aboutsummaryrefslogtreecommitdiff
path: root/lib/portability.c
blob: 91c019006b06eefd13264d9a6cfeae32f8535fd9 (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
638
/* portability.c - code to workaround the deficiencies of various platforms.
 *
 * Copyright 2012 Rob Landley <rob@landley.net>
 * Copyright 2012 Georgi Chorbadzhiyski <gf@unixsol.org>
 */

#include "toys.h"

// We can't fork() on nommu systems, and vfork() requires an exec() or exit()
// before resuming the parent (because they share a heap until then). And no,
// we can't implement our own clone() call that does the equivalent of fork()
// because nommu heaps use physical addresses so if we copy the heap all our
// pointers are wrong. (You need an mmu in order to map two heaps to the same
// address range without interfering with each other.) In the absence of
// a portable way to tell malloc() to start a new heap without freeing the old
// one, you pretty much need the exec().)

// So we exec ourselves (via /proc/self/exe, if anybody knows a way to
// re-exec self without depending on the filesystem, I'm all ears),
// and use the arguments to signal reentry.

#if CFG_TOYBOX_FORK
pid_t xfork(void)
{
  pid_t pid = fork();

  if (pid < 0) perror_exit("fork");

  return pid;
}
#endif

int xgetrandom(void *buf, unsigned buflen, unsigned flags)
{
  int fd;

#if CFG_TOYBOX_GETRANDOM
  if (buflen == getrandom(buf, buflen, flags&~WARN_ONLY)) return 1;
  if (errno!=ENOSYS && !(flags&WARN_ONLY)) perror_exit("getrandom");
#endif
  fd = xopen(flags ? "/dev/random" : "/dev/urandom",O_RDONLY|(flags&WARN_ONLY));
  if (fd == -1) return 0;
  xreadall(fd, buf, buflen);
  close(fd);

  return 1;
}

// Get list of mounted filesystems, including stat and statvfs info.
// Returns a reversed list, which is good for finding overmounts and such.

#if defined(__APPLE__) || defined(__FreeBSD__)

#include <sys/mount.h>

struct mtab_list *xgetmountlist(char *path)
{
  struct mtab_list *mtlist = 0, *mt;
  struct statfs *entries;
  int i, count;

  if (path) error_exit("xgetmountlist");
  if ((count = getmntinfo(&entries, 0)) == 0) perror_exit("getmntinfo");

  // The "test" part of the loop is done before the first time through and
  // again after each "increment", so putting the actual load there avoids
  // duplicating it. If the load was NULL, the loop stops.

  for (i = 0; i < count; ++i) {
    struct statfs *me = &entries[i];

    mt = xzalloc(sizeof(struct mtab_list) + strlen(me->f_fstypename) +
      strlen(me->f_mntonname) + strlen(me->f_mntfromname) + strlen("") + 4);
    dlist_add_nomalloc((void *)&mtlist, (void *)mt);

    // Collect details about mounted filesystem.
    // Don't report errors, just leave data zeroed.
    stat(me->f_mntonname, &(mt->stat));
    statvfs(me->f_mntonname, &(mt->statvfs));

    // Remember information from struct statfs.
    mt->dir = stpcpy(mt->type, me->f_fstypename)+1;
    mt->device = stpcpy(mt->dir, me->f_mntonname)+1;
    mt->opts = stpcpy(mt->device, me->f_mntfromname)+1;
    strcpy(mt->opts, ""); /* TODO: reverse from f_flags? */
  }

  return mtlist;
}

#else

#include <mntent.h>

static void octal_deslash(char *s)
{
  char *o = s;

  while (*s) {
    if (*s == '\\') {
      int i, oct = 0;

      for (i = 1; i < 4; i++) {
        if (!isdigit(s[i])) break;
        oct = (oct<<3)+s[i]-'0';
      }
      if (i == 4) {
        *o++ = oct;
        s += i;
        continue;
      }
    }
    *o++ = *s++;
  }

  *o = 0;
}

// Check if this type matches list.
// Odd syntax: typelist all yes = if any, typelist all no = if none.

