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<title>Mu - subx/012elf.cc</title>
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<a href='https://github.com/akkartik/mu/blob/master/subx/012elf.cc'>https://github.com/akkartik/mu/blob/master/subx/012elf.cc</a>
<pre id='vimCodeElement'>
<span id="L1" class="LineNr">  1 </span><span class="Comment">//: Loading SubX programs from ELF binaries.</span>
<span id="L2" class="LineNr">  2 </span><span class="Comment">//: This will allow us to run them natively on a Linux kernel.</span>
<span id="L3" class="LineNr">  3 </span><span class="Comment">//: Based on <a href="https://github.com/kragen/stoneknifeforth/blob/702d2ebe1b/386.c">https://github.com/kragen/stoneknifeforth/blob/702d2ebe1b/386.c</a></span>
<span id="L4" class="LineNr">  4 </span>
<span id="L5" class="LineNr">  5 </span><span class="Delimiter">:(before &quot;End Main&quot;)</span>
<span id="L6" class="LineNr">  6 </span>assert<span class="Delimiter">(</span>argc &gt; <span class="Constant">1</span><span class="Delimiter">);</span>
<span id="L7" class="LineNr">  7 </span><span class="Normal">if</span> <span class="Delimiter">(</span><a href='001help.cc.html#L98'>is_equal</a><span class="Delimiter">(</span>argv[<span class="Constant">1</span>]<span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">))</span> <span class="Delimiter">{</span>
<span id="L8" class="LineNr">  8 </span>  <a href='003trace.cc.html#L228'>START_TRACING_UNTIL_END_OF_SCOPE</a><span class="Delimiter">;</span>
<span id="L9" class="LineNr">  9 </span>  assert<span class="Delimiter">(</span>argc &gt; <span class="Constant">2</span><span class="Delimiter">);</span>
<span id="L10" class="LineNr"> 10 </span>  <a href='000organization.cc.html#L148'>reset</a><span class="Delimiter">();</span>
<span id="L11" class="LineNr"> 11 </span>  cerr &lt;&lt; std::hex<span class="Delimiter">;</span>
<span id="L12" class="LineNr"> 12 </span>  <a href='012elf.cc.html#L20'>load_elf</a><span class="Delimiter">(</span>argv[<span class="Constant">2</span>]<span class="Delimiter">,</span> argc<span class="Delimiter">,</span> argv<span class="Delimiter">);</span>
<span id="L13" class="LineNr"> 13 </span>  <span class="Normal">while</span> <span class="Delimiter">(</span><a href='010---vm.cc.html#L29'>EIP</a> &lt; <span class="Special"><a href='010---vm.cc.html#L194'>End_of_program</a></span><span class="Delimiter">)</span>  <span class="Comment">// weak final-gasp termination check</span>
<span id="L14" class="LineNr"> 14 </span>    <a href='010---vm.cc.html#L296'>run_one_instruction</a><span class="Delimiter">();</span>
<span id="L15" class="LineNr"> 15 </span>  <a href='003trace.cc.html#L190'>raise</a> &lt;&lt; <span class="Constant">&quot;executed past end of the world: &quot;</span> &lt;&lt; <a href='010---vm.cc.html#L29'>EIP</a> &lt;&lt; <span class="Constant">&quot; vs &quot;</span> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L194'>End_of_program</a></span> &lt;&lt; <span class="cSpecial">'\n'</span> &lt;&lt; end<span class="Delimiter">();</span>
<span id="L16" class="LineNr"> 16 </span>  <span class="Identifier">return</span> <span class="Constant">1</span><span class="Delimiter">;</span>
<span id="L17" class="LineNr"> 17 </span><span class="Delimiter">}</span>
<span id="L18" class="LineNr"> 18 </span>
<span id="L19" class="LineNr"> 19 </span><span class="Delimiter">:(code)</span>
<span id="L20" class="LineNr"> 20 </span><span class="Normal">void</span> <a href='012elf.cc.html#L20'>load_elf</a><span class="Delimiter">(</span><span class="Normal">const</span> string&amp; filename<span class="Delimiter">,</span> <span class="Normal">int</span> argc<span class="Delimiter">,</span> <span class="Normal">char</span>* argv[]<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L21" class="LineNr"> 21 </span>  <span class="Normal">int</span> fd = open<span class="Delimiter">(</span>filename<span class="Delimiter">.</span>c_str<span class="Delimiter">(),</span> O_RDONLY<span class="Delimiter">);</span>
<span id="L22" class="LineNr"> 22 </span>  <span class="Normal">if</span> <span class="Delimiter">(</span>fd &lt; <span class="Constant">0</span><span class="Delimiter">)</span> <a href='003trace.cc.html#L190'>raise</a> &lt;&lt; filename<span class="Delimiter">.</span>c_str<span class="Delimiter">()</span> &lt;&lt; <span class="Constant">&quot;: open&quot;</span> &lt;&lt; <a href='012elf.cc.html#L159'>perr</a><span class="Delimiter">()</span> &lt;&lt; <span class="cSpecial">'\n'</span> &lt;&lt; <a href='012elf.cc.html#L168'>die</a><span class="Delimiter">();</span>
<span id="L23" class="LineNr"> 23 </span>  <span class="Normal">off_t</span> size = lseek<span class="Delimiter">(</span>fd<span class="Delimiter">,</span> <span class="Constant">0</span><span class="Delimiter">,</span> <span class="Constant">SEEK_END</span><span class="Delimiter">);</span>
