NAME

lmdbg-run - runs a program and traces the malloc/realloc/free calls

SYNOPSIS

lmdbg-run [OPTIONS] <progname> [args...]

DESCRIPTION

lmdbg-run lmdbg-run runs an external command progname args and creates a log file where all invocations of malloc, calloc, realloc, memalign, posix_memalign, aligned_alloc and free are registered accompanied by the following information: full stacktrace (addresses), input argument(s) (requested size and/or address), result value (returned address, if any) and ordinal number of function invocation. Also, some special information is output about the program being run. Before being saved to the log file, stacktrace info can be filtered through a custom command.

OPTIONS

-h: Display the help message.
-V: Display the lmdbg version.
-v: Enable verbose mode.
-o filename: Specify the log file name.
-f|-p command: Filter stacktraces through a filtering command/pipe. The result is sent to the log file specified in -o option or to stdout otherwise.
-n: Do not enable logging on startup. To enable it, send SIGUSR1 signal to the process.
-N filename: Save pid of progname to filename.
-T number: Specify the number of addresses to skip from the top of the stacktrace (farther from function main).
-B number: Specify the number of addresses to skip from the bottom of the stacktrace (nearer to function main).
-M number: Limit the number of addresses shown in a stacktrace. An incomplete stacktrace may be generated, that includes the top of the stack.

EXAMPLE

The output of lmdbg-run may look like the following

 realloc ( 0xbb901800 , 777 ) --> 0xbb901c00
  0xbbbe58e8
  0xbbbe5a37
  0x8048764
  0x8048584
  0x80484e7

This output means that realloc function was given the pointer 0xbb901800 and 777 bytes were requested. As a result realloc returned the address 0xbb901c00. Addresses 0xbbbe58e8, 0xbbbe5a37 etc. are a part of the stacktrace.

EXAMPLE

$ cat test2.c
#include <stdlib.h>
int main ()
{
   void *p1 = NULL;
   void *p2 = NULL;
   p1 = malloc (555);
   p2 = realloc (p2, 666);
   p2 = realloc (p2, 777);
   p2 = realloc (p2, 888);
   return 0;
}
$ cc -O0 -g -o test2 test2.c
$ lmdbg-run -o log ./test2 
$ cat log
info section 0x0xbbace000 0x0xbbbc6000 /lib/libc.so.12.179
info section 0x0xbbbdd000 0x0xbbbe1000 /usr/pkg/lib/liblmdbg.so.0.0
info section 0x0xbbbee000 0x0xbbbfe000 /libexec/ld.elf_so
info progname ./test2
malloc ( 555 ) --> 0xbb90a400 num: 1
 0xbbbddb7a
 0xbbbde53b
 0x8048769
 0x804863d
 0x8048678
realloc ( NULL , 666 ) --> 0xbb90a800 num: 2
 0xbbbddb7a
 0xbbbde68c
 0x8048781
 0x804863d
 0x8048678
realloc ( 0xbb90a800 , 777 ) --> 0xbb90ac00 num: 3
 0xbbbddb7a
 0xbbbde68c
 0x8048799
 0x804863d
 0x8048678
realloc ( 0xbb90ac00 , 888 ) --> 0xbb90a800 num: 4
 0xbbbddb7a
 0xbbbde68c
 0x80487b1
 0x804863d
 0x8048678
$

EXAMPLE

lmdbg-run -o log ./my_app &&
  lmdbg-leaks log > log_leaks &&
  lmdbg-sym ./my_app log_leaks > log_leaks2 &&
  lmdbg-sysleaks -s log_leaks2 > log_final
lmdbg-run -B2 -M6 -f 'lmdbg-leaks | lmdbg-sym > log' ./my_app <args>

ENVIRONMENT

LMDBG_LIB: Path to LD_PRELOAD'ed liblmdbg dynamic library. It defaults to /usr/local/lib/liblmdbg.so

NOTES

Full stacktrace allows analysing an application on per-module basis. It helps determine what libraries and/or components require more memory than others and why. See lmdbg-stat and lmdbg-sort.

BUGS

The current implementation of lmdbg-run relies on several GCC's extensions, namely, __builtin_return_address, __builtin_frame_address, __attribute__((constructor)) and __attribute__((destructor)). In my knowledge, Besides GCC these extensions are also supported by Intel C compiler and Clang. If you know a solution that works for other compilers let me now ;-)

AUTHOR

Aleksey Cheusov <vle@gmx.net>