int mountlist_istype(struct mtab_list *ml, char *typelist)
{
  int len, skip;
  char *t;

  if (!typelist) return 1;

  skip = strncmp(typelist, "no", 2);

  for (;;) {
    if (!(t = comma_iterate(&typelist, &len))) break;
    if (!skip) {
      // If one -t starts with "no", the rest must too
      if (strncmp(t, "no", 2)) error_exit("bad typelist");
      if (!strncmp(t+2, ml->type, len-2)) {
        skip = 1;
        break;
      }
    } else if (!strncmp(t, ml->type, len) && !ml->type[len]) {
      skip = 0;
      break;
    }
  }

  return !skip;
}

struct mtab_list *xgetmountlist(char *path)
{
  struct mtab_list *mtlist = 0, *mt;
  struct mntent *me;
  FILE *fp;
  char *p = path ? path : "/proc/mounts";

  if (!(fp = setmntent(p, "r"))) perror_exit("bad %s", p);

  // The "test" part of the loop is done before the first time through and
  // again after each "increment", so putting the actual load there avoids
  // duplicating it. If the load was NULL, the loop stops.

  while ((me = getmntent(fp))) {
    mt = xzalloc(sizeof(struct mtab_list) + strlen(me->mnt_fsname) +
      strlen(me->mnt_dir) + strlen(me->mnt_type) + strlen(me->mnt_opts) + 4);
    dlist_add_nomalloc((void *)&mtlist, (void *)mt);

    // Collect details about mounted filesystem
    // Don't report errors, just leave data zeroed
    if (!path) {
      stat(me->mnt_dir, &(mt->stat));
      statvfs(me->mnt_dir, &(mt->statvfs));
    }

    // Remember information from /proc/mounts
    mt->dir = stpcpy(mt->type, me->mnt_type)+1;
    mt->device = stpcpy(mt->dir, me->mnt_dir)+1;
    mt->opts = stpcpy(mt->device, me->mnt_fsname)+1;
    strcpy(mt->opts, me->mnt_opts);

    octal_deslash(mt->dir);
    octal_deslash(mt->device);
  }
  endmntent(fp);

  return mtlist;
}

#endif

#ifdef __APPLE__

#include <sys/event.h>

struct xnotify *xnotify_init(int max)
{
  struct xnotify *not = xzalloc(sizeof(struct xnotify));

  not->max = max;
  if ((not->kq = kqueue()) == -1) perror_exit("kqueue");
  not->paths = xmalloc(max * sizeof(char *));
  not->fds = xmalloc(max * sizeof(int));

  return not;
}

int xnotify_add(struct xnotify *not, int fd, char *path)
{
  struct kevent event;

  if (not->count == not->max) error_exit("xnotify_add overflow");
  EV_SET(&event, fd, EVFILT_VNODE, EV_ADD|EV_CLEAR, NOTE_WRITE, 0, NULL);
  if (kevent(not->kq, &event, 1, NULL, 0, NULL) == -1 || event.flags & EV_ERROR)
    return -1;
  not->paths[not->count] = path;
  not->fds[not->count++] = fd;

  return 0;
}

int xnotify_wait(struct xnotify *not, char **path)
{
  struct kevent event;
  int i;

  for (;;) {
    if (kevent(not->kq, NULL, 0, &event, 1, NULL) != -1) {
      // We get the fd for free, but still have to search for the path.
      for (i = 0; i<not->count; i++) if (not->fds[i]==event.ident) {
        *path = not->paths[i];

        return event.ident;
      }
    }
  }
}

#else

#include <sys/inotify.h>

struct xnotify *xnotify_init(int max)
{
  struct xnotify *not = xzalloc(sizeof(struct xnotify));

  not->max = max;
  if ((not->kq = inotify_init()) < 0) perror_exit("inotify_init");
  not->paths = xmalloc(max * sizeof(char *));
  not->fds = xmalloc(max * 2 * sizeof(int));

  return not;
}

int xnotify_add(struct xnotify *not, int fd, char *path)
{
  int i = 2*not->count;

