From c01289dddea2398fe7f4335f5d0babc4a9e789c5 Mon Sep 17 00:00:00 2001 From: Kartik Agaram Date: Mon, 9 Nov 2020 21:16:09 -0800 Subject: 7218 This bug was incredibly painful to track down: the one-line fix is to replace 'line' with 'first-line' in the call to 'evaluate' in render-line before recursing. Things that made it challenging: - A high degree of coiling with recursive calls and multiple places of evaluation. - An accidental aliasing in bindings (when rendering the main column in render-line) that masked the underlying bug and made things seem to work most of the time. - Too many fucking arguments to render-line, a maze of twisty line objects all alike. --- apps/tile/environment.mu | 35 +++++++++++++++++++++++++++++++---- 1 file changed, 31 insertions(+), 4 deletions(-) (limited to 'apps/tile/environment.mu') diff --git a/apps/tile/environment.mu b/apps/tile/environment.mu index 597cad95..d9718525 100644 --- a/apps/tile/environment.mu +++ b/apps/tile/environment.mu @@ -1276,7 +1276,8 @@ fn call-path-element-length _x: (addr handle call-path-element) -> _/eax: int { # # Along the way, compute the column the cursor should be positioned at (cursor-col-addr). fn render-line screen: (addr screen), functions: (addr handle function), bindings: (addr table), first-line: (addr line), _line: (addr line), expanded-words: (addr handle call-path), top-row: int, left-col: int, curr-path: (addr handle call-path-element), cursor-word: (addr word), cursor-call-path: (addr handle call-path-element), cursor-row-addr: (addr int), cursor-col-addr: (addr int) -> _/ecx: int { -#? print-string 0, "--\n" + print-string 0, "## render-line: " + dump-table bindings # curr-word var line/esi: (addr line) <- copy _line var first-word-ah/eax: (addr handle word) <- get line, data @@ -1290,6 +1291,9 @@ fn render-line screen: (addr screen), functions: (addr handle function), binding { compare curr-word, 0 break-if-= + print-string 0, "-- word " + print-word 0, curr-word + print-string 0, "\n" #? print-string 0, "-- word in final line: " #? { #? var foo/eax: int <- copy curr-word @@ -1326,6 +1330,8 @@ fn render-line screen: (addr screen), functions: (addr handle function), binding increment top-row } # obtain stack at call site + print-string 0, "sub 0 bindings: " + dump-table bindings var stack-storage: value-stack var stack/edx: (addr value-stack) <- address stack-storage initialize-value-stack stack, 0x10 @@ -1334,8 +1340,12 @@ fn render-line screen: (addr screen), functions: (addr handle function), binding var prev-word/eax: (addr word) <- lookup *prev-word-ah compare prev-word, 0 break-if-= - evaluate functions, bindings, line, prev-word, stack + print-string 0, "sub 1 bindings: " + dump-table bindings + evaluate functions, bindings, first-line, prev-word, stack } + print-string 0, "sub 2 bindings: " + dump-table bindings # construct new bindings var callee-bindings-storage: table var callee-bindings/esi: (addr table) <- address callee-bindings-storage @@ -1347,7 +1357,11 @@ fn render-line screen: (addr screen), functions: (addr handle function), binding var callee-body-first-word/edx: (addr handle word) <- get callee-body, data # - render subsidiary stack push-to-call-path-element curr-path, callee-body-first-word # leak + print-string 0, "subsidiary { " + dump-table callee-bindings + syscall_exit curr-col <- render-line screen, functions, callee-bindings, callee-body, callee-body, expanded-words, top-row, curr-col, curr-path, cursor-word, cursor-call-path, cursor-row-addr, cursor-col-addr + print-string 0, "}\n" drop-from-call-path-element curr-path # move-cursor screen, top-row, curr-col @@ -1363,10 +1377,23 @@ fn render-line screen: (addr screen), functions: (addr handle function), binding #? print-string 0, "rendering column from " #? print-int32-decimal 0, curr-col #? print-string 0, "\n" + print-string 0, "main 0 bindings: " + dump-table bindings var bindings2-storage: table var bindings2/ebx: (addr table) <- address bindings2-storage shallow-copy-table-values bindings, bindings2 + print-string 0, "main 1 bindings: " + dump-table bindings + print-string 0, "main 1 bindings2: " + dump-table bindings2 + print-string 0, "word: " + print-word 0, curr-word + print-string 0, "\n" curr-col <- render-column screen, functions, bindings2, first-line, line, curr-word, top-row, curr-col + print-string 0, "main 2 bindings: " + dump-table bindings + print-string 0, "main 2 bindings2: " + dump-table bindings2 # cache cursor column if necessary $render-line:cache-cursor-column: { #? print-string 0, "cache cursor? " @@ -1423,8 +1450,8 @@ fn callee functions: (addr handle function), word: (addr word), out: (addr handl # # Return the farthest column written. fn render-column screen: (addr screen), functions: (addr handle function), bindings: (addr table), first-line: (addr line), line: (addr line), final-word: (addr word), top-row: int, left-col: int -> _/ecx: int { -#? print-string 0, "== " -#? print-string 0, "render-column\n" + print-string 0, "render-column: " + dump-table bindings var max-width/esi: int <- copy 0 { # indent stack -- cgit 1.4.1-2-gfad0 '>7ca19e4e ^
