidfile, uid, gid) == -1)
+ error("Cannot chown '%s' to %u:%u", pidfile, (unsigned int)uid, (unsigned int)gid);
+ }
+
+ int ngroups = (int)sysconf(_SC_NGROUPS_MAX);
+ gid_t *supplementary_groups = NULL;
+ if(ngroups > 0) {
+ supplementary_groups = mallocz(sizeof(gid_t) * ngroups);
+#ifdef __APPLE__
+ if(getgrouplist(username, gid, (int *)supplementary_groups, &ngroups) == -1) {
+#else
+ if(getgrouplist(username, gid, supplementary_groups, &ngroups) == -1) {
+#endif /* __APPLE__ */
+ if(am_i_root)
+ error("Cannot get supplementary groups of user '%s'.", username);
+
+ 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 > 0) {
+ if(setgroups((size_t)ngroups, supplementary_groups) == -1) {
+ if(am_i_root)
+ error("Cannot set supplementary groups for user '%s'", username);
+ }
+ ngroups = 0;
+ }
+
+ if(supplementary_groups)
+ freez(supplementary_groups);
+
+#ifdef __APPLE__
+ if(setregid(gid, gid) != 0) {
+#else
+ if(setresgid(gid, gid, gid) != 0) {
+#endif /* __APPLE__ */
+ error("Cannot switch to user's %s group (gid: %u).", username, gid);
+ return -1;
+ }
+
+#ifdef __APPLE__
+ if(setreuid(uid, uid) != 0) {
+#else
+ if(setresuid(uid, uid, uid) != 0) {
+#endif /* __APPLE__ */
+ 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);
+}
+
+#ifndef OOM_SCORE_ADJ_MAX
+#define OOM_SCORE_ADJ_MAX (1000)
+#endif
+#ifndef OOM_SCORE_ADJ_MIN
+#define OOM_SCORE_ADJ_MIN (-1000)
+#endif
+
+static void oom_score_adj(void) {
+ char buf[30 + 1];
+ long long int old_score, wanted_score = 0, final_score = 0;
+
+ // read the existing score
+ if(read_single_signed_number_file("/proc/self/oom_score_adj", &old_score)) {
+ error("Out-Of-Memory (OOM) score setting is not supported on this system.");
+ return;
+ }
+
+ if (old_score != 0) {
+ wanted_score = old_score;
+ analytics_report_oom_score(old_score);
+ }
+
+ // check the environment
+ char *s = getenv("OOMScoreAdjust");
+ if(!s || !*s) {
+ snprintfz(buf, 30, "%d", (int)wanted_score);
+ s = buf;
+ }
+
+ // check netdata.conf configuration
+ s = config_get(CONFIG_SECTION_GLOBAL, "OOM score", s);
+ if(s && *s && (isdigit(*s) || *s == '-' || *s == '+'))
+ wanted_score = atoll(s);
+ else if(s && !strcmp(s, "keep")) {
+ info("Out-Of-Memory (OOM) kept as-is (running with %d)", (int) old_score);
+ return;
+ }
+ else {
+ info("Out-Of-Memory (OOM) score not changed due to non-numeric setting: '%s' (running with %d)", s, (int)old_score);
+ return;
+ }
+
+ if(wanted_score < OOM_SCORE_ADJ_MIN) {
+ error("Wanted Out-Of-Memory (OOM) score %d is too small. Using %d", (int)wanted_score, (int)OOM_SCORE_ADJ_MIN);
+ wanted_score = OOM_SCORE_ADJ_MIN;
+ }
+
+ if(wanted_score > OOM_SCORE_ADJ_MAX) {
+ error("Wanted Out-Of-Memory (OOM) score %d is too big. Using %d", (int)wanted_score, (int)OOM_SCORE_ADJ_MAX);
+ wanted_score = OOM_SCORE_ADJ_MAX;
+ }
+
+ if(old_score == wanted_score) {
+ info("Out-Of-Memory (OOM) score is already set to the wanted value %d", (int)old_score);
+ return;
+ }
+
+ int written = 0;
+ int fd = open("/proc/self/oom_score_adj", O_WRONLY);
+ if(fd != -1) {
+ snprintfz(buf, 30, "%d", (int)wanted_score);
+ ssize_t len = strlen(buf);
+ if(len > 0 && write(fd, buf, (size_t)len) == len) written = 1;
+ close(fd);
+
+ if(written) {
+ if(read_single_signed_number_file("/proc/self/oom_score_adj", &final_score))
+ error("Adjusted my Out-Of-Memory (OOM) score to %d, but cannot verify it.", (int)wanted_score);