<span id="L24" class="LineNr"> 24 </span>  lseek<span class="Delimiter">(</span>fd<span class="Delimiter">,</span> <span class="Constant">0</span><span class="Delimiter">,</span> <span class="Constant">SEEK_SET</span><span class="Delimiter">);</span>
<span id="L25" class="LineNr"> 25 </span>  <span class="Normal">uint8_t</span>* elf_contents = <span class="Normal">static_cast</span>&lt;<span class="Normal">uint8_t</span>*&gt;<span class="Delimiter">(</span>malloc<span class="Delimiter">(</span>size<span class="Delimiter">));</span>
<span id="L26" class="LineNr"> 26 </span>  <span class="Normal">if</span> <span class="Delimiter">(</span>elf_contents == <span class="Constant">NULL</span><span class="Delimiter">)</span> <a href='003trace.cc.html#L190'>raise</a> &lt;&lt; <span class="Constant">&quot;malloc(&quot;</span> &lt;&lt; size &lt;&lt; <span class="Constant">')'</span> &lt;&lt; <a href='012elf.cc.html#L159'>perr</a><span class="Delimiter">()</span> &lt;&lt; <span class="cSpecial">'\n'</span> &lt;&lt; <a href='012elf.cc.html#L168'>die</a><span class="Delimiter">();</span>
<span id="L27" class="LineNr"> 27 </span>  <span class="Normal">ssize_t</span> read_size = read<span class="Delimiter">(</span>fd<span class="Delimiter">,</span> elf_contents<span class="Delimiter">,</span> size<span class="Delimiter">);</span>
<span id="L28" class="LineNr"> 28 </span>  <span class="Normal">if</span> <span class="Delimiter">(</span>size != read_size<span class="Delimiter">)</span> <a href='003trace.cc.html#L190'>raise</a> &lt;&lt; <span class="Constant">&quot;read → &quot;</span> &lt;&lt; size &lt;&lt; <span class="Constant">&quot; (!= &quot;</span> &lt;&lt; read_size &lt;&lt; <span class="Constant">')'</span> &lt;&lt; <a href='012elf.cc.html#L159'>perr</a><span class="Delimiter">()</span> &lt;&lt; <span class="cSpecial">'\n'</span> &lt;&lt; <a href='012elf.cc.html#L168'>die</a><span class="Delimiter">();</span>
<span id="L29" class="LineNr"> 29 </span>  <a href='012elf.cc.html#L33'>load_elf_contents</a><span class="Delimiter">(</span>elf_contents<span class="Delimiter">,</span> size<span class="Delimiter">,</span> argc<span class="Delimiter">,</span> argv<span class="Delimiter">);</span>
<span id="L30" class="LineNr"> 30 </span>  free<span class="Delimiter">(</span>elf_contents<span class="Delimiter">);</span>
<span id="L31" class="LineNr"> 31 </span><span class="Delimiter">}</span>
<span id="L32" class="LineNr"> 32 </span>
<span id="L33" class="LineNr"> 33 </span><span class="Normal">void</span> <a href='012elf.cc.html#L33'>load_elf_contents</a><span class="Delimiter">(</span><span class="Normal">uint8_t</span>* elf_contents<span class="Delimiter">,</span> <span class="Normal">size_t</span> size<span class="Delimiter">,</span> <span class="Normal">int</span> argc<span class="Delimiter">,</span> <span class="Normal">char</span>* argv[]<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L34" class="LineNr"> 34 </span>  <span class="Normal">uint8_t</span> magic[<span class="Constant">5</span>] = <span class="Delimiter">{</span><span class="Constant">0</span><span class="Delimiter">};</span>
<span id="L35" class="LineNr"> 35 </span>  memcpy<span class="Delimiter">(</span>magic<span class="Delimiter">,</span> elf_contents<span class="Delimiter">,</span> <span class="Constant">4</span><span class="Delimiter">);</span>
<span id="L36" class="LineNr"> 36 </span>  <span class="Normal">if</span> <span class="Delimiter">(</span>memcmp<span class="Delimiter">(</span>magic<span class="Delimiter">,</span> <span class="Constant">&quot;\177ELF&quot;</span><span class="Delimiter">,</span> <span class="Constant">4</span><span class="Delimiter">)</span> != <span class="Constant">0</span><span class="Delimiter">)</span>
<span id="L37" class="LineNr"> 37 </span>    <a href='003trace.cc.html#L190'>raise</a> &lt;&lt; <span class="Constant">&quot;Invalid ELF file; starts with \&quot;&quot; &lt;&lt; magic &lt;&lt; '&quot;</span>' &lt;&lt; <a href='012elf.cc.html#L168'>die</a><span class="Delimiter">();</span>
<span id="L38" class="LineNr"> 38 </span>  <span class="Normal">if</span> <span class="Delimiter">(</span>elf_contents[<span class="Constant">4</span>] != <span class="Constant">1</span><span class="Delimiter">)</span>
<span id="L39" class="LineNr"> 39 </span>    <a href='003trace.cc.html#L190'>raise</a> &lt;&lt; <span class="Constant">&quot;Only 32-bit ELF files (4-byte words; virtual addresses up to 4GB) supported.\n&quot;</span> &lt;&lt; <a href='012elf.cc.html#L168'>die</a><span class="Delimiter">();</span>
<span id="L40" class="LineNr"> 40 </span>  <span class="Normal">if</span> <span class="Delimiter">(</span>elf_contents[<span class="Constant">5</span>] != <span class="Constant">1</span><span class="Delimiter">)</span>
<span id="L41" class="LineNr"> 41 </span>    <a href='003trace.cc.html#L190'>raise</a> &lt;&lt; <span class="Constant">&quot;Only little-endian ELF files supported.\n&quot;</span> &lt;&lt; <a href='012elf.cc.html#L168'>die</a><span class="Delimiter">();</span>
