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(init_header): Fix buffer-overrun error.

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Allocated buffer was sometimes too small.
Reported by Greg McGary (who found this bug using his
bounded-pointers-enabled gcc).
(init_header): Move declarations of several variables into the
inner scope where they are used.
This commit is contained in:
Jim Meyering
2000-08-05 10:56:12 +00:00
parent f79bc88685
commit b3197453ad
1 changed files with 21 additions and 11 deletions
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32
src/pr.c
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@@ -1645,6 +1645,15 @@ print_files (int number_of_files, char **av)
time: "yy-mm-dd HH:MM" and: "Page NNNN". */
#define CHARS_FOR_DATE_AND_PAGE 25
#define T_BUF_FMT "%Y-%m-%d %H:%M" /* date/time short format */
/* Add `2' because the expansion of %Y occupies 4 bytes, which is two more
than the length of `%Y'. Each of the other formats expand to two bytes. */
#define T_BUF_SIZE (2 + sizeof T_BUF_FMT)
/* This string is exactly the same length as the expansion of T_BUF_FMT. */
#define NO_DATE "-- Date/Time -- "
/* Initialize header information.
If DESC is non-negative, it is a file descriptor open to
FILENAME for reading.
@@ -1657,28 +1666,28 @@ print_files (int number_of_files, char **av)
static void
init_header (char *filename, int desc)
{
int chars_per_middle, chars_free, lhs_blanks, rhs_blanks;
char *f = filename;
char *no_middle = "";
char *header_text;
struct tm *tmptr;
struct stat st;
char *datim = "-- Date/Time -- ";
size_t header_buf_size;
if (filename == NULL)
f = "";
if (header != NULL)
free (header);
header = (char *) xmalloc (chars_per_line + 1);
/* Allow a space on each side of the the filename-or-header. */
header_buf_size = MAX (chars_per_line, CHARS_FOR_DATE_AND_PAGE + 2) + 1;
header = (char *) xmalloc (header_buf_size);
if (!standard_header && *custom_header == '\0')
*header = '\0'; /* blank line header */
else
{
#define T_BUF_FMT "%Y-%m-%d %H:%M" /* date/time short format */
#define T_BUF_SIZE 17 /* FIXME: using a literal here is fragile. */
int chars_per_middle, lhs_blanks, rhs_blanks;
struct tm *tmptr;
char t_buf[T_BUF_SIZE];
char *header_text;
/* If parallel files or standard input, use current time. */
if (desc < 0 || STREQ (filename, "-") || fstat (desc, &st))
@@ -1687,15 +1696,16 @@ init_header (char *filename, int desc)
tmptr = localtime (&st.st_mtime);
strftime (t_buf, T_BUF_SIZE, T_BUF_FMT, tmptr);
chars_per_middle = chars_per_line - CHARS_FOR_DATE_AND_PAGE;
chars_per_middle = header_buf_size - 1 - CHARS_FOR_DATE_AND_PAGE;
if (chars_per_middle < 3)
{
header_text = no_middle; /* Nothing free for a heading */
header_text = ""; /* Nothing free for a heading */
lhs_blanks = 1;
rhs_blanks = 1;
}
else
{
int chars_free;
header_text = standard_header ? f : custom_header;
chars_free = chars_per_middle - (int) strlen (header_text);
if (chars_free > 1)
@@ -1712,7 +1722,7 @@ init_header (char *filename, int desc)
}
}
sprintf (header, _("%s%*s%s%*sPage"), (test_suite ? datim : t_buf),
sprintf (header, _("%s%*s%s%*sPage"), (test_suite ? NO_DATE : t_buf),
lhs_blanks, " ", header_text, rhs_blanks, " ");
}
}