+ else if(final_score == wanted_score)
+ info("Adjusted my Out-Of-Memory (OOM) score from %d to %d.", (int)old_score, (int)final_score);
+ else
+ error("Adjusted my Out-Of-Memory (OOM) score from %d to %d, but it has been set to %d.", (int)old_score, (int)wanted_score, (int)final_score);
+ analytics_report_oom_score(final_score);
+ }
+ else
+ error("Failed to adjust my Out-Of-Memory (OOM) score to %d. Running with %d. (systemd systems may change it via netdata.service)", (int)wanted_score, (int)old_score);
+ }
+ else
+ error("Failed to adjust my Out-Of-Memory (OOM) score. Cannot open /proc/self/oom_score_adj for writing.");
+}
+
+static void process_nice_level(void) {
+#ifdef HAVE_NICE
+ int nice_level = (int)config_get_number(CONFIG_SECTION_GLOBAL, "process nice level", 19);
+ if(nice(nice_level) == -1) error("Cannot set netdata CPU nice level to %d.", nice_level);
+ else debug(D_SYSTEM, "Set netdata nice level to %d.", nice_level);
+#endif // HAVE_NICE
+};
+
+#define SCHED_FLAG_NONE 0x00
+#define SCHED_FLAG_PRIORITY_CONFIGURABLE 0x01 // the priority is user configurable
+#define SCHED_FLAG_KEEP_AS_IS 0x04 // do not attempt to set policy, priority or nice()
+#define SCHED_FLAG_USE_NICE 0x08 // use nice() after setting this policy
+
+struct sched_def {
+ char *name;
+ int policy;
+ int priority;
+ uint8_t flags;
+} scheduler_defaults[] = {
+
+ // the order of array members is important!
+ // the first defined is the default used by netdata
+
+ // the available members are important too!
+ // these are all the possible scheduling policies supported by netdata
+
+#ifdef SCHED_BATCH
+ { "batch", SCHED_BATCH, 0, SCHED_FLAG_USE_NICE },
+#endif
+
+#ifdef SCHED_OTHER
+ { "other", SCHED_OTHER, 0, SCHED_FLAG_USE_NICE },
+ { "nice", SCHED_OTHER, 0, SCHED_FLAG_USE_NICE },
+#endif
+
+#ifdef SCHED_IDLE
+ { "idle", SCHED_IDLE, 0, SCHED_FLAG_NONE },
+#endif
+
+#ifdef SCHED_RR
+ { "rr", SCHED_RR, 0, SCHED_FLAG_PRIORITY_CONFIGURABLE },
+#endif
+
+#ifdef SCHED_FIFO
+ { "fifo", SCHED_FIFO, 0, SCHED_FLAG_PRIORITY_CONFIGURABLE },
+#endif
+
+ // do not change the scheduling priority
+ { "keep", 0, 0, SCHED_FLAG_KEEP_AS_IS },
+ { "none", 0, 0, SCHED_FLAG_KEEP_AS_IS },
+
+ // array termination
+ { NULL, 0, 0, 0 }
+};
+
+
+#ifdef HAVE_SCHED_GETSCHEDULER
+static void sched_getscheduler_report(void) {
+ int sched = sched_getscheduler(0);
+ if(sched == -1) {
+ error("Cannot get my current process scheduling policy.");
+ return;
+ }
+ else {
+ int i;
+ for(i = 0 ; scheduler_defaults[i].name ; i++) {
+ if(scheduler_defaults[i].policy == sched) {
+ if(scheduler_defaults[i].flags & SCHED_FLAG_PRIORITY_CONFIGURABLE) {
+ struct sched_param param;
+ if(sched_getparam(0, &param) == -1) {
+ error("Cannot get the process scheduling priority for my policy '%s'", scheduler_defaults[i].name);
+ return;
+ }
+ else {
+ info("Running with process scheduling policy '%s', priority %d", scheduler_defaults[i].name, param.sched_priority);
+ }
+ }
+ else if(scheduler_defaults[i].flags & SCHED_FLAG_USE_NICE) {
+ #ifdef HAVE_GETPRIORITY
+ int n = getpriority(PRIO_PROCESS, 0);
+ info("Running with process scheduling policy '%s', nice level %d", scheduler_defaults[i].name, n);
+ #else // !HAVE_GETPRIORITY
+ info("Running with process scheduling policy '%s'", scheduler_defaults[i].name);
+ #endif // !HAVE_GETPRIORITY
+ }
+ else {
+ info("Running with process scheduling policy '%s'", scheduler_defaults[i].name);
