summaryrefslogtreecommitdiff
path: root/src/buffer.h
diff options
context:
space:
mode:
authorPaul Eggert <eggert@cs.ucla.edu>2011-06-05 23:16:12 -0700
committerPaul Eggert <eggert@cs.ucla.edu>2011-06-05 23:16:12 -0700
commitd1f3d2afe1057a99b9dec6d1bd5b57bfee81fdff (patch)
treef471bdf3143b2d4ba0cf2d4c4e530304b7a67c88 /src/buffer.h
parentdd52fcea063f37a9875bf9196dbe11a442e8adfc (diff)
downloademacs-d1f3d2afe1057a99b9dec6d1bd5b57bfee81fdff.tar.gz
emacs-d1f3d2afe1057a99b9dec6d1bd5b57bfee81fdff.tar.bz2
emacs-d1f3d2afe1057a99b9dec6d1bd5b57bfee81fdff.zip
Check for buffer and string overflow more precisely.
* buffer.h (BUF_BYTES_MAX): New macro. * lisp.h (STRING_BYTES_MAX): New macro. * alloc.c (Fmake_string): * character.c (string_escape_byte8): * coding.c (coding_alloc_by_realloc): * doprnt.c (doprnt): * editfns.c (Fformat): * eval.c (verror): Use STRING_BYTES_MAX, not MOST_POSITIVE_FIXNUM, since they may not be the same number. * editfns.c (Finsert_char): * fileio.c (Finsert_file_contents): Likewise for BUF_BYTES_MAX.
Diffstat (limited to 'src/buffer.h')
-rw-r--r--src/buffer.h5
1 files changed, 5 insertions, 0 deletions
diff --git a/src/buffer.h b/src/buffer.h
index 8c64a24e804..3c91bdfe570 100644
--- a/src/buffer.h
+++ b/src/buffer.h
@@ -306,6 +306,11 @@ do \
} \
while (0)
+/* Maximum number of bytes in a buffer.
+ A buffer cannot contain more bytes than a 1-origin fixnum can represent,
+ nor can it be so large that C pointer arithmetic stops working. */
+#define BUF_BYTES_MAX min (MOST_POSITIVE_FIXNUM - 1, min (SIZE_MAX, PTRDIFF_MAX))
+
/* Return the address of byte position N in current buffer. */
#define BYTE_POS_ADDR(n) \