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
|
/* file.c - describe file type
*
* Copyright 2016 The Android Open Source Project
*
* See http://pubs.opengroup.org/onlinepubs/9699919799/utilities/file.html
USE_FILE(NEWTOY(file, "<1bhLs[!hL]", TOYFLAG_USR|TOYFLAG_BIN))
config FILE
bool "file"
default y
help
usage: file [-bhLs] [FILE...]
Examine the given files and describe their content types.
-b Brief (no filename)
-h Don't follow symlinks (default)
-L Follow symlinks
-s Show block/char device contents
*/
#define FOR_file
#include "toys.h"
GLOBALS(
int max_name_len;
off_t len;
)
// We don't trust elf.h to be there, and two codepaths for 32/64 is awkward
// anyway, so calculate struct offsets manually. (It's a fixed ABI.)
static void do_elf_file(int fd)
{
int endian = toybuf[5], bits = toybuf[4], i, j, dynamic = 0, stripped = 1,
phentsize, phnum, shsize, shnum;
int64_t (*elf_int)(void *ptr, unsigned size);
char *map = 0;
off_t phoff, shoff;
printf("ELF ");
elf_int = (endian==2) ? peek_be : peek_le;
// executable type
i = elf_int(toybuf+16, 2);
if (i == 1) printf("relocatable");
else if (i == 2) printf("executable");
else if (i == 3) printf("shared object");
else if (i == 4) printf("core dump");
else printf("(bad type %d)", i);
if (elf_int(toybuf+36+12*(bits==2), 4) & 0x8000) printf(" (fdpic)");
printf(", ");
// "64-bit"
if (bits == 1) printf("32-bit ");
else if (bits == 2) printf("64-bit ");
else {
printf("(bad class %d) ", bits);
bits = 0;
}
// "LSB"
if (endian == 1) printf("LSB ");
else if (endian == 2) printf("MSB ");
else {
printf("(bad endian %d) \n", endian);
endian = 0;
}
// "x86".
printf("%s", elf_arch_name(elf_int(toybuf+18, 2)));
bits--;
// If what we've seen so far doesn't seem consistent, bail.
if (!((bits&1)==bits && endian)) {
printf(", corrupt?\n");
return;
}
// Parsing ELF means following tables that may point to data earlier in
// the file, so sequential reading involves buffering unknown amounts of
// data. Just skip it if we can't mmap.
if (MAP_FAILED == (map = mmap(0, TT.len, PROT_READ, MAP_SHARED, fd, 0)))
goto bad;
// Stash what we need from the header; it's okay to reuse toybuf after this.
phentsize = elf_int(toybuf+42+12*bits, 2);
phnum = elf_int(toybuf+44+12*bits, 2);
phoff = elf_int(toybuf+28+4*bits, 4+4*bits);
shsize = elf_int(toybuf+46+12*bits, 2);
shnum = elf_int(toybuf+48+12*bits, 2);
shoff = elf_int(toybuf+32+8*bits, 4+4*bits);
// With binutils, phentsize seems to only be non-zero if phnum is non-zero.
// Such ELF files are rare, but do exist. (Android's crtbegin files, say.)
if (phnum && (phentsize != 32+24*bits)) {
printf(", corrupt phentsize %d?", phentsize);
goto bad;
}
// Parsing ELF means following tables that may point to data earlier in
// the file, so sequential reading involves buffering unknown amounts of
// data. Just skip it if we can't mmap.
if (MAP_FAILED == (map = mmap(0, TT.len, PROT_READ, MAP_SHARED, fd, 0)))
goto bad;
// We need to read the phdrs for dynamic vs static.
// (Note: fields got reordered for 64 bit)
if (phoff+phnum*phentsize>TT.len) goto bad;
for (i = 0; i<phnum; i++) {
char *phdr = map+phoff+i*phentsize;
int p_type = elf_int(phdr, 4);
long long p_offset, p_filesz;
if (p_type==2 /*PT_DYNAMIC*/) dynamic = 1;
if (p_type!=3 /*PT_INTERP*/ && p_type!=4 /*PT_NOTE*/) continue;
j = bits+1;
p_offset = elf_int(phdr+4*j, 4*j);
p_filesz = elf_int(phdr+16*j, 4*j);
if (p_type==3 /*PT_INTERP*/) {
if (p_offset+p_filesz>TT.len) goto bad;
printf(", dynamic (%.*s)", (int)p_filesz, map+p_offset);
}
}
if (!dynamic) printf(", static");
// We need to read the shdrs for stripped/unstripped and any notes.
