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