2 * Copyright (c) 2007 S.Sam Arun Raj
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 #include <sys/cdefs.h>
29 #include <sys/types.h>
49 ELFTC_VCSID("$Id: strings.c 2351 2011-12-19 11:20:37Z jkoshy $");
67 ENCODING_16BIT_LITTLE,
72 #define PRINTABLE(c) \
73 ((c) >= 0 && (c) <= 255 && \
74 ((c) == '\t' || isprint((c)) || \
75 (encoding == ENCODING_8BIT && (c) > 127)))
78 static int encoding_size, entire_file, min_len, show_filename, show_loc;
79 static enum encoding_style encoding;
80 static enum radix_style radix;
82 static struct option strings_longopts[] = {
83 { "all", no_argument, NULL, 'a'},
84 { "bytes", required_argument, NULL, 'n'},
85 { "encoding", required_argument, NULL, 'e'},
86 { "help", no_argument, NULL, 'h'},
87 { "print-file-name", no_argument, NULL, 'f'},
88 { "radix", required_argument, NULL, 't'},
89 { "version", no_argument, NULL, 'v'},
93 long getcharacter(void);
94 int handle_file(const char *);
95 int handle_elf(const char *, int);
96 int handle_binary(const char *, int);
97 int find_strings(const char *, off_t, off_t);
98 void show_version(void);
102 * strings(1) extracts text(contiguous printable characters)
103 * from elf and binary files.
106 main(int argc, char **argv)
113 if (elf_version(EV_CURRENT) == EV_NONE)
114 errx(EXIT_FAILURE, "ELF library initialization failed: %s",
117 while ((ch = getopt_long(argc, argv, "1234567890ae:fhn:ot:Vv",
118 strings_longopts, NULL)) != -1)
124 if (*optarg == 's') {
125 encoding = ENCODING_7BIT;
126 } else if (*optarg == 'S') {
127 encoding = ENCODING_8BIT;
128 } else if (*optarg == 'b') {
129 encoding = ENCODING_16BIT_BIG;
131 } else if (*optarg == 'B') {
132 encoding = ENCODING_32BIT_BIG;
134 } else if (*optarg == 'l') {
135 encoding = ENCODING_16BIT_LITTLE;
137 } else if (*optarg == 'L') {
138 encoding = ENCODING_32BIT_LITTLE;
148 min_len = (int)strtoimax(optarg, (char**)NULL, 10);
157 radix = RADIX_DECIMAL;
158 else if (*optarg == 'o')
160 else if (*optarg == 'x')
195 rc = handle_file("{standard input}");
197 rc = handle_file(*argv);
204 handle_file(const char *name)
209 return (RETURN_NOINPUT);
210 if (strcmp("{standard input}", name) != 0) {
211 if (freopen(name, "rb", stdin) == NULL) {
212 warnx("'%s': %s", name, strerror(errno));
213 return (RETURN_NOINPUT);
216 return (find_strings(name, (off_t)0, (off_t)0));
221 return (RETURN_NOINPUT);
222 rt = handle_elf(name, fd);
227 * Files not understood by handle_elf, will be passed off here and will
228 * treated as a binary file. This would include text file, core dumps ...
231 handle_binary(const char *name, int fd)
235 memset(&buf, 0, sizeof(struct stat));
236 (void) lseek(fd, (off_t)0, SEEK_SET);
237 if (!fstat(fd, &buf))
238 return (find_strings(name, (off_t)0, buf.st_size));
239 return (RETURN_SOFTWARE);
243 * Will analyse a file to see if it ELF, other files including ar(1),
244 * core dumps are passed off and treated as flat binary files. Unlike
245 * GNU size in FreeBSD this routine will not treat ELF object from
246 * different archs as flat binary files(has to overridden using -a).
