jammy (8) memdump.8.gz

Provided by: memdump_1.01-9_amd64 bug

NAME 

     memdump - memory dumper

SYNOPSIS 

     memdump [-kv] [-b buffer_size] [-d dump_size] [-m map_file] [-p page_size]

DESCRIPTION 

     This  program  dumps  system  memory to the standard output stream, skipping over holes in
     memory maps.  By default, the program dumps the contents of physical memory (/dev/mem).
     Output is in the form of a raw dump; if necessary, use the -m  option  to  capture  memory
     layout information.
     Output  should  be sent off-host over the network, to avoid changing all the memory in the
     file system cache. Use netcat, stunnel, or openssl, depending on your requirements.
     The size arguments below understand the k (kilo) m (mega) and g (giga) suffixes.  Suffixes
     are case insensitive.
     Options
  1. k Attempt to dump kernel memory (/dev/kmem) rather than physical memory.
            Warning:  this  can  lock up the system to the point that you have to use the power
            switch (for example, Solaris 8 on 64-bit SPARC).
            Warning: this produces bogus results on Linux 2.2 kernels.
            Warning: this is very slow on 64-bit machines because  the  entire  memory  address
            range has to be searched.
            Warning:  kernel  virtual  memory  mappings  change  frequently.  Depending  on the
            operating system, mappings smaller than page_size or buffer_size may be  missed  or
            may be reported incorrectly.
  1. b buffer_size (default: 0)

Number of bytes per memory read operation. By default, the program uses the 

            page_size value.
            Warning: a too large read buffer size causes memory to  be  missed  on  FreeBSD  or
            Solaris.
  1. s dump-size (default: 0)

Number of memory bytes to dump. By default, the program runs until the memory 

            device reports an end-of-file (Linux), or until it has dumped from /dev/mem as much
            memory as reported present by the kernel (FreeBSD, Solaris), or until pointer wrap-
            around happens.
            Warning: a too large value causes the program to spend a lot of time skipping  over
            non-existent memory on Solaris systems.
            Warning:  a too large value causes the program to copy non-existent data on FreeBSD
            systems.
  1. m map_file

Write the memory map to map_file, one entry per line. Specify -m- to write to the 

            standard  error  stream.  Each map entry consists of a region start address and the
            first address beyond that region. Addresses are separated by space, and are printed
            as hexadecimal numbers (0xhhhh).
  1. p page_size (default: 0)

Use page_size as the memory page size. By default the program uses the system page 

            size.
            Warning: a too large page size causes memory to be missed while skipping over holes
            in memory.
  1. v Enable verbose logging for debugging purposes. Multiple -v options make the program

more verbose.

BUGS 

     On many hardware platforms the firmware (boot PROM, BIOS, etc.)  takes away  some  memory.
     This memory is not accessible through /dev/mem.
     This program should produce output in a format that supports structure information such as
     ELF.

LICENSE 

     This software is distributed under the IBM Public License.

AUTHOR 

     Wietse Venema
     IBM T.J. Watson Research
     P.O. Box 704
     USA
                                                                                     MEMDUMP(8)