[vdr] get a segmentation fault when starting vdr (backtrace included)

Dieter Bloms vdr at bloms.de
Fri Nov 30 12:08:53 CET 2012


Hi Werner,

On Fri, Nov 30, Dr. Werner Fink wrote:

> On Fri, Nov 30, 2012 at 11:00:52AM +0100, Dieter Bloms wrote:
> > 
> > I changed it this way:
> > 
> > --snip--
> >   32 bool tComponent::FromString(const char *s)
> >   33 {
> >   34   unsigned int Stream, Type;
> >   35   description = NULL;
> >   36   int n = sscanf(s, "%X %02X %7s %a[^\n]", &Stream, &Type, language, &description); // 7 = MAXLANGCODE2 - 1
> >   37   esyslog("dbloms: \"%X\" \"%02X\" \"%7s\" \"%a\"", Stream, Type, language, description);
> >   38 
> >   39   if (n != 4 || isempty(description)) {
> >   40      free(description);
> >   41      description = NULL;
> >   42      }
> >   43   stream = Stream;
> >   44   type = Type;
> >   45   return n >= 3;
> >   46 }
> > --snip--
> 
> IMHO the %a should become %s in esyslog() whereas in sscanf() the %a should become %as
> for the GNU extension of dynamically allocating string conversions.

Now I've the following code:

--snip--
  25 cString tComponent::ToString(void)
  26 {
  27   char buffer[256];
  28   snprintf(buffer, sizeof(buffer), "%X %02X %s %s", stream, type, language, description ? description : "");
  29   return buffer;
  30 }
  31 
  32 bool tComponent::FromString(const char *s)
  33 {
  34   unsigned int Stream, Type;
  35   description = NULL;
  36   int n = sscanf(s, "%X %02X %7s %as[^\n]", &Stream, &Type, language, &description); // 7 = MAXLANGCODE2 - 1
  37   esyslog("dbloms: \"%X\" \"%02X\" \"%7s\" \"%s\"", Stream, Type, language, description);
  38 
  39   if (n != 4 || isempty(description)) {
  40      free(description);
  41      description = NULL;
  42      }
  43   stream = Stream;
  44   type = Type;
  45   return n >= 3;
  46 }
--snip--


and get a core dump with this:

--snip--
vdrservernew:/tmp# gdb --core /tmp/core /usr/local/bin/vdr
GNU gdb (GDB) 7.5
Copyright (C) 2012 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-unknown-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /usr/local/bin/vdr...done.
[New LWP 8986]
[New LWP 8985]
[New LWP 8987]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/libthread_db.so.1".
Core was generated by `/usr/local/bin/vdr --config=/etc/vdr --epgfile=/tmp/epg.data --grab=/dev/shm --'.
Program terminated with signal 11, Segmentation fault.
#0  0x00006b2476b263b3 in strnlen () from /lib/libc.so.0.9.32
(gdb) bt
#0  0x00006b2476b263b3 in strnlen () from /lib/libc.so.0.9.32
#1  0x00006b2476b1ff56 in ?? () from /lib/libc.so.0.9.32
#2  0x00006b2476b1d5dc in vsnprintf () from /lib/libc.so.0.9.32
#3  0x00006b2476b14c29 in vsyslog () from /lib/libc.so.0.9.32
#4  0x000000000052e510 in syslog_with_tid (priority=3, format=0x551ab8 "dbloms: \"%X\" \"%02X\" \"%7s\" \"%s\"") at tools.c:40
#5  0x00000000004a1e4e in FromString (s=<optimized out>, this=0x3dabc20) at epg.c:37
#6  cComponents::SetComponent (this=<optimized out>, Index=<optimized out>, s=s at entry=0x3daaaa2 "1 01 deu 4:3") at epg.c:84
#7  0x00000000004a4163 in cEvent::Parse (this=0x3d9f4d0, s=<optimized out>) at epg.c:498
#8  0x00000000004e9f16 in cRecordingInfo::Read (this=0x3da8640, f=f at entry=0x3d9f840) at recording.c:468
#9  0x00000000004eb553 in cRecording::cRecording (this=0x3da05c0, FileName=0x3d8aa7c "Sex_and_the_City_2/2012-11-19.20.10.27-0.rec") at recording.c:723
#10 0x00000000004ecf21 in cRecordings::ScanVideoDir (this=0x7fe880 <Recordings>, DirName=0x3d9d4c0 "/remote/vdr/Sex_and_the_City_2", Foreground=false, LinkLevel=0) at recording.c:1165
#11 0x00000000004ed39c in cRecordings::ScanVideoDir (this=0x7fe880 <Recordings>, DirName=0x3d83a20 "/remote/vdr", Foreground=false, LinkLevel=0) at recording.c:1180
#12 0x00000000005269be in cThread::StartThread (Thread=0x7fe8a0 <Recordings+32>) at thread.c:262
#13 0x00006b247844a406 in start_thread () from /lib/libpthread.so.0.9.32
#14 0x00006b2478442885 in clone () from /lib/libpthread.so.0.9.32
#15 0x0000000000000000 in ?? ()
(gdb) 
--snip--


-- 
Gruß

  Dieter

--
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