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authorJim Meyering <jim@meyering.net>2000-10-21 19:16:37 +0000
committerJim Meyering <jim@meyering.net>2000-10-21 19:16:37 +0000
commit51e2ffc52458de9b96079cf2b9fd2301eae0ec0a (patch)
tree98ace012c9edb94c3b3ca188b65501b9e695b73b
parent379688e35da0d34055fc3436aa1f4fd72de05a8c (diff)
downloadcoreutils-51e2ffc52458de9b96079cf2b9fd2301eae0ec0a.tar.xz
Prevent a counter buffer overrun when numbering lines and when
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.
-rw-r--r--src/cat.c36
1 files changed, 24 insertions, 12 deletions
diff --git a/src/cat.c b/src/cat.c
index fad5bc14c..84634c2cc 100644
--- a/src/cat.c
+++ b/src/cat.c
@@ -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,