+ }
+
+ return;
+ }
+ }
+ }
+}
+#endif /* HAVE_SCHED_GETSCHEDULER */
+
+#ifdef HAVE_SCHED_SETSCHEDULER
+
+static void sched_setscheduler_set(void) {
+
+ if(scheduler_defaults[0].name) {
+ const char *name = scheduler_defaults[0].name;
+ int policy = scheduler_defaults[0].policy, priority = scheduler_defaults[0].priority;
+ uint8_t flags = scheduler_defaults[0].flags;
+ int found = 0;
+
+ // read the configuration
+ name = config_get(CONFIG_SECTION_GLOBAL, "process scheduling policy", name);
+ int i;
+ for(i = 0 ; scheduler_defaults[i].name ; i++) {
+ if(!strcmp(name, scheduler_defaults[i].name)) {
+ found = 1;
+ policy = scheduler_defaults[i].policy;
+ priority = scheduler_defaults[i].priority;
+ flags = scheduler_defaults[i].flags;
+
+ if(flags & SCHED_FLAG_KEEP_AS_IS)
+ goto report;
+
+ if(flags & SCHED_FLAG_PRIORITY_CONFIGURABLE)
+ priority = (int)config_get_number(CONFIG_SECTION_GLOBAL, "process scheduling priority", priority);
+
+#ifdef HAVE_SCHED_GET_PRIORITY_MIN
+ errno = 0;
+ if(priority < sched_get_priority_min(policy)) {
+ error("scheduler %s (%d) priority %d is below the minimum %d. Using the minimum.", name, policy, priority, sched_get_priority_min(policy));
+ priority = sched_get_priority_min(policy);
+ }
+#endif
+#ifdef HAVE_SCHED_GET_PRIORITY_MAX
+ errno = 0;
+ if(priority > sched_get_priority_max(policy)) {
+ error("scheduler %s (%d) priority %d is above the maximum %d. Using the maximum.", name, policy, priority, sched_get_priority_max(policy));
+ priority = sched_get_priority_max(policy);
+ }
+#endif
+ break;
+ }
+ }
+
+ if(!found) {
+ error("Unknown scheduling policy '%s' - falling back to nice", name);
+ goto fallback;
+ }
+
+ const struct sched_param param = {
+ .sched_priority = priority
+ };
+
+ errno = 0;
+ i = sched_setscheduler(0, policy, &param);
+ if(i != 0) {
+ error("Cannot adjust netdata scheduling policy to %s (%d), with priority %d. Falling back to nice.", name, policy, priority);
+ }
+ else {
+ info("Adjusted netdata scheduling policy to %s (%d), with priority %d.", name, policy, priority);
+ if(!(flags & SCHED_FLAG_USE_NICE))
+ goto report;
+ }
+ }
+
+fallback:
+ process_nice_level();
+
+report:
+ sched_getscheduler_report();
+}
+#else /* HAVE_SCHED_SETSCHEDULER */
+static void sched_setscheduler_set(void) {
+ process_nice_level();
+}
+#endif /* HAVE_SCHED_SETSCHEDULER */
+
+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(0007);
+
+ // adjust my Out-Of-Memory score
+ oom_score_adj();
+
+ // never become a problem
+ sched_setscheduler_set();
+
+ // Set claiming directory based on user config directory with correct ownership
+ snprintfz(claimingdirectory, FILENAME_MAX, "%s/cloud.d", netdata_configured_varlib_dir);
+
+ if(user && *user) {
+ if(become_user(user, pidfd) != 0) {
+ error("Cannot become user '%s'. Continuing as we are.", user);
+ }
+ else debug(D_SYSTEM, "Successfully became user '%s'.", user);
+ }
+ else {
+ create_needed_dir(netdata_configured_cache_dir, getuid(), getgid());
+ create_needed_dir(netdata_configured_varlib_dir, getuid(), getgid());
+ create_needed_dir(netdata_configured_lock_dir, getuid(), getgid());
+ create_needed_dir(claimingdirectory, getuid(), getgid());
+
+ clean_directory(netdata_configured_lock_dir);
+ }
+
+ if(pidfd != -1)
+ close(pidfd);
+
+ return(0);
+}
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