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<a href='https://github.com/akkartik/mu/blob/master/subx/020syscalls.cc'>https://github.com/akkartik/mu/blob/master/subx/020syscalls.cc</a>
<pre id='vimCodeElement'>
<span id="L1" class="LineNr">  1 </span><span class="Delimiter">:(before &quot;End Initialize Op Names&quot;)</span>
<span id="L2" class="LineNr">  2 </span><a href='001help.cc.html#L262'>put_new</a><span class="Delimiter">(</span><span class="Special"><a href='010---vm.cc.html#L380'>Name</a></span><span class="Delimiter">,</span> <span class="Constant">&quot;cd&quot;</span><span class="Delimiter">,</span> <span class="Constant">&quot;software interrupt (int)&quot;</span><span class="Delimiter">);</span>
<span id="L3" class="LineNr">  3 </span>
<span id="L4" class="LineNr">  4 </span><span class="Delimiter">:(before &quot;End Single-Byte Opcodes&quot;)</span>
<span id="L5" class="LineNr">  5 </span><span class="Normal">case</span> <span class="Constant">0xcd</span>: <span class="Delimiter">{</span>  <span class="Comment">// int imm8 (software interrupt)</span>
<span id="L6" class="LineNr">  6 </span>  <a href='003trace.cc.html#L98'>trace</a><span class="Delimiter">(</span><span class="Special">Callstack_depth</span>+<span class="Constant">1</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;syscall&quot;</span> &lt;&lt; end<span class="Delimiter">();</span>
<span id="L7" class="LineNr">  7 </span>  <span class="Normal">uint8_t</span> <a href='031check_operands.cc.html#L11'>code</a> = <a href='010---vm.cc.html#L363'>next</a><span class="Delimiter">();</span>
<span id="L8" class="LineNr">  8 </span>  <span class="Normal">if</span> <span class="Delimiter">(</span><a href='031check_operands.cc.html#L11'>code</a> != <span class="Constant">0x80</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L9" class="LineNr">  9 </span>    <a href='003trace.cc.html#L217'>raise</a> &lt;&lt; <span class="Constant">&quot;Unimplemented interrupt <a href='031check_operands.cc.html#L11'>code</a> &quot;</span> &lt;&lt; <a href='010---vm.cc.html#L432'>HEXBYTE</a> &lt;&lt; <a href='031check_operands.cc.html#L11'>code</a> &lt;&lt; <span class="cSpecial">'\n'</span> &lt;&lt; end<span class="Delimiter">();</span>
<span id="L10" class="LineNr"> 10 </span>    <a href='003trace.cc.html#L217'>raise</a> &lt;&lt; <span class="Constant">&quot;  Only `int 80h` supported for now.\n&quot;</span> &lt;&lt; end<span class="Delimiter">();</span>
<span id="L11" class="LineNr"> 11 </span>    <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L12" class="LineNr"> 12 </span>  <span class="Delimiter">}</span>
<span id="L13" class="LineNr"> 13 </span>  <a href='020syscalls.cc.html#L18'>process_int80</a><span class="Delimiter">();</span>
<span id="L14" class="LineNr"> 14 </span>  <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L15" class="LineNr"> 15 </span><span class="Delimiter">}</span>
<span id="L16" class="LineNr"> 16 </span>
<span id="L17" class="LineNr"> 17 </span><span class="Delimiter">:(code)</span>
<span id="L18" class="LineNr"> 18 </span><span class="Normal">void</span> <a href='020syscalls.cc.html#L18'>process_int80</a><span class="Delimiter">()</span> <span class="Delimiter">{</span>
<span id="L19" class="LineNr"> 19 </span>  <span class="Normal">switch</span> <span class="Delimiter">(</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EAX]<span class="Delimiter">.</span>u<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L20" class="LineNr"> 20 </span>  <span class="Normal">case</span> <span class="Constant">1</span>:
<span id="L21" class="LineNr"> 21 </span>    exit<span class="Delimiter">(</span><span class="Comment">/*</span><span class="Comment">exit <a href='031check_operands.cc.html#L11'>code</a></span><span class="Comment">*/</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EBX]<span class="Delimiter">.</span>u<span class="Delimiter">);</span>
<span id="L22" class="LineNr"> 22 </span>    <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L23" class="LineNr"> 23 </span>  <span class="Normal">case</span> <span class="Constant">3</span>:
<span id="L24" class="LineNr"> 24 </span>    <a href='003trace.cc.html#L98'>trace</a><span class="Delimiter">(</span><span class="Special">Callstack_depth</span>+<span class="Constant">1</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;read: &quot;</span> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EBX]<span class="Delimiter">.</span>u &lt;&lt; <span class="Constant">' '</span> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[ECX]<span class="Delimiter">.</span>u &lt;&lt; <span class="Constant">' '</span> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EDX]<span class="Delimiter">.</span>u &lt;&lt; end<span class="Delimiter">();</span>
