[6801] try to create a dir file if it's empty; allocate extra byte for strncat

[Gavin D. Smith]

Revision: 6801
          http://svn.sv.gnu.org/viewvc/?view=rev&root=texinfo&revision=6801
Author:   gavin
Date:     2015-11-22 20:50:06 +0000 (Sun, 22 Nov 2015)
Log Message:
-----------
try to create a dir file if it's empty; allocate extra byte for strncat

Modified Paths:
--------------
    trunk/ChangeLog
    trunk/install-info/install-info.c

Modified: trunk/ChangeLog
===================================================================
--- trunk/ChangeLog     2015-11-22 16:30:30 UTC (rev 6800)
+++ trunk/ChangeLog     2015-11-22 20:50:06 UTC (rev 6801)
@@ -1,5 +1,15 @@
 2015-11-22  Gavin Smith  <address@hidden>
 
+       * install-info/install-info.c (open_possibly_compressed_file): 
+       If file is empty, try to create it if passed a callback for 
+       doing so.  Problem with zero-sized dir files reported by
+       Pedrum Mohageri.
+       (format_entry): Use xmalloc instead of malloc.  Allocate an 
+       extra byte.  Crash with strncat under Mac OS X Yosemite reported 
+       by Alan Wehmann.
+
+2015-11-22  Gavin Smith  <address@hidden>
+
        * info/infodoc.c (info_get_info_help_node): Resort to 
        "(info-stnd)" if "(info)" isn't found.  Look for "(info)" 
        instead of "(Info)".

Modified: trunk/install-info/install-info.c
===================================================================
--- trunk/install-info/install-info.c   2015-11-22 16:30:30 UTC (rev 6800)
+++ trunk/install-info/install-info.c   2015-11-22 20:50:06 UTC (rev 6801)
@@ -670,6 +670,7 @@
   else
     close (desc); /* It already existed, so fine.  */
 }
+
 
 /* Open FILENAME and return the resulting stream pointer.  If it doesn't
    exist, try FILENAME.gz.  If that doesn't exist either, call
@@ -769,11 +770,28 @@
   nread = fread (data, sizeof (data), 1, f);
   if (nread != 1)
     {
-      /* Empty files don't set errno.  Calling code can check for
-         this, so make sure errno == 0 just in case it isn't already. */
       if (nread == 0)
-        errno = 0;
-      return 0;
+        {
+          /* Try to create the file if its empty. */
+          if (feof (f) && create_callback)
+            {
+              if (fclose (f) != 0)
+                return 0; /* unknown error closing file */
+
+              if (remove (filename) != 0)
+                return 0; /* unknown error deleting file */
+
+              (*create_callback) (filename);
+              f = fopen (*opened_filename, FOPEN_RBIN);
+              if (!f)
+                return 0;
+              nread = fread (data, sizeof (data), 1, f);
+              if (nread == 0)
+                return 0;
+            }
+        }
+      errno = 0;
+      return 0; /* unknown error */
     }
 
   if (!compression_program)
@@ -1404,9 +1422,8 @@
   if (!desc || !name)
     return 1;
 
-  outstr = malloc (width  + 
-                    (((desc_len  + width) / (width - align)) * width) * 2 
-                    * sizeof (char));
+  outstr = xmalloc (width
+         + (desc_len + width) / (width - align) * width * 2 * sizeof (char));
   outstr[0] = '\0';
 
   strncat (outstr, name, name_len);
@@ -1444,7 +1461,9 @@
       if (offset_out + 1 >= allocated_out)
         {
           allocated_out = offset_out + 1;
-          line_out = (char *) realloc ((void *)line_out, allocated_out);
+          line_out = (char *) xrealloc ((void *)line_out, allocated_out + 1);
+          /* The + 1 here shouldn't be necessary, but a crash was reported
+             for a following strncat call. */
         }
 
       if (c == '\n')