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Prevent a counter buffer overrun when numbering lines and when

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processing 100 billion lines (or more) of input.

(LINE_COUNTER_BUF_LEN): Define to allow numbering as
many as 10^18 - 1 lines (the old limit was 10^11 - 1, and could
be exceeded without too much trouble).	Use this symbol rather
than hard-coding the constant everywhere.  Rather than overruning
for input with more lines, mark the line number by putting a
`>' in the leftmost slot.
(next_line_num): Fixed (now academic) possible line buffer overrun.
Patch by Jan Nieuwenhuizen.
This commit is contained in:
Jim Meyering
2000-10-21 19:16:37 +00:00
parent 379688e35d
commit 51e2ffc524
1 changed files with 24 additions and 12 deletions
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src/cat.c
+24 -12
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@@ -55,19 +55,26 @@ static char *infile;
/* Descriptor on which input file is open. */
static int input_desc;
/* Buffer for line numbers. */
static char line_buf[13] =
{' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', '0', '\t', '\0'};
/* Buffer for line numbers.
An 11 digit counter may overflow within an hour on a P2/466,
an 18 digit counter needs about 1000y */
#define LINE_COUNTER_BUF_LEN 20
static char line_buf[LINE_COUNTER_BUF_LEN] =
{
' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ',
' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', '0',
'\t', '\0'
};
/* Position in `line_buf' where printing starts. This will not change
unless the number of lines is larger than 999999. */
static char *line_num_print = line_buf + 5;
static char *line_num_print = line_buf + LINE_COUNTER_BUF_LEN - 8;
/* Position of the first digit in `line_buf'. */
static char *line_num_start = line_buf + 10;
static char *line_num_start = line_buf + LINE_COUNTER_BUF_LEN - 3;
/* Position of the last digit in `line_buf'. */
static char *line_num_end = line_buf + 10;
static char *line_num_end = line_buf + LINE_COUNTER_BUF_LEN - 3;
/* Preserves the `cat' function's local `newlines' between invocations. */
static int newlines2 = 0;
@@ -129,7 +136,10 @@ next_line_num (void)
*endp-- = '0';
}
while (endp >= line_num_start);
*--line_num_start = '1';
if (line_num_start > line_buf)
*--line_num_start = '1';
else
*line_buf = '>';
if (line_num_start < line_num_print)
line_num_print--;
}
@@ -775,8 +785,8 @@ main (int argc, char **argv)
{
inbuf = (unsigned char *) xmalloc (insize + 1);
/* Why are (OUTSIZE - 1 + INSIZE * 4 + 13) bytes allocated for
the output buffer?
/* Why are (OUTSIZE - 1 + INSIZE * 4 + LINE_COUNTER_BUF_LEN)
bytes allocated for the output buffer?
A test whether output needs to be written is done when the input
buffer empties or when a newline appears in the input. After
@@ -788,10 +798,12 @@ main (int argc, char **argv)
If the last character in the preceding block of input was a
newline, a line number may be written (according to the given
options) as the first thing in the output buffer. (Done after the
new input is read, but before processing of the input begins.) A
line number requires seldom more than 13 positions. */
new input is read, but before processing of the input begins.)
A line number requires seldom more than LINE_COUNTER_BUF_LEN
positions. */
outbuf = (unsigned char *) xmalloc (outsize - 1 + insize * 4 + 13);
outbuf = (unsigned char *) xmalloc (outsize - 1 + insize * 4
+ LINE_COUNTER_BUF_LEN);
cat (inbuf, insize, outbuf, outsize, quote,
output_tabs, numbers, numbers_at_empty_lines, mark_line_ends,