Fixed handling error conditions in the index file

CONTRIBUTORS

@@ -2536,6 +2536,7 @@ Markus Ehrnsperger <markus.ehrnsperger@googlemail.com>
  for reporting a problem with missing 'INCLUDES += -I$(DVBDIR)/include' in an existing
  Make.config
  for reporting a bug in error handling when loading a plugin
+ for reporting a possible crash in cIndexFile::GetClosestIFrame()
 
 Werner Färber <w.faerber@gmx.de>
  for reporting a bug in handling the cPluginManager::Active() result when pressing

HISTORY

@@ -9766,7 +9766,7 @@ Video Disk Recorder Revision History
   (reported by Timo Weingärtner).
 - Official release.
 
-2022-01-18:
+2022-01-24:
 
 - Replaced strncpy() with memcpy() in strreplace() to avoid a compiler warning
   (reported by Marco Mäkelä).
@@ -9774,3 +9774,4 @@ Video Disk Recorder Revision History
 - Updated the Italian OSD texts (thanks to Diego Pierotto).
 - Added some missing "AUTO" values to vdr.5 (thanks to Winfried Köhler).
 - Fixed handling zero bytes in cH264Parser (thanks to Christoph Haubrich).
+- Fixed handling error conditions in the index file (reported by Markus Ehrnsperger).

recording.c

@@ -4,7 +4,7 @@
  * See the main source file 'vdr.c' for copyright information and
  * how to reach the author.
  *
- * $Id: recording.c 5.13 2021/07/01 15:40:46 kls Exp $
+ * $Id: recording.c 5.14 2022/01/24 10:44:21 kls Exp $
  */
 
 #include "recording.h"
@@ -2604,6 +2604,8 @@ cIndexFile::cIndexFile(const char *FileName, bool Record, bool IsPesRecording, b
                     if (safe_read(f, index, size_t(buf.st_size)) != buf.st_size) {
                        esyslog("ERROR: can't read from file '%s'", *fileName);
                        free(index);
+                       size = 0;
+                       last = -1;
                        index = NULL;
                        }
                     else if (isPesRecording)
@@ -2617,8 +2619,11 @@ cIndexFile::cIndexFile(const char *FileName, bool Record, bool IsPesRecording, b
                  else
                     LOG_ERROR_STR(*fileName);
                  }
-              else
+              else {
                  esyslog("ERROR: can't allocate %zd bytes for index '%s'", size * sizeof(tIndexTs), *fileName);
+                 size = 0;
+                 last = -1;
+                 }
               }
            }
         else
@@ -2817,7 +2822,7 @@ int cIndexFile::GetNextIFrame(int Index, bool Forward, uint16_t *FileNumber, off
 
 int cIndexFile::GetClosestIFrame(int Index)
 {
-  if (last > 0) {
+  if (index && last > 0) {
      Index = constrain(Index, 0, last);
      if (index[Index].independent)
         return Index;