MirBSD manpage: procmap(1)

PROCMAP(1)                   BSD Reference Manual                   PROCMAP(1)


     procmap - display process memory map


     procmap [-adlmPsv] [-D number] [-M core] [-N system] [-p pid] [pid ...]


     The procmap utility lists the virtual memory mappings underlying the
     given process. The start address of each entry is always given, and,
     depending on the options given, other information such as the end ad-
     dress, the underlying file's device and inode numbers, and various pro-
     tection information will be displayed, along with the path to the file,
     if such data is available.

     By default, procmap displays information for its parent process, so that
     when run from a shell prompt, the shell's memory information is
     displayed. If other PIDs are given as arguments on the command line, in-
     formation for those processes will be printed also. If the special PID of
     0 is given, then information for the kernel's memory map is printed.

     The options are as follows:

     -a           Display "all" information from the process's memory map.
                  This output mode is an amalgam of the contents of the
                  Solaris, Linux, and NetBSD style output modes.

     -D number    Enable various debug facilities. The number is a bit mask of
                  the values:

                  1     dump the process's vmspace structure
                  2     dump the process's vm_map structure
                  4     dump the vm_map.header structure
                  8     dump each vm_map_entry in its entirety
                  16    dump the namei cache as it is traversed

     -d           Dumps the vm_map and vm_map_entry structures in a style
                  similar to that of ddb(4). When combined with the -v option,
                  the device number, inode number, name, vnode addresses, or
                  other identifying information from the vm_map_entry fields
                  will be printed.

     -l           Dumps information in a format like the contents of the maps
                  pseudo-file under the /proc filesystem which was, in turn,
                  modeled after the similarly named entry in the Linux /proc
                  filesystem. When combined with the -v option, identifiers
                  for all entries are printed.

     -M core      Extract values associated with the name list from the speci-
                  fied core instead of the default /dev/kmem.

     -m           Dumps information in the same format as the map pseudo-file
                  of the /proc filesystem. When the -v option is also given,
                  device number, inode number, and filename or other identify-
                  ing information is printed.

     -N system    Extract the name list from the specified system instead of
                  the running kernel.

     -P           Causes procmap to print information about itself.

     -p pid       Tells procmap to print information about the given process.
                  If -p pid occurs last on the command line, the -p is option-

     -s           The Solaris style output format, modeled after the Solaris
                  command "pmap". This is the default output style.

     -v           Verbose output. When used with -d, -l, or -m, more informa-
                  tion is printed, possibly including device and inode
                  numbers, file path names, or other identifying information.
                  If specified more than once, a '*' will be printed in
                  between two entries that are not adjacent, making the visual
                  identification of spaces in the process's map easier to see.

     The -P and -p options override each other, so the last one to appear on
     the command line takes effect. If you do wish to see information about
     procmap and another process as the same time, simply omit the -p and
     place the extra PID at the end of the command line.

     procmap exits 0 on success, and >0 if an error occurred.


     While the meaning most of the output is self-evident, some pieces of it
     may appear to be a little inscrutable.

     Here a portion of the default output from procmap being run at a sh(1)
     prompt shows the starting address of the map entry, the size of the map
     entry, the current protection level of the map entry, and either the name
     of the file backing the entry or some other descriptive text.

           $ procmap
           08048000    420K read/exec         /bin/sh
           080B1000      8K read/write        /bin/sh
           080B3000     28K read/write          [ anon ]
           080BA000     16K read/write/exec     [ heap ]

     When the ddb(4) output style is selected, the first thing printed is the
     contents of the vm_map structure, followed by the individual map entries.

           $ procmap -d
           MAP 0xcf7cac84: [0x0->0xbfbfe000]
                   #ent=8, sz=34041856, ref=1, version=20, flags=0x21
            - 0xcfa3a358: 0x8048000->0x80b1000: obj=0xcf45a8e8/0x0, amap=0x0/0
                   submap=F, cow=T, nc=T, prot(max)=5/7, inh=1, wc=0, adv=0

     The value of the flags field (in hexadecimal) is taken from the include
     file <uvm/uvm_map.h>:

           VM_MAP_PAGEABLE      0x01   ro: entries are pageable
           VM_MAP_INTRSAFE      0x02   ro: interrupt safe map
           VM_MAP_WIREFUTURE    0x04   rw: wire future mappings
           VM_MAP_BUSY          0x08   rw: map is busy
           VM_MAP_WANTLOCK      0x10   rw: want to write-lock

