User manual REDHAT ENTERPRISE LINUX 3 DEBUGGING WITH GDB

[. . . ] Red Hat Enterprise Linux 3 Debugging with gdb Red Hat Enterprise Linux 3: Debugging with gdb Copyright © 1987, 1989, 1991-2003 by Free Software Foundation, Inc. Copyright © 2003 by Red Hat, Inc. This documentation has been prepared by Red Hat, Inc. 1801 Varsity Drive Raleigh NC 27606-2072 USA Phone: +1 919 754 3700 Phone: 888 733 4281 Fax: +1 919 754 3701 PO Box 13588 Research Triangle Park NC 27709 USA Manual identifier: · PDF: rhds-gdb-EN-3-PDF-RHI (2003-09-24T01:08) · HTML: rhds-gdb-EN-3-HTML-RHI (2003-09-24T01:08) Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1. 1 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License". [. . . ] Choosing target byte order Some types of processors, such as the MIPS, PowerPC, and Hitachi SH, offer the ability to run either big-endian or little-endian byte orders. Usually the executable or symbol will include a bit to designate the endian-ness, and you will not need to worry about which to use. However, you may still find it useful to adjust gdb's idea of processor endian-ness manually. set endian big Instruct gdb to assume the target is big-endian. set endian little Instruct gdb to assume the target is little-endian. set endian auto Instruct gdb to use the byte order associated with the executable. show endian Display gdb's current idea of the target byte order. Note that these commands merely adjust interpretation of symbolic data on the host, and that they have absolutely no effect on the target system. 18. 4. Remote debugging If you are trying to debug a program running on a machine that cannot run gdb in the usual way, it is often useful to use remote debugging. For example, you might use remote debugging on an operating system kernel, or on a small system which does not have a general purpose operating system powerful enough to run a full-featured debugger. Some configurations of gdb have special serial or TCP/IP interfaces to make this work with particular debugging targets. In addition, gdb comes with a generic serial protocol (specific to gdb, but not specific to any particular target system) which you can use if you write the remote stubs--the code that runs on the remote system to communicate with gdb. Other remote targets may be available in your configuration of gdb; use help target to list them. 152 Chapter 18. Kernel Object Display Some targets support kernel object display. Using this facility, gdb communicates specially with the underlying operating system and can display information about operating system-level objects such as mutexes and other synchronization objects. Exactly which objects can be displayed is determined on a per-OS basis. Use the set os command to set the operating system. This tells gdb which kernel object display module to initialize: (gdb) set os cisco If set os succeeds, gdb will display some information about the operating system, and will create a new info command which can be used to query the target. The info command is named after the operating system: (gdb) info cisco List of Cisco Kernel Objects Object Description any Any and all objects Further subcommands can be used to query about particular objects known by the kernel. There is currently no way to determine whether a given operating system is supported other than to try it. Chapter 19. Connecting to a remote target On the gdb host machine, you will need an unstripped copy of your program, since gdb needs symobl and debugging information. Start up gdb as usual, using the name of the local copy of your program as the first argument. If you're using a serial line, you may want to give gdb the -baud option, or use the set remotebaud command before the target command. After that, use target remote to establish communications with the target machine. Its argument specifies how to communicate--either via a devicename attached to a direct serial line, or a TCP or UDP port (possibly to a terminal server which in turn has a serial line to the target). For example, to use a serial line connected to the device named /dev/ttyb: target remote /dev/ttyb To use a TCP connection, use an argument of the form host:port or tcp:host:port. [. . . ] FUTURE REVISIONS OF THIS LICENSE Appendix G. GNU Free Documentation License 375 The Free Software Foundation may publish new, revised versions of the GNU Free Documentation License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. Each version of the License is given a distinguishing version number. [. . . ]