  if (not->max == not->count) error_exit("xnotify_add overflow");
  if ((not->fds[i] = inotify_add_watch(not->kq, path, IN_MODIFY))==-1)
    return -1;
  not->fds[i+1] = fd;
  not->paths[not->count++] = path;

  return 0;
}

int xnotify_wait(struct xnotify *not, char **path)
{
  struct inotify_event ev;
  int i;

  for (;;) {
    if (sizeof(ev)!=read(not->kq, &ev, sizeof(ev))) perror_exit("inotify");

    for (i = 0; i<not->count; i++) if (ev.wd==not->fds[2*i]) {
      *path = not->paths[i];

      return not->fds[2*i+1];
    }
  }
}

#endif

#ifdef __APPLE__

ssize_t xattr_get(const char *path, const char *name, void *value, size_t size)
{
  return getxattr(path, name, value, size, 0, 0);
}

ssize_t xattr_lget(const char *path, const char *name, void *value, size_t size)
{
  return getxattr(path, name, value, size, 0, XATTR_NOFOLLOW);
}

ssize_t xattr_fget(int fd, const char *name, void *value, size_t size)
{
  return fgetxattr(fd, name, value, size, 0, 0);
}

ssize_t xattr_list(const char *path, char *list, size_t size)
{
  return listxattr(path, list, size, 0);
}

ssize_t xattr_llist(const char *path, char *list, size_t size)
{
  return listxattr(path, list, size, XATTR_NOFOLLOW);
}

ssize_t xattr_flist(int fd, char *list, size_t size)
{
  return flistxattr(fd, list, size, 0);
}

ssize_t xattr_set(const char* path, const char* name,
                  const void* value, size_t size, int flags)
{
  return setxattr(path, name, value, size, 0, flags);
}

ssize_t xattr_lset(const char* path, const char* name,
                   const void* value, size_t size, int flags)
{
  return setxattr(path, name, value, size, 0, flags | XATTR_NOFOLLOW);
}

ssize_t xattr_fset(int fd, const char* name,
                   const void* value, size_t size, int flags)
{
  return fsetxattr(fd, name, value, size, 0, flags);
}

#else

ssize_t xattr_get(const char *path, const char *name, void *value, size_t size)
{
  return getxattr(path, name, value, size);
}

ssize_t xattr_lget(const char *path, const char *name, void *value, size_t size)
{
  return lgetxattr(path, name, value, size);
}

ssize_t xattr_fget(int fd, const char *name, void *value, size_t size)
{
  return fgetxattr(fd, name, value, size);
}

ssize_t xattr_list(const char *path, char *list, size_t size)
{
  return listxattr(path, list, size);
}

ssize_t xattr_llist(const char *path, char *list, size_t size)
{
  return llistxattr(path, list, size);
}

ssize_t xattr_flist(int fd, char *list, size_t size)
{
  return flistxattr(fd, list, size);
}

ssize_t xattr_set(const char* path, const char* name,
                  const void* value, size_t size, int flags)
{
  return setxattr(path, name, value, size, flags);
}

ssize_t xattr_lset(const char* path, const char* name,
                   const void* value, size_t size, int flags)
{
  return lsetxattr(path, name, value, size, flags);
}

ssize_t xattr_fset(int fd, const char* name,
                   const void* value, size_t size, int flags)
{
  return fsetxattr(fd, name, value, size, flags);
}


#endif

#ifdef __APPLE__
// In the absence of a mknodat system call, fchdir to dirfd and back
// around a regular mknod call...
int mknodat(int dirfd, const char *path, mode_t mode, dev_t dev)
{
  int old_dirfd = open(".", O_RDONLY), result;

  if (old_dirfd == -1 || fchdir(dirfd) == -1) return -1;
  result = mknod(path, mode, dev);
  if (fchdir(old_dirfd) == -1) perror_exit("mknodat couldn't return");
  return result;
}

