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<a href='https://github.com/akkartik/mu/blob/master/012elf.cc'>https://github.com/akkartik/mu/blob/master/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 "End Main")</span>
<span id="L6" class="LineNr"> 6 </span>assert<span class="Delimiter">(</span>argc > <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#L102'>is_equal</a><span class="Delimiter">(</span>argv[<span class="Constant">1</span>]<span class="Delimiter">,</span> <span class="Constant">"run"</span><span class="Delimiter">))</span> <span class="Delimiter">{</span>
<span id="L8" class="LineNr"> 8 </span> <span class="Comment">// Outside of tests, traces must be explicitly requested.</span>
<span id="L9" class="LineNr"> 9 </span> <span class="Normal">if</span> <span class="Delimiter">(</span><span class="Special"><a href='003trace.cc.html#L448'>Trace_file</a></span><span class="Delimiter">.</span>is_open<span class="Delimiter">())</span> <span class="Special"><a href='003trace.cc.html#L72'>Trace_stream</a></span> = <span class="Normal">new</span> trace_stream<span class="Delimiter">;</span>
<span id="L10" class="LineNr"> 10 </span> <a href='003trace.cc.html#L96'>trace</a><span class="Delimiter">(</span><span class="Constant">2</span><span class="Delimiter">,</span> <span class="Constant">"run"</span><span class="Delimiter">)</span> << <span class="Constant">"=== Starting to run"</span> << end<span class="Delimiter">();</span>
<span id="L11" class="LineNr"> 11 </span> <span class="Normal">if</span> <span class="Delimiter">(</span>argc <= <span class="Constant">2</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L12" class="LineNr"> 12 </span> <a href='003trace.cc.html#L228'>raise</a> << <span class="Constant">"Not enough arguments provided.\n"</span> << <a href='003trace.cc.html#L173'>die</a><span class="Delimiter">();</span>
<span id="L13" class="LineNr"> 13 </span> <span class="Delimiter">}</span>
<span id="L14" class="LineNr"> 14 </span> <a href='000organization.cc.html#L150'>reset</a><span class="Delimiter">();</span>
<span id="L15" class="LineNr"> 15 </span> cerr << std::hex<span class="Delimiter">;</span>
<span id="L16" class="LineNr"> 16 </span> <a href='012elf.cc.html#L24'>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="L17" class="LineNr"> 17 </span> <span class="Normal">while</span> <span class="Delimiter">(</span><a href='010---vm.cc.html#L26'>EIP</a> < <span class="Special"><a href='010---vm.cc.html#L157'>End_of_program</a></span><span class="Delimiter">)</span> <span class="Comment">// weak final-gasp termination check</span>
<span id="L18" class="LineNr"> 18 </span> <a href='010---vm.cc.html#L264'>run_one_instruction</a><span class="Delimiter">();</span>
<span id="L19" class="LineNr"> 19 </span> <a href='003trace.cc.html#L228'>raise</a> << <span class="Constant">"executed past end of the world: "</span> << <a href='010---vm.cc.html#L26'>EIP</a> << <span class="Constant">" vs "</span> << <span class="Special"><a href='010---vm.cc.html#L157'>End_of_program</a></span> << <span class="cSpecial">'\n'</span> << end<span class="Delimiter">();</span>
<span id="L20" class="LineNr"> 20 </span> <span class="Identifier">return</span> <span class="Constant">1</span><span class="Delimiter">;</span>
<span id="L21" class="LineNr"> 21 </span><span class="Delimiter">}</span>
<span id="L22" class="LineNr"> 22 </span>
<span id="L23" class="LineNr"> 23 </span><span class="Delimiter">:(code)</span>
<span id="L24" class="LineNr"> 24 </span><span class="Normal">void</span> <a href='012elf.cc.html#L24'>load_elf</a><span class="Delimiter">(</span><span class="Normal">const</span> string& 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="L25" class="LineNr"> 25 </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="L26" class="LineNr"> 26 </span> <span class="Normal">if</span> <span class="Delimiter">(</span>fd < <span class="Constant">0</span><span class="Delimiter">)</span> <a href='003trace.cc.html#L228'>raise</a> << filename<span class="Delimiter">.</span>c_str<span class="Delimiter">()</span> << <span class="Constant">": open"</span> << <a href='012elf.cc.html#L179'>perr</a><span class="Delimiter">()</span> << <span class="cSpecial">'\n'</span> << <a href='003trace.cc.html#L173'>die</a><span class="Delimiter">();</span>