<span id="L25" class="LineNr"> 25 </span>    <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EAX]<span class="Delimiter">.</span>i = read<span class="Delimiter">(</span><span class="Comment">/*</span><span class="Comment">file descriptor</span><span class="Comment">*/</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EBX]<span class="Delimiter">.</span>u<span class="Delimiter">,</span> <span class="Comment">/*</span><span class="Comment">memory buffer</span><span class="Comment">*/</span><a href='010---vm.cc.html#L217'>mem_addr_u8</a><span class="Delimiter">(</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[ECX]<span class="Delimiter">.</span>u<span class="Delimiter">),</span> <span class="Comment">/*</span><span class="Comment">size</span><span class="Comment">*/</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EDX]<span class="Delimiter">.</span>u<span class="Delimiter">);</span>
<span id="L26" class="LineNr"> 26 </span>    <a href='003trace.cc.html#L98'>trace</a><span class="Delimiter">(</span><span class="Special">Callstack_depth</span>+<span class="Constant">1</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;result: &quot;</span> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EAX]<span class="Delimiter">.</span>i &lt;&lt; end<span class="Delimiter">();</span>
<span id="L27" class="LineNr"> 27 </span>    <span class="Normal">if</span> <span class="Delimiter">(</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EAX]<span class="Delimiter">.</span>i == -<span class="Constant">1</span><span class="Delimiter">)</span> <a href='003trace.cc.html#L217'>raise</a> &lt;&lt; strerror<span class="Delimiter">(</span>errno<span class="Delimiter">)</span> &lt;&lt; <span class="cSpecial">'\n'</span> &lt;&lt; end<span class="Delimiter">();</span>
<span id="L28" class="LineNr"> 28 </span>    <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L29" class="LineNr"> 29 </span>  <span class="Normal">case</span> <span class="Constant">4</span>:
<span id="L30" class="LineNr"> 30 </span>    <a href='003trace.cc.html#L98'>trace</a><span class="Delimiter">(</span><span class="Special">Callstack_depth</span>+<span class="Constant">1</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;write: &quot;</span> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EBX]<span class="Delimiter">.</span>u &lt;&lt; <span class="Constant">' '</span> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[ECX]<span class="Delimiter">.</span>u &lt;&lt; <span class="Constant">' '</span> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EDX]<span class="Delimiter">.</span>u &lt;&lt; end<span class="Delimiter">();</span>
<span id="L31" class="LineNr"> 31 </span>    <a href='003trace.cc.html#L98'>trace</a><span class="Delimiter">(</span><span class="Special">Callstack_depth</span>+<span class="Constant">1</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[ECX]<span class="Delimiter">.</span>u &lt;&lt; <span class="Constant">&quot; =&gt; &quot;</span> &lt;&lt; <a href='010---vm.cc.html#L255'>mem_addr_string</a><span class="Delimiter">(</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[ECX]<span class="Delimiter">.</span>u<span class="Delimiter">,</span> <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EDX]<span class="Delimiter">.</span>u<span class="Delimiter">)</span> &lt;&lt; end<span class="Delimiter">();</span>
<span id="L32" class="LineNr"> 32 </span>    <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EAX]<span class="Delimiter">.</span>i = write<span class="Delimiter">(</span><span class="Comment">/*</span><span class="Comment">file descriptor</span><span class="Comment">*/</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EBX]<span class="Delimiter">.</span>u<span class="Delimiter">,</span> <span class="Comment">/*</span><span class="Comment">memory buffer</span><span class="Comment">*/</span><a href='010---vm.cc.html#L217'>mem_addr_u8</a><span class="Delimiter">(</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[ECX]<span class="Delimiter">.</span>u<span class="Delimiter">),</span> <span class="Comment">/*</span><span class="Comment">size</span><span class="Comment">*/</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EDX]<span class="Delimiter">.</span>u<span class="Delimiter">);</span>
<span id="L33" class="LineNr"> 33 </span>    <a href='003trace.cc.html#L98'>trace</a><span class="Delimiter">(</span><span class="Special">Callstack_depth</span>+<span class="Constant">1</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;result: &quot;</span> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EAX]<span class="Delimiter">.</span>i &lt;&lt; end<span class="Delimiter">();</span>
