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-rw-r--r--toys/posix/file.c308
1 files changed, 308 insertions, 0 deletions
diff --git a/toys/posix/file.c b/toys/posix/file.c
new file mode 100644
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--- /dev/null
+++ b/toys/posix/file.c
@@ -0,0 +1,308 @@
+/* file.c - describe file type
+ *
+ * Copyright 2016 The Android Open Source Project
+ *
+ * See http://pubs.opengroup.org/onlinepubs/9699919799/utilities/file.html
+ *
+ * TODO: ar
+
+USE_FILE(NEWTOY(file, "<1", TOYFLAG_USR|TOYFLAG_BIN))
+
+config FILE
+ bool "file"
+ default y
+ help
+ usage: file [file...]
+
+ Examine the given files and describe their content types.
+*/
+
+#define FOR_file
+#include "toys.h"
+
+GLOBALS(
+ int max_name_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, struct stat *sb)
+{
+ int endian = toybuf[5], bits = toybuf[4], i, j;
+ 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 (sometimes before 32/64 bit merges)
+ struct {int val; char *name;} type[] = {{0x9026, "alpha"}, {93, "arc"},
+ {195, "arcv2"}, {40, "arm"}, {183, "arm64"}, {0x18ad, "avr32"},
+ {106, "blackfin"}, {140, "c6x"}, {23, "cell"}, {76, "cris"},
+ {0x5441, "frv"}, {46, "h8300"}, {164, "hexagon"}, {50, "ia64"},
+ {88, "m32r"}, {0x9041, "m32r"}, {4, "m68k"}, {174, "metag"},
+ {0xbaab, "microblaze"}, {8, "mips"}, {10, "mips-old"}, {89, "mn10300"},
+ {0xbeef, "mn10300-old"}, {113, "nios2"}, {92, "openrisc"},
+ {0x8472, "openrisc-old"}, {15, "parisc"}, {20, "ppc"}, {21, "ppc64"},
+ {22, "s390"}, {0xa390, "s390-old"}, {135, "score"}, {42, "sh"},
+ {2, "sparc"}, {18, "sparc8+"}, {43, "sparc9"}, {188, "tile"},
+ {191, "tilegx"}, {3, "386"}, {6, "486"}, {62, "x86-64"}, {94, "xtensa"},
+ {0xabc7, "xtensa-old"}
+ };
+ int dynamic = 0;
+ int stripped = 1;
+ char *map;
+ off_t phoff, shoff;
+ int phsize, phnum, shsize, shnum;
+
+ printf("ELF ");
+
+ // executable (ELF says this is short but reality says byte, not MSB swapped)
+ i = toybuf[16];
+ 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);
+ 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 ");
+ elf_int = peek_be;
+ } else {
+ printf("(bad endian %d) \n", endian);
+ endian = 0;
+ }
+
+ // e_machine, ala "x86", from big table above
+ j = elf_int(toybuf+18, 2);
+ for (i = 0; i<ARRAY_LEN(type); i++) if (j==type[i].val) break;
+ if (i<ARRAY_LEN(type)) printf("%s", type[i].name);
+ else printf("(unknown arch %d)", j);
+
+ bits--;
+ // If what we've seen so far doesn't seem consistent, bail.
+ if (!((bits&1)==bits && endian &&
+ (i = elf_int(toybuf+42+12*bits, 2)) == 32+24*bits)) {
+ printf(", corrupt?\n");
+ return;
+ }
+
+ // Stash what we need from the header; it's okay to reuse toybuf after this.
+ phsize = i;
+ 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);
+
+ map = mmap(0, sb->st_size, PROT_READ, MAP_SHARED, fd, 0);
+ if (!map) perror_exit("mmap");
+
+ // We need to read the phdrs for dynamic vs static and any notes.
+ // (Note: fields got reordered for 64 bit)
+ for (i = 0; i<phnum; i++) {
+ char *phdr = map+phoff+i*phsize;
+ 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*/)
+ printf(", dynamic (%.*s)", (int)p_filesz, map+p_offset);
+ else {
+ char *note = map+p_offset;
+
+ // A PT_NOTE phdr 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 (p_filesz >= 3*4) { // Don't try to read a truncated entry.
+ int n_namesz = elf_int(note, 4);
+ int n_descsz = elf_int(note+4, 4);
+ int n_type = elf_int(note+8, 4);
+ int notesz = 3*4 + ((n_namesz+3)&~3) + ((n_descsz+3)&~3);
+
+ if (n_namesz==4 && !memcmp(note+12, "GNU", 4)) {
+ if (n_type == 3 /*NT_GNU_BUILD_ID*/) {
+ printf(", BuildID[%s]=", (n_descsz==20)?"sha1":"md5");
+ 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) printf(", for Android %d", (int)elf_int(note+20, 4));
+ }
+
+ note += notesz;
+ p_filesz -= notesz;
+ }
+ }
+ }
+ if (!dynamic) printf(", static");
+
+ // We need to read the shdrs for stripped/unstripped.
+ // (Note: fields got reordered for 64 bit)
+ for (i = 0; i<shnum; i++) {
+ char *shdr = map+shoff+i*shsize;
+ int sh_type = elf_int(shdr+4, 4);
+
+ if (sh_type == 2 /*SHT_SYMTAB*/) {
+ stripped = 0;
+ break;
+ }
+ }
+ printf(", %sstripped", stripped ? "" : "not ");
+ xputc('\n');
+
+ munmap(map, sb->st_size);
+}
+
+static void do_regular_file(int fd, char *name, struct stat *sb)
+{
+ char *s;
+ int len = read(fd, s = toybuf, sizeof(toybuf)-256);
+ int magic;
+
+ if (len<0) perror_msg("%s", name);
+
+ if (len>40 && strstart(&s, "\177ELF")) do_elf_file(fd, sb);
+ 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+2, 2), (int)peek_be(s, 2));
+
+ // 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 ");
+ xprintf("cpio archive\n");
+ }
+ // tar archive (ustar/pax or gnu)
+ else if (len>500 && !strncmp(s+257, "ustar", 5)) {
+ xprintf("POSIX tar archive%s\n", 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 = (int)(char)(toybuf[4]);
+ xprintf("Zip archive data");
+ if (ver)
+ xprintf(", requires at least v%d.%d to extract", ver/10, ver%10);
+ xputc('\n');
+ }
+ 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 = 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");
+ }
+}
+
+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++) {
+ struct stat sb;
+ char *name = *arg, *what = "cannot open";
+
+ xprintf("%s: %*s", name, (int)(TT.max_name_len - strlen(name)), "");
+
+ if (!lstat(name, &sb)) {
+ if (S_ISFIFO(sb.st_mode)) what = "fifo";
+ else if (S_ISREG(sb.st_mode)) {
+ int fd = !strcmp(name, "-") ? 0 : open(name, O_RDONLY);
+
+ if (fd!=-1) {
+ if (!sb.st_size) what = "empty";
+ else do_regular_file(fd, name, &sb);
+ if (fd) close(fd);
+ if (sb.st_size) continue;
+ }
+ } 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_ISSOCK(sb.st_mode)) what = "socket";
+ else if (S_ISLNK(sb.st_mode)) what = "symbolic link";
+ else what = "unknown";
+ }
+
+ xputs(what);
+ }
+}