LibCalloc - a memory allocation checker library

About LibCalloc

This library helps to check memory allocation

This library need to be link to the application under debugging or to be preloaded before starting the application. Depending to the environment variable MEMORY_ALLOCATION_, on signal catch or on program exit, it will display lots of useful debugging information on previously allocated memory blocks such as:

3 or 5 character status
- first is F for freed, A for allocated, and R for reallocated,
- second is . or B if the block begin is corrupted,
- third is . or E if the block end is corrupted,
- if block has be reallocated, forth is . or B if the block begin is corrupted,
- if block has be reallocated, fiveth is . or E if the block end is corrupted.
last reference pointer,
allocated block size (in bytes),
source file and line number of initial allocation or last re-allocation and, if the block has already been free, its source file and line number. Those information are only avaiable if snd/calloc.h has been include in all files and that program has been linked with LibCalloc.

Variable

If MEMORY_ALLOCATION_ contains 't' (for tolerant) or any value greater than 1, LibCalloc activates the display of memory allocation checks on exit and on signal catch (for signal SIGSEGV, SIGILL and SIGBUS).

If MEMORY_ALLOCATION_ contains 'y' (for yes) or 1, LibCalloc hangs on first memory corruption (check are done on free). A coredump will be generated.

LibCalloc prints on stderr traces for every allocation and every freeing.

Examples

The following example shows what is needed during linking to get memory allocation checker activated.

echo '#include 
int main (int argc, char *argv[]) {
   char *a = malloc (8);
   char *b = malloc (4);
   switch (argv[argc-1][0]) {
     case '´a´': a[8] = 0;
     case '´b´': b[-1] = 0; break;
  }
  free (a);
  return 0;
}' > test.c

gcc -lcalloc test.c
MEMORY_ALLOCATION_=t ./a.out a

The following example shows what is needed at execution time.

echo '#include 
int main (int argc, char *argv[]) {
   char *a = malloc (8);
   char *b = malloc (4);
   switch (argv[argc-1][0]) {
     case '´a´': a[8] = 0;
     case '´b´': b[-1] = 0; break;
  }
  free (a);
  return 0;
}' > test.c

gcc -g test.c
LD_PRELOAD=/usr/lib/libcalloc.so MEMORY_ALLOCATION_=y ./a.out b
gdb a.out core -q << EOF
bt
EOF

Screen-shot

Shell view

Downloads

Source packages

Debian packages

Requirements

This library only need a C compiler to be build.

To install, one only needs to

unpack the archive,
do a 'make',
and a 'make install'.

Changelogs

LibCalloc 1.2.2 (Thu, 28 Mar 2024 07:45:15 +0100)

Fixes from gcc 12 compilation warnings

LibCalloc 1.2.1 (Mon, 02 Jun 2014 21:10:26 +0200)

Split debian packaging
Minor cleanings

LibCalloc 1.2 (Tue, 17 Sep 2013 12:15:50 +0200)

First public version
Adaptation for gcc 4.7
Fix memory allocation checker (internal printf)
Adapt to 64bit compiler

LibCalloc 1.0 (Sat, 8 Jun 2013 19:53:51 +0200)

Enhance consistency checking for reallocation
Enhance report on consistency checking
Enable malloc hooks
Tolerance can be 2 to 9 or T
Improvement of display memory

LibCalloc 0.1 (Sun, 14 Jun 2009 23:06:57 +0200)

Initial version