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Systemd/src/basic/util.c
Lennart Poettering 0c69794138 tree-wide: remove Lennart's copyright lines 
These lines are generally out-of-date, incomplete and unnecessary. With
SPDX and git repository much more accurate and fine grained information
about licensing and authorship is available, hence let's drop the
per-file copyright notice. Of course, removing copyright lines of others
is problematic, hence this commit only removes my own lines and leaves
all others untouched. It might be nicer if sooner or later those could
go away too, making git the only and accurate source of authorship
information.
2018-06-14 10:20:20 +02:00

624 lines
17 KiB
C
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/* SPDX-License-Identifier: LGPL-2.1+ */
#include <alloca.h>
#include <errno.h>
#include <fcntl.h>
#include <sched.h>
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/prctl.h>
#include <sys/statfs.h>
#include <sys/sysmacros.h>
#include <sys/types.h>
#include <unistd.h>
#include "alloc-util.h"
#include "btrfs-util.h"
#include "build.h"
#include "cgroup-util.h"
#include "def.h"
#include "device-nodes.h"
#include "dirent-util.h"
#include "fd-util.h"
#include "fileio.h"
#include "format-util.h"
#include "hashmap.h"
#include "hostname-util.h"
#include "log.h"
#include "macro.h"
#include "missing.h"
#include "parse-util.h"
#include "path-util.h"
#include "process-util.h"
#include "procfs-util.h"
#include "set.h"
#include "signal-util.h"
#include "stat-util.h"
#include "string-util.h"
#include "strv.h"
#include "time-util.h"
#include "umask-util.h"
#include "user-util.h"
#include "util.h"
#include "virt.h"
int saved_argc = 0;
char **saved_argv = NULL;
static int saved_in_initrd = -1;
size_t page_size(void) {
static thread_local size_t pgsz = 0;
long r;
if (_likely_(pgsz > 0))
return pgsz;
r = sysconf(_SC_PAGESIZE);
assert(r > 0);
pgsz = (size_t) r;
return pgsz;
}
bool plymouth_running(void) {
return access("/run/plymouth/pid", F_OK) >= 0;
}
bool display_is_local(const char *display) {
assert(display);
return
display[0] == ':' &&
display[1] >= '0' &&
display[1] <= '9';
}
int socket_from_display(const char *display, char **path) {
size_t k;
char *f, *c;
assert(display);
assert(path);
if (!display_is_local(display))
return -EINVAL;
k = strspn(display+1, "0123456789");
f = new(char, STRLEN("/tmp/.X11-unix/X") + k + 1);
if (!f)
return -ENOMEM;
c = stpcpy(f, "/tmp/.X11-unix/X");
memcpy(c, display+1, k);
c[k] = 0;
*path = f;
return 0;
}
bool kexec_loaded(void) {
_cleanup_free_ char *s = NULL;
if (read_one_line_file("/sys/kernel/kexec_loaded", &s) < 0)
return false;
return s[0] == '1';
}
int prot_from_flags(int flags) {
switch (flags & O_ACCMODE) {
case O_RDONLY:
return PROT_READ;
case O_WRONLY:
return PROT_WRITE;
case O_RDWR:
return PROT_READ|PROT_WRITE;
default:
return -EINVAL;
}
}
bool in_initrd(void) {
struct statfs s;
if (saved_in_initrd >= 0)
return saved_in_initrd;
/* We make two checks here:
*
* 1. the flag file /etc/initrd-release must exist
* 2. the root file system must be a memory file system
*
* The second check is extra paranoia, since misdetecting an
* initrd can have bad consequences due the initrd
* emptying when transititioning to the main systemd.