<span id="L42" class="LineNr"> 42 </span>  <span class="Comment">// unused: remaining 10 bytes of e_ident</span>
<span id="L43" class="LineNr"> 43 </span>  <span class="Normal">uint32_t</span> e_machine_type = <a href='012elf.cc.html#L150'>u32_in</a><span class="Delimiter">(</span>&amp;elf_contents[<span class="Constant">16</span>]<span class="Delimiter">);</span>
<span id="L44" class="LineNr"> 44 </span>  <span class="Normal">if</span> <span class="Delimiter">(</span>e_machine_type != <span class="Constant">0x00030002</span><span class="Delimiter">)</span>
<span id="L45" class="LineNr"> 45 </span>    <a href='003trace.cc.html#L190'>raise</a> &lt;&lt; <span class="Constant">&quot;ELF type/machine 0x&quot;</span> &lt;&lt; <a href='010---vm.cc.html#L413'>HEXWORD</a> &lt;&lt; e_machine_type &lt;&lt; <span class="Constant">&quot; isn't i386 executable\n&quot;</span> &lt;&lt; die<span class="Delimiter">();</span>
<span id="L46" class="LineNr"> 46 </span>  <span class="Comment">// unused: e_version. We only support version 1, and later versions will be backwards compatible.</span>
<span id="L47" class="LineNr"> 47 </span>  <span class="Normal">uint32_t</span> e_entry = <a href='012elf.cc.html#L150'>u32_in</a><span class="Delimiter">(</span>&amp;elf_contents[<span class="Constant">24</span>]<span class="Delimiter">);</span>
<span id="L48" class="LineNr"> 48 </span>  <span class="Normal">uint32_t</span> e_phoff = <a href='012elf.cc.html#L150'>u32_in</a><span class="Delimiter">(</span>&amp;elf_contents[<span class="Constant">28</span>]<span class="Delimiter">);</span>
<span id="L49" class="LineNr"> 49 </span>  <span class="Comment">// unused: e_shoff</span>
<span id="L50" class="LineNr"> 50 </span>  <span class="Comment">// unused: e_flags</span>
<span id="L51" class="LineNr"> 51 </span>  <span class="Normal">uint32_t</span> e_ehsize = <a href='012elf.cc.html#L154'>u16_in</a><span class="Delimiter">(</span>&amp;elf_contents[<span class="Constant">40</span>]<span class="Delimiter">);</span>
<span id="L52" class="LineNr"> 52 </span>  <span class="Normal">if</span> <span class="Delimiter">(</span>e_ehsize &lt; <span class="Constant">52</span><span class="Delimiter">)</span> <a href='003trace.cc.html#L190'>raise</a> &lt;&lt; <span class="Constant">&quot;Invalid binary; ELF header too small\n&quot;</span> &lt;&lt; <a href='012elf.cc.html#L168'>die</a><span class="Delimiter">();</span>
<span id="L53" class="LineNr"> 53 </span>  <span class="Normal">uint32_t</span> e_phentsize = <a href='012elf.cc.html#L154'>u16_in</a><span class="Delimiter">(</span>&amp;elf_contents[<span class="Constant">42</span>]<span class="Delimiter">);</span>
<span id="L54" class="LineNr"> 54 </span>  <span class="Normal">uint32_t</span> e_phnum = <a href='012elf.cc.html#L154'>u16_in</a><span class="Delimiter">(</span>&amp;elf_contents[<span class="Constant">44</span>]<span class="Delimiter">);</span>
<span id="L55" class="LineNr"> 55 </span>  <a href='003trace.cc.html#L183'>trace</a><span class="Delimiter">(</span><span class="Constant">90</span><span class="Delimiter">,</span> <span class="Constant">&quot;load&quot;</span><span class="Delimiter">)</span> &lt;&lt; e_phnum &lt;&lt; <span class="Constant">&quot; entries in the <a href='011run.cc.html#L99'>program</a> header, each &quot;</span> &lt;&lt; e_phentsize &lt;&lt; <span class="Constant">&quot; bytes long&quot;</span> &lt;&lt; end<span class="Delimiter">();</span>
<span id="L56" class="LineNr"> 56 </span>  <span class="Comment">// unused: e_shentsize</span>
<span id="L57" class="LineNr"> 57 </span>  <span class="Comment">// unused: e_shnum</span>
<span id="L58" class="LineNr"> 58 </span>  <span class="Comment">// unused: e_shstrndx</span>
<span id="L59" class="LineNr"> 59 </span>
<span id="L60" class="LineNr"> 60 </span>  set&lt;<span class="Normal">uint32_t</span>&gt; overlap<span class="Delimiter">;</span>  <span class="Comment">// to detect overlapping segments</span>
<span id="L61" class="LineNr"> 61 </span>  <span class="Normal">for</span> <span class="Delimiter">(</span><span class="Normal">size_t</span> i = <span class="Constant">0</span><span class="Delimiter">;</span>  i &lt; e_phnum<span class="Delimiter">;</span>  ++i<span class="Delimiter">)</span>
<span id="L62" class="LineNr"> 62 </span>    <a href='012elf.cc.html#L96'>load_segment_from_program_header</a><span class="Delimiter">(</span>elf_contents<span class="Delimiter">,</span> i<span class="Delimiter">,</span> size<span class="Delimiter">,</span> e_phoff + i*e_phentsize<span class="Delimiter">,</span> e_ehsize<span class="Delimiter">,</span> overlap<span class="Delimiter">);</span>
<span id="L63" class="LineNr"> 63 </span>
<span id="L64" class="LineNr"> 64 </span>  <span class="Comment">// initialize code and stack</span>