<span id="L34" class="LineNr"> 34 </span>    <span class="Normal">if</span> <span class="Delimiter">(</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EAX]<span class="Delimiter">.</span>i == -<span class="Constant">1</span><span class="Delimiter">)</span> <a href='003trace.cc.html#L217'>raise</a> &lt;&lt; strerror<span class="Delimiter">(</span>errno<span class="Delimiter">)</span> &lt;&lt; <span class="cSpecial">'\n'</span> &lt;&lt; end<span class="Delimiter">();</span>
<span id="L35" class="LineNr"> 35 </span>    <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L36" class="LineNr"> 36 </span>  <span class="Normal">case</span> <span class="Constant">5</span>: <span class="Delimiter">{</span>
<span id="L37" class="LineNr"> 37 </span>    <a href='020syscalls.cc.html#L93'>check_flags</a><span class="Delimiter">(</span><a href='010---vm.cc.html#L14'>ECX</a><span class="Delimiter">);</span>
<span id="L38" class="LineNr"> 38 </span>    <a href='020syscalls.cc.html#L105'>check_mode</a><span class="Delimiter">(</span><a href='010---vm.cc.html#L15'>EDX</a><span class="Delimiter">);</span>
<span id="L39" class="LineNr"> 39 </span>    <a href='003trace.cc.html#L98'>trace</a><span class="Delimiter">(</span><span class="Special">Callstack_depth</span>+<span class="Constant">1</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;open: &quot;</span> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EBX]<span class="Delimiter">.</span>u &lt;&lt; <span class="Constant">' '</span> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[ECX]<span class="Delimiter">.</span>u &lt;&lt; end<span class="Delimiter">();</span>
<span id="L40" class="LineNr"> 40 </span>    <a href='003trace.cc.html#L98'>trace</a><span class="Delimiter">(</span><span class="Special">Callstack_depth</span>+<span class="Constant">1</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EBX]<span class="Delimiter">.</span>u &lt;&lt; <span class="Constant">&quot; =&gt; &quot;</span> &lt;&lt; <a href='010---vm.cc.html#L252'>mem_addr_kernel_string</a><span class="Delimiter">(</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EBX]<span class="Delimiter">.</span>u<span class="Delimiter">)</span> &lt;&lt; end<span class="Delimiter">();</span>
<span id="L41" class="LineNr"> 41 </span>    <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EAX]<span class="Delimiter">.</span>i = open<span class="Delimiter">(</span><span class="Comment">/*</span><span class="Comment">filename</span><span class="Comment">*/</span><a href='010---vm.cc.html#L252'>mem_addr_kernel_string</a><span class="Delimiter">(</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EBX]<span class="Delimiter">.</span>u<span class="Delimiter">),</span> <span class="Comment">/*</span><span class="Comment">flags</span><span class="Comment">*/</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[ECX]<span class="Delimiter">.</span>u<span class="Delimiter">,</span> <span class="Comment">/*</span><span class="Comment">mode</span><span class="Comment">*/</span><span class="PreProc">0</span><span class="Constant">640</span><span class="Delimiter">);</span>
<span id="L42" class="LineNr"> 42 </span>    <a href='003trace.cc.html#L98'>trace</a><span class="Delimiter">(</span><span class="Special">Callstack_depth</span>+<span class="Constant">1</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;result: &quot;</span> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EAX]<span class="Delimiter">.</span>i &lt;&lt; end<span class="Delimiter">();</span>
<span id="L43" class="LineNr"> 43 </span>    <span class="Normal">if</span> <span class="Delimiter">(</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EAX]<span class="Delimiter">.</span>i == -<span class="Constant">1</span><span class="Delimiter">)</span> <a href='003trace.cc.html#L217'>raise</a> &lt;&lt; strerror<span class="Delimiter">(</span>errno<span class="Delimiter">)</span> &lt;&lt; <span class="cSpecial">'\n'</span> &lt;&lt; end<span class="Delimiter">();</span>
<span id="L44" class="LineNr"> 44 </span>    <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L45" class="LineNr"> 45 </span>  <span class="Delimiter">}</span>
<span id="L46" class="LineNr"> 46 </span>  <span class="Normal">case</span> <span class="Constant">6</span>:
<span id="L47" class="LineNr"> 47 </span>    <a href='003trace.cc.html#L98'>trace</a><span class="Delimiter">(</span><span class="Special">Callstack_depth</span>+<span class="Constant">1</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;close: &quot;</span> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EBX]<span class="Delimiter">.</span>u &lt;&lt; end<span class="Delimiter">();</span>
<span id="L48" class="LineNr"> 48 </span>    <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EAX]<span class="Delimiter">.</span>i = close<span class="Delimiter">(</span><span class="Comment">/*</span><span class="Comment">file descriptor</span><span class="Comment">*/</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EBX]<span class="Delimiter">.</span>u<span class="Delimiter">);</span>