*/
saved_in_initrd = access("/etc/initrd-release", F_OK) >= 0 &&
statfs("/", &s) >= 0 &&
is_temporary_fs(&s);
return saved_in_initrd;
}
void in_initrd_force(bool value) {
saved_in_initrd = value;
}
/* hey glibc, APIs with callbacks without a user pointer are so useless */
void *xbsearch_r(const void *key, const void *base, size_t nmemb, size_t size,
int (*compar) (const void *, const void *, void *), void *arg) {
size_t l, u, idx;
const void *p;
int comparison;
assert(!size_multiply_overflow(nmemb, size));
l = 0;
u = nmemb;
while (l < u) {
idx = (l + u) / 2;
p = (const uint8_t*) base + idx * size;
comparison = compar(key, p, arg);
if (comparison < 0)
u = idx;
else if (comparison > 0)
l = idx + 1;
else
return (void *)p;
}
return NULL;
}
int on_ac_power(void) {
bool found_offline = false, found_online = false;
_cleanup_closedir_ DIR *d = NULL;
struct dirent *de;
d = opendir("/sys/class/power_supply");
if (!d)
return errno == ENOENT ? true : -errno;
FOREACH_DIRENT(de, d, return -errno) {
_cleanup_close_ int fd = -1, device = -1;
char contents[6];
ssize_t n;
device = openat(dirfd(d), de->d_name, O_DIRECTORY|O_RDONLY|O_CLOEXEC|O_NOCTTY);
if (device < 0) {
if (IN_SET(errno, ENOENT, ENOTDIR))
continue;
return -errno;
}
fd = openat(device, "type", O_RDONLY|O_CLOEXEC|O_NOCTTY);
if (fd < 0) {
if (errno == ENOENT)
continue;
return -errno;
}
n = read(fd, contents, sizeof(contents));
if (n < 0)
return -errno;
if (n != 6 || memcmp(contents, "Mains\n", 6))
continue;
safe_close(fd);
fd = openat(device, "online", O_RDONLY|O_CLOEXEC|O_NOCTTY);
if (fd < 0) {
if (errno == ENOENT)
continue;
return -errno;
}
n = read(fd, contents, sizeof(contents));
if (n < 0)
return -errno;
if (n != 2 || contents[1] != '\n')
return -EIO;
if (contents[0] == '1') {
found_online = true;
break;
} else if (contents[0] == '0')
found_offline = true;
else
return -EIO;
}
return found_online || !found_offline;
}
int container_get_leader(const char *machine, pid_t *pid) {
_cleanup_free_ char *s = NULL, *class = NULL;
const char *p;
pid_t leader;
int r;
assert(machine);
assert(pid);
if (!machine_name_is_valid(machine))
return -EINVAL;
p = strjoina("/run/systemd/machines/", machine);
r = parse_env_file(NULL, p, NEWLINE, "LEADER", &s, "CLASS", &class, NULL);
if (r == -ENOENT)
return -EHOSTDOWN;
if (r < 0)
return r;
if (!s)
return -EIO;
if (!streq_ptr(class, "container"))
return -EIO;
r = parse_pid(s, &leader);
if (r < 0)
return r;
if (leader <= 1)
return -EIO;
*pid = leader;
return 0;
}
int namespace_open(pid_t pid, int *pidns_fd, int *mntns_fd, int *netns_fd, int *userns_fd, int *root_fd) {
_cleanup_close_ int pidnsfd = -1, mntnsfd = -1, netnsfd = -1, usernsfd = -1;
int rfd = -1;
assert(pid >= 0);
if (mntns_fd) {
const char *mntns;
mntns = procfs_file_alloca(pid, "ns/mnt");
mntnsfd = open(mntns, O_RDONLY|O_NOCTTY|O_CLOEXEC);
if (mntnsfd < 0)
return -errno;
}
if (pidns_fd) {
const char *pidns;
pidns = procfs_file_alloca(pid, "ns/pid");
pidnsfd = open(pidns, O_RDONLY|O_NOCTTY|O_CLOEXEC);
if (pidnsfd < 0)
return -errno;
}
if (netns_fd) {
const char *netns;
netns = procfs_file_alloca(pid, "ns/net");
netnsfd = open(netns, O_RDONLY|O_NOCTTY|O_CLOEXEC);
if (netnsfd < 0)
return -errno;