<span id="L27" class="LineNr"> 27 </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="L28" class="LineNr"> 28 </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="L29" class="LineNr"> 29 </span> <span class="Normal">uint8_t</span>* elf_contents = <span class="Normal">static_cast</span><<span class="Normal">uint8_t</span>*><span class="Delimiter">(</span>malloc<span class="Delimiter">(</span>size<span class="Delimiter">));</span>
<span id="L30" class="LineNr"> 30 </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#L228'>raise</a> << <span class="Constant">"malloc("</span> << size << <span class="Constant">')'</span> << <a href='012elf.cc.html#L179'>perr</a><span class="Delimiter">()</span> << <span class="cSpecial">'\n'</span> << <a href='003trace.cc.html#L173'>die</a><span class="Delimiter">();</span>
<span id="L31" class="LineNr"> 31 </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="L32" class="LineNr"> 32 </span> <span class="Normal">if</span> <span class="Delimiter">(</span>size != read_size<span class="Delimiter">)</span> <a href='003trace.cc.html#L228'>raise</a> << <span class="Constant">"read → "</span> << size << <span class="Constant">" (!= "</span> << read_size << <span class="Constant">')'</span> << <a href='012elf.cc.html#L179'>perr</a><span class="Delimiter">()</span> << <span class="cSpecial">'\n'</span> << <a href='003trace.cc.html#L173'>die</a><span class="Delimiter">();</span>
<span id="L33" class="LineNr"> 33 </span> <a href='012elf.cc.html#L37'>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="L34" class="LineNr"> 34 </span> free<span class="Delimiter">(</span>elf_contents<span class="Delimiter">);</span>
<span id="L35" class="LineNr"> 35 </span><span class="Delimiter">}</span>
<span id="L36" class="LineNr"> 36 </span>
<span id="L37" class="LineNr"> 37 </span><span class="Normal">void</span> <a href='012elf.cc.html#L37'>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="L38" class="LineNr"> 38 </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="L39" class="LineNr"> 39 </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="L40" class="LineNr"> 40 </span> <span class="Normal">if</span> <span class="Delimiter">(</span>memcmp<span class="Delimiter">(</span>magic<span class="Delimiter">,</span> <span class="Constant">"\177ELF"</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="L41" class="LineNr"> 41 </span> <a href='003trace.cc.html#L228'>raise</a> << <span class="Constant">"Invalid ELF file; starts with \"" << magic << '"</span>' << <a href='003trace.cc.html#L173'>die</a><span class="Delimiter">();</span>
<span id="L42" class="LineNr"> 42 </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="L43" class="LineNr"> 43 </span> <a href='003trace.cc.html#L228'>raise</a> << <span class="Constant">"Only 32-bit ELF files (4-byte words; virtual addresses up to 4GB) supported.\n"</span> << <a href='003trace.cc.html#L173'>die</a><span class="Delimiter">();</span>
<span id="L44" class="LineNr"> 44 </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="L45" class="LineNr"> 45 </span> <a href='003trace.cc.html#L228'>raise</a> << <span class="Constant">"Only little-endian ELF files supported.\n"</span> << <a href='003trace.cc.html#L173'>die</a><span class="Delimiter">();</span>
<span id="L46" class="LineNr"> 46 </span> <span class="Comment">// unused: remaining 10 bytes of e_ident</span>
<span id="L47" class="LineNr"> 47 </span> <span class="Normal">uint32_t</span> e_machine_type = <a href='012elf.cc.html#L170'>u32_in</a><span class="Delimiter">(</span>&elf_contents[<span class="Constant">16</span>]<span class="Delimiter">);</span>
<span id="L48" class="LineNr"> 48 </span> <span class="Normal">if</span> <span class="Delimiter">(</span>e_machine_type != <span class="Constant">0x00030002</span><span class="Delimiter">)</span>
<span id="L49" class="LineNr"> 49 </span> <a href='003trace.cc.html#L228'>raise</a> << <span class="Constant">"ELF type/machine 0x"</span> << <a href='010---vm.cc.html#L395'>HEXWORD</a> << e_machine_type << <span class="Constant">" isn't i386 executable\n"</span> << die<span class="Delimiter">();</span>
<span id="L50" class="LineNr"> 50 </span> <span class="Comment">// unused: e_version. We only support version 1, and later versions will be backwards compatible.</span>
<span id="L51" class="LineNr"> 51 </span> <span class="Normal">uint32_t</span> e_entry = <a href='012elf.cc.html#L170'>u32_in</a><span class="Delimiter">(</span>&elf_contents[<span class="Constant">24</span>]<span class="Delimiter">);</span>