<span id="L65" class="LineNr"> 65 </span>  assert<span class="Delimiter">(</span>overlap<span class="Delimiter">.</span>find<span class="Delimiter">(</span><a href='012elf.cc.html#L137'>STACK_SEGMENT</a><span class="Delimiter">)</span> == overlap<span class="Delimiter">.</span>end<span class="Delimiter">());</span>
<span id="L66" class="LineNr"> 66 </span>  <span class="Special"><a href='010---vm.cc.html#L180'>Mem</a></span><span class="Delimiter">.</span>push_back<span class="Delimiter">(</span>vma<span class="Delimiter">(</span><a href='012elf.cc.html#L137'>STACK_SEGMENT</a><span class="Delimiter">));</span>
<span id="L67" class="LineNr"> 67 </span>  assert<span class="Delimiter">(</span>overlap<span class="Delimiter">.</span>find<span class="Delimiter">(</span><a href='012elf.cc.html#L138'>AFTER_STACK</a><span class="Delimiter">)</span> == overlap<span class="Delimiter">.</span>end<span class="Delimiter">());</span>
<span id="L68" class="LineNr"> 68 </span>  <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[ESP]<span class="Delimiter">.</span>u = <a href='012elf.cc.html#L138'>AFTER_STACK</a><span class="Delimiter">;</span>
<span id="L69" class="LineNr"> 69 </span>  <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EBP]<span class="Delimiter">.</span>u = <span class="Constant">0</span><span class="Delimiter">;</span>
<span id="L70" class="LineNr"> 70 </span>  <a href='010---vm.cc.html#L29'>EIP</a> = e_entry<span class="Delimiter">;</span>
<span id="L71" class="LineNr"> 71 </span>
<span id="L72" class="LineNr"> 72 </span>  <span class="Comment">// initialize args on stack</span>
<span id="L73" class="LineNr"> 73 </span>  <span class="Comment">// no envp for now</span>
<span id="L74" class="LineNr"> 74 </span>  <span class="Comment">// we wastefully use a separate page of memory for argv</span>
<span id="L75" class="LineNr"> 75 </span>  <span class="Special"><a href='010---vm.cc.html#L180'>Mem</a></span><span class="Delimiter">.</span>push_back<span class="Delimiter">(</span>vma<span class="Delimiter">(</span><a href='012elf.cc.html#L139'>ARGV_DATA_SEGMENT</a><span class="Delimiter">));</span>
<span id="L76" class="LineNr"> 76 </span>  <span class="Normal">uint32_t</span> argv_data = <a href='012elf.cc.html#L139'>ARGV_DATA_SEGMENT</a><span class="Delimiter">;</span>
<span id="L77" class="LineNr"> 77 </span>  <span class="Normal">for</span> <span class="Delimiter">(</span><span class="Normal">int</span> i = argc-<span class="Constant">1</span><span class="Delimiter">;</span>  i &gt;= <span class="Comment">/*</span><span class="Comment">skip 'subx_bin' and 'run'</span><span class="Comment">*/</span><span class="Constant">2</span><span class="Delimiter">;</span>  --i<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L78" class="LineNr"> 78 </span>    <a href='012elf.cc.html#L89'>push</a><span class="Delimiter">(</span>argv_data<span class="Delimiter">);</span>
<span id="L79" class="LineNr"> 79 </span>    <span class="Normal">for</span> <span class="Delimiter">(</span><span class="Normal">size_t</span> j = <span class="Constant">0</span><span class="Delimiter">;</span>  j &lt;= strlen<span class="Delimiter">(</span>argv[i]<span class="Delimiter">);</span>  ++j<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L80" class="LineNr"> 80 </span>      assert<span class="Delimiter">(</span>overlap<span class="Delimiter">.</span>find<span class="Delimiter">(</span>argv_data<span class="Delimiter">)</span> == overlap<span class="Delimiter">.</span>end<span class="Delimiter">());</span>  <span class="Comment">// don't bother comparing ARGV and STACK</span>
<span id="L81" class="LineNr"> 81 </span>      <a href='010---vm.cc.html#L263'>write_mem_u8</a><span class="Delimiter">(</span>argv_data<span class="Delimiter">,</span> argv[i][j]<span class="Delimiter">);</span>
<span id="L82" class="LineNr"> 82 </span>      argv_data += <span class="Normal">sizeof</span><span class="Delimiter">(</span><span class="Normal">char</span><span class="Delimiter">);</span>
<span id="L83" class="LineNr"> 83 </span>      assert<span class="Delimiter">(</span>argv_data &lt; <a href='012elf.cc.html#L139'>ARGV_DATA_SEGMENT</a> + <a href='010---vm.cc.html#L115'>SEGMENT_ALIGNMENT</a><span class="Delimiter">);</span>
<span id="L84" class="LineNr"> 84 </span>    <span class="Delimiter">}</span>
<span id="L85" class="LineNr"> 85 </span>  <span class="Delimiter">}</span>
<span id="L86" class="LineNr"> 86 </span>  <a href='012elf.cc.html#L89'>push</a><span class="Delimiter">(</span>argc-<span class="Comment">/*</span><span class="Comment">skip 'subx_bin' and 'run'</span><span class="Comment">*/</span><span class="Constant">2</span><span class="Delimiter">);</span>
<span id="L87" class="LineNr"> 87 </span><span class="Delimiter">}</span>
<span id="L88" class="LineNr"> 88 </span>
<span id="L89" class="LineNr"> 89 </span><span class="Normal">void</span> <a href='012elf.cc.html#L89'>push</a><span class="Delimiter">(</span><span class="Normal">uint32_t</span> val<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L90" class="LineNr"> 90 </span>  <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[ESP]<span class="Delimiter">.</span>u -= <span class="Constant">4</span><span class="Delimiter">;</span>