}
if (userns_fd) {
const char *userns;
userns = procfs_file_alloca(pid, "ns/user");
usernsfd = open(userns, O_RDONLY|O_NOCTTY|O_CLOEXEC);
if (usernsfd < 0 && errno != ENOENT)
return -errno;
}
if (root_fd) {
const char *root;
root = procfs_file_alloca(pid, "root");
rfd = open(root, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
if (rfd < 0)
return -errno;
}
if (pidns_fd)
*pidns_fd = pidnsfd;
if (mntns_fd)
*mntns_fd = mntnsfd;
if (netns_fd)
*netns_fd = netnsfd;
if (userns_fd)
*userns_fd = usernsfd;
if (root_fd)
*root_fd = rfd;
pidnsfd = mntnsfd = netnsfd = usernsfd = -1;
return 0;
}
int namespace_enter(int pidns_fd, int mntns_fd, int netns_fd, int userns_fd, int root_fd) {
if (userns_fd >= 0) {
/* Can't setns to your own userns, since then you could
* escalate from non-root to root in your own namespace, so
* check if namespaces equal before attempting to enter. */
_cleanup_free_ char *userns_fd_path = NULL;
int r;
if (asprintf(&userns_fd_path, "/proc/self/fd/%d", userns_fd) < 0)
return -ENOMEM;
r = files_same(userns_fd_path, "/proc/self/ns/user", 0);
if (r < 0)
return r;
if (r)
userns_fd = -1;
}
if (pidns_fd >= 0)
if (setns(pidns_fd, CLONE_NEWPID) < 0)
return -errno;
if (mntns_fd >= 0)
if (setns(mntns_fd, CLONE_NEWNS) < 0)
return -errno;
if (netns_fd >= 0)
if (setns(netns_fd, CLONE_NEWNET) < 0)
return -errno;
if (userns_fd >= 0)
if (setns(userns_fd, CLONE_NEWUSER) < 0)
return -errno;
if (root_fd >= 0) {
if (fchdir(root_fd) < 0)
return -errno;
if (chroot(".") < 0)
return -errno;
}
return reset_uid_gid();
}
uint64_t physical_memory(void) {
_cleanup_free_ char *root = NULL, *value = NULL;
uint64_t mem, lim;
size_t ps;
long sc;
int r;
/* We return this as uint64_t in case we are running as 32bit process on a 64bit kernel with huge amounts of
* memory.
*
* In order to support containers nicely that have a configured memory limit we'll take the minimum of the
* physically reported amount of memory and the limit configured for the root cgroup, if there is any. */
sc = sysconf(_SC_PHYS_PAGES);
assert(sc > 0);
ps = page_size();
mem = (uint64_t) sc * (uint64_t) ps;
r = cg_get_root_path(&root);
if (r < 0) {
log_debug_errno(r, "Failed to determine root cgroup, ignoring cgroup memory limit: %m");
return mem;
}
r = cg_all_unified();
if (r < 0) {
log_debug_errno(r, "Failed to determine root unified mode, ignoring cgroup memory limit: %m");
return mem;
}
if (r > 0) {
r = cg_get_attribute("memory", root, "memory.max", &value);
if (r < 0) {
log_debug_errno(r, "Failed to read memory.max cgroup attribute, ignoring cgroup memory limit: %m");
return mem;
}
if (streq(value, "max"))
return mem;
} else {
r = cg_get_attribute("memory", root, "memory.limit_in_bytes", &value);
if (r < 0) {
log_debug_errno(r, "Failed to read memory.limit_in_bytes cgroup attribute, ignoring cgroup memory limit: %m");
return mem;
}
}
r = safe_atou64(value, &lim);
if (r < 0) {
log_debug_errno(r, "Failed to parse cgroup memory limit '%s', ignoring: %m", value);
return mem;
}
if (lim == UINT64_MAX)
return mem;
/* Make sure the limit is a multiple of our own page size */
lim /= ps;
lim *= ps;
return MIN(mem, lim);
}
uint64_t physical_memory_scale(uint64_t v, uint64_t max) {
