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<h1>io.c</h1><a href="io_8c.html">Go to the documentation of this file.</a><div class="fragment"><pre class="fragment">00001 <span class="comment">/* -*- linux-c -*- */</span><span class="comment"></span>
00002 <span class="comment">/** @file io.c</span>
00003 <span class="comment"> * @brief I/O functions</span>
00004 <span class="comment"> */</span>
00005 <span class="comment"></span>
00006 <span class="comment">/** Logs data.</span>
00007 <span class="comment"> * This function is compatible with printk. In fact it currently</span>
00008 <span class="comment"> * sends all output to vprintk, after sending "STP: ". This allows</span>
00009 <span class="comment"> * us to easily detect SystemTap output in the log file.</span>
00010 <span class="comment"> *</span>
00011 <span class="comment"> * @param fmt A variable number of args.</span>
00012 <span class="comment"> * @bug Lines are limited in length by printk buffer.</span>
00013 <span class="comment"> * @todo Needs replaced with something much faster that does not</span>
00014 <span class="comment"> * use the system log.</span>
00015 <span class="comment"> */</span>
<a name="l00016"></a><a class="code" href="io_8c.html#a4">00016</a> <span class="keywordtype">void</span> <a class="code" href="io_8c.html#a4">dlog</a> (<span class="keyword">const</span> <span class="keywordtype">char</span> *fmt, ...)
00017 {
00018 va_list args;
00019 printk(<span class="stringliteral">"STP: "</span>);
00020 va_start(args, fmt);
00021 vprintk(fmt, args);
00022 va_end(args);
00023 }
00024
00025 <span class="comment"></span>
00026 <span class="comment">/** Lookup symbol.</span>
00027 <span class="comment"> * This simply calls the kernel function kallsyms_lookup().</span>
00028 <span class="comment"> * That function is not exported, so this workaround is required.</span>
00029 <span class="comment"> * See the kernel source, kernel/kallsyms.c for more information.</span>
00030 <span class="comment"> */</span>
<a name="l00031"></a><a class="code" href="io_8c.html#a1">00031</a> <span class="keyword">static</span> <span class="keyword">const</span> <span class="keywordtype">char</span> * (*_stp_kallsyms_lookup)(<span class="keywordtype">unsigned</span> <span class="keywordtype">long</span> addr,
00032 <span class="keywordtype">unsigned</span> <span class="keywordtype">long</span> *symbolsize,
00033 <span class="keywordtype">unsigned</span> <span class="keywordtype">long</span> *offset,
00034 <span class="keywordtype">char</span> **modname, <span class="keywordtype">char</span> *namebuf)=(<span class="keywordtype">void</span> *)KALLSYMS_LOOKUP;
00035
00036
00037 <span class="preprocessor">#define STP_BUF_LEN 8191</span>
00038 <span class="preprocessor"></span><span class="comment"></span>
00039 <span class="comment">/** Static buffer for printing */</span>
<a name="l00040"></a><a class="code" href="io_8c.html#a2">00040</a> <span class="keyword">static</span> <span class="keywordtype">char</span> <a class="code" href="io_8c.html#a2">_stp_pbuf</a>[STP_BUF_LEN+1];
00041 <span class="keyword">static</span> <span class="keywordtype">int</span> _stp_pbuf_len = STP_BUF_LEN;
00042 <span class="comment"></span>
00043 <span class="comment">/** Print into the print buffer.</span>
00044 <span class="comment"> * Like printf, except output goes into _stp_pbuf,</span>
00045 <span class="comment"> * which will contain the null-terminated output.</span>
00046 <span class="comment"> * Safe because overflowing _stp_pbuf is not allowed.</span>
00047 <span class="comment"> * Size is limited by length of print buffer.</span>
00048 <span class="comment"> *</span>
00049 <span class="comment"> * @param fmt A variable number of args.</span>
00050 <span class="comment"> * @note Formatting output should never be done within</span>
00051 <span class="comment"> * a probe. Use at module exit time.</span>
00052 <span class="comment"> * @sa _stp_print_buf_init</span>
00053 <span class="comment"> */</span>
00054
<a name="l00055"></a><a class="code" href="io_8c.html#a5">00055</a> <span class="keywordtype">void</span> <a class="code" href="io_8c.html#a5">_stp_print_buf</a> (<span class="keyword">const</span> <span class="keywordtype">char</span> *fmt, ...)
