Mercurial > hg > toybox
annotate toys/cksum.c @ 543:60b97ba66a70
Extensive semi-gratuitous refactoring: factor out common code, handle euid!=uid and egid!=gid cases. (Note: test suite requires root access, possibly container support.)
| author | Rob Landley <rob@landley.net> |
|---|---|
| date | Mon, 12 Mar 2012 23:00:28 -0500 |
| parents | 0cc0c0e879d1 |
| children |
| rev | line source |
|---|---|
| 333 | 1 /* vi: set sw=4 ts=4: |
| 2 * | |
| 3 * cksum.c - produce crc32 checksum value for each input | |
| 4 * | |
| 5 * Copyright 2008 Rob Landley <rob@landley.net> | |
| 6 * | |
| 7 * See http://www.opengroup.org/onlinepubs/009695399/utilities/cksum.html | |
| 8 | |
|
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9 USE_CKSUM(NEWTOY(cksum, "IPLN", TOYFLAG_BIN)) |
| 333 | 10 |
| 11 config CKSUM | |
| 12 bool "cksum" | |
| 13 default y | |
| 14 help | |
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15 usage: cksum [-IPLN] [file...] |
| 336 | 16 |
| 333 | 17 For each file, output crc32 checksum value, length and name of file. |
| 18 If no files listed, copy from stdin. Filename "-" is a synonym for stdin. | |
| 336 | 19 |
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20 -L Little endian (defaults to big endian) |
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21 -P Pre-inversion |
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22 -I Skip post-inversion |
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parents:
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23 -N Do not include length in CRC calculation |
| 333 | 24 */ |
| 25 | |
| 26 #include "toys.h" | |
| 27 | |
| 28 DEFINE_GLOBALS( | |
| 29 unsigned crc_table[256]; | |
| 30 ) | |
| 31 | |
| 32 #define TT this.cksum | |
| 33 | |
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34 static unsigned cksum_be(unsigned crc, unsigned char c) |
| 333 | 35 { |
| 36 return (crc<<8)^TT.crc_table[(crc>>24)^c]; | |
| 37 } | |
| 38 | |
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39 static unsigned cksum_le(unsigned crc, unsigned char c) |
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40 { |
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41 return TT.crc_table[(crc^c)&0xff] ^ (crc>>8); |
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42 } |
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43 |
| 333 | 44 static void do_cksum(int fd, char *name) |
| 45 { | |
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46 unsigned crc = (toys.optflags&4) ? 0xffffffff : 0; |
| 333 | 47 uint64_t llen = 0, llen2; |
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48 unsigned (*cksum)(unsigned crc, unsigned char c); |
| 333 | 49 |
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50 |
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51 cksum = (toys.optflags&2) ? cksum_le : cksum_be; |
| 333 | 52 // CRC the data |
| 53 | |
| 54 for (;;) { | |
| 55 int len, i; | |
| 56 | |
| 57 len = read(fd, toybuf, sizeof(toybuf)); | |
| 58 if (len<0) { | |
| 59 perror_msg("%s",name); | |
| 60 toys.exitval = EXIT_FAILURE; | |
| 61 } | |
| 62 if (len<1) break; | |
| 63 | |
| 64 llen += len; | |
| 65 for (i=0; i<len; i++) crc=cksum(crc, toybuf[i]); | |
| 66 } | |
| 67 | |
| 68 // CRC the length | |
| 69 | |
| 70 llen2 = llen; | |
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71 if (!(toys.optflags&1)) { |
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72 while (llen) { |
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73 crc = cksum(crc, llen); |
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aaafa1ceaa91
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parents:
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74 llen >>= 8; |
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aaafa1ceaa91
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parents:
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75 } |
| 333 | 76 } |
| 77 | |
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parents:
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78 printf("%u %"PRIu64, (toys.optflags&8) ? crc : ~crc, llen2); |
| 333 | 79 if (strcmp("-", name)) printf(" %s", name); |
| 80 xputc('\n'); | |
| 81 } | |
| 82 | |
| 83 void cksum_main(void) | |
| 84 { | |
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parents:
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85 crc_init(TT.crc_table, toys.optflags&2); |
| 333 | 86 loopfiles(toys.optargs, do_cksum); |
| 87 } |