<span id="L52" class="LineNr"> 52 </span> <span class="Normal">uint32_t</span> e_phoff = <a href='012elf.cc.html#L170'>u32_in</a><span class="Delimiter">(</span>&elf_contents[<span class="Constant">28</span>]<span class="Delimiter">);</span>
<span id="L53" class="LineNr"> 53 </span> <span class="Comment">// unused: e_shoff</span>
<span id="L54" class="LineNr"> 54 </span> <span class="Comment">// unused: e_flags</span>
<span id="L55" class="LineNr"> 55 </span> <span class="Normal">uint32_t</span> e_ehsize = <a href='012elf.cc.html#L174'>u16_in</a><span class="Delimiter">(</span>&elf_contents[<span class="Constant">40</span>]<span class="Delimiter">);</span>
<span id="L56" class="LineNr"> 56 </span> <span class="Normal">if</span> <span class="Delimiter">(</span>e_ehsize < <span class="Constant">52</span><span class="Delimiter">)</span> <a href='003trace.cc.html#L228'>raise</a> << <span class="Constant">"Invalid binary; ELF header too small\n"</span> << <a href='003trace.cc.html#L173'>die</a><span class="Delimiter">();</span>
<span id="L57" class="LineNr"> 57 </span> <span class="Normal">uint32_t</span> e_phentsize = <a href='012elf.cc.html#L174'>u16_in</a><span class="Delimiter">(</span>&elf_contents[<span class="Constant">42</span>]<span class="Delimiter">);</span>
<span id="L58" class="LineNr"> 58 </span> <span class="Normal">uint32_t</span> e_phnum = <a href='012elf.cc.html#L174'>u16_in</a><span class="Delimiter">(</span>&elf_contents[<span class="Constant">44</span>]<span class="Delimiter">);</span>
<span id="L59" class="LineNr"> 59 </span> <a href='003trace.cc.html#L96'>trace</a><span class="Delimiter">(</span><span class="Constant">90</span><span class="Delimiter">,</span> <span class="Constant">"load"</span><span class="Delimiter">)</span> << e_phnum << <span class="Constant">" entries in the program header, each "</span> << e_phentsize << <span class="Constant">" bytes long"</span> << end<span class="Delimiter">();</span>
<span id="L60" class="LineNr"> 60 </span> <span class="Comment">// unused: e_shentsize</span>
<span id="L61" class="LineNr"> 61 </span> <span class="Comment">// unused: e_shnum</span>
<span id="L62" class="LineNr"> 62 </span> <span class="Comment">// unused: e_shstrndx</span>
<span id="L63" class="LineNr"> 63 </span>
<span id="L64" class="LineNr"> 64 </span> set<<span class="Normal">uint32_t</span>> overlap<span class="Delimiter">;</span> <span class="Comment">// to detect overlapping segments</span>
<span id="L65" class="LineNr"> 65 </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 < e_phnum<span class="Delimiter">;</span> ++i<span class="Delimiter">)</span>
<span id="L66" class="LineNr"> 66 </span> <a href='012elf.cc.html#L107'>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="L67" class="LineNr"> 67 </span>
<span id="L68" class="LineNr"> 68 </span> <span class="Comment">// initialize code and stack</span>
<span id="L69" class="LineNr"> 69 </span> assert<span class="Delimiter">(</span>overlap<span class="Delimiter">.</span>find<span class="Delimiter">(</span><a href='012elf.cc.html#L152'>STACK_SEGMENT</a><span class="Delimiter">)</span> == overlap<span class="Delimiter">.</span>end<span class="Delimiter">());</span>
<span id="L70" class="LineNr"> 70 </span> <span class="Special"><a href='010---vm.cc.html#L154'>Mem</a></span><span class="Delimiter">.</span>push_back<span class="Delimiter">(</span>vma<span class="Delimiter">(</span><a href='012elf.cc.html#L152'>STACK_SEGMENT</a><span class="Delimiter">));</span>
<span id="L71" class="LineNr"> 71 </span> assert<span class="Delimiter">(</span>overlap<span class="Delimiter">.</span>find<span class="Delimiter">(</span><a href='012elf.cc.html#L153'>AFTER_STACK</a><span class="Delimiter">)</span> == overlap<span class="Delimiter">.</span>end<span class="Delimiter">());</span>
<span id="L72" class="LineNr"> 72 </span> <span class="Comment">// The stack grows downward.</span>
<span id="L73" class="LineNr"> 73 </span> <span class="Special"><a href='010---vm.cc.html#L25'>Reg</a></span>[ESP]<span class="Delimiter">.</span>u = <a href='012elf.cc.html#L153'>AFTER_STACK</a><span class="Delimiter">;</span>
<span id="L74" class="LineNr"> 74 </span> <span class="Special"><a href='010---vm.cc.html#L25'>Reg</a></span>[EBP]<span class="Delimiter">.</span>u = <span class="Constant">0</span><span class="Delimiter">;</span>