// As of 10.15, macOS offers an fcntl F_PREALLOCATE rather than fallocate()
// or posix_fallocate() calls.
int posix_fallocate(int fd, off_t offset, off_t length)
{
  int e = errno, result;
  fstore_t f;

  f.fst_flags = F_ALLOCATEALL;
  f.fst_posmode = F_PEOFPOSMODE;
  f.fst_offset = offset;
  f.fst_length = length;
  if (fcntl(fd, F_PREALLOCATE, &f) == -1) result = errno;
  else result = ftruncate(fd, length);
  errno = e;
  return result;
}
#endif

// Signals required by POSIX 2008:
// http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/signal.h.html

#define SIGNIFY(x) {SIG##x, #x}

static const struct signame signames[] = {
  // POSIX
  SIGNIFY(ABRT), SIGNIFY(ALRM), SIGNIFY(BUS),
  SIGNIFY(FPE), SIGNIFY(HUP), SIGNIFY(ILL), SIGNIFY(INT), SIGNIFY(KILL),
  SIGNIFY(PIPE), SIGNIFY(QUIT), SIGNIFY(SEGV), SIGNIFY(TERM),
  SIGNIFY(USR1), SIGNIFY(USR2), SIGNIFY(SYS), SIGNIFY(TRAP),
  SIGNIFY(VTALRM), SIGNIFY(XCPU), SIGNIFY(XFSZ),
  // Non-POSIX signals that cause termination
  SIGNIFY(PROF), SIGNIFY(IO),
  // signals only present/absent on some targets (mips and macos)
#ifdef SIGEMT
  SIGNIFY(EMT),
#endif
#ifdef SIGINFO
  SIGNIFY(INFO),
#endif
#ifdef SIGPOLL
  SIGNIFY(POLL),
#endif
#ifdef SIGPWR
  SIGNIFY(PWR),
#endif
#ifdef SIGSTKFLT
  SIGNIFY(STKFLT),
#endif

  // Note: sigatexit relies on all the signals with a default disposition that
  // terminates the process coming *before* SIGCHLD.

  // POSIX signals that don't cause termination
  SIGNIFY(CHLD), SIGNIFY(CONT), SIGNIFY(STOP), SIGNIFY(TSTP),
  SIGNIFY(TTIN), SIGNIFY(TTOU), SIGNIFY(URG),
  // Non-POSIX signals that don't cause termination
  SIGNIFY(WINCH),
};
int signames_len = ARRAY_LEN(signames);

#undef SIGNIFY

void xsignal_all_killers(void *handler)
{
  int i;

  if (!handler) handler = SIG_DFL;
  for (i = 0; signames[i].num != SIGCHLD; i++)
    if (signames[i].num != SIGKILL) xsignal(signames[i].num, handler);
}

// Convert a string like "9", "KILL", "SIGHUP", or "SIGRTMIN+2" to a number.
int sig_to_num(char *sigstr)
{
  int i, offset;
  char *s;

  // Numeric?
  i = estrtol(sigstr, &s, 10);
  if (!errno && !*s) return i;

  // Skip leading "SIG".
  strcasestart(&sigstr, "sig");

  // Named signal?
  for (i=0; i<ARRAY_LEN(signames); i++)
    if (!strcasecmp(sigstr, signames[i].name)) return signames[i].num;

  // Real-time signal?
#ifdef SIGRTMIN
  if (strcasestart(&sigstr, "rtmin")) i = SIGRTMIN;
  else if (strcasestart(&sigstr, "rtmax")) i = SIGRTMAX;
  else return -1;

  // No offset?
  if (!*sigstr) return i;

  // We allow any offset that's still a real-time signal: SIGRTMIN+20 is fine.
  // Others are more restrictive, only accepting what they show with -l.
  offset = estrtol(sigstr, &s, 10);
  if (errno || *s) return -1;
  i += offset;
  if (i >= SIGRTMIN && i <= SIGRTMAX) return i;
#endif

  return -1;
}

char *num_to_sig(int sig)
{
  int i;

  // A named signal?
  for (i=0; i<signames_len; i++)
    if (signames[i].num == sig) return signames[i].name;