<span id="L49" class="LineNr"> 49 </span>    <a href='003trace.cc.html#L98'>trace</a><span class="Delimiter">(</span><span class="Special">Callstack_depth</span>+<span class="Constant">1</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;result: &quot;</span> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EAX]<span class="Delimiter">.</span>i &lt;&lt; end<span class="Delimiter">();</span>
<span id="L50" class="LineNr"> 50 </span>    <span class="Normal">if</span> <span class="Delimiter">(</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EAX]<span class="Delimiter">.</span>i == -<span class="Constant">1</span><span class="Delimiter">)</span> <a href='003trace.cc.html#L217'>raise</a> &lt;&lt; strerror<span class="Delimiter">(</span>errno<span class="Delimiter">)</span> &lt;&lt; <span class="cSpecial">'\n'</span> &lt;&lt; end<span class="Delimiter">();</span>
<span id="L51" class="LineNr"> 51 </span>    <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L52" class="LineNr"> 52 </span>  <span class="Normal">case</span> <span class="Constant">8</span>:
<span id="L53" class="LineNr"> 53 </span>    <a href='020syscalls.cc.html#L105'>check_mode</a><span class="Delimiter">(</span><a href='010---vm.cc.html#L14'>ECX</a><span class="Delimiter">);</span>
<span id="L54" class="LineNr"> 54 </span>    <a href='003trace.cc.html#L98'>trace</a><span class="Delimiter">(</span><span class="Special">Callstack_depth</span>+<span class="Constant">1</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;creat: &quot;</span> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EBX]<span class="Delimiter">.</span>u &lt;&lt; end<span class="Delimiter">();</span>
<span id="L55" class="LineNr"> 55 </span>    <a href='003trace.cc.html#L98'>trace</a><span class="Delimiter">(</span><span class="Special">Callstack_depth</span>+<span class="Constant">1</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EBX]<span class="Delimiter">.</span>u &lt;&lt; <span class="Constant">&quot; =&gt; &quot;</span> &lt;&lt; <a href='010---vm.cc.html#L252'>mem_addr_kernel_string</a><span class="Delimiter">(</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EBX]<span class="Delimiter">.</span>u<span class="Delimiter">)</span> &lt;&lt; end<span class="Delimiter">();</span>
<span id="L56" class="LineNr"> 56 </span>    <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EAX]<span class="Delimiter">.</span>i = creat<span class="Delimiter">(</span><span class="Comment">/*</span><span class="Comment">filename</span><span class="Comment">*/</span><a href='010---vm.cc.html#L252'>mem_addr_kernel_string</a><span class="Delimiter">(</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EBX]<span class="Delimiter">.</span>u<span class="Delimiter">),</span> <span class="Comment">/*</span><span class="Comment">mode</span><span class="Comment">*/</span><span class="PreProc">0</span><span class="Constant">640</span><span class="Delimiter">);</span>
<span id="L57" class="LineNr"> 57 </span>    <a href='003trace.cc.html#L98'>trace</a><span class="Delimiter">(</span><span class="Special">Callstack_depth</span>+<span class="Constant">1</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;result: &quot;</span> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EAX]<span class="Delimiter">.</span>i &lt;&lt; end<span class="Delimiter">();</span>
<span id="L58" class="LineNr"> 58 </span>    <span class="Normal">if</span> <span class="Delimiter">(</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EAX]<span class="Delimiter">.</span>i == -<span class="Constant">1</span><span class="Delimiter">)</span> <a href='003trace.cc.html#L217'>raise</a> &lt;&lt; strerror<span class="Delimiter">(</span>errno<span class="Delimiter">)</span> &lt;&lt; <span class="cSpecial">'\n'</span> &lt;&lt; end<span class="Delimiter">();</span>
<span id="L59" class="LineNr"> 59 </span>    <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L60" class="LineNr"> 60 </span>  <span class="Normal">case</span> <span class="Constant">10</span>:
<span id="L61" class="LineNr"> 61 </span>    <a href='003trace.cc.html#L98'>trace</a><span class="Delimiter">(</span><span class="Special">Callstack_depth</span>+<span class="Constant">1</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;unlink: &quot;</span> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EBX]<span class="Delimiter">.</span>u &lt;&lt; end<span class="Delimiter">();</span>
<span id="L62" class="LineNr"> 62 </span>    <a href='003trace.cc.html#L98'>trace</a><span class="Delimiter">(</span><span class="Special">Callstack_depth</span>+<span class="Constant">1</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EBX]<span class="Delimiter">.</span>u &lt;&lt; <span class="Constant">&quot; =&gt; &quot;</span> &lt;&lt; <a href='010---vm.cc.html#L252'>mem_addr_kernel_string</a><span class="Delimiter">(</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EBX]<span class="Delimiter">.</span>u<span class="Delimiter">)</span> &lt;&lt; end<span class="Delimiter">();</span>
