Segmentation fault

[ccc]

hi

why using freecolor -o on my freeBSD 7.0 , I get Segmentation fault ?

bsd# freecolor -o
             total       used       free     shared    buffers     cached
Mem:        509852     175180     334672          0          0        268
Swap:      2048000          0    2048000
Segmentation fault

[Carpetsmoker]

Works fine for me (7 STABLE Jun 5).

Try rebuilding the port with -DWITH_DEBUG and running it with gdb.

[ccc]

Originally Posted by Carpetsmoker

Works fine for me (7 STABLE Jun 5).

Try rebuilding the port with -DWITH_DEBUG and running it with gdb.

thx, but could you pls give some more details, how this should work ?

[ccc]

I've done:

# echo 'WITH_DEBUG=yes' >> /etc/make.conf
# cd /usr/ports/sysutils/freecolor
# make deinstall clean
# make install clean

and Segmentation fault is gone:

# freecolor -o
             total       used       free     shared    buffers     cached
Mem:        509852     168140     341712          0          0        360
Swap:      2048000          0    2048000
#

should I leave

WITH_DEBUG=yes

in /etc/make.conf ?

[Nirbo]

Leaving WITH_DEBUG in will just compile the ports with debugging info. As a user you're generally not going to need it (i.e. a waste of your time)

10 to 1, it was the reinstall of freecolor that fixed it, not that you compiled it with WITH_DEBUG.

[Carpetsmoker]

No, if I compile it without debug I have the same error, when I use WITH_DEBUG it works fine...
Not sure what's going on here ... I'll look tomorrow...

[Nirbo]

That is odd. I don't use freecolor myself so I didn't actually check.

[robbak]

Ah, the ever-unpopular heisenbug.
When I had one of them, it turned out to be an uninitialized variable. Building it with debug zeroed off the variable, and things worked. Mind you, that was my own code, and own mistake.

Best of luck tracking it down!

[ephemera]

think i found the bug.
it triggers a segfault only when compiled with optimization enabled (-DWITH_DEBUG switches off optimization).
the bug causes the return address from main to be corrupted resulting in a segfault,

here's a patch, put this in /usr/ports/sysutils/freecolor/files/patch-freecolor.c:

--- freecolor.c.bak     2005-10-19 01:39:52.000000000 +0530
+++ freecolor.c 2008-06-28 19:16:13.000000000 +0530
@@ -62,9 +62,6 @@
 #include <unistd.h>
 #include <stdlib.h>
 #include <stdio.h>
-#ifndef NO_GETOPT
-#include <getopt.h>
-#endif
 #define BARLEN 35
 #define HEADERLEN 14
 #define VERSION "0.8.7"
@@ -76,9 +73,9 @@
 void bargraph(float percent, float secondper, char marks[BARLEN+HEADERLEN],int usefull) {
   char percentone[BARLEN], percenttwo[BARLEN], remain[BARLEN];
   unsigned int numberofmarks, numofmarkstwo, remainnum;
-  numberofmarks=(int) ((float) (BARLEN*(percent/100)));
-  if (!usefull) numofmarkstwo=(int) ((float) (BARLEN*(secondper/100))); else numofmarkstwo=(BARLEN-numberofmarks);
-  remainnum=BARLEN-(numberofmarks+numofmarkstwo);
+  numberofmarks=(int) ((float) ((BARLEN-1)*(percent/100)));
+  if (!usefull) numofmarkstwo=(int) ((float) ((BARLEN-1)*(secondper/100))); else numofmarkstwo=((BARLEN-1)-numberofmarks);
+  remainnum=(BARLEN-1)-(numberofmarks+numofmarkstwo);
   memset(percentone, '#', numberofmarks);
   memset(percenttwo, '%', numofmarkstwo);
   memset(remain, '.', remainnum);