1 /*strings.c - print the strings of printable characters in files.
2 *
3 * Copyright 2014 Kyung-su Kim <kaspyx@gmail.com>
4 * Copyright 2014 Kyungwan Han <asura321@gmail.com>
5 *
6 * See http://pubs.opengroup.org/onlinepubs/9699919799/utilities/strings.html
7 *
8 * Deviations from posix: we don't readahead to the end of the string to see
9 * if it ends with NUL or newline before printing. Add -o. We always do -a
10 * (and accept but don't document the flag), but that's sort of conformant.
11 * Posix' STDOUT section says things like "%o %s" and we support 64 bit offsets.
12 *
13 * TODO: utf8 strings
14
15 USE_STRINGS(NEWTOY(strings, "t:an#=4<1fo", TOYFLAG_USR|TOYFLAG_BIN))
16
17 config STRINGS
18 bool "strings"
19 default y
20 help
21 usage: strings [-fo] [-t oxd] [-n LEN] [FILE...]
22
23 Display printable strings in a binary file
24
25 -f Show filename
26 -n At least LEN characters form a string (default 4)
27 -o Show offset (ala -t d)
28 -t Show offset type (o=octal, d=decimal, x=hexadecimal)
29 */
30
31 #define FOR_strings
32 #include "toys.h"
33
GLOBALS(long num;char * t;)34 GLOBALS(
35 long num;
36 char *t;
37 )
38
39 static void do_strings(int fd, char *filename)
40 {
41 int nread, i, wlen = TT.num, count = 0;
42 off_t offset = 0;
43 char *string = 0, pattern[8];
44
45 if (TT.t) if (!(string = strchr("oxd", *TT.t))) error_exit("-t needs oxd");
46 sprintf(pattern, "%%7ll%c ", string ? *string : 'd');
47
48 // input buffer can wrap before we have enough data to output, so
49 // copy start of string to temporary buffer until enough to output
50 string = xzalloc(wlen+1);
51
52 for (i = nread = 0; ;i++) {
53 if (i >= nread) {
54 nread = read(fd, toybuf, sizeof(toybuf));
55 i = 0;
56 if (nread < 0) perror_msg_raw(filename);
57 if (nread < 1) {
58 if (count) goto flush;
59 break;
60 }
61 }
62
63 offset++;
64 if ((toybuf[i]>=32 && toybuf[i]<=126) || toybuf[i]=='\t') {
65 if (count == wlen) fputc(toybuf[i], stdout);
66 else {
67 string[count++] = toybuf[i];
68 if (count == wlen) {
69 if (toys.optflags & FLAG_f) printf("%s: ", filename);
70 if (toys.optflags & (FLAG_o|FLAG_t))
71 printf(pattern, (long long)(offset - wlen));
72 printf("%s", string);
73 }
74 }
75 continue;
76 }
77 flush:
78 // End of previous string
79 if (count == wlen) xputc('\n');
80 count = 0;
81 }
82 xclose(fd);
83 free(string);
84 }
85
strings_main(void)86 void strings_main(void)
87 {
88 loopfiles(toys.optargs, do_strings);
89 }
90