<span id="L63" class="LineNr"> 63 </span>    <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EAX]<span class="Delimiter">.</span>i = unlink<span class="Delimiter">(</span><span class="Comment">/*</span><span class="Comment">filename</span><span class="Comment">*/</span><a href='010---vm.cc.html#L252'>mem_addr_kernel_string</a><span class="Delimiter">(</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EBX]<span class="Delimiter">.</span>u<span class="Delimiter">));</span>
<span id="L64" class="LineNr"> 64 </span>    <a href='003trace.cc.html#L98'>trace</a><span class="Delimiter">(</span><span class="Special">Callstack_depth</span>+<span class="Constant">1</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;result: &quot;</span> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EAX]<span class="Delimiter">.</span>i &lt;&lt; end<span class="Delimiter">();</span>
<span id="L65" class="LineNr"> 65 </span>    <span class="Normal">if</span> <span class="Delimiter">(</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EAX]<span class="Delimiter">.</span>i == -<span class="Constant">1</span><span class="Delimiter">)</span> <a href='003trace.cc.html#L217'>raise</a> &lt;&lt; strerror<span class="Delimiter">(</span>errno<span class="Delimiter">)</span> &lt;&lt; <span class="cSpecial">'\n'</span> &lt;&lt; end<span class="Delimiter">();</span>
<span id="L66" class="LineNr"> 66 </span>    <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L67" class="LineNr"> 67 </span>  <span class="Normal">case</span> <span class="Constant">38</span>:
<span id="L68" class="LineNr"> 68 </span>    <a href='003trace.cc.html#L98'>trace</a><span class="Delimiter">(</span><span class="Special">Callstack_depth</span>+<span class="Constant">1</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;rename: &quot;</span> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EBX]<span class="Delimiter">.</span>u &lt;&lt; <span class="Constant">&quot; -&gt; &quot;</span> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[ECX]<span class="Delimiter">.</span>u &lt;&lt; end<span class="Delimiter">();</span>
<span id="L69" class="LineNr"> 69 </span>    <a href='003trace.cc.html#L98'>trace</a><span class="Delimiter">(</span><span class="Special">Callstack_depth</span>+<span class="Constant">1</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EBX]<span class="Delimiter">.</span>u &lt;&lt; <span class="Constant">&quot; =&gt; &quot;</span> &lt;&lt; <a href='010---vm.cc.html#L252'>mem_addr_kernel_string</a><span class="Delimiter">(</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EBX]<span class="Delimiter">.</span>u<span class="Delimiter">)</span> &lt;&lt; end<span class="Delimiter">();</span>
<span id="L70" class="LineNr"> 70 </span>    <a href='003trace.cc.html#L98'>trace</a><span class="Delimiter">(</span><span class="Special">Callstack_depth</span>+<span class="Constant">1</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[ECX]<span class="Delimiter">.</span>u &lt;&lt; <span class="Constant">&quot; =&gt; &quot;</span> &lt;&lt; <a href='010---vm.cc.html#L252'>mem_addr_kernel_string</a><span class="Delimiter">(</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[ECX]<span class="Delimiter">.</span>u<span class="Delimiter">)</span> &lt;&lt; end<span class="Delimiter">();</span>
<span id="L71" class="LineNr"> 71 </span>    <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EAX]<span class="Delimiter">.</span>i = rename<span class="Delimiter">(</span><span class="Comment">/*</span><span class="Comment">old filename</span><span class="Comment">*/</span><a href='010---vm.cc.html#L252'>mem_addr_kernel_string</a><span class="Delimiter">(</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EBX]<span class="Delimiter">.</span>u<span class="Delimiter">),</span> <span class="Comment">/*</span><span class="Comment">new filename</span><span class="Comment">*/</span><a href='010---vm.cc.html#L252'>mem_addr_kernel_string</a><span class="Delimiter">(</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[ECX]<span class="Delimiter">.</span>u<span class="Delimiter">));</span>
<span id="L72" class="LineNr"> 72 </span>    <a href='003trace.cc.html#L98'>trace</a><span class="Delimiter">(</span><span class="Special">Callstack_depth</span>+<span class="Constant">1</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;result: &quot;</span> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EAX]<span class="Delimiter">.</span>i &lt;&lt; end<span class="Delimiter">();</span>
