NJAMDPM(1)						      General Commands Manual							NJAMDPM(1)

NAME

       njamdpm - Not Just Another Malloc Debugger Post-Mortem

SYNOPSIS

       njamdpm [OPTIONS] <HEAP FILE>

DESCRIPTION

       njamdpm is a companion utility that allows you to examine the persistent heap saved by libnjamd(3) You can do things like query for certain
       addresses, show memory leaks, and show all past allocated memory. As of NJAMD 0.6.0, gdb(1)  is	required  to  make  sense  of  the  return
       addresses.

USAGE

   Options
       HEAP FILE
	      The  heap  file  will be in the current directory with a name of the form njamd-<pid>-heap, but only if NJAMD_PERSISTANT_HEAP was in
	      the environment at the time of program execution

       -a address
	      Search through the heap file for a chunk of memory that contains address.  This can be VERY helpful when using gdb. Simply find  the
	      address  that  you accessed to cause the segmentation fault, use njamdpm to look it up in the heap, and viola! You have all sorts of
	      info about the chunk: When it was allocated, when it was freed, how big is is, etc.

       -d depth
	      When displaying return address info, only display depth return addresses. The max  is  specified	in  ./include/lib/njamd.h  in  the
	      define TRACE_DEPTH (default is 3).

       -t     Trim  the  heap file down to only the used portion. This is useful if for some reason the program somehow exits without trimming its
	      own heap file down first. Note that when the heap file appears huge it's not actually taking up disk space.

       -s     Dump basic status info about peak memory usage, NJAMD overhead, etc. Useful for determining if you should buy more ram, or write	me
	      an angry email :)

       -l     Dump  memory  leaks  in the heap. Also shows you info about where the memory was leaked, along with a total. Do note that this total
	      and the subtotals are aligned bytes. They are aligned to the alignment of your architecture,  or	as  specified  by  the	value  the
	      NJAMD_ALIGN environment variable had when the heap was created.

       -f     Dump freed memory in the heap. This option is only available if LIBNJAMD ran without NJAMD_CHK_FREE=none set.

   Using gdb with njamdpm
       When  a	segmentation fault happens, it's because, of course, you accessed an invalid address. So all you need to do is get gdb to give you
       the address you accessed, and then feed it to njamdpm. Ie if the segfault occurs on a line that does buf[i] = 2,  issue	print  &buf[i]	to
       gdb. Note that libnjamd(3) now has a function __nj_ptr_info that can be called from gdb that performs all this without njamdpm.

       To get gdb to translate these return addresses into something meaningful, issue

       info line *0xaddress

       to obtain the line number of the allocation request, or

       list *0xaddress

       to see the adjacent code as well.

NOTES

       Eventually I hope to add symbol translation right into njamdpm.

AUTHORS

       Mike Perry <mikepery@fscked.org>

SEE ALSO

       http://freshmeat.net/appindex/development/debugging.html

       njamd(3), efence(3), malloc(3), mmap(2), mprotect(2)

								NJAMD - 5 Oct 2000							NJAMDPM(1)