     The "submap", "cow", and "nc" fields are true or false, and indicate
     whether the map is a submap, whether it is marked for copy on write, and
     whether it needs a copy. The "prot" (or protection) field, along with
     "max" (maximum protection allowed) are made up of the following flags
     from <uvm/uvm_extern.h>:

           UVM_PROT_READ        0x01   read allowed
           UVM_PROT_WRITE       0x02   write allowed
           UVM_PROT_EXEC        0x04   execute allowed

     The "obj" and "amap" fields are pointers to, and offsets into, the under-
     lying uvm_object or vm_amap object. The value for resident is always unk-
     nown because digging such information out of the kernel is beyond the
     scope of this application.

     The two output styles that mirror the contents of the /proc filesystem
     appear as follows:

           $ procmap -m
           0x8048000 0x80b1000 r-x rwx COW NC 1 0 0
           0x80b1000 0x80b3000 rw- rwx COW NC 1 0 0
           0x80b3000 0x80ba000 rw- rwx COW NNC 1 0 0
           0x80ba000 0x80be000 rwx rwx COW NNC 1 0 0

           $ procmap -l
           08048000-080b1000 r-xp 00000000 00:00 70173     /bin/sh
           080b1000-080b3000 rw-p 00068000 00:00 70173     /bin/sh
           080b3000-080ba000 rw-p 00000000 00:00 0
           080ba000-080be000 rwxp 00000000 00:00 0

     Here the protection and maximum protection values are indicated with 'r',
     'w', and 'x' characters, indicating read permission, write permission,
     and execute permission, respectively. The "COW", "NC", and "NNC" values
     that follow indicate, again, that the map is marked for copy on write and
     either needs or does not need a copy. It is also possible to see the
     value "NCOW" here, which indicates that an entry will not be copied. The
     three following numbers indicate the inheritance type of the map, the
     wired count of the map, and any advice value assigned via madvise(2).

     In the second form, the permissions indicated are followed by a 'p' or
     's' character indicating whether the map entry is private or shared (copy
     on write or not), and the numbers are the offset into the underlying ob-
     ject, the device and numbers of the object if it is a file, and the path
     to the file (if available).

     As noted above (see section DESCRIPTION), the "all" output format is an
     amalgam of the previous output formats.

           $ procmap -a
           Start    End         Size  Offset   rwxpc  RWX  I/W/A ...
           08048000-080b0fff     420k 00000000 r-xp+ (rwx) 1/0/0 ...

     In this format, the column labeled "rwxpc" contains the permissions for
     the mapping along with the shared/private flag, and a character indicat-
     ing whether the mapping needs to be copied on write ('+') or has already
     been copied ('-') and is followed by a column that indicates the maximum
     permissions for the map entry. The column labeled "I/W/A" indicates the
     inheritance, wired, and advice values for the map entry, as previously


     ls(1), madvise(2), mmap(2), kvm(3), ddb(4), mount_procfs(8), namei(9),


     The procmap utility first appeared in OpenBSD 3.5. It was derived from
     the NetBSD utility known as "pmap".


     The procmap utility and documentation was written by Andrew Brown


     Very little will work unless procmap is reading from the correct kernel
     in order to retrieve the proper symbol information.

     Since processes can change state while procmap is running, some of the
     information printed may be inaccurate. This is especially important to
     consider when examining the kernel's map, since merely executing procmap
     will cause some of the information to change.

     The pathnames to files backing certain vnodes (such as the text and data
     sections of programs and shared libraries) are extracted from the
     kernel's namei cache which is considerably volatile. If a path is not
     found there in its entirety, as much information as was available will be
     printed. In most cases, simply running ls(1) with the expected path to
     the file will cause the information to be reentered into the cache.

     The Solaris version ("pmap") has some interesting command line flags that
     would be nice to emulate here. In particular, the -r option that lists a
     process's reserved addresses, and the -x option that prints
     resident/shared/private mapping details for each entry.

     Some of the output modes can be or are wider than the standard 80 columns
     of a terminal. Some sort of formatting might be nice.

MirBSD #10-current             August 29, 2002                               3

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