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/* 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, "<1", TOYFLAG_USR|TOYFLAG_BIN))
config FILE
bool "file"
default n
help
usage: file [file...]
Examine the given files and describe their content types.
*/
#define FOR_file
#include "toys.h"
GLOBALS(
int max_name_len;
)
static void do_elf_file()
{
int elf_endian = toybuf[5], e_type, e_machine, i;
int64_t (*elf_int)(void *ptr, unsigned size) = peek_le;
// Values from include/linux/elf-em.h (plus arch/*/include/asm/elf.h)
// Names are linux/arch/ directory name
struct {int val; char *name;} type[] = {{0x9026, "alpha"},
{40, "arm"}, {183, "arm"}, {0x18ad, "avr32"}, {106, "blackfin"},
{76, "cris"}, {0x5441, "frv"}, {46, "h8300"}, {50, "ia64"},//ia intel ftaghn
{88, "m32r"}, {4, "m68k"}, {0xbaab, "microblaze"}, {8, "mips"},
{10, "mips"}, {89, "mn10300"}, {15, "parisc"}, {22, "s390"},
{135, "score"}, {42, "sh"}, {2, "sparc"}, {18, "sparc"}, {43, "sparc"},
{187, "tile"}, {188, "tile"}, {191, "tile"}, {3, "x86"}, {6, "x86"},
{62, "x86"}, {94, "xtensa"}, {0xabc7, "xtensa"}};
xprintf("ELF ");
// "64-bit"
if (toybuf[4] == 1) xprintf("32-bit ");
else if (toybuf[4] == 2) xprintf("64-bit ");
else xprintf("(bad class %d)", toybuf[4]);
// "LSB"
if (elf_endian == 1) xprintf("LSB ");
else if (elf_endian == 2) {
xprintf("MSB ");
elf_int = peek_be;
} else {
xprintf("(bad endian %d)\n", elf_endian);
// At this point we can't parse remaining fields.
return;
}
// ", executable"
e_type = elf_int(&toybuf[0x10], 2);
if (e_type == 1) xprintf("relocatable");
else if (e_type == 2) xprintf("executable");
else if (e_type == 3) xprintf("shared object");
else if (e_type == 4) xprintf("core dump");
else xprintf("(invalid type %d)", e_type);
// ", x86-64"
e_machine = elf_int(&toybuf[0x12], 2);
for (i = 0; i<ARRAY_LEN(type); i++) if (e_machine == type[i].val) break;
if (i<ARRAY_LEN(type)) xprintf(", %s", type[i].name);
else xprintf(", (unknown arch %d)", e_machine);
// "version 1"
xprintf(", version %d", toybuf[6]);
// " (SYSV)"
// TODO: will we ever meet any of the others in practice?
if (!toybuf[7]) xprintf(" (SYSV)");
else xprintf(" (OS %d)", toybuf[7]);
// TODO: we'd need to actually parse the ELF file to report the rest...
// ", dynamically linked"
// " (uses shared libs)"
// ", for Linux 2.6.24"
// ", BuildID[sha1]=SHA"
// ", stripped"
xputc('\n');
}
static void do_regular_file(int fd, char *name)
{
char *s;
int len = read(fd, s = toybuf, sizeof(toybuf)-256);
if (len<0) perror_msg("%s", name);
if (len>20 && strstart(&s, "\177ELF")) {
do_elf_file(len);
} 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) == 0)
xprintf("JPEG image data\n");
// https://docs.oracle.com/javase/specs/jvms/se7/html/jvms-4.html
else if (len>8 && strstart(&s, "\xca\xfe\xba\xbe"))
xprintf("Java class file, version %d.%d\n",
(int)peek_be(s+6, 2), (int)peek_be(s, 2));
// TODO: cpio archive.
// TODO: tar archive.
// TODO: zip/jar/apk archive.
else {
char *what = 0;
int i, bytes;
// If shell script, report which interpreter
if (len>3 && strstart(&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 = mbrtowc(&wc, s+i, len-i, 0))>0 && wcwidth(wc)>=0) {
i += bytes-1;
if (!what) what = "UTF-8 text";
} else {
what = "data";
break;
}
}
}
xputs(what ? what : "ASCII text");
}
}
static void do_file(int fd, char *name)
{
struct stat sb;
char *what = "unknown";
xprintf("%s: %*s", name, (int)(TT.max_name_len - strlen(name)), "");
if (!fstat(fd, &sb)) what = "cannot open";
if (S_ISREG(sb.st_mode)) {
if (sb.st_size == 0) what = "empty";
else {
do_regular_file(fd, name);
return;
}
} else if (S_ISBLK(sb.st_mode)) what = "block special";
else if (S_ISCHR(sb.st_mode)) what = "character special";
else if (S_ISDIR(sb.st_mode)) what = "directory";
else if (S_ISFIFO(sb.st_mode)) what = "fifo";
else if (S_ISSOCK(sb.st_mode)) what = "socket";
else if (S_ISLNK(sb.st_mode)) what = "symbolic link";
xputs(what);
}
void file_main(void)
{
char **name;
for (name = toys.optargs; *name; ++name) {
int name_len = strlen(*name);
if (name_len > TT.max_name_len) TT.max_name_len = name_len;
}
loopfiles(toys.optargs, do_file);
}
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