Fix unlikely core dump in init_tty, and simplify terminfo case.

* term.c (init_tty) [TERMINFO]: Fix check for buffer overrun.
The old version incorrectly dumped core if malloc returned a
buffer containing only non-NUL bytes.
(init_tty): Do not allocate or free termcap buffers; the
struct does that for us now.
* termchar.h (TERMCAP_BUFFER_SIZE) [!TERMINFO]: New constant.
(struct tty_display_info): Define members termcap_term_buffer and
termcap_strings_buffer only if !TERMINFO, since terminfo doesn't
use them.  Allocate them directly in struct rather than indirectly
via a pointer, to simplify init_tty.

1 files changed, 10 insertions, 5 deletions

diff --git a/src/termchar.h b/src/termchar.h
index 1c8e8646d4e..601b9fe8205 100644
--- a/src/termchar.h
+++ b/src/termchar.h
@@ -28,6 +28,10 @@ struct tty_output
   /* There is nothing else here at the moment... */
 };
 
+#ifndef TERMINFO
+enum { TERMCAP_BUFFER_SIZE = 4096 };
+#endif
+
 /* Parameters that are shared between frames on the same tty device. */
 
 struct tty_display_info
@@ -72,14 +76,15 @@ struct tty_display_info
      mouse-face.  */
   Mouse_HLInfo mouse_highlight;
 
+#ifndef TERMINFO
   /* Buffer used internally by termcap (see tgetent in the Termcap
-     manual).  Only init_tty and delete_tty should change this.  */
-  char *termcap_term_buffer;
+     manual).  Only init_tty should use this.  */
+  char termcap_term_buffer[TERMCAP_BUFFER_SIZE];
 
   /* Buffer storing terminal description strings (see tgetstr in the
-     Termcap manual).  Only init_tty and delete_tty should change
-     this.  */
-  char *termcap_strings_buffer;
+     Termcap manual).  Only init_tty should use this.  */
+  char termcap_strings_buffer[TERMCAP_BUFFER_SIZE];
+#endif
 
   /* Strings, numbers and flags taken from the termcap entry.  */