<span id="L91" class="LineNr"> 91 </span>  <a href='003trace.cc.html#L183'>trace</a><span class="Delimiter">(</span><span class="Constant">90</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;decrementing <a href='010---vm.cc.html#L17'>ESP</a> to 0x&quot;</span> &lt;&lt; <a href='010---vm.cc.html#L413'>HEXWORD</a> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[ESP]<span class="Delimiter">.</span>u &lt;&lt; end<span class="Delimiter">();</span>
<span id="L92" class="LineNr"> 92 </span>  <a href='003trace.cc.html#L183'>trace</a><span class="Delimiter">(</span><span class="Constant">90</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;pushing value 0x&quot;</span> &lt;&lt; <a href='010---vm.cc.html#L413'>HEXWORD</a> &lt;&lt; val &lt;&lt; end<span class="Delimiter">();</span>
<span id="L93" class="LineNr"> 93 </span>  <a href='010---vm.cc.html#L271'>write_mem_u32</a><span class="Delimiter">(</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[ESP]<span class="Delimiter">.</span>u<span class="Delimiter">,</span> val<span class="Delimiter">);</span>
<span id="L94" class="LineNr"> 94 </span><span class="Delimiter">}</span>
<span id="L95" class="LineNr"> 95 </span>
<span id="L96" class="LineNr"> 96 </span><span class="Normal">void</span> <a href='012elf.cc.html#L96'>load_segment_from_program_header</a><span class="Delimiter">(</span><span class="Normal">uint8_t</span>* elf_contents<span class="Delimiter">,</span> <span class="Normal">int</span> segment_index<span class="Delimiter">,</span> <span class="Normal">size_t</span> size<span class="Delimiter">,</span> <span class="Normal">uint32_t</span> offset<span class="Delimiter">,</span> <span class="Normal">uint32_t</span> e_ehsize<span class="Delimiter">,</span> set&lt;<span class="Normal">uint32_t</span>&gt;&amp; overlap<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L97" class="LineNr"> 97 </span>  <span class="Normal">uint32_t</span> p_type = <a href='012elf.cc.html#L150'>u32_in</a><span class="Delimiter">(</span>&amp;elf_contents[offset]<span class="Delimiter">);</span>
<span id="L98" class="LineNr"> 98 </span>  <a href='003trace.cc.html#L183'>trace</a><span class="Delimiter">(</span><span class="Constant">90</span><span class="Delimiter">,</span> <span class="Constant">&quot;load&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;program header at offset &quot;</span> &lt;&lt; offset &lt;&lt; <span class="Constant">&quot;: type &quot;</span> &lt;&lt; p_type &lt;&lt; end<span class="Delimiter">();</span>
<span id="L99" class="LineNr"> 99 </span>  <span class="Normal">if</span> <span class="Delimiter">(</span>p_type != <span class="Constant">1</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L100" class="LineNr">100 </span>    <a href='003trace.cc.html#L183'>trace</a><span class="Delimiter">(</span><span class="Constant">90</span><span class="Delimiter">,</span> <span class="Constant">&quot;load&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;ignoring segment at offset &quot;</span> &lt;&lt; offset &lt;&lt; <span class="Constant">&quot; of non PT_LOAD type &quot;</span> &lt;&lt; p_type &lt;&lt; <span class="Constant">&quot; (see <a href="http://refspecs.linuxbase.org/elf/elf.pdf">http://refspecs.linuxbase.org/elf/elf.pdf</a>)&quot;</span> &lt;&lt; end<span class="Delimiter">();</span>
<span id="L101" class="LineNr">101 </span>    <span class="Identifier">return</span><span class="Delimiter">;</span>
<span id="L102" class="LineNr">102 </span>  <span class="Delimiter">}</span>
<span id="L103" class="LineNr">103 </span>  <span class="Normal">uint32_t</span> p_offset = <a href='012elf.cc.html#L150'>u32_in</a><span class="Delimiter">(</span>&amp;elf_contents[offset + <span class="Constant">4</span>]<span class="Delimiter">);</span>
<span id="L104" class="LineNr">104 </span>  <span class="Normal">uint32_t</span> p_vaddr = <a href='012elf.cc.html#L150'>u32_in</a><span class="Delimiter">(</span>&amp;elf_contents[offset + <span class="Constant">8</span>]<span class="Delimiter">);</span>
<span id="L105" class="LineNr">105 </span>  <span class="Normal">if</span> <span class="Delimiter">(</span>e_ehsize &gt; p_vaddr<span class="Delimiter">)</span> <a href='003trace.cc.html#L190'>raise</a> &lt;&lt; <span class="Constant">&quot;Invalid binary; <a href='011run.cc.html#L99'>program</a> header overlaps ELF header\n&quot;</span> &lt;&lt; <a href='012elf.cc.html#L168'>die</a><span class="Delimiter">();</span>
<span id="L106" class="LineNr">106 </span>  <span class="Comment">// unused: p_paddr</span>
<span id="L107" class="LineNr">107 </span>  <span class="Normal">uint32_t</span> p_filesz = <a href='012elf.cc.html#L150'>u32_in</a><span class="Delimiter">(</span>&amp;elf_contents[offset + <span class="Constant">16</span>]<span class="Delimiter">);</span>