<span id="L75" class="LineNr"> 75 </span> <a href='010---vm.cc.html#L26'>EIP</a> = e_entry<span class="Delimiter">;</span>
<span id="L76" class="LineNr"> 76 </span>
<span id="L77" class="LineNr"> 77 </span> <span class="Comment">// initialize args on stack</span>
<span id="L78" class="LineNr"> 78 </span> <span class="Comment">// no envp for now</span>
<span id="L79" class="LineNr"> 79 </span> <span class="Comment">// we wastefully use a separate page of memory for argv</span>
<span id="L80" class="LineNr"> 80 </span> <span class="Special"><a href='010---vm.cc.html#L154'>Mem</a></span><span class="Delimiter">.</span>push_back<span class="Delimiter">(</span>vma<span class="Delimiter">(</span><a href='012elf.cc.html#L154'>ARGV_DATA_SEGMENT</a><span class="Delimiter">));</span>
<span id="L81" class="LineNr"> 81 </span> <span class="Normal">uint32_t</span> argv_data = <a href='012elf.cc.html#L154'>ARGV_DATA_SEGMENT</a><span class="Delimiter">;</span>
<span id="L82" class="LineNr"> 82 </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 >= <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="L83" class="LineNr"> 83 </span> <a href='012elf.cc.html#L94'>push</a><span class="Delimiter">(</span>argv_data<span class="Delimiter">);</span>
<span id="L84" class="LineNr"> 84 </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 <= strlen<span class="Delimiter">(</span>argv[i]<span class="Delimiter">);</span> ++j<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L85" class="LineNr"> 85 </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="L86" class="LineNr"> 86 </span> <a href='010---vm.cc.html#L231'>write_mem_u8</a><span class="Delimiter">(</span>argv_data<span class="Delimiter">,</span> argv[i][j]<span class="Delimiter">);</span>
<span id="L87" class="LineNr"> 87 </span> argv_data += <span class="Normal">sizeof</span><span class="Delimiter">(</span><span class="Normal">char</span><span class="Delimiter">);</span>
<span id="L88" class="LineNr"> 88 </span> assert<span class="Delimiter">(</span>argv_data < <a href='012elf.cc.html#L154'>ARGV_DATA_SEGMENT</a> + <a href='010---vm.cc.html#L89'>SEGMENT_ALIGNMENT</a><span class="Delimiter">);</span>
<span id="L89" class="LineNr"> 89 </span> <span class="Delimiter">}</span>
<span id="L90" class="LineNr"> 90 </span> <span class="Delimiter">}</span>
<span id="L91" class="LineNr"> 91 </span> <a href='012elf.cc.html#L94'>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="L92" class="LineNr"> 92 </span><span class="Delimiter">}</span>
<span id="L93" class="LineNr"> 93 </span>
<span id="L94" class="LineNr"> 94 </span><span class="Normal">void</span> <a href='012elf.cc.html#L94'>push</a><span class="Delimiter">(</span><span class="Normal">uint32_t</span> val<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L95" class="LineNr"> 95 </span> <span class="Special"><a href='010---vm.cc.html#L25'>Reg</a></span>[ESP]<span class="Delimiter">.</span>u -= <span class="Constant">4</span><span class="Delimiter">;</span>
<span id="L96" class="LineNr"> 96 </span> <span class="Normal">if</span> <span class="Delimiter">(</span><span class="Special"><a href='010---vm.cc.html#L25'>Reg</a></span>[ESP]<span class="Delimiter">.</span>u < <a href='012elf.cc.html#L152'>STACK_SEGMENT</a><span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L97" class="LineNr"> 97 </span> <a href='003trace.cc.html#L228'>raise</a> << <span class="Constant">"The stack overflowed its segment. "</span>
<span id="L98" class="LineNr"> 98 </span> << <span class="Constant">"Maybe SPACE_FOR_SEGMENT should be larger? "</span>
<span id="L99" class="LineNr"> 99 </span> << <span class="Constant">"Or you need to carve out an exception for the stack segment "</span>
<span id="L100" class="LineNr">100 </span> << <span class="Constant">"to be larger.\n"</span> << <a href='003trace.cc.html#L173'>die</a><span class="Delimiter">();</span>
<span id="L101" class="LineNr">101 </span> <span class="Delimiter">}</span>
<span id="L102" class="LineNr">102 </span> <a href='003trace.cc.html#L96'>trace</a><span class="Delimiter">(</span><span class="Special">Callstack_depth</span>+<span class="Constant">1</span><span class="Delimiter">,</span> <span class="Constant">"run"</span><span class="Delimiter">)</span> << <span class="Constant">"decrementing <a href='010---vm.cc.html#L14'>ESP</a> to 0x"</span> << <a href='010---vm.cc.html#L395'>HEXWORD</a> << <span class="Special"><a href='010---vm.cc.html#L25'>Reg</a></span>[ESP]<span class="Delimiter">.</span>u << end<span class="Delimiter">();</span>