// Notes are in program headers *and* section headers, but some files don't
// contain program headers, so we prefer to check here.
// (Note: fields got reordered for 64 bit)
if (shoff+i*shnum>TT.len) goto bad;
for (i = 0; i<shnum; i++) {
char *shdr = map+shoff+i*shsize;
int sh_type = elf_int(shdr+4, 4);
long sh_offset = elf_int(shdr+8+8*(bits+1), 4*(bits+1));
int sh_size = elf_int(shdr+8+12*(bits+1), 4);
if (sh_type == 2 /*SHT_SYMTAB*/) {
stripped = 0;
break;
} else if (sh_type == 7 /*SHT_NOTE*/) {
char *note = map+sh_offset;
// An ELF note is a sequence of entries, each consisting of an
// ndhr followed by n_namesz+n_descsz bytes of data (each of those
// rounded up to the next 4 bytes, without this being reflected in
// the header byte counts themselves).
while (sh_size >= 3*4) { // Don't try to read a truncated entry.
unsigned n_namesz, n_descsz, n_type, notesz;
if (sh_offset+sh_size>TT.len) goto bad;
n_namesz = elf_int(note, 4);
n_descsz = elf_int(note+4, 4);
n_type = elf_int(note+8, 4);
notesz = 3*4 + ((n_namesz+3)&~3) + ((n_descsz+3)&~3);
// Does the claimed size of this note actually fit in the section?
if (notesz > sh_size) goto bad;
if (n_namesz==4 && !memcmp(note+12, "GNU", 4)) {
if (n_type==3 /*NT_GNU_BUILD_ID*/) {
printf(", BuildID=");
for (j = 0; j < n_descsz; ++j) printf("%02x", note[16 + j]);
}
} else if (n_namesz==8 && !memcmp(note+12, "Android", 8)) {
if (n_type==1 /*.android.note.ident*/ && n_descsz >= 4) {
printf(", for Android %d", (int)elf_int(note+20, 4));
// NDK r14 and later also include NDK version info. OS binaries
// and binaries built by older NDKs don't have this.
if (n_descsz >= 4+64+64)
printf(", built by NDK %.64s (%.64s)", note+24, note+24+64);
}
}
note += notesz;
sh_size -= notesz;
}
}
}
printf(", %sstripped", stripped ? "" : "not ");
bad:
xputc('\n');
if (map && map != MAP_FAILED) munmap(map, TT.len);
}
static void do_regular_file(int fd, char *name)
{
char *s;
int len, magic;
// zero through elf shnum, just in case
memset(toybuf, 0, 80);
if ((len = readall(fd, s = toybuf, sizeof(toybuf)))<0) perror_msg("%s", name);
if (!len) xputs("empty");
// 45 bytes: https://www.muppetlabs.com/~breadbox/software/tiny/teensy.html
else if (len>=45 && strstart(&s, "\177ELF")) do_elf_file(fd);
else if (len>=8 && strstart(&s, "!<arch>\n")) xputs("ar archive");
else if (len>28 && strstart(&s, "\x89PNG\x0d\x0a\x1a\x0a")) {
// PNG is big-endian: https://www.w3.org/TR/PNG/#7Integers-and-byte-order
int chunk_length = peek_be(s, 4);
xprintf("PNG image data");
// The IHDR chunk comes first: https://www.w3.org/TR/PNG/#11IHDR
s += 4;
if (chunk_length == 13 && strstart(&s, "IHDR")) {
// https://www.w3.org/TR/PNG/#6Colour-values
char *c = 0, *colors[] = {"grayscale", 0, "color RGB", "indexed color",
"grayscale with alpha", 0, "color RGBA"};
if (s[9]<ARRAY_LEN(colors)) c = colors[s[9]];
if (!c) c = "unknown";
xprintf(", %d x %d, %d-bit/%s, %sinterlaced", (int)peek_be(s, 4),
(int)peek_be(s+4, 4), s[8], c, s[12] ? "" : "non-");
}
xputc('\n');
// https://www.w3.org/Graphics/GIF/spec-gif89a.txt
} else if (len>16 && (strstart(&s, "GIF87a") || strstart(&s, "GIF89a")))
xprintf("GIF image data, %d x %d\n",
(int)peek_le(s, 2), (int)peek_le(s+8, 2));
// TODO: parsing JPEG for width/height is harder than GIF or PNG.
