miscutils/strings.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * strings implementation for busybox
   4  *
   5  * Copyright 2003 Tito Ragusa <farmatito@tiscali.it>
   6  *
   7  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   8  */
   9 //config:config STRINGS
  10 //config:       bool "strings (4.8 kb)"
  11 //config:       default y
  12 //config:       help
  13 //config:       strings prints the printable character sequences for each file
  14 //config:       specified.
  15
  16 //applet:IF_STRINGS(APPLET(strings, BB_DIR_USR_BIN, BB_SUID_DROP))
  17
  18 //kbuild:lib-$(CONFIG_STRINGS) += strings.o
  19
  20 //usage:#define strings_trivial_usage
  21 //usage:       "[-fo] [-t o|d|x] [-n LEN] [FILE]..."
  22 //usage:#define strings_full_usage "\n\n"
  23 //usage:       "Display printable strings in a binary file\n"
  24 //We usually don't bother user with "nop" options. They work, but are not shown:
  25 ////usage:     "\n      -a              Scan whole file (default)"
  26 //unimplemented alternative is -d: Only strings from initialized, loaded data sections
  27 //usage:     "\n        -f              Precede strings with filenames"
  28 //usage:     "\n        -o              Precede strings with octal offsets"
  29 //usage:     "\n        -t o|d|x        Precede strings with offsets in base 8/10/16"
  30 //usage:     "\n        -n LEN          At least LEN characters form a string (default 4)"
  31
  32 #include "libbb.h"
  33
  34 #define WHOLE_FILE    1
  35 #define PRINT_NAME    2
  36 #define PRINT_OFFSET  4
  37 #define SIZE          8
  38 #define PRINT_RADIX  16
  39
  40 int strings_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  41 int strings_main(int argc UNUSED_PARAM, char **argv)
  42 {
  43         int n, c;
  44         exitcode_t status = EXIT_SUCCESS;
  45         unsigned count;
  46         off_t offset;
  47         FILE *file;
  48         char *string;
  49         const char *fmt = "%s: ";
  50         const char *n_arg = "4";
  51         /* default for -o */
  52         const char *radix = "o";
  53         char *radix_fmt;
  54
  55         getopt32(argv, "afon:t:", &n_arg, &radix);
  56         /* -a is our default behaviour */
  57         /*argc -= optind;*/
  58         argv += optind;
  59
  60         n = xatou_range(n_arg, 1, INT_MAX);
  61         string = xzalloc(n + 1);
  62         n--;
  63
  64         if ((radix[0] != 'd' && radix[0] != 'o' && radix[0] != 'x') || radix[1] != 0)
  65                 bb_show_usage();
  66
  67         radix_fmt = xasprintf("%%7"OFF_FMT"%s ", radix);
  68
  69         if (!*argv) {
  70                 fmt = "{%s}: ";
  71                 *--argv = (char *)bb_msg_standard_input;
  72         }
  73
  74         do {
  75                 file = fopen_or_warn_stdin(*argv);
  76                 if (!file) {
  77                         status = EXIT_FAILURE;
  78                         continue;
  79                 }
  80                 offset = 0;
  81                 count = 0;
  82                 do {
  83                         c = fgetc(file);
  84                         if (isprint_asciionly(c) || c == '\t') {
  85                                 if (count > n) {
  86                                         bb_putchar(c);
  87                                 } else {
  88                                         string[count] = c;
  89                                         if (count == n) {
  90                                                 if (option_mask32 & PRINT_NAME) {
  91                                                         printf(fmt, *argv);
  92                                                 }
  93                                                 if (option_mask32 & (PRINT_OFFSET | PRINT_RADIX)) {
  94                                                         printf(radix_fmt, offset - n);
  95                                                 }
  96                                                 fputs_stdout(string);
  97                                         }
  98                                         count++;
  99                                 }
 100                         } else {
 101                                 if (count > n) {
 102                                         bb_putchar('\n');
 103                                 }
 104                                 count = 0;
 105                         }
 106                         offset++;
 107                 } while (c != EOF);
 108                 fclose_if_not_stdin(file);
 109         } while (*++argv);
 110
 111         if (ENABLE_FEATURE_CLEAN_UP) {
 112                 free(string);
 113                 free(radix_fmt);
 114         }
 115
 116         fflush_stdout_and_exit(status);
 117 }