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Fix bugs when computing length of large files.

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Add overflow and write error checks.  Use uint_fast32_t, not
unsigned long, to do checksum calculation, as C99 says
uint_fast32_t should be no slower and might be faster.

Include <stdio.h> and "system.h" even if CRCTAB is defined,
so that the code will compile if CRCTAB is defined.
Include "human.h" if CRCTAB is not defined.
(uint_fast32_t): Define if it appears that stdint.h didn't.
(BIT, remainder, main, crctab): Use uint_fast32_t, not unsigned long,
for checksums.
(fill_r, remainder, main): Use ANSI prototypes.
(fill_r, remainder, main): Omit duplicate code.
(main): Use uintmax_t, not unsigned long, for file lengths.
Use size_t, not long, for result of fread.
Check for overflow when computing file lengths.
Check for write error immediately after printing a line, so that
we don't write to stdout indefinitely after an error.
This commit is contained in:
Jim Meyering
2001-04-22 08:31:24 +00:00
parent 2d0f3f2e74
commit 519b707b4e
1 changed files with 47 additions and 41 deletions
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88
src/cksum.c
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@@ -47,12 +47,17 @@
#define AUTHORS "Q. Frank Xia"
#include <stdio.h>
#include "system.h"
#if !defined UINT_FAST32_MAX && !defined uint_fast32_t
# define uint_fast32_t unsigned int
#endif
#ifdef CRCTAB
# include <stdio.h>
# define BIT(x) ( (unsigned long)1 << (x) )
# define SBIT BIT(31)
# define BIT(x) ((uint_fast32_t) 1 << (x))
# define SBIT BIT (31)
/* The generating polynomial is
@@ -61,47 +66,48 @@
The i bit in GEN is set if X^i is a summand of G(X) except X^32. */
# define GEN (BIT(26)|BIT(23)|BIT(22)|BIT(16)|BIT(12)|BIT(11)|BIT(10)\
|BIT(8) |BIT(7) |BIT(5) |BIT(4) |BIT(2) |BIT(1) |BIT(0));
# define GEN (BIT (26) | BIT (23) | BIT (22) | BIT (16) | BIT (12) \
| BIT (11) | BIT (10) | BIT (8) | BIT (7) | BIT (5) \
| BIT (4) | BIT (2) | BIT (1) | BIT (0))
static unsigned long r[8];
static uint_fast32_t r[8];
static void
fill_r ()
fill_r (void)
{
int i;
r[0] = GEN;
for (i = 1; i < 8; i++)
r[i] = (r[i - 1] & SBIT) ? (r[i - 1] << 1) ^ r[0] : r[i - 1] << 1;
r[i] = (r[i - 1] << 1) ^ ((r[i - 1] & SBIT) ? GEN : 0);
}
static unsigned long
remainder (m)
int m;
static uint_fast32_t
remainder (int m)
{
unsigned long rem = 0;
uint_fast32_t rem = 0;
int i;
for (i = 0; i < 8; i++)
if (BIT (i) & m)
rem = rem ^ r[i];
rem ^= r[i];
return rem & 0xFFFFFFFF; /* Make it run on 64-bit machine. */
}
int
main ()
main (void)
{
int i;
fill_r ();
printf ("unsigned long crctab[256] = {\n 0x0");
printf ("static uint_fast32_t crctab[256] =\n{\n 0x0");
for (i = 0; i < 51; i++)
{
printf (",\n 0x%08X, 0x%08X, 0x%08X, 0x%08X, 0x%08X",
remainder (i * 5 + 1), remainder (i * 5 + 2), remainder (i * 5 + 3),
remainder (i * 5 + 4), remainder (i * 5 + 5));
remainder (i * 5 + 1), remainder (i * 5 + 2),
remainder (i * 5 + 3), remainder (i * 5 + 4),
remainder (i * 5 + 5));
}
printf ("\n};\n");
exit (EXIT_SUCCESS);
@@ -109,13 +115,12 @@ main ()
#else /* !CRCTAB */
# include <stdio.h>
# include <getopt.h>
# include <sys/types.h>
# include "system.h"
# include "closeout.h"
# include "long-options.h"
# include "error.h"
# include "human.h"
/* Number of bytes to read at once. */
# define BUFLEN (1 << 16)
@@ -128,7 +133,7 @@ static struct option const long_options[] =
{0, 0, 0, 0}
};
static unsigned long const crctab[256] =
static uint_fast32_t crctab[256] =
{
0x0,
0x04C11DB7, 0x09823B6E, 0x0D4326D9, 0x130476DC, 0x17C56B6B,
@@ -196,10 +201,12 @@ static int
cksum (const char *file, int print_name)
{
unsigned char buf[BUFLEN];
unsigned long crc = 0;
long length = 0;
long bytes_read;
uint_fast32_t crc = 0;
uintmax_t length = 0;
size_t bytes_read;
register FILE *fp;
char hbuf[LONGEST_HUMAN_READABLE + 1];
char *hp;
if (STREQ (file, "-"))
{
@@ -223,9 +230,11 @@ cksum (const char *file, int print_name)
{
unsigned char *cp = buf;
if (length + bytes_read < length)
error (EXIT_FAILURE, 0, _("%s: file too long"), file);
length += bytes_read;
while (bytes_read--)
crc = (crc << 8) ^ crctab[((crc >> 24) ^ *(cp++)) & 0xFF];
crc = (crc << 8) ^ crctab[((crc >> 24) ^ *cp++) & 0xFF];
}
if (ferror (fp))
@@ -242,19 +251,20 @@ cksum (const char *file, int print_name)
return -1;
}
bytes_read = length;
while (bytes_read > 0)
{
crc = (crc << 8) ^ crctab[((crc >> 24) ^ bytes_read) & 0xFF];
bytes_read >>= 8;
}
hp = human_readable (length, hbuf, 1, 1);
for (; length; length >>= 8)
crc = (crc << 8) ^ crctab[((crc >> 24) ^ length) & 0xFF];
crc = ~crc & 0xFFFFFFFF;
printf ("%lu %ld", crc, length);
if (print_name)
printf (" %s", file);
putchar ('\n');
printf ("%u %s %s\n", (unsigned) crc, hp, file);
else
printf ("%u %s\n", (unsigned) crc, hp);
if (ferror (stdout))
error (EXIT_FAILURE, errno, "-: %s", _("write error"));
return 0;
}
@@ -313,16 +323,12 @@ main (int argc, char **argv)
}
}
if (optind >= argc)
{
if (cksum ("-", 0) < 0)
errors = 1;
}
if (optind == argc)
errors |= cksum ("-", 0);
else
{
for (i = optind; i < argc; i++)
if (cksum (argv[i], 1) < 0)
errors = 1;
errors |= cksum (argv[i], 1);
}
if (have_read_stdin && fclose (stdin) == EOF)