00056 {
00057 <span class="keywordtype">int</span> num;
00058 va_list args;
00059 <span class="keywordtype">char</span> *buf = <a class="code" href="io_8c.html#a2">_stp_pbuf</a> + STP_BUF_LEN - _stp_pbuf_len;
00060 va_start(args, fmt);
00061 num = vscnprintf(buf, _stp_pbuf_len, fmt, args);
00062 va_end(args);
00063 <span class="keywordflow">if</span> (num > 0)
00064 _stp_pbuf_len -= num;
00065 }
00066 <span class="comment"></span>
00067 <span class="comment">/** Clear the print buffer.</span>
00068 <span class="comment"> * Output from _stp_print_buf() will accumulate in the buffer</span>
00069 <span class="comment"> * until this is called.</span>
00070 <span class="comment"> */</span>
00071
<a name="l00072"></a><a class="code" href="io_8c.html#a6">00072</a> <span class="keywordtype">void</span> <a class="code" href="io_8c.html#a6">_stp_print_buf_init</a> (<span class="keywordtype">void</span>)
00073 {
00074 _stp_pbuf_len = STP_BUF_LEN;
00075 <a class="code" href="io_8c.html#a2">_stp_pbuf</a>[0] = 0;
00076 }
00077 <span class="comment"></span>
00078 <span class="comment">/** Print addresses symbolically into the print buffer.</span>
00079 <span class="comment"> * @param fmt A variable number of args.</span>
00080 <span class="comment"> * @param address The address to lookup.</span>
00081 <span class="comment"> * @note Formatting output should never be done within</span>
00082 <span class="comment"> * a probe. Use at module exit time.</span>
00083 <span class="comment"> */</span>
00084
<a name="l00085"></a><a class="code" href="io_8c.html#a7">00085</a> <span class="keywordtype">void</span> <a class="code" href="io_8c.html#a7">_stp_print_symbol</a>(<span class="keyword">const</span> <span class="keywordtype">char</span> *fmt, <span class="keywordtype">unsigned</span> <span class="keywordtype">long</span> address)
00086 {
00087 <span class="keywordtype">char</span> *modname;
00088 <span class="keyword">const</span> <span class="keywordtype">char</span> *name;
00089 <span class="keywordtype">unsigned</span> <span class="keywordtype">long</span> offset, size;
00090 <span class="keywordtype">char</span> namebuf[KSYM_NAME_LEN+1];
00091
00092 name = <a class="code" href="io_8c.html#a1">_stp_kallsyms_lookup</a>(address, &size, &offset, &modname, namebuf);
00093
00094 <span class="keywordflow">if</span> (!name)
00095 <a class="code" href="io_8c.html#a5">_stp_print_buf</a>(<span class="stringliteral">"0x%lx"</span>, address);
00096 <span class="keywordflow">else</span> {
00097 <span class="keywordflow">if</span> (modname)
00098 <a class="code" href="io_8c.html#a5">_stp_print_buf</a>(<span class="stringliteral">"%s+%#lx/%#lx [%s]"</span>, name, offset,
00099 size, modname);
00100 <span class="keywordflow">else</span>
00101 <a class="code" href="io_8c.html#a5">_stp_print_buf</a>(<span class="stringliteral">"%s+%#lx/%#lx"</span>, name, offset, size);
00102 }
00103 }
00104 <span class="comment"></span>
00105 <span class="comment">/** Get the current return address.</span>
00106 <span class="comment"> * Call from kprobes (not jprobes).</span>
00107 <span class="comment"> * @param regs The pt_regs saved by the kprobe.</span>
00108 <span class="comment"> * @return The return address saved in esp or rsp.</span>
00109 <span class="comment"> * @note i386 and x86_64 only.</span>
00110 <span class="comment"> */</span>
00111
<a name="l00112"></a><a class="code" href="io_8c.html#a8">00112</a> <span class="keywordtype">unsigned</span> <span class="keywordtype">long</span> <a class="code" href="io_8c.html#a8">cur_ret_addr</a> (<span class="keyword">struct</span> pt_regs *regs)
00113 {
00114 <span class="preprocessor">#ifdef __x86_64__</span>
00115 <span class="preprocessor"></span> <span class="keywordtype">unsigned</span> <span class="keywordtype">long</span> *ra = (<span class="keywordtype">unsigned</span> <span class="keywordtype">long</span> *)regs->rsp;
00116 <span class="preprocessor">#else</span>
00117 <span class="preprocessor"></span> <span class="keywordtype">unsigned</span> <span class="keywordtype">long</span> *ra = (<span class="keywordtype">unsigned</span> <span class="keywordtype">long</span> *)regs->esp;
00118 <span class="preprocessor">#endif</span>
00119 <span class="preprocessor"></span> <span class="keywordflow">if</span> (ra)
00120 <span class="keywordflow">return</span> *ra;
00121 <span class="keywordflow">else</span>
00122 <span class="keywordflow">return</span> 0;
00123 }
</pre></div><hr size="1"><address style="align: right;"><small>
Generated on Tue Mar 22 10:27:36 2005 for SystemTap.</small></body>
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