<span id="L73" class="LineNr"> 73 </span>    <span class="Normal">if</span> <span class="Delimiter">(</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EAX]<span class="Delimiter">.</span>i == -<span class="Constant">1</span><span class="Delimiter">)</span> <a href='003trace.cc.html#L217'>raise</a> &lt;&lt; strerror<span class="Delimiter">(</span>errno<span class="Delimiter">)</span> &lt;&lt; <span class="cSpecial">'\n'</span> &lt;&lt; end<span class="Delimiter">();</span>
<span id="L74" class="LineNr"> 74 </span>    <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L75" class="LineNr"> 75 </span>  <span class="Normal">case</span> <span class="Constant">45</span>:  <span class="Comment">// brk: modify size of data segment</span>
<span id="L76" class="LineNr"> 76 </span>    <a href='003trace.cc.html#L98'>trace</a><span class="Delimiter">(</span><span class="Special">Callstack_depth</span>+<span class="Constant">1</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;grow data segment to &quot;</span> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EBX]<span class="Delimiter">.</span>u &lt;&lt; end<span class="Delimiter">();</span>
<span id="L77" class="LineNr"> 77 </span>    <a href='010---vm.cc.html#L189'>grow_data_segment</a><span class="Delimiter">(</span><span class="Comment">/*</span><span class="Comment">new end address</span><span class="Comment">*/</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EBX]<span class="Delimiter">.</span>u<span class="Delimiter">);</span>
<span id="L78" class="LineNr"> 78 </span>    <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L79" class="LineNr"> 79 </span>  <span class="Normal">case</span> <span class="Constant">90</span>:  <span class="Comment">// mmap: allocate memory outside existing segment allocations</span>
<span id="L80" class="LineNr"> 80 </span>    <a href='003trace.cc.html#L98'>trace</a><span class="Delimiter">(</span><span class="Special">Callstack_depth</span>+<span class="Constant">1</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;mmap: allocate new segment&quot;</span> &lt;&lt; end<span class="Delimiter">();</span>
<span id="L81" class="LineNr"> 81 </span>    <span class="Comment">// Ignore most arguments for now: address hint, protection flags, sharing flags, fd, offset.</span>
<span id="L82" class="LineNr"> 82 </span>    <span class="Comment">// We only support anonymous maps.</span>
<span id="L83" class="LineNr"> 83 </span>    <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EAX]<span class="Delimiter">.</span>u = <a href='020syscalls.cc.html#L116'>new_segment</a><span class="Delimiter">(</span><span class="Comment">/*</span><span class="Comment">length</span><span class="Comment">*/</span><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>[EBX]<span class="Delimiter">.</span>u+<span class="Constant">0x4</span><span class="Delimiter">));</span>
<span id="L84" class="LineNr"> 84 </span>    <a href='003trace.cc.html#L98'>trace</a><span class="Delimiter">(</span><span class="Special">Callstack_depth</span>+<span class="Constant">1</span><span class="Delimiter">,</span> <span class="Constant">&quot;run&quot;</span><span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;result: &quot;</span> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EAX]<span class="Delimiter">.</span>u &lt;&lt; end<span class="Delimiter">();</span>
<span id="L85" class="LineNr"> 85 </span>    <span class="Identifier">break</span><span class="Delimiter">;</span>
<span id="L86" class="LineNr"> 86 </span>  <span class="Normal">default</span>:
<span id="L87" class="LineNr"> 87 </span>    <a href='003trace.cc.html#L217'>raise</a> &lt;&lt; <a href='010---vm.cc.html#L433'>HEXWORD</a> &lt;&lt; EIP &lt;&lt; <span class="Constant">&quot;: unimplemented syscall &quot;</span> &lt;&lt; <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[EAX]<span class="Delimiter">.</span>u &lt;&lt; <span class="cSpecial">'\n'</span> &lt;&lt; end<span class="Delimiter">();</span>
<span id="L88" class="LineNr"> 88 </span>  <span class="Delimiter">}</span>
<span id="L89" class="LineNr"> 89 </span><span class="Delimiter">}</span>
<span id="L90" class="LineNr"> 90 </span>
<span id="L91" class="LineNr"> 91 </span><span class="Comment">// SubX is oblivious to file permissions, directories, symbolic links, terminals, and much else besides.</span>
<span id="L92" class="LineNr"> 92 </span><span class="Comment">// Also ignoring any concurrency considerations for now.</span>
<span id="L93" class="LineNr"> 93 </span><span class="Normal">void</span> <a href='020syscalls.cc.html#L93'>check_flags</a><span class="Delimiter">(</span><span class="Normal">int</span> <a href='010---vm.cc.html#L23'>reg</a><span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L94" class="LineNr"> 94 </span>  <span class="Normal">uint32_t</span> flags = <span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[reg]<span class="Delimiter">.</span>u<span class="Delimiter">;</span>
<span id="L95" class="LineNr"> 95 </span>  <span class="Normal">if</span> <span class="Delimiter">(</span>flags != <span class="Delimiter">((</span>flags &amp; O_RDONLY<span class="Delimiter">)</span> | <span class="Delimiter">(</span>flags &amp; O_WRONLY<span class="Delimiter">)))</span> <span class="Delimiter">{</span>
