6866 - mu - Soul of a tiny new machine. More thorough tests → