124 lines
6.6 KiB
HTML
124 lines
6.6 KiB
HTML
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<html lang="en">
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<head>
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<title>Remote Stub - Debugging with GDB</title>
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<meta name="description" content="Debugging with GDB">
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<meta name="generator" content="makeinfo 4.13">
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<link title="Top" rel="start" href="index.html#Top">
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<link rel="up" href="Remote-Debugging.html#Remote-Debugging" title="Remote Debugging">
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<link rel="prev" href="Remote-Configuration.html#Remote-Configuration" title="Remote Configuration">
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Copyright (C) 1988-2019 Free Software Foundation, Inc.
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Permission is granted to copy, distribute and/or modify this document
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under the terms of the GNU Free Documentation License, Version 1.3 or
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any later version published by the Free Software Foundation; with the
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Free Documentation'', with the Front-Cover Texts being ``A GNU Manual,''
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</head>
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<body>
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<div class="node">
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<a name="Remote-Stub"></a>
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<p>
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Previous: <a rel="previous" accesskey="p" href="Remote-Configuration.html#Remote-Configuration">Remote Configuration</a>,
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Up: <a rel="up" accesskey="u" href="Remote-Debugging.html#Remote-Debugging">Remote Debugging</a>
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<hr>
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</div>
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<h3 class="section">20.5 Implementing a Remote Stub</h3>
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<p><a name="index-debugging-stub_002c-example-1405"></a><a name="index-remote-stub_002c-example-1406"></a><a name="index-stub-example_002c-remote-debugging-1407"></a>The stub files provided with <span class="sc">gdb</span> implement the target side of the
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communication protocol, and the <span class="sc">gdb</span> side is implemented in the
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<span class="sc">gdb</span> source file <samp><span class="file">remote.c</span></samp>. Normally, you can simply allow
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these subroutines to communicate, and ignore the details. (If you're
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implementing your own stub file, you can still ignore the details: start
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with one of the existing stub files. <samp><span class="file">sparc-stub.c</span></samp> is the best
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organized, and therefore the easiest to read.)
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<p><a name="index-remote-serial-debugging_002c-overview-1408"></a>To debug a program running on another machine (the debugging
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<dfn>target</dfn> machine), you must first arrange for all the usual
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prerequisites for the program to run by itself. For example, for a C
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program, you need:
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<ol type=1 start=1>
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<li>A startup routine to set up the C runtime environment; these usually
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have a name like <samp><span class="file">crt0</span></samp>. The startup routine may be supplied by
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your hardware supplier, or you may have to write your own.
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<li>A C subroutine library to support your program's
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subroutine calls, notably managing input and output.
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<li>A way of getting your program to the other machine—for example, a
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download program. These are often supplied by the hardware
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manufacturer, but you may have to write your own from hardware
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documentation.
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</ol>
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<p>The next step is to arrange for your program to use a serial port to
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communicate with the machine where <span class="sc">gdb</span> is running (the <dfn>host</dfn>
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machine). In general terms, the scheme looks like this:
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<dl>
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<dt><em>On the host,</em><dd><span class="sc">gdb</span> already understands how to use this protocol; when everything
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else is set up, you can simply use the ‘<samp><span class="samp">target remote</span></samp>’ command
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(see <a href="Targets.html#Targets">Specifying a Debugging Target</a>).
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<br><dt><em>On the target,</em><dd>you must link with your program a few special-purpose subroutines that
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implement the <span class="sc">gdb</span> remote serial protocol. The file containing these
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subroutines is called a <dfn>debugging stub</dfn>.
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<p>On certain remote targets, you can use an auxiliary program
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<code>gdbserver</code> instead of linking a stub into your program.
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See <a href="Server.html#Server">Using the <code>gdbserver</code> Program</a>, for details.
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</dl>
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<p>The debugging stub is specific to the architecture of the remote
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machine; for example, use <samp><span class="file">sparc-stub.c</span></samp> to debug programs on
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<span class="sc">sparc</span> boards.
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<p><a name="index-remote-serial-stub-list-1409"></a>These working remote stubs are distributed with <span class="sc">gdb</span>:
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<dl>
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<dt><code>i386-stub.c</code><dd><a name="index-g_t_0040file_007bi386_002dstub_002ec_007d-1410"></a><a name="index-Intel-1411"></a><a name="index-i386-1412"></a>For Intel 386 and compatible architectures.
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<br><dt><code>m68k-stub.c</code><dd><a name="index-g_t_0040file_007bm68k_002dstub_002ec_007d-1413"></a><a name="index-Motorola-680x0-1414"></a><a name="index-m680x0-1415"></a>For Motorola 680x0 architectures.
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<br><dt><code>sh-stub.c</code><dd><a name="index-g_t_0040file_007bsh_002dstub_002ec_007d-1416"></a><a name="index-Renesas-1417"></a><a name="index-SH-1418"></a>For Renesas SH architectures.
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<br><dt><code>sparc-stub.c</code><dd><a name="index-g_t_0040file_007bsparc_002dstub_002ec_007d-1419"></a><a name="index-Sparc-1420"></a>For <span class="sc">sparc</span> architectures.
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<br><dt><code>sparcl-stub.c</code><dd><a name="index-g_t_0040file_007bsparcl_002dstub_002ec_007d-1421"></a><a name="index-Fujitsu-1422"></a><a name="index-SparcLite-1423"></a>For Fujitsu <span class="sc">sparclite</span> architectures.
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</dl>
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<p>The <samp><span class="file">README</span></samp> file in the <span class="sc">gdb</span> distribution may list other
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recently added stubs.
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<ul class="menu">
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<li><a accesskey="1" href="Stub-Contents.html#Stub-Contents">Stub Contents</a>: What the stub can do for you
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<li><a accesskey="2" href="Bootstrapping.html#Bootstrapping">Bootstrapping</a>: What you must do for the stub
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<li><a accesskey="3" href="Debug-Session.html#Debug-Session">Debug Session</a>: Putting it all together
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</ul>
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</body></html>
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