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// 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 ==
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