VMS Help V73 Features, Programming Features, New Process Dump Tools (Alpha)  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    OpenVMS Version 7.3 contains new tools for processing dump files.
    Note that these new-style process dump and process dump analysis
    tools are not compatible with the old-style process dumps. That
    is, if you have a problem you want to analyze with the new tools,
    you must generate a new process dump using the new process dump
    image.

    The following sections describe the new tools.

1 - DCL ANALYZE PROCESS DUMP (Alpha)

    The DCL ANALYZE/PROCESS_DUMP command invokes the OpenVMS debugger
    to analyze a process dump, giving you access to debugger commands
    for your analysis. In OpenVMS Version 7.3, most of the old DCL
    ANALYZE/PROCESS_DUMP qualifiers have no effect. Only the /FULL
    and /IMAGE qualifiers are still valid. Both these qualifiers are
    still optional.

    /FULL now causes the debugger to execute the debugger SHOW IMAGE,
    SHOW CALL, and SHOW THREAD/ALL commands after a process dump file
    has been opened.

    /IMAGE has been renamed to /IMAGE_PATH, and is now a directory
    specification, rather than a file specification. /IMPAGE_PATH
    specifies a directory in which to look for the debug symbol
    information files (.DSF or .EXE files, in that order) that belong
    to the process dump file. The name of the symbol file must be
    the same as the image name in the process dump file. For example,
    for MYIMAGE.DMP, the debugger searches for file MYIMAGE.DSF or
    MYIMAGE.EXE.

    Version 7.3 and later debuggers check for dumpfile image
    specification and DST file link date-time mismatches and issue
    a warning if one is discovered.

    For more information about the DCL ANALYZE/PROCESS_DUMP command,
    refer to the OpenVMS DCL Dictionary: A-M.

2 - Debugger ANALYZE PROCESS DUMP Command

    The debugger has a new command:

    ANALYZE/PROCESS_DUMP/IMAGE_PATH[=directory-spec] dumpfile.

    This command is available only in the kept debugger. The kept
    debugger is the image you invoke with the command DEBUG/KEEP,
    which allows you to run and rerun programs from the same
    debugging session.

    The qualifier /PROCESS_DUMP is required.

    For more information, refer to the OpenVMS Debugger Manual.

3 - Debugger SDA Command

    The new debugger SDA command invokes the System Dump Analyzer
    (SDA) to allow you to look at a process dump from within the
    OpenVMS debugger. For example:

     DBG> SDA

     OpenVMS (TM) Alpha process dump analyzer

     SDA> ..
     .
     .
     SDA> EXIT
     DBG>

    This allows you to use SDA to analyze a process dump without
    terminating a debugger session.

    For more information, refer to the OpenVMS Debugger Manual.

4 - Analyzing Process Dumps on Different Systems

    You can analyze a process dump file on a system different from
    the one on which it was generated. However, if there is a base
    image link date/time mismatch between the generating system
    and analyzing system, you must copy SYS$BASE_IMAGE.EXE from the
    generating system and point to it with the SDA$READ_DIR logical
    name.

    For threaded process dump analysis on a system different from the
    one on which it was generated, it may also be necessary to copy
    and logically point to the generating system's PTHREAD$RTL and
    PTHREAD$DBGSHR (POSIX Threads Library debug assistant).

5 - Forcing a Process Dump

    You can force a process dump with the DCL command
    SET PROCESS/DUMP=NOW process-spec. This command causes the
    contents of the address space occupied by process-spec to be
    written immediately to the file named image-name.DMP in the
    current directory (image-name is the same as the file name).

    For more information about the DCL SET PROCESS/DUMP command,
    refer to the OpenVMS DCL Dictionary: N-Z.

6 - Security and Diskquotas

    A process dump is either complete or partial. A complete process
    dump contains all of process space and all process-pertinent data
    from system space. A partial process dump contains only user-
    readable data from process space and only those data structures
    from system space that are not deemed sensitive. Privileged
    or protected data, such as an encryption key in third-party
    software, might be considered sensitive.