<span id="L103" class="LineNr">103 </span> <a href='003trace.cc.html#L96'>trace</a><span class="Delimiter">(</span><span class="Special">Callstack_depth</span>+<span class="Constant">1</span><span class="Delimiter">,</span> <span class="Constant">"run"</span><span class="Delimiter">)</span> << <span class="Constant">"pushing value 0x"</span> << <a href='010---vm.cc.html#L395'>HEXWORD</a> << val << end<span class="Delimiter">();</span>
<span id="L104" class="LineNr">104 </span> <a href='010---vm.cc.html#L239'>write_mem_u32</a><span class="Delimiter">(</span><span class="Special"><a href='010---vm.cc.html#L25'>Reg</a></span>[ESP]<span class="Delimiter">.</span>u<span class="Delimiter">,</span> val<span class="Delimiter">);</span>
<span id="L105" class="LineNr">105 </span><span class="Delimiter">}</span>
<span id="L106" class="LineNr">106 </span>
<span id="L107" class="LineNr">107 </span><span class="Normal">void</span> <a href='012elf.cc.html#L107'>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<<span class="Normal">uint32_t</span>>& overlap<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L108" class="LineNr">108 </span> <span class="Normal">uint32_t</span> p_type = <a href='012elf.cc.html#L170'>u32_in</a><span class="Delimiter">(</span>&elf_contents[offset]<span class="Delimiter">);</span>
<span id="L109" class="LineNr">109 </span> <a href='003trace.cc.html#L96'>trace</a><span class="Delimiter">(</span><span class="Constant">90</span><span class="Delimiter">,</span> <span class="Constant">"load"</span><span class="Delimiter">)</span> << <span class="Constant">"program header at offset "</span> << offset << <span class="Constant">": type "</span> << p_type << end<span class="Delimiter">();</span>
<span id="L110" class="LineNr">110 </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="L111" class="LineNr">111 </span> <a href='003trace.cc.html#L96'>trace</a><span class="Delimiter">(</span><span class="Constant">90</span><span class="Delimiter">,</span> <span class="Constant">"load"</span><span class="Delimiter">)</span> << <span class="Constant">"ignoring segment at offset "</span> << offset << <span class="Constant">" of non PT_LOAD type "</span> << p_type << <span class="Constant">" (see <a href="http://refspecs.linuxbase.org/elf/elf.pdf)">http://refspecs.linuxbase.org/elf/elf.pdf)</a>"</span> << end<span class="Delimiter">();</span>
<span id="L112" class="LineNr">112 </span> <span class="Identifier">return</span><span class="Delimiter">;</span>
<span id="L113" class="LineNr">113 </span> <span class="Delimiter">}</span>
<span id="L114" class="LineNr">114 </span> <span class="Normal">uint32_t</span> p_offset = <a href='012elf.cc.html#L170'>u32_in</a><span class="Delimiter">(</span>&elf_contents[offset + <span class="Constant">4</span>]<span class="Delimiter">);</span>
<span id="L115" class="LineNr">115 </span> <span class="Normal">uint32_t</span> p_vaddr = <a href='012elf.cc.html#L170'>u32_in</a><span class="Delimiter">(</span>&elf_contents[offset + <span class="Constant">8</span>]<span class="Delimiter">);</span>
<span id="L116" class="LineNr">116 </span> <span class="Normal">if</span> <span class="Delimiter">(</span>e_ehsize > p_vaddr<span class="Delimiter">)</span> <a href='003trace.cc.html#L228'>raise</a> << <span class="Constant">"Invalid binary; program header overlaps ELF header\n"</span> << <a href='003trace.cc.html#L173'>die</a><span class="Delimiter">();</span>
<span id="L117" class="LineNr">117 </span> <span class="Comment">// unused: p_paddr</span>
<span id="L118" class="LineNr">118 </span> <span class="Normal">uint32_t</span> p_filesz = <a href='012elf.cc.html#L170'>u32_in</a><span class="Delimiter">(</span>&elf_contents[offset + <span class="Constant">16</span>]<span class="Delimiter">);</span>
<span id="L119" class="LineNr">119 </span> <span class="Normal">uint32_t</span> p_memsz = <a href='012elf.cc.html#L170'>u32_in</a><span class="Delimiter">(</span>&elf_contents[offset + <span class="Constant">20</span>]<span class="Delimiter">);</span>
<span id="L120" class="LineNr">120 </span> <span class="Normal">if</span> <span class="Delimiter">(</span>p_filesz != p_memsz<span class="Delimiter">)</span>
