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author | Paul Eggert <eggert@cs.ucla.edu> | 2021-08-22 13:54:04 -0700 |
---|---|---|
committer | Paul Eggert <eggert@cs.ucla.edu> | 2021-08-22 14:02:22 -0700 |
commit | 57e5c514dfe12ccaf6c12d2b07047bd15ee306fb (patch) | |
tree | 8d6a230d065498df8def47dcbf4cac73d880029f /src/io.c | |
parent | dadc7f231f524b08a2d6497d55e702ef418c0b60 (diff) | |
download | diffutils-57e5c514dfe12ccaf6c12d2b07047bd15ee306fb.tar.gz |
maint: refactor integer overflow checking
Rely on more-modern Gnulib capabilities instead of doing
integer overflow checking by hand, in some cases.
* lib/cmpbuf.c (buffer_lcm):
* src/io.c (slurp, find_identical_ends):
Use INT_ADD_WRAPV and INT_MULTIPLY_WRAPV rather than checking
overflow by hand.
* src/diff3.c (process_diff):
* src/dir.c (dir_read):
* src/io.c (find_identical_ends, read_files):
Use xnmalloc rather than checking overflow by hand.
(read_files): Rely on xcalloc to do overflow checking.
Diffstat (limited to 'src/io.c')
-rw-r--r-- | src/io.c | 21 |
1 files changed, 8 insertions, 13 deletions
@@ -165,10 +165,9 @@ slurp (struct file_data *current) /* Get the size out of the stat block. Allocate just enough room for appended newline plus word sentinel, plus word-alignment since we want the buffer word-aligned. */ - size_t file_size = current->stat.st_size; - cc = file_size + 2 * sizeof (word) - file_size % sizeof (word); - if (file_size != current->stat.st_size || cc < file_size - || PTRDIFF_MAX <= cc) + off_t file_size = current->stat.st_size; + if (INT_ADD_WRAPV (2 * sizeof (word) - file_size % sizeof (word), + file_size, &cc)) xalloc_die (); if (current->bufsize < cc) @@ -716,11 +715,11 @@ find_identical_ends (struct file_data filevec[]) middle_guess = guess_lines (lines, p0 - buffer0, p1 - filevec[1].prefix_end); suffix_guess = guess_lines (lines, p0 - buffer0, buffer1 + n1 - p1); - alloc_lines1 = buffered_prefix + middle_guess + MIN (context, suffix_guess); - if (alloc_lines1 < buffered_prefix - || PTRDIFF_MAX / sizeof *linbuf1 <= alloc_lines1) + if (INT_ADD_WRAPV (buffered_prefix, + middle_guess + MIN (context, suffix_guess), + &alloc_lines1)) xalloc_die (); - linbuf1 = xmalloc (alloc_lines1 * sizeof *linbuf1); + linbuf1 = xnmalloc (alloc_lines1, sizeof *linbuf1); if (buffered_prefix != lines) { @@ -791,9 +790,7 @@ read_files (struct file_data filevec[], bool pretend_binary) find_identical_ends (filevec); equivs_alloc = filevec[0].alloc_lines + filevec[1].alloc_lines + 1; - if (PTRDIFF_MAX / sizeof *equivs <= equivs_alloc) - xalloc_die (); - equivs = xmalloc (equivs_alloc * sizeof *equivs); + equivs = xnmalloc (equivs_alloc, sizeof *equivs); /* Equivalence class 0 is permanently safe for lines that were not hashed. Real equivalence classes start at 1. */ equivs_index = 1; @@ -804,8 +801,6 @@ read_files (struct file_data filevec[], bool pretend_binary) for (i = 9; (size_t) 1 << i < equivs_alloc / 3; i++) continue; nbuckets = ((size_t) 1 << i) - prime_offset[i]; - if (PTRDIFF_MAX / sizeof *buckets <= nbuckets) - xalloc_die (); buckets = xcalloc (nbuckets + 1, sizeof *buckets); buckets++; |