else if (len>32 && !memcmp(toybuf, "\xff\xd8", 2)) xputs("JPEG image data");
// https://en.wikipedia.org/wiki/Java_class_file#General_layout
else if (len>8 && strstart(&s, "\xca\xfe\xba\xbe"))
xprintf("Java class file, version %d.%d (Java 1.%d)\n",
(int)peek_be(s+2, 2), (int)peek_be(s, 2), (int)peek_be(s+2, 2)-44);
// https://source.android.com/devices/tech/dalvik/dex-format#dex-file-magic
else if (len>8 && strstart(&s, "dex\n") && s[3] == 0)
xprintf("Android dex file, version %s\n", s);
// https://people.freebsd.org/~kientzle/libarchive/man/cpio.5.txt
// the lengths for cpio are size of header + 9 bytes, since any valid
// cpio archive ends with a record for "TARGET!!!"
else if (len>85 && strstart(&s, "07070")) {
char *cpioformat = "unknown type";
if (toybuf[5] == '7') cpioformat = "pre-SVR4 or odc";
else if (toybuf[5] == '1') cpioformat = "SVR4 with no CRC";
else if (toybuf[5] == '2') cpioformat = "SVR4 with CRC";
xprintf("ASCII cpio archive (%s)\n", cpioformat);
} else if (len>33 && (magic=peek(&s,2), magic==0143561 || magic==070707)) {
if (magic == 0143561) printf("byte-swapped ");
xputs("cpio archive");
// tar archive (old, ustar/pax, or gnu)
} else if (len>500 && is_tar_header(s))
xprintf("%s tar archive%s\n", s[257] ? "POSIX" : "old",
strncmp(s+262," ",2)?"":" (GNU)");
// zip/jar/apk archive, ODF/OOXML document, or such
else if (len>5 && strstart(&s, "PK\03\04")) {
int ver = toybuf[4];
xprintf("Zip archive data");
if (ver) xprintf(", requires at least v%d.%d to extract", ver/10, ver%10);
xputc('\n');
} else if (len>4 && strstart(&s, "BZh") && isdigit(*s))
xprintf("bzip2 compressed data, block size = %c00k\n", *s);
else if (len > 31 && peek_be(s, 7) == 0xfd377a585a0000UL)
xputs("xz compressed data");
else if (len>10 && strstart(&s, "\x1f\x8b")) xputs("gzip compressed data");
else if (len>32 && !memcmp(s+1, "\xfa\xed\xfe", 3)) {
int bit = s[0]=='\xce'?32:64;
char *what;
xprintf("Mach-O %d-bit ", bit);
if (s[4] == 7) what = (bit==32)?"x86":"x86-";
else if (s[4] == 12) what = "arm";
else if (s[4] == 18) what = "ppc";
else what = NULL;
if (what) xprintf("%s%s ", what, (bit==32)?"":"64");
else xprintf("(bad arch %d) ", s[4]);
if (s[12] == 1) what = "object";
else if (s[12] == 2) what = "executable";
else if (s[12] == 6) what = "shared library";
else what = NULL;
if (what) xprintf("%s\n", what);
else xprintf("(bad type %d)\n", s[9]);
} else if (len>36 && !memcmp(s, "OggS\x00\x02", 6)) {
xprintf("Ogg data");
// https://wiki.xiph.org/MIMETypesCodecs
if (!memcmp(s+28, "CELT ", 8)) xprintf(", celt audio");
else if (!memcmp(s+28, "CMML ", 8)) xprintf(", cmml text");
else if (!memcmp(s+28, "BBCD\0", 5)) xprintf(", dirac video");
else if (!memcmp(s+28, "\177FLAC", 5)) xprintf(", flac audio");
else if (!memcmp(s+28, "\x8bJNG\r\n\x1a\n", 8)) xprintf(", jng video");
else if (!memcmp(s+28, "\x80kate\0\0\0", 8)) xprintf(", kate text");
else if (!memcmp(s+28, "OggMIDI\0", 8)) xprintf(", midi text");
else if (!memcmp(s+28, "\x8aMNG\r\n\x1a\n", 8)) xprintf(", mng video");
else if (!memcmp(s+28, "OpusHead", 8)) xprintf(", opus audio");