<span id="L121" class="LineNr">121 </span> <a href='003trace.cc.html#L228'>raise</a> << <span class="Constant">"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"</span> << die<span class="Delimiter">();</span>
<span id="L122" class="LineNr">122 </span>
<span id="L123" class="LineNr">123 </span> <span class="Normal">if</span> <span class="Delimiter">(</span>p_offset + p_filesz > size<span class="Delimiter">)</span>
<span id="L124" class="LineNr">124 </span> <a href='003trace.cc.html#L228'>raise</a> << <span class="Constant">"Invalid binary; segment at offset "</span> << offset << <span class="Constant">" is too large: wants to end at "</span> << p_offset+p_filesz << <span class="Constant">" but the file ends at "</span> << size << <span class="cSpecial">'\n'</span> << <a href='003trace.cc.html#L173'>die</a><span class="Delimiter">();</span>
<span id="L125" class="LineNr">125 </span> <span class="Normal">if</span> <span class="Delimiter">(</span>p_memsz >= <a href='010---vm.cc.html#L89'>SEGMENT_ALIGNMENT</a><span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L126" class="LineNr">126 </span> <a href='003trace.cc.html#L228'>raise</a> << <span class="Constant">"Code segment too small for SubX; for now please manually increase SEGMENT_ALIGNMENT.\n"</span> << end<span class="Delimiter">();</span>
<span id="L127" class="LineNr">127 </span> <span class="Identifier">return</span><span class="Delimiter">;</span>
<span id="L128" class="LineNr">128 </span> <span class="Delimiter">}</span>
<span id="L129" class="LineNr">129 </span> <a href='003trace.cc.html#L96'>trace</a><span class="Delimiter">(</span><span class="Constant">90</span><span class="Delimiter">,</span> <span class="Constant">"load"</span><span class="Delimiter">)</span> << <span class="Constant">"blitting file offsets ("</span> << p_offset << <span class="Constant">", "</span> << <span class="Delimiter">(</span>p_offset+p_filesz<span class="Delimiter">)</span> << <span class="Constant">") to addresses ("</span> << p_vaddr << <span class="Constant">", "</span> << <span class="Delimiter">(</span>p_vaddr+p_memsz<span class="Delimiter">)</span> << <span class="Constant">')'</span> << end<span class="Delimiter">();</span>
<span id="L130" class="LineNr">130 </span> <span class="Normal">if</span> <span class="Delimiter">(</span>size > p_memsz<span class="Delimiter">)</span> size = p_memsz<span class="Delimiter">;</span>
<span id="L131" class="LineNr">131 </span> <span class="Special"><a href='010---vm.cc.html#L154'>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="L132" class="LineNr">132 </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 < p_filesz<span class="Delimiter">;</span> ++i<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L133" class="LineNr">133 </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="L134" class="LineNr">134 </span> <a href='010---vm.cc.html#L231'>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="L135" class="LineNr">135 </span> overlap<span class="Delimiter">.</span>insert<span class="Delimiter">(</span>p_vaddr+i<span class="Delimiter">);</span>
<span id="L136" class="LineNr">136 </span> <span class="Delimiter">}</span>
<span id="L137" class="LineNr">137 </span> <span class="Normal">if</span> <span class="Delimiter">(</span>segment_index == <span class="Constant">0</span> && <span class="Special"><a href='010---vm.cc.html#L157'>End_of_program</a></span> < p_vaddr+p_memsz<span class="Delimiter">)</span>
<span id="L138" class="LineNr">138 </span> <span class="Special"><a href='010---vm.cc.html#L157'>End_of_program</a></span> = p_vaddr+p_memsz<span class="Delimiter">;</span>
<span id="L139" class="LineNr">139 </span><span class="Delimiter">}</span>
<span id="L140" class="LineNr">140 </span>
<span id="L141" class="LineNr">141 </span><span class="Delimiter">:(before "End Includes")</span>
<span id="L142" class="LineNr">142 </span><span class="Comment">// Very primitive/fixed/insecure ELF segments for now.</span>
<span id="L143" class="LineNr">143 </span><span class="Comment">// --- inaccessible: 0x00000000 -> 0x08047fff</span>
<span id="L144" class="LineNr">144 </span><span class="Comment">// code: 0x09000000 -> 0x09ffffff (specified in ELF binary)</span>
<span id="L145" class="LineNr">145 </span><span class="Comment">// data: 0x0a000000 -> 0x0affffff (specified in ELF binary)</span>
<span id="L146" class="LineNr">146 </span><span class="Comment">// --- heap gets mmap'd somewhere here ---</span>
