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<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968" /><title>tracehook_report_syscall_entry</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /><link rel="home" href="index.html" title="The utrace User Debugging Infrastructure" /><link rel="up" href="ch04.html#tracehook" title="Core Calls In" /><link rel="prev" href="re39.html" title="tracehook_expect_breakpoints" /><link rel="next" href="re41.html" title="tracehook_report_syscall_exit" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center"><span>tracehook_report_syscall_entry</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="re39.html">Prev</a> </td><th width="60%" align="center">Core Calls In</th><td width="20%" align="right"> <a accesskey="n" href="re41.html">Next</a></td></tr></table><hr /></div><div class="refentry" title="tracehook_report_syscall_entry"><a id="API-tracehook-report-syscall-entry"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>tracehook_report_syscall_entry —
task is about to attempt a system call
</p></div><div class="refsynopsisdiv" title="Synopsis"><h2>Synopsis</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">__must_check int <b class="fsfunc">tracehook_report_syscall_entry </b>(</code></td><td>struct pt_regs * <var class="pdparam">regs</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1" title="Arguments"><a id="id2898099"></a><h2>Arguments</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>regs</code></em></span></dt><dd><p>
user register state of current task
</p></dd></dl></div></div><div class="refsect1" title="Description"><a id="id2898125"></a><h2>Description</h2><p>
This will be called if <code class="constant">TIF_SYSCALL_TRACE</code> has been set, when the
current task has just entered the kernel for a system call.
Full user register state is available here. Changing the values
in <em class="parameter"><code>regs</code></em> can affect the system call number and arguments to be tried.
It is safe to block here, preventing the system call from beginning.
</p><p>
Returns zero normally, or nonzero if the calling arch code should abort
the system call. That must prevent normal entry so no system call is
made. If <em class="parameter"><code>task</code></em> ever returns to user mode after this, its register state
is unspecified, but should be something harmless like an <code class="constant">ENOSYS</code> error
return. It should preserve enough information so that <code class="function">syscall_rollback</code>
can work (see asm-generic/syscall.h).
</p><p>
Called without locks, just after entering kernel mode.
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