else if (!memcmp(s+28, "PCM ", 8)) xprintf(", pcm audio");
else if (!memcmp(s+28, "\x89PNG\r\n\x1a\n", 8)) xprintf(", png video");
else if (!memcmp(s+28, "Speex ", 8)) xprintf(", speex audio");
else if (!memcmp(s+28, "\x80theora", 7)) xprintf(", theora video");
else if (!memcmp(s+28, "\x01vorbis", 7)) xprintf(", vorbis audio");
else if (!memcmp(s+28, "YUV4MPEG", 8)) xprintf(", yuv4mpeg video");
xputc('\n');
} else if (len>32 && !memcmp(s, "RIF", 3) && !memcmp(s+8, "WAVEfmt ", 8)) {
// https://en.wikipedia.org/wiki/WAV
int le = (s[3] == 'F');
int format = le ? peek_le(s+20,2) : peek_be(s+20,2);
int channels = le ? peek_le(s+22,2) : peek_be(s+22,2);
int hz = le ? peek_le(s+24,4) : peek_be(s+24,4);
int bits = le ? peek_le(s+34,2) : peek_be(s+34,2);
xprintf("WAV audio, %s, ", le ? "LE" : "BE");
if (bits != 0) xprintf("%d-bit, ", bits);
if (channels==1||channels==2) xprintf("%s, ", channels==1?"mono":"stereo");
else xprintf("%d-channel, ", channels);
xprintf("%d Hz, ", hz);
// See https://tools.ietf.org/html/rfc2361, though there appear to be bugs
// in the RFC. This assumes wikipedia's example files are more correct.
if (format == 0x01) xprintf("PCM");
else if (format == 0x03) xprintf("IEEE float");
else if (format == 0x06) xprintf("A-law");
else if (format == 0x07) xprintf("µ-law");
else if (format == 0x11) xprintf("ADPCM");
else if (format == 0x22) xprintf("Truespeech");
else if (format == 0x31) xprintf("GSM");
else if (format == 0x55) xprintf("MP3");
else if (format == 0x70) xprintf("CELP");
else if (format == 0xfffe) xprintf("extensible");
else xprintf("unknown format %d", format);
xputc('\n');
} else if (len>12 && !memcmp(s, "\x00\x01\x00\x00", 4)) {
xputs("TrueType font");
} else if (len>12 && !memcmp(s, "ttcf\x00", 5)) {
xprintf("TrueType font collection, version %d, %d fonts\n",
(int)peek_be(s+4, 2), (int)peek_be(s+8, 4));
// https://docs.microsoft.com/en-us/typography/opentype/spec/otff
} else if (len>12 && !memcmp(s, "OTTO", 4)) {
xputs("OpenType font");
} else if (len>4 && !memcmp(s, "BC\xc0\xde", 4)) {
xputs("LLVM IR bitcode");
} else if (strstart(&s, "-----BEGIN CERTIFICATE-----")) {
xputs("PEM certificate");
// https://msdn.microsoft.com/en-us/library/windows/desktop/ms680547(v=vs.85).aspx
} else if (len>0x70 && !memcmp(s, "MZ", 2) &&
(magic=peek_le(s+0x3c,4))<len-4 && !memcmp(s+magic, "\x50\x45\0\0", 4)) {
xprintf("MS PE32%s executable %s", (peek_le(s+magic+24, 2)==0x20b)?"+":"",
(peek_le(s+magic+22, 2)&0x2000)?"(DLL) ":"");
if (peek_le(s+magic+20, 2)>70) {
char *types[] = {0, "native", "GUI", "console", "OS/2", "driver", "CE",
"EFI", "EFI boot", "EFI runtime", "EFI ROM", "XBOX", 0, "boot"};
int type = peek_le(s+magic+92, 2);
char *name = (type>0 && type<ARRAY_LEN(types))?types[type]:0;
xprintf("(%s) ", name?name:"unknown");
}
xprintf("%s\n", (peek_le(s+magic+4, 2)==0x14c)?"x86":"x86-64");
// https://en.wikipedia.org/wiki/BMP_file_format
} else if (len > 0x32 && !memcmp(s, "BM", 2) && !memcmp(s+6, "\0\0\0\0", 4)) {
int w = peek_le(s+0x12,4), h = peek_le(s+0x16,4), bpp = peek_le(s+0x1c,2);
