Fix bug uncovered by changing alloca to auto buffer.

* coding.c (growable_destination): New function.
(produce_chars): Use it for sanity checks.  Do not fiddle with
dst_end if the source and destination are both nil, as it's
the caller's responsibility to avoid overlap.
* keyboard.c (read_decoded_event_from_main_queue):
The destination must be MAX_MULTIBYTE_LENGTH times the max source
length, not 4 times, to prevent decode_coding_c_string from trying
to reallocate a destination.  This removes the need for the FIXME.

Fixes: debbugs:18410

1 files changed, 10 insertions, 0 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 88ab1eedca8..2654abd32d4 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,15 @@
 2014-09-07  Paul Eggert  <eggert@cs.ucla.edu>
 
+        Fix bug uncovered by changing alloca to auto buffer (Bug#18410).
+        * coding.c (growable_destination): New function.
+        (produce_chars): Use it for sanity checks.  Do not fiddle with
+        dst_end if the source and destination are both nil, as it's
+        the caller's responsibility to avoid overlap.
+        * keyboard.c (read_decoded_event_from_main_queue):
+        The destination must be MAX_MULTIBYTE_LENGTH times the max source
+        length, not 4 times, to prevent decode_coding_c_string from trying
+        to reallocate a destination.  This removes the need for the FIXME.
+
         * callproc.c (exec_failed) [DOS_NT]: Define a dummy.
         All callers simplified.  Add a comment about exec_failed, vfork,
         and alloca.