    In general, nonprivileged users should not be able to read
    complete process dumps, and by default they cannot do so.
    However, certain situations require nonprivileged users to be
    able to read complete process dumps. Other situations require
    enabling a user to create a complete process dump while at
    the same time preventing that user from being able to read the
    complete process dump.

    By default, process dumps are written to the current default
    directory of the user. The user can override this by defining
    the logical name SYS$PROCDMP to identify an alternate directory
    path. Note that the name of the process dump file is always the
    same as the name of the main image at the time the process dump
    is written, with the file extension .DMP.

 6.1 - Special Rights Identifiers

    You can use the new rights identifier IMGDMP$READALL to allow
    a nonprivileged user to read a complete process dump. You
    can use the new rights identifier IMGDMP$PROTECT to protect
    a complete process dump from being read by the user that
    created the process dump. These rights identifiers are created
    during the installation of OpenVMS Version 7.3 by the image
    SYS$SYSTEM:IMGDMP_RIGHTS.EXE, which is also run automatically
    during system startup to ensure that these rights identifiers
    exist with the correct values and attributes.

    If these rights identifiers have been deleted, you can run
    SYS$SYSTEM:IMGDMP_RIGHTS.EXE to recreate them.

    Note that IMGDMP$READALL has no attributes, but IMGDMP$PROTECT is
    created with the RESOURCE attribute.

 6.2 - Privileged Users

    For this discussion, a privileged user is one who satisfies one
    of the following conditions:

    o  Has one or more of the privileges CMKRNL, CMEXEC, SYSPRV,
       READALL, or BYPASS

    o  Is a member of a system UIC group (by default [10,n] or
       lower). Such users are treated as though they hold SYSPRV
       privilege.

    Holders of CMKRNL or CMEXEC can write complete process dumps.
    Holders of any of the other privileges can read a process dump
    wherever it has been written.

 6.3 - Nonprivileged Users

    To allow a nonprivileged user to write and read complete process
    dumps, grant the rights identifier IMGDMP$READALL to the user.
    If the IMGDMP$READALL rights identifier does not exist, run the
    image SYS$SYSTEM:IMGDMP_RIGHTS.EXE to create it (see Special
    Rights Identifiers). Then use AUTHORIZE to grant the rights
    identifier to the user. For example:

        $ DEFINE /USER SYSUAF SYS$SYSTEM:SYSUAF.DAT  !if necessary
        $ RUN SYS$SYSTEM:AUTHORIZE
        UAF> GRANT /IDENTIFIER IMGDMP$READALL <user>
        UAF> EXIT

    Note that the user must log out and log in again to be able to
    receive the rights identifier. A nonprivileged user with rights
    identifier IMGDMP$READALL can read and write complete process
    dumps without restriction.

 6.4 - Protecting Process Dumps

    You can allow a nonprivileged user to write a complete process
    dump and at the same time prevent the user from reading the
    process dump just written. To do so, perform the following
    procedure:

    1. If the IMGDMP$PROTECT rights identifier does not exist, run
       the image SYS$SYSTEM:IMGDMP_RIGHTS.EXE to create it (see
       Special Rights Identifiers).

    2. Create a protected directory with rights identifier
       IMGDMP$PROTECT.

    3. Define protected logical name SYS$PROTECTED_PROCDMP to point
       to the protected directory.

       If DISKQUOTA is to be used on the disk containing the
       protected directory, specify the maximum disk space to be
       used for process dumps.

                                 CAUTION

       Do not grant IMGDMP$PROTECT to any user. It is granted and
       revoked as needed by SYS$SHARE:IMGDMP.EXE from executive
       mode while writing a process dump. If you grant it
       permanently to a user, that user has access to all process
       dumps written to the protected directory.

    You can choose to set up additional ACLs on the protected
    directory to further control which users are allowed to read
    and write process dumps there.

    Note that to take a process dump when the image is installed with
    elevated privileges or belongs to a protected subsystem, the user
    must hold CMKRNL privilege, and is by definition a privileged
    user (see Privileged Users).