<span id="L108" class="LineNr">108 </span>  <span class="Normal">uint32_t</span> p_memsz = <a href='012elf.cc.html#L150'>u32_in</a><span class="Delimiter">(</span>&amp;elf_contents[offset + <span class="Constant">20</span>]<span class="Delimiter">);</span>
<span id="L109" class="LineNr">109 </span>  <span class="Normal">if</span> <span class="Delimiter">(</span>p_filesz != p_memsz<span class="Delimiter">)</span>
<span id="L110" class="LineNr">110 </span>    <a href='003trace.cc.html#L190'>raise</a> &lt;&lt; <span class="Constant">&quot;Can't yet handle segments where p_filesz != p_memsz (see <a href="http://refspecs.linuxbase.org/elf/elf.pdf">http://refspecs.linuxbase.org/elf/elf.pdf</a>)\n&quot;</span> &lt;&lt; die<span class="Delimiter">();</span>
<span id="L111" class="LineNr">111 </span>
<span id="L112" class="LineNr">112 </span>  <span class="Normal">if</span> <span class="Delimiter">(</span>p_offset + p_filesz &gt; size<span class="Delimiter">)</span>
<span id="L113" class="LineNr">113 </span>    <a href='003trace.cc.html#L190'>raise</a> &lt;&lt; <span class="Constant">&quot;Invalid binary; segment at offset &quot;</span> &lt;&lt; offset &lt;&lt; <span class="Constant">&quot; is too large: wants to end at &quot;</span> &lt;&lt; p_offset+p_filesz &lt;&lt; <span class="Constant">&quot; but the file ends at &quot;</span> &lt;&lt; size &lt;&lt; <span class="cSpecial">'\n'</span> &lt;&lt; <a href='012elf.cc.html#L168'>die</a><span class="Delimiter">();</span>
<span id="L114" class="LineNr">114 </span>  <span class="Normal">if</span> <span class="Delimiter">(</span>p_memsz &gt;= <a href='010---vm.cc.html#L115'>SEGMENT_ALIGNMENT</a><span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L115" class="LineNr">115 </span>    <a href='003trace.cc.html#L190'>raise</a> &lt;&lt; <span class="Constant">&quot;Code segment too small for SubX; for now please manually increase SEGMENT_ALIGNMENT.\n&quot;</span> &lt;&lt; end<span class="Delimiter">();</span>
<span id="L116" class="LineNr">116 </span>    <span class="Identifier">return</span><span class="Delimiter">;</span>
<span id="L117" class="LineNr">117 </span>  <span class="Delimiter">}</span>
<span id="L118" class="LineNr">118 </span>  <a href='003trace.cc.html#L183'>trace</a><span class="Delimiter">(</span><span class="Constant">90</span><span class="Delimiter">,</span> <span class="Constant">&quot;load&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;blitting file offsets (&quot;</span> &lt;&lt; p_offset &lt;&lt; <span class="Constant">&quot;, &quot;</span> &lt;&lt; <span class="Delimiter">(</span>p_offset+p_filesz<span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;) to addresses (&quot;</span> &lt;&lt; p_vaddr &lt;&lt; <span class="Constant">&quot;, &quot;</span> &lt;&lt; <span class="Delimiter">(</span>p_vaddr+p_memsz<span class="Delimiter">)</span> &lt;&lt; <span class="Constant">')'</span> &lt;&lt; end<span class="Delimiter">();</span>
<span id="L119" class="LineNr">119 </span>  <span class="Normal">if</span> <span class="Delimiter">(</span>size &gt; p_memsz<span class="Delimiter">)</span> size = p_memsz<span class="Delimiter">;</span>
<span id="L120" class="LineNr">120 </span>  <span class="Special"><a href='010---vm.cc.html#L180'>Mem</a></span><span class="Delimiter">.</span>push_back<span class="Delimiter">(</span>vma<span class="Delimiter">(</span>p_vaddr<span class="Delimiter">));</span>
<span id="L121" class="LineNr">121 </span>  <span class="Normal">for</span> <span class="Delimiter">(</span><span class="Normal">size_t</span> i = <span class="Constant">0</span><span class="Delimiter">;</span>  i &lt; p_filesz<span class="Delimiter">;</span>  ++i<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L122" class="LineNr">122 </span>    assert<span class="Delimiter">(</span>overlap<span class="Delimiter">.</span>find<span class="Delimiter">(</span>p_vaddr+i<span class="Delimiter">)</span> == overlap<span class="Delimiter">.</span>end<span class="Delimiter">());</span>
<span id="L123" class="LineNr">123 </span>    <a href='010---vm.cc.html#L263'>write_mem_u8</a><span class="Delimiter">(</span>p_vaddr+i<span class="Delimiter">,</span> elf_contents[p_offset+i]<span class="Delimiter">);</span>
<span id="L124" class="LineNr">124 </span>    overlap<span class="Delimiter">.</span>insert<span class="Delimiter">(</span>p_vaddr+i<span class="Delimiter">);</span>
<span id="L125" class="LineNr">125 </span>  <span class="Delimiter">}</span>
<span id="L126" class="LineNr">126 </span>  <span class="Normal">if</span> <span class="Delimiter">(</span>segment_index == <span class="Constant">0</span> &amp;&amp; <span class="Special"><a href='010---vm.cc.html#L194'>End_of_program</a></span> &lt; p_vaddr+p_memsz<span class="Delimiter">)</span>
<span id="L127" class="LineNr">127 </span>    <span class="Special"><a href='010---vm.cc.html#L194'>End_of_program</a></span> = p_vaddr+p_memsz<span class="Delimiter">;</span>