<span id="L147" class="LineNr">147 </span><span class="Comment">// stack: 0xbdffffff -> 0xbd000000 (downward; not in ELF binary)</span>
<span id="L148" class="LineNr">148 </span><span class="Comment">// argv hack: 0xbf000000 -> 0xbfffffff (not in ELF binary)</span>
<span id="L149" class="LineNr">149 </span><span class="Comment">// --- reserved for kernel: 0xc0000000 -> ...</span>
<span id="L150" class="LineNr">150 </span><span class="Normal">const</span> <span class="Normal">uint32_t</span> <a href='012elf.cc.html#L150'>START_HEAP</a> = <span class="Constant">0x0b000000</span><span class="Delimiter">;</span>
<span id="L151" class="LineNr">151 </span><span class="Normal">const</span> <span class="Normal">uint32_t</span> <a href='012elf.cc.html#L151'>END_HEAP</a> = <span class="Constant">0xbd000000</span><span class="Delimiter">;</span>
<span id="L152" class="LineNr">152 </span><span class="Normal">const</span> <span class="Normal">uint32_t</span> <a href='012elf.cc.html#L152'>STACK_SEGMENT</a> = <span class="Constant">0xbd000000</span><span class="Delimiter">;</span>
<span id="L153" class="LineNr">153 </span><span class="Normal">const</span> <span class="Normal">uint32_t</span> <a href='012elf.cc.html#L153'>AFTER_STACK</a> = <span class="Constant">0xbe000000</span><span class="Delimiter">;</span>
<span id="L154" class="LineNr">154 </span><span class="Normal">const</span> <span class="Normal">uint32_t</span> <a href='012elf.cc.html#L154'>ARGV_DATA_SEGMENT</a> = <span class="Constant">0xbf000000</span><span class="Delimiter">;</span>
<span id="L155" class="LineNr">155 </span><span class="Comment">// When updating the above memory map, don't forget to update `mmap`'s</span>
<span id="L156" class="LineNr">156 </span><span class="Comment">// implementation in the 'syscalls' layer.</span>
<span id="L157" class="LineNr">157 </span><span class="Delimiter">:(before "End Dump Info for Instruction")</span>
<span id="L158" class="LineNr">158 </span><span class="CommentedCode">//? dump_stack(); // slow</span>
<span id="L159" class="LineNr">159 </span><span class="Delimiter">:(code)</span>
<span id="L160" class="LineNr">160 </span><span class="Normal">void</span> <a href='012elf.cc.html#L160'>dump_stack</a><span class="Delimiter">()</span> <span class="Delimiter">{</span>
<span id="L161" class="LineNr">161 </span> ostringstream out<span class="Delimiter">;</span>
<span id="L162" class="LineNr">162 </span> <a href='003trace.cc.html#L96'>trace</a><span class="Delimiter">(</span><span class="Special">Callstack_depth</span>+<span class="Constant">1</span><span class="Delimiter">,</span> <span class="Constant">"run"</span><span class="Delimiter">)</span> << <span class="Constant">"stack:"</span> << end<span class="Delimiter">();</span>
<span id="L163" class="LineNr">163 </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 > <span class="Special"><a href='010---vm.cc.html#L25'>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="L164" class="LineNr">164 </span> <a href='003trace.cc.html#L96'>trace</a><span class="Delimiter">(</span><span class="Special">Callstack_depth</span>+<span class="Constant">2</span><span class="Delimiter">,</span> <span class="Constant">"run"</span><span class="Delimiter">)</span> << <span class="Constant">" 0x"</span> << <a href='010---vm.cc.html#L395'>HEXWORD</a> << a << <span class="Constant">" => 0x"</span> << <a href='010---vm.cc.html#L395'>HEXWORD</a> << <a href='010---vm.cc.html#L172'>read_mem_u32</a><span class="Delimiter">(</span>a<span class="Delimiter">)</span> << end<span class="Delimiter">();</span>
<span id="L165" class="LineNr">165 </span> <a href='003trace.cc.html#L96'>trace</a><span class="Delimiter">(</span><span class="Special">Callstack_depth</span>+<span class="Constant">2</span><span class="Delimiter">,</span> <span class="Constant">"run"</span><span class="Delimiter">)</span> << <span class="Constant">" 0x"</span> << <a href='010---vm.cc.html#L395'>HEXWORD</a> << <span class="Special"><a href='010---vm.cc.html#L25'>Reg</a></span>[ESP]<span class="Delimiter">.</span>u << <span class="Constant">" => 0x"</span> << <a href='010---vm.cc.html#L395'>HEXWORD</a> << <a href='010---vm.cc.html#L172'>read_mem_u32</a><span class="Delimiter">(</span><span class="Special"><a href='010---vm.cc.html#L25'>Reg</a></span>[ESP]<span class="Delimiter">.</span>u<span class="Delimiter">)</span> << <span class="Constant">" <=== ESP"</span> << end<span class="Delimiter">();</span>