<span id="L96" class="LineNr"> 96 </span>    cerr &lt;&lt; <a href='010---vm.cc.html#L433'>HEXWORD</a> &lt;&lt; EIP &lt;&lt; <span class="Constant">&quot;: most POSIX flags to the open() syscall are not supported. Just O_RDONLY and O_WRONLY for now. Zero concurrent access support.\n&quot;</span><span class="Delimiter">;</span>
<span id="L97" class="LineNr"> 97 </span>    exit<span class="Delimiter">(</span><span class="Constant">1</span><span class="Delimiter">);</span>
<span id="L98" class="LineNr"> 98 </span>  <span class="Delimiter">}</span>
<span id="L99" class="LineNr"> 99 </span>  <span class="Normal">if</span> <span class="Delimiter">((</span>flags &amp; O_RDONLY<span class="Delimiter">)</span> &amp;&amp; <span class="Delimiter">(</span>flags &amp; O_WRONLY<span class="Delimiter">))</span> <span class="Delimiter">{</span>
<span id="L100" class="LineNr">100 </span>    cerr &lt;&lt; <a href='010---vm.cc.html#L433'>HEXWORD</a> &lt;&lt; EIP &lt;&lt; <span class="Constant">&quot;: can't open a file for both reading and writing at once. See <a href="http://man7.org/linux/man-pages/man2/open.2.html">http://man7.org/linux/man-pages/man2/open.2.html</a>.\n&quot;</span><span class="Delimiter">;</span>
<span id="L101" class="LineNr">101 </span>    exit<span class="Delimiter">(</span><span class="Constant">1</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="Delimiter">}</span>
<span id="L104" class="LineNr">104 </span>
<span id="L105" class="LineNr">105 </span><span class="Normal">void</span> <a href='020syscalls.cc.html#L105'>check_mode</a><span class="Delimiter">(</span><span class="Normal">int</span> <a href='010---vm.cc.html#L23'>reg</a><span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L106" class="LineNr">106 </span>  <span class="Normal">if</span> <span class="Delimiter">(</span><span class="Special"><a href='010---vm.cc.html#L28'>Reg</a></span>[reg]<span class="Delimiter">.</span>u != <span class="PreProc">0</span><span class="Constant">600</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L107" class="LineNr">107 </span>    cerr &lt;&lt; <a href='010---vm.cc.html#L433'>HEXWORD</a> &lt;&lt; EIP &lt;&lt; <span class="Constant">&quot;: SubX is oblivious to file permissions; register &quot;</span> &lt;&lt; <a href='010---vm.cc.html#L23'>reg</a> &lt;&lt; <span class="Constant">&quot; must be 0.\n&quot;</span><span class="Delimiter">;</span>
<span id="L108" class="LineNr">108 </span>    exit<span class="Delimiter">(</span><span class="Constant">1</span><span class="Delimiter">);</span>
<span id="L109" class="LineNr">109 </span>  <span class="Delimiter">}</span>
<span id="L110" class="LineNr">110 </span><span class="Delimiter">}</span>
<span id="L111" class="LineNr">111 </span>
<span id="L112" class="LineNr">112 </span><span class="Delimiter">:(before &quot;End Globals&quot;)</span>
<span id="L113" class="LineNr">113 </span><span class="Normal">uint32_t</span> <span class="Special"><a href='020syscalls.cc.html#L113'>Next_segment</a></span> = <span class="Constant">0xb0000000</span><span class="Delimiter">;</span>  <span class="Comment">// 0xc0000000 and up is reserved for Linux kernel</span>
<span id="L114" class="LineNr">114 </span><span class="Normal">const</span> <span class="Normal">uint32_t</span> <a href='020syscalls.cc.html#L114'>SPACE_FOR_SEGMENT</a> = <span class="Constant">0x01000000</span><span class="Delimiter">;</span>
<span id="L115" class="LineNr">115 </span><span class="Delimiter">:(code)</span>
<span id="L116" class="LineNr">116 </span><span class="Normal">uint32_t</span> <a href='020syscalls.cc.html#L116'>new_segment</a><span class="Delimiter">(</span><span class="Normal">uint32_t</span> length<span class="Delimiter">)</span> <span class="Delimiter">{</span>
<span id="L117" class="LineNr">117 </span>  <span class="Normal">uint32_t</span> result = <span class="Special"><a href='020syscalls.cc.html#L113'>Next_segment</a></span><span class="Delimiter">;</span>
<span id="L118" class="LineNr">118 </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><span class="Special"><a href='020syscalls.cc.html#L113'>Next_segment</a></span><span class="Delimiter">,</span> <span class="Special"><a href='020syscalls.cc.html#L113'>Next_segment</a></span>+length<span class="Delimiter">));</span>
<span id="L119" class="LineNr">119 </span>  <span class="Special"><a href='020syscalls.cc.html#L113'>Next_segment</a></span> -= <a href='020syscalls.cc.html#L114'>SPACE_FOR_SEGMENT</a><span class="Delimiter">;</span>
<span id="L120" class="LineNr">120 </span>  <span class="Identifier">return</span> result<span class="Delimiter">;</span>
<span id="L121" class="LineNr">121 </span><span class="Delimiter">}</span>
</pre>
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