summaryrefslogtreecommitdiff
path: root/src/basic/util.c
blob: e577c93e60d61b058d09aae6ffb4c87680082d19 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
/* 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 "env-file.h"
#include "env-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';
}

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;
        int r;

        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.
         */

        r = getenv_bool_secure("SYSTEMD_IN_INITRD");
        if (r < 0 && r != -ENXIO)
                log_debug_errno(r, "Failed to parse $SYSTEMD_IN_INITRD, ignoring: %m");

        if (r >= 0)
                saved_in_initrd = r > 0;
        else
                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,
                 __compar_d_fn_t compar, 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;
}

bool memeqzero(const void *data, size_t length) {
        /* Does the buffer consist entirely of NULs?
         * Copied from https://github.com/systemd/casync/, copied in turn from
         * https://github.com/rustyrussell/ccan/blob/master/ccan/mem/mem.c#L92,
         * which is licensed CC-0.
         */

        const uint8_t *p = data;
        size_t i;

        /* Check first 16 bytes manually */
        for (i = 0; i < 16; i++, length--) {
                if (length == 0)
                        return true;
                if (p[i])
                        return false;
        }

        /* Now we know first 16 bytes are NUL, memcmp with self.  */
        return memcmp(data, p + i, length) == 0;
}

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 (streq(machine, ".host")) {
                *pid = 1;
                return 0;
        }

        if (!machine_name_is_valid(machine))
                return -EINVAL;

        p = strjoina("/run/systemd/machines/", machine);
        r = parse_env_file(NULL, p,
                           "LEADER", &s,
                           "CLASS", &class);
        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("systemd " STRINGIFY(PROJECT_VERSION) " (" GIT_VERSION ")\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", WRITE_STRING_FILE_DISABLE_BUFFER);
        if (r < 0)
                log_debug_errno(r, "Failed to turn off coredumps, ignoring: %m");
}