92 lines
4.1 KiB
HTML
92 lines
4.1 KiB
HTML
|
<html lang="en">
|
||
|
|
<head>
|
||
|
|
<title>system - Debugging with GDB</title>
|
||
|
|
<meta http-equiv="Content-Type" content="text/html">
|
||
|
|
<meta name="description" content="Debugging with GDB">
|
||
|
|
<meta name="generator" content="makeinfo 4.13">
|
||
|
|
<link title="Top" rel="start" href="index.html#Top">
|
||
|
|
<link rel="up" href="List-of-Supported-Calls.html#List-of-Supported-Calls" title="List of Supported Calls">
|
||
|
|
<link rel="prev" href="isatty.html#isatty" title="isatty">
|
||
|
|
<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
|
||
|
|
<!--
|
||
|
|
Copyright (C) 1988-2019 Free Software Foundation, Inc.
|
||
|
|
|
||
|
|
Permission is granted to copy, distribute and/or modify this document
|
||
|
|
under the terms of the GNU Free Documentation License, Version 1.3 or
|
||
|
|
any later version published by the Free Software Foundation; with the
|
||
|
|
Invariant Sections being ``Free Software'' and ``Free Software Needs
|
||
|
|
Free Documentation'', with the Front-Cover Texts being ``A GNU Manual,''
|
||
|
|
and with the Back-Cover Texts as in (a) below.
|
||
|
|
|
||
|
|
(a) The FSF's Back-Cover Text is: ``You are free to copy and modify
|
||
|
|
this GNU Manual. Buying copies from GNU Press supports the FSF in
|
||
|
|
developing GNU and promoting software freedom.''
|
||
|
|
-->
|
||
|
|
<meta http-equiv="Content-Style-Type" content="text/css">
|
||
|
|
<style type="text/css"><!--
|
||
|
|
pre.display { font-family:inherit }
|
||
|
|
pre.format { font-family:inherit }
|
||
|
|
pre.smalldisplay { font-family:inherit; font-size:smaller }
|
||
|
|
pre.smallformat { font-family:inherit; font-size:smaller }
|
||
|
|
pre.smallexample { font-size:smaller }
|
||
|
|
pre.smalllisp { font-size:smaller }
|
||
|
|
span.sc { font-variant:small-caps }
|
||
|
|
span.roman { font-family:serif; font-weight:normal; }
|
||
|
|
span.sansserif { font-family:sans-serif; font-weight:normal; }
|
||
|
|
--></style>
|
||
|
|
</head>
|
||
|
|
<body>
|
||
|
|
<div class="node">
|
||
|
|
<a name="system"></a>
|
||
|
|
<p>
|
||
|
|
Previous: <a rel="previous" accesskey="p" href="isatty.html#isatty">isatty</a>,
|
||
|
|
Up: <a rel="up" accesskey="u" href="List-of-Supported-Calls.html#List-of-Supported-Calls">List of Supported Calls</a>
|
||
|
|
<hr>
|
||
|
|
</div>
|
||
|
|
|
||
|
|
<h5 class="unnumberedsubsubsec">system</h5>
|
||
|
|
|
||
|
|
<p><a name="index-system_002c-file_002di_002fo-system-call-3615"></a>
|
||
|
|
<dl>
|
||
|
|
<dt>Synopsis:<dd>
|
||
|
|
<pre class="smallexample"> int system(const char *command);
|
||
|
|
</pre>
|
||
|
|
<br><dt>Request:<dd>‘<samp><span class="samp">Fsystem,</span><var>commandptr</var><span class="samp">/</span><var>len</var></samp>’
|
||
|
|
|
||
|
|
<br><dt>Return value:<dd>If <var>len</var> is zero, the return value indicates whether a shell is
|
||
|
|
available. A zero return value indicates a shell is not available.
|
||
|
|
For non-zero <var>len</var>, the value returned is -1 on error and the
|
||
|
|
return status of the command otherwise. Only the exit status of the
|
||
|
|
command is returned, which is extracted from the host's <code>system</code>
|
||
|
|
return value by calling <code>WEXITSTATUS(retval)</code>. In case
|
||
|
|
<samp><span class="file">/bin/sh</span></samp> could not be executed, 127 is returned.
|
||
|
|
|
||
|
|
<br><dt>Errors:<dd>
|
||
|
|
<dl>
|
||
|
|
<dt><code>EINTR</code><dd>The call was interrupted by the user.
|
||
|
|
</dl>
|
||
|
|
|
||
|
|
</dl>
|
||
|
|
|
||
|
|
<p><span class="sc">gdb</span> takes over the full task of calling the necessary host calls
|
||
|
|
to perform the <code>system</code> call. The return value of <code>system</code> on
|
||
|
|
the host is simplified before it's returned
|
||
|
|
to the target. Any termination signal information from the child process
|
||
|
|
is discarded, and the return value consists
|
||
|
|
entirely of the exit status of the called command.
|
||
|
|
|
||
|
|
<p>Due to security concerns, the <code>system</code> call is by default refused
|
||
|
|
by <span class="sc">gdb</span>. The user has to allow this call explicitly with the
|
||
|
|
<code>set remote system-call-allowed 1</code> command.
|
||
|
|
|
||
|
|
<dl>
|
||
|
|
<dt><code>set remote system-call-allowed</code><dd><a name="index-set-remote-system_002dcall_002dallowed-3616"></a>Control whether to allow the <code>system</code> calls in the File I/O
|
||
|
|
protocol for the remote target. The default is zero (disabled).
|
||
|
|
|
||
|
|
<br><dt><code>show remote system-call-allowed</code><dd><a name="index-show-remote-system_002dcall_002dallowed-3617"></a>Show whether the <code>system</code> calls are allowed in the File I/O
|
||
|
|
protocol.
|
||
|
|
</dl>
|
||
|
|
|
||
|
|
</body></html>
|
||
|
|
|