blob: 5ec24919ee6bb7755896477f48ee02832f693c36 [file] [log] [blame]
/* 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, version %3.3s, %d x %d\n",
s-3, (int)peek_le(s, 2), (int)peek_le(s+2, 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>9 && strstart(&s, "7z\xbc\xaf\x27\x1c")) {
int ver = toybuf[6]*10+toybuf[7];
xprintf("7-zip archive data");
if (ver) xprintf(", version %d.%d", 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("ยต-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));
}
}