<span id="L166" class="LineNr">166 </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#L25'>Reg</a></span>[ESP]<span class="Delimiter">.</span>u-<span class="Constant">4</span><span class="Delimiter">;</span> a > <span class="Special"><a href='010---vm.cc.html#L25'>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="L167" class="LineNr">167 </span> <a href='003trace.cc.html#L96'>trace</a><span class="Delimiter">(</span><span class="Special">Callstack_depth</span>+<span class="Constant">2</span><span class="Delimiter">,</span> <span class="Constant">"run"</span><span class="Delimiter">)</span> << <span class="Constant">" 0x"</span> << <a href='010---vm.cc.html#L395'>HEXWORD</a> << a << <span class="Constant">" => 0x"</span> << <a href='010---vm.cc.html#L395'>HEXWORD</a> << <a href='010---vm.cc.html#L172'>read_mem_u32</a><span class="Delimiter">(</span>a<span class="Delimiter">)</span> << end<span class="Delimiter">();</span>
<span id="L168" class="LineNr">168 </span><span class="Delimiter">}</span>
<span id="L169" class="LineNr">169 </span>
<span id="L170" class="LineNr">170 </span><span class="Normal">inline</span> <span class="Normal">uint32_t</span> <a href='012elf.cc.html#L170'>u32_in</a><span class="Delimiter">(</span><span class="Normal">uint8_t</span>* p<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L171" class="LineNr">171 </span> <span class="Identifier">return</span> p[<span class="Constant">0</span>] | p[<span class="Constant">1</span>] << <span class="Constant">8</span> | p[<span class="Constant">2</span>] << <span class="Constant">16</span> | p[<span class="Constant">3</span>] << <span class="Constant">24</span><span class="Delimiter">;</span>
<span id="L172" class="LineNr">172 </span><span class="Delimiter">}</span>
<span id="L173" class="LineNr">173 </span>
<span id="L174" class="LineNr">174 </span><span class="Normal">inline</span> <span class="Normal">uint16_t</span> <a href='012elf.cc.html#L174'>u16_in</a><span class="Delimiter">(</span><span class="Normal">uint8_t</span>* p<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L175" class="LineNr">175 </span> <span class="Identifier">return</span> p[<span class="Constant">0</span>] | p[<span class="Constant">1</span>] << <span class="Constant">8</span><span class="Delimiter">;</span>
<span id="L176" class="LineNr">176 </span><span class="Delimiter">}</span>
<span id="L177" class="LineNr">177 </span>
<span id="L178" class="LineNr">178 </span><span class="Delimiter">:(before "End Types")</span>
<span id="L179" class="LineNr">179 </span><span class="Normal">struct</span> <a href='012elf.cc.html#L179'>perr</a> <span class="Delimiter">{};</span>
<span id="L180" class="LineNr">180 </span><span class="Delimiter">:(code)</span>
<span id="L181" class="LineNr">181 </span>ostream& <span class="Normal">operator</span><<<span class="Delimiter">(</span>ostream& os<span class="Delimiter">,</span> <a href='012elf.cc.html#L179'>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="L182" class="LineNr">182 </span> <span class="Normal">if</span> <span class="Delimiter">(</span>errno<span class="Delimiter">)</span>
<span id="L183" class="LineNr">183 </span> os << <span class="Constant">": "</span> << strerror<span class="Delimiter">(</span>errno<span class="Delimiter">);</span>
<span id="L184" class="LineNr">184 </span> <span class="Identifier">return</span> os<span class="Delimiter">;</span>
<span id="L185" class="LineNr">185 </span><span class="Delimiter">}</span>
<span id="L186" class="LineNr">186 </span>
<span id="L187" class="LineNr">187 </span><span class="Delimiter">:(before "End Includes")</span>
<span id="L188" class="LineNr">188 </span><span class="PreProc">#include </span><span class="Constant"><sys/types.h></span>
<span id="L189" class="LineNr">189 </span><span class="PreProc">#include </span><span class="Constant"><sys/stat.h></span>
<span id="L190" class="LineNr">190 </span><span class="PreProc">#include </span><span class="Constant"><fcntl.h></span>
<span id="L191" class="LineNr">191 </span><span class="PreProc">#include </span><span class="Constant"><stdarg.h></span>
<span id="L192" class="LineNr">192 </span><span class="PreProc">#include </span><span class="Constant"><errno.h></span>
<span id="L193" class="LineNr">193 </span><span class="PreProc">#include </span><span class="Constant"><unistd.h></span>
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