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 (4.3 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, status = EXIT_SUCCESS;
  44         unsigned count;
  45         off_t offset;
  46         FILE *file;
  47         char *string;
  48         const char *fmt = "%s: ";
  49         const char *n_arg = "4";
  50         /* default for -o */
  51         const char *radix = "o";
  52         char *radix_fmt;
  53
  54         getopt32(argv, "afon:t:", &n_arg, &radix);
  55         /* -a is our default behaviour */
  56         /*argc -= optind;*/
  57         argv += optind;
  58
  59         n = xatou_range(n_arg, 1, INT_MAX);
  60         string = xzalloc(n + 1);
  61         n--;
  62
  63         if ((radix[0] != 'd' && radix[0] != 'o' && radix[0] != 'x') || radix[1] != 0)
  64                 bb_show_usage();
  65
  66         radix_fmt = xasprintf("%%7"OFF_FMT"%s ", radix);
  67
  68         if (!*argv) {
  69                 fmt = "{%s}: ";
  70                 *--argv = (char *)bb_msg_standard_input;
  71         }
  72
  73         do {
  74                 file = fopen_or_warn_stdin(*argv);
  75                 if (!file) {
  76                         status = EXIT_FAILURE;
  77                         continue;
  78                 }
  79                 offset = 0;
  80                 count = 0;
  81                 do {
  82                         c = fgetc(file);
  83                         if (isprint_asciionly(c) || c == '\t') {
  84                                 if (count > n) {
  85                                         bb_putchar(c);
  86                                 } else {
  87                                         string[count] = c;
  88                                         if (count == n) {
  89                                                 if (option_mask32 & PRINT_NAME) {
  90                                                         printf(fmt, *argv);
  91                                                 }
  92                                                 if (option_mask32 & (PRINT_OFFSET | PRINT_RADIX)) {
  93                                                         printf(radix_fmt, offset - n);
  94                                                 }
  95                                                 fputs(string, stdout);
  96                                         }
  97                                         count++;
  98                                 }
  99                         } else {
 100                                 if (count > n) {
 101                                         bb_putchar('\n');
 102                                 }
 103                                 count = 0;
 104                         }
 105                         offset++;
 106                 } while (c != EOF);
 107                 fclose_if_not_stdin(file);
 108         } while (*++argv);
 109
 110         if (ENABLE_FEATURE_CLEAN_UP) {
 111                 free(string);
 112                 free(radix_fmt);
 113         }
 114
 115         fflush_stdout_and_exit(status);
 116 }