uint64_t p, m, ps, r;
assert(max > 0);
/* Returns the physical memory size, multiplied by v divided by max. Returns UINT64_MAX on overflow. On success
* the result is a multiple of the page size (rounds down). */
ps = page_size();
assert(ps > 0);
p = physical_memory() / ps;
assert(p > 0);
m = p * v;
if (m / p != v)
return UINT64_MAX;
m /= max;
r = m * ps;
if (r / ps != m)
return UINT64_MAX;
return r;
}
uint64_t system_tasks_max(void) {
uint64_t a = TASKS_MAX, b = TASKS_MAX;
_cleanup_free_ char *root = NULL;
int r;
/* Determine the maximum number of tasks that may run on this system. We check three sources to determine this
* limit:
*
* a) the maximum tasks value the kernel allows on this architecture
* b) the cgroups pids_max attribute for the system
* c) the kernel's configured maximum PID value
*
* And then pick the smallest of the three */
r = procfs_tasks_get_limit(&a);
if (r < 0)
log_debug_errno(r, "Failed to read maximum number of tasks from /proc, ignoring: %m");
r = cg_get_root_path(&root);
if (r < 0)
log_debug_errno(r, "Failed to determine cgroup root path, ignoring: %m");
else {
_cleanup_free_ char *value = NULL;
r = cg_get_attribute("pids", root, "pids.max", &value);
if (r < 0)
log_debug_errno(r, "Failed to read pids.max attribute of cgroup root, ignoring: %m");
else if (!streq(value, "max")) {
r = safe_atou64(value, &b);
if (r < 0)
log_debug_errno(r, "Failed to parse pids.max attribute of cgroup root, ignoring: %m");
}
}
return MIN3(TASKS_MAX,
a <= 0 ? TASKS_MAX : a,
b <= 0 ? TASKS_MAX : b);
}
uint64_t system_tasks_max_scale(uint64_t v, uint64_t max) {
uint64_t t, m;
assert(max > 0);
/* Multiply the system's task value by the fraction v/max. Hence, if max==100 this calculates percentages
* relative to the system's maximum number of tasks. Returns UINT64_MAX on overflow. */
t = system_tasks_max();
assert(t > 0);
m = t * v;
if (m / t != v) /* overflow? */
return UINT64_MAX;
return m / max;
}
int version(void) {
puts(PACKAGE_STRING "\n"
SYSTEMD_FEATURES);
return 0;
}
/* This is a direct translation of str_verscmp from boot.c */
static bool is_digit(int c) {
return c >= '0' && c <= '9';
}
static int c_order(int c) {
if (c == 0 || is_digit(c))
return 0;
if ((c >= 'a') && (c <= 'z'))
return c;
return c + 0x10000;
}
int str_verscmp(const char *s1, const char *s2) {
const char *os1, *os2;
assert(s1);
assert(s2);
os1 = s1;
os2 = s2;
while (*s1 || *s2) {
int first;
while ((*s1 && !is_digit(*s1)) || (*s2 && !is_digit(*s2))) {
int order;
order = c_order(*s1) - c_order(*s2);
if (order != 0)
return order;
s1++;
s2++;
}
while (*s1 == '0')
s1++;
while (*s2 == '0')
s2++;
first = 0;
while (is_digit(*s1) && is_digit(*s2)) {
if (first == 0)
first = *s1 - *s2;
s1++;
s2++;
}
if (is_digit(*s1))
return 1;
if (is_digit(*s2))
return -1;
if (first != 0)
return first;
}
return strcmp(os1, os2);
}
/* Turn off core dumps but only if we're running outside of a container. */
void disable_coredumps(void) {
int r;
if (detect_container() > 0)
return;
r = write_string_file("/proc/sys/kernel/core_pattern", "|/bin/false", 0);
if (r < 0)
log_debug_errno(r, "Failed to turn off coredumps, ignoring: %m");
}
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