<span id="L128" class="LineNr">128 </span><span class="Delimiter">}</span>
<span id="L129" class="LineNr">129 </span>
<span id="L130" class="LineNr">130 </span><span class="Delimiter">:(before &quot;End Includes&quot;)</span>
<span id="L131" class="LineNr">131 </span><span class="Comment">// Very primitive/fixed/insecure ELF segments for now: just consecutive VMAs.</span>
<span id="L132" class="LineNr">132 </span><span class="Comment">//   code: 0x09000000 -&gt; 0x09ffffff</span>
<span id="L133" class="LineNr">133 </span><span class="Comment">//   data/heap: 0x0a000000 -&gt; 0x0affffff</span>
<span id="L134" class="LineNr">134 </span><span class="Comment">//   stack: 0x0b000ffc -&gt; 0x0b000000 (downward)</span>
<span id="L135" class="LineNr">135 </span><span class="Normal">const</span> <span class="Normal">int</span> <a href='012elf.cc.html#L135'>CODE_SEGMENT</a> = <span class="Constant">0x09000000</span><span class="Delimiter">;</span>
<span id="L136" class="LineNr">136 </span><span class="Normal">const</span> <span class="Normal">int</span> <a href='012elf.cc.html#L136'>DATA_SEGMENT</a> = <span class="Constant">0x0a000000</span><span class="Delimiter">;</span>  <span class="Comment">// keep sync'd with `Heap.limit` in allocate.subx</span>
<span id="L137" class="LineNr">137 </span><span class="Normal">const</span> <span class="Normal">int</span> <a href='012elf.cc.html#L137'>STACK_SEGMENT</a> = <span class="Constant">0x0b000000</span><span class="Delimiter">;</span>
<span id="L138" class="LineNr">138 </span><span class="Normal">const</span> <span class="Normal">int</span> <a href='012elf.cc.html#L138'>AFTER_STACK</a> = <span class="Constant">0x0c000000</span><span class="Delimiter">;</span>
<span id="L139" class="LineNr">139 </span><span class="Normal">const</span> <span class="Normal">int</span> <a href='012elf.cc.html#L139'>ARGV_DATA_SEGMENT</a> = <span class="Constant">0x0c000000</span><span class="Delimiter">;</span>
<span id="L140" class="LineNr">140 </span><span class="Delimiter">:(code)</span>
<span id="L141" class="LineNr">141 </span><span class="Normal">void</span> <a href='012elf.cc.html#L141'>dump_stack</a><span class="Delimiter">()</span> <span class="Delimiter">{</span>
<span id="L142" class="LineNr">142 </span>  cerr &lt;&lt; <span class="Constant">&quot;stack:\n&quot;</span><span class="Delimiter">;</span>
<span id="L143" class="LineNr">143 </span>  <span class="Normal">for</span> <span class="Delimiter">(</span><span class="Normal">uint32_t</span> a = AFTER_STACK-<span class="Constant">4</span><span class="Delimiter">;</span>  a &gt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[ESP]<span class="Delimiter">.</span>u<span class="Delimiter">;</span>  a -= <span class="Constant">4</span><span class="Delimiter">)</span>
<span id="L144" class="LineNr">144 </span>    cerr &lt;&lt; <span class="Constant">&quot;  0x&quot;</span> &lt;&lt; <a href='010---vm.cc.html#L413'>HEXWORD</a> &lt;&lt; a &lt;&lt; <span class="Constant">&quot; =&gt; 0x&quot;</span> &lt;&lt; <a href='010---vm.cc.html#L413'>HEXWORD</a> &lt;&lt; <a href='010---vm.cc.html#L209'>read_mem_u32</a><span class="Delimiter">(</span>a<span class="Delimiter">)</span> &lt;&lt; <span class="cSpecial">'\n'</span><span class="Delimiter">;</span>
<span id="L145" class="LineNr">145 </span>  cerr &lt;&lt; <span class="Constant">&quot;  0x&quot;</span> &lt;&lt; <a href='010---vm.cc.html#L413'>HEXWORD</a> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[ESP]<span class="Delimiter">.</span>u &lt;&lt; <span class="Constant">&quot; =&gt; 0x&quot;</span> &lt;&lt; <a href='010---vm.cc.html#L413'>HEXWORD</a> &lt;&lt; <a href='010---vm.cc.html#L209'>read_mem_u32</a><span class="Delimiter">(</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[ESP]<span class="Delimiter">.</span>u<span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;  &lt;=== ESP\n&quot;</span><span class="Delimiter">;</span>
<span id="L146" class="LineNr">146 </span>  <span class="Normal">for</span> <span class="Delimiter">(</span><span class="Normal">uint32_t</span> a = <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[ESP]<span class="Delimiter">.</span>u-<span class="Constant">4</span><span class="Delimiter">;</span>  a &gt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[ESP]<span class="Delimiter">.</span>u-<span class="Constant">40</span><span class="Delimiter">;</span>  a -= <span class="Constant">4</span><span class="Delimiter">)</span>
<span id="L147" class="LineNr">147 </span>    cerr &lt;&lt; <span class="Constant">&quot;  0x&quot;</span> &lt;&lt; <a href='010---vm.cc.html#L413'>HEXWORD</a> &lt;&lt; a &lt;&lt; <span class="Constant">&quot; =&gt; 0x&quot;</span> &lt;&lt; <a href='010---vm.cc.html#L413'>HEXWORD</a> &lt;&lt; <a href='010---vm.cc.html#L209'>read_mem_u32</a><span class="Delimiter">(</span>a<span class="Delimiter">)</span> &lt;&lt; <span class="cSpecial">'\n'</span><span class="Delimiter">;</span>