  // A real-time signal?
#ifdef SIGRTMIN
  if (sig == SIGRTMIN) return "RTMIN";
  if (sig == SIGRTMAX) return "RTMAX";
  if (sig > SIGRTMIN && sig < SIGRTMAX) {
    if (sig-SIGRTMIN <= SIGRTMAX-sig) sprintf(libbuf, "RTMIN+%d", sig-SIGRTMIN);
    else sprintf(libbuf, "RTMAX-%d", SIGRTMAX-sig);
    return libbuf;
  }
#endif

  return NULL;
}

int dev_minor(int dev)
{
#if defined(__linux__)
  return ((dev&0xfff00000)>>12)|(dev&0xff);
#elif defined(__APPLE__)
  return dev&0xffffff;
#else
#error
#endif
}

int dev_major(int dev)
{
#if defined(__linux__)
  return (dev&0xfff00)>>8;
#elif defined(__APPLE__)
  return (dev>>24)&0xff;
#else
#error
#endif
}

int dev_makedev(int major, int minor)
{
#if defined(__linux__)
  return (minor&0xff)|((major&0xfff)<<8)|((minor&0xfff00)<<12);
#elif defined(__APPLE__)
  return (minor&0xffffff)|((major&0xff)<<24);
#else
#error
#endif
}

char *fs_type_name(struct statfs *statfs)
{
#if defined(__APPLE__)
  // macOS has an `f_type` field, but assigns values dynamically as filesystems
  // are registered. They do give you the name directly though, so use that.
  return statfs->f_fstypename;
#else
  char *s = NULL;
  struct {unsigned num; char *name;} nn[] = {
    {0xADFF, "affs"}, {0x5346544e, "ntfs"}, {0x1Cd1, "devpts"},
    {0x137D, "ext"}, {0xEF51, "ext2"}, {0xEF53, "ext3"},
    {0x1BADFACE, "bfs"}, {0x9123683E, "btrfs"}, {0x28cd3d45, "cramfs"},
    {0x3153464a, "jfs"}, {0x7275, "romfs"}, {0x01021994, "tmpfs"},
    {0x3434, "nilfs"}, {0x6969, "nfs"}, {0x9fa0, "proc"},
    {0x534F434B, "sockfs"}, {0x62656572, "sysfs"}, {0x517B, "smb"},
    {0x4d44, "msdos"}, {0x4006, "fat"}, {0x43415d53, "smackfs"},
    {0x73717368, "squashfs"}
  };
  int i;

  for (i=0; i<ARRAY_LEN(nn); i++)
    if (nn[i].num == statfs->f_type) s = nn[i].name;
  if (!s) sprintf(s = libbuf, "0x%x", (unsigned)statfs->f_type);
  return s;
#endif
}

#if defined(__APPLE__)
#include <sys/disk.h>
int get_block_device_size(int fd, unsigned long long* size)
{
  unsigned long block_size, block_count;

  if (!ioctl(fd, DKIOCGETBLOCKSIZE, &block_size) &&
      !ioctl(fd, DKIOCGETBLOCKCOUNT, &block_count)) {
    *size = block_count * block_size;
    return 1;
  }
  return 0;
}
#elif defined(__linux__)
int get_block_device_size(int fd, unsigned long long* size)
{
  return (ioctl(fd, BLKGETSIZE64, size) >= 0);
}
#endif

// TODO copy_file_range
// Return bytes copied from in to out. If bytes <0 copy all of in to out.
// If consuemd isn't null, amount read saved there (return is written or error)
long long sendfile_len(int in, int out, long long bytes, long long *consumed)
{
  long long total = 0, len, ww;

  if (consumed) *consumed = 0;
  if (in<0) return 0;
  while (bytes != total) {
    ww = 0;
    len = bytes-total;
    if (bytes<0 || len>sizeof(libbuf)) len = sizeof(libbuf);

#if CFG_TOYBOX_COPYFILERANGE
    len = copy_file_range(in, 0, out, 0, bytes, 0);
#else
    ww = len = read(in, libbuf, len);
#endif
    if (!len && errno==EAGAIN) continue;
    if (len<1) break;
    if (consumed) *consumed += len;
    if (ww && writeall(out, libbuf, len) != len) return -1;
    total += len;
  }

  return total;
}