New upstream version 1.11.0+dfsgupstream/1.11.0+dfsg

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 452 insertions, 0 deletions

diff --git a/daemon/daemon.c b/daemon/daemon.c
new file mode 100644
index 00000000..4ad082b9
--- /dev/null
+++ b/daemon/daemon.c
@@ -0,0 +1,452 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "common.h"
+#include <sched.h>
+
+char pidfile[FILENAME_MAX + 1] = "";
+
+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);
+}
+
+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);
+
+    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);
+        if(getgrouplist(username, gid, supplementary_groups, &ngroups) == -1) {
+            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 = OOM_SCORE_ADJ_MAX, 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;
+
+    // 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);
+        }
+        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_IDLE
+        { "idle", SCHED_IDLE, 0, SCHED_FLAG_NONE },
+#endif
+
+#ifdef SCHED_OTHER
+        { "other", SCHED_OTHER, 0, SCHED_FLAG_USE_NICE },
+        { "nice",  SCHED_OTHER, 0, SCHED_FLAG_USE_NICE },
+#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
+
+#ifdef SCHED_BATCH
+        { "batch", SCHED_BATCH, 0, SCHED_FLAG_USE_NICE },
+#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;
+            }
+        }
+    }
+}
+#else // !HAVE_SCHED_GETSCHEDULER
+static void sched_getscheduler_report(void) {
+#ifdef HAVE_GETPRIORITY
+    info("Running with priority %d", getpriority(PRIO_PROCESS, 0));
+#endif // HAVE_GETPRIORITY
+}
+#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();
+
+    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());
+    }
+
+    if(pidfd != -1)
+        close(pidfd);
+
+    return(0);
+}