xprintf("BMP image, %d x %d, %d bpp\n", w, h, bpp);
// https://github.com/torvalds/linux/blob/master/tools/perf/Documentation/perf.data-file-format.txt
} else if (len>=104 && !memcmp(s, "PERFILE2", 8)) {
xputs("Linux perf data");
// https://android.googlesource.com/platform/system/core/+/master/libsparse/sparse_format.h
} else if (len>28 && peek_le(s, 4) == 0xed26ff3a) {
xprintf("Android sparse image v%d.%d, %d %d-byte blocks (%d chunks)\n",
(int) peek_le(s+4, 2), (int) peek_le(s+6, 2), (int) peek_le(s+16, 4),
(int) peek_le(s+12, 4), (int) peek_le(s+20, 4));
// https://android.googlesource.com/platform/system/tools/mkbootimg/+/refs/heads/master/include/bootimg/bootimg.h
} else if (len>1632 && !memcmp(s, "ANDROID!", 8)) {
xprintf("Android boot image v%d\n", (int) peek_le(s+40, 4));
// https://source.android.com/devices/architecture/dto/partitions
} else if (len>32 && peek_be(s, 4) == 0xd7b7ab1e) {
xprintf("Android DTB/DTBO v%d, %d entries\n", (int) peek_be(s+28, 4),
(int) peek_be(s+16, 4));
} else {
char *what = 0;
int i, bytes;
// If shell script, report which interpreter
if (len>3 && strstart(&s, "#!")) {
// Whitespace is allowed between the #! and the interpreter
while (isspace(*s)) s++;
if (strstart(&s, "/usr/bin/env")) while (isspace(*s)) s++;
for (what = s; (s-toybuf)<len && !isspace(*s); s++);
strcpy(s, " script");
// Distinguish ASCII text, UTF-8 text, or data
} else for (i = 0; i<len; ++i) {
if (!(isprint(toybuf[i]) || isspace(toybuf[i]))) {
wchar_t wc;
if ((bytes = utf8towc(&wc, s+i, len-i))>0 && wcwidth(wc)>=0) {
i += bytes-1;
if (!what) what = "UTF-8 text";
} else {
what = "data";
break;
}
}
}
xputs(what ? what : "ASCII text");
}
}
void file_main(void)
{
char **arg;
for (arg = toys.optargs; *arg; ++arg) {
int name_len = strlen(*arg);
if (name_len > TT.max_name_len) TT.max_name_len = name_len;
}
// Can't use loopfiles here because it doesn't call function when can't open
for (arg = toys.optargs; *arg; arg++) {
char *name = *arg, *what = "unknown";
struct stat sb;
int fd = !strcmp(name, "-");
if (!FLAG(b))
xprintf("%s: %*s", name, (int)(TT.max_name_len - strlen(name)), "");
sb.st_size = 0;
if (fd || !(FLAG(L) ? stat : lstat)(name, &sb)) {
if (!fd && !FLAG(s) && (S_ISBLK(sb.st_mode) || S_ISCHR(sb.st_mode))) {
sprintf(what = toybuf, "%s special (%u/%u)",
S_ISBLK(sb.st_mode) ? "block" : "character",
dev_major(sb.st_rdev), dev_minor(sb.st_rdev));
} else if (fd || S_ISREG(sb.st_mode)) {
TT.len = sb.st_size;
// This test identifies an empty file we don't have permission to read
if (!fd && !sb.st_size) what = "empty";
else if ((fd = openro(name, O_RDONLY)) != -1) {
do_regular_file(fd, name);
if (fd) close(fd);
continue;
}
} else if (S_ISFIFO(sb.st_mode)) what = "fifo";
else if (S_ISDIR(sb.st_mode)) what = "directory";
else if (S_ISSOCK(sb.st_mode)) what = "socket";
else if (S_ISLNK(sb.st_mode)) {
char *lnk = xreadlink(name);
sprintf(what = toybuf, "%ssymbolic link to %s",
stat(name, &sb) ? "broken " : "", lnk);
free(lnk);
}
xputs(what);
} else xprintf("cannot open: %s\n", strerror(errno));
}
}
|