249 handle_elf(const char *name, int fd)
258 /* If entire file is choosen, treat it as a binary file */
260 return (handle_binary(name, fd));
262 (void) lseek(fd, (off_t)0, SEEK_SET);
263 elf = elf_begin(fd, ELF_C_READ, NULL);
264 if (elf_kind(elf) != ELF_K_ELF) {
266 return (handle_binary(name, fd));
269 if (gelf_getehdr(elf, &elfhdr) == NULL) {
271 warnx("%s: ELF file could not be processed", name);
272 return (RETURN_SOFTWARE);
275 if (elfhdr.e_shnum == 0 && elfhdr.e_type == ET_CORE) {
277 return (handle_binary(name, fd));
280 while ((scn = elf_nextscn(elf, scn)) != NULL) {
281 if (gelf_getshdr(scn, &shdr) == NULL)
283 if (shdr.sh_type != SHT_NOBITS &&
284 (shdr.sh_flags & SHF_ALLOC) != 0) {
285 rc = find_strings(name, shdr.sh_offset,
295 * Retrieves a character from input stream based on the encoding
306 for(i = 0; i < encoding_size; i++) {
318 case ENCODING_16BIT_BIG:
319 rt = (buf[0] << 8) | buf[1];
321 case ENCODING_16BIT_LITTLE:
322 rt = buf[0] | (buf[1] << 8);
324 case ENCODING_32BIT_BIG:
325 rt = ((long) buf[0] << 24) | ((long) buf[1] << 16) |
326 ((long) buf[2] << 8) | buf[3];
328 case ENCODING_32BIT_LITTLE:
329 rt = buf[0] | ((long) buf[1] << 8) | ((long) buf[2] << 16) |
330 ((long) buf[3] << 24);
337 * Input stream stdin is read until the end of file is reached or until
338 * the section size is reached in case of ELF files. Contiguous
339 * characters of >= min_size(default 4) will be displayed.
342 find_strings(const char *name, off_t offset, off_t size)
344 off_t cur_off, start_off;
349 if ((obuf = (char*)calloc(1, min_len + 1)) == NULL) {
350 (void) fprintf(stderr, "Unable to allocate memory: %s\n",
352 return (RETURN_SOFTWARE);
355 (void) fseeko(stdin, offset, SEEK_SET);
359 if ((offset + size) && (cur_off >= offset + size))
362 memset(obuf, 0, min_len+1);
363 for(i = 0; i < min_len; i++) {
365 if (c == EOF && feof(stdin))
370 cur_off += encoding_size;
372 if (encoding == ENCODING_8BIT &&
376 cur_off += encoding_size;
379 cur_off += encoding_size;
384 if (i >= min_len && ((cur_off <= offset + size) ||
387 printf ("%s: ", name);
391 (void) printf("%7ju ",
392 (uintmax_t)start_off);
395 (void) printf("%7jx ",
396 (uintmax_t)start_off);
399 (void) printf("%7jo ",
400 (uintmax_t)start_off);
407 if ((offset + size) &&
408 (cur_off >= offset + size))
411 cur_off += encoding_size;
412 if (encoding == ENCODING_8BIT &&
417 if (!PRINTABLE(c) || c == EOF)
429 #define USAGE_MESSAGE "\
430 Usage: %s [options] [file...]\n\
431 Print contiguous sequences of printable characters.\n\n\
433 -a | --all Scan the entire file for strings.\n\
434 -e ENC | --encoding=ENC Select the character encoding to use.\n\
435 -f | --print-file-name Print the file name before each string.\n\
436 -h | --help Print a help message and exit.\n\
437 -n N | --bytes=N | -N Print sequences with 'N' or more characters.\n\
438 -o Print offsets in octal.\n\
439 -t R | --radix=R Print offsets using the radix named by 'R'.\n\
440 -v | --version Print a version identifier and exit.\n"
445 (void) fprintf(stderr, USAGE_MESSAGE, ELFTC_GETPROGNAME());
452 (void) printf("%s (%s)\n", ELFTC_GETPROGNAME(), elftc_version());