<span id="L148" class="LineNr">148 </span><span class="Delimiter">}</span>
<span id="L149" class="LineNr">149 </span>
<span id="L150" class="LineNr">150 </span><span class="Normal">inline</span> <span class="Normal">uint32_t</span> <a href='012elf.cc.html#L150'>u32_in</a><span class="Delimiter">(</span><span class="Normal">uint8_t</span>* p<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L151" class="LineNr">151 </span>  <span class="Identifier">return</span> p[<span class="Constant">0</span>] | p[<span class="Constant">1</span>] &lt;&lt; <span class="Constant">8</span> | p[<span class="Constant">2</span>] &lt;&lt; <span class="Constant">16</span> | p[<span class="Constant">3</span>] &lt;&lt; <span class="Constant">24</span><span class="Delimiter">;</span>
<span id="L152" class="LineNr">152 </span><span class="Delimiter">}</span>
<span id="L153" class="LineNr">153 </span>
<span id="L154" class="LineNr">154 </span><span class="Normal">inline</span> <span class="Normal">uint16_t</span> <a href='012elf.cc.html#L154'>u16_in</a><span class="Delimiter">(</span><span class="Normal">uint8_t</span>* p<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L155" class="LineNr">155 </span>  <span class="Identifier">return</span> p[<span class="Constant">0</span>] | p[<span class="Constant">1</span>] &lt;&lt; <span class="Constant">8</span><span class="Delimiter">;</span>
<span id="L156" class="LineNr">156 </span><span class="Delimiter">}</span>
<span id="L157" class="LineNr">157 </span>
<span id="L158" class="LineNr">158 </span><span class="Delimiter">:(before &quot;End Types&quot;)</span>
<span id="L159" class="LineNr">159 </span><span class="Normal">struct</span> <a href='012elf.cc.html#L159'>perr</a> <span class="Delimiter">{};</span>
<span id="L160" class="LineNr">160 </span><span class="Delimiter">:(code)</span>
<span id="L161" class="LineNr">161 </span>ostream&amp; <span class="Normal">operator</span>&lt;&lt;<span class="Delimiter">(</span>ostream&amp; os<span class="Delimiter">,</span> <a href='012elf.cc.html#L159'>perr</a> <span class="Comment">/*</span><span class="Comment">unused</span><span class="Comment">*/</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L162" class="LineNr">162 </span>  <span class="Normal">if</span> <span class="Delimiter">(</span>errno<span class="Delimiter">)</span>
<span id="L163" class="LineNr">163 </span>    os &lt;&lt; <span class="Constant">&quot;: &quot;</span> &lt;&lt; strerror<span class="Delimiter">(</span>errno<span class="Delimiter">);</span>
<span id="L164" class="LineNr">164 </span>  <span class="Identifier">return</span> os<span class="Delimiter">;</span>
<span id="L165" class="LineNr">165 </span><span class="Delimiter">}</span>
<span id="L166" class="LineNr">166 </span>
<span id="L167" class="LineNr">167 </span><span class="Delimiter">:(before &quot;End Types&quot;)</span>
<span id="L168" class="LineNr">168 </span><span class="Normal">struct</span> <a href='012elf.cc.html#L168'>die</a> <span class="Delimiter">{};</span>
<span id="L169" class="LineNr">169 </span><span class="Delimiter">:(code)</span>
<span id="L170" class="LineNr">170 </span>ostream&amp; <span class="Normal">operator</span>&lt;&lt;<span class="Delimiter">(</span>ostream&amp; <span class="Comment">/*</span><span class="Comment">unused</span><span class="Comment">*/</span><span class="Delimiter">,</span> <a href='012elf.cc.html#L168'>die</a> <span class="Comment">/*</span><span class="Comment">unused</span><span class="Comment">*/</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L171" class="LineNr">171 </span>  <span class="Normal">if</span> <span class="Delimiter">(</span><span class="Special"><a href='003trace.cc.html#L154'>Trace_stream</a></span><span class="Delimiter">)</span> <span class="Special"><a href='003trace.cc.html#L154'>Trace_stream</a></span><span class="Delimiter">-&gt;</span><a href='003trace.cc.html#L127'>newline</a><span class="Delimiter">();</span>
<span id="L172" class="LineNr">172 </span>  exit<span class="Delimiter">(</span><span class="Constant">1</span><span class="Delimiter">);</span>
<span id="L173" class="LineNr">173 </span><span class="Delimiter">}</span>
<span id="L174" class="LineNr">174 </span>
<span id="L175" class="LineNr">175 </span><span class="Delimiter">:(before &quot;End Includes&quot;)</span>
<span id="L176" class="LineNr">176 </span><span class="Comment">#include &lt;sys/types.h&gt;</span>
<span id="L177" class="LineNr">177 </span><span class="Comment">#include &lt;sys/stat.h&gt;</span>
<span id="L178" class="LineNr">178 </span><span class="Comment">#include &lt;fcntl.h&gt;</span>
<span id="L179" class="LineNr">179 </span><span class="Comment">#include &lt;stdarg.h&gt;</span>
<span id="L180" class="LineNr">180 </span><span class="Comment">#include &lt;errno.h&gt;</span>
<span id="L181" class="LineNr">181 </span><span class="Comment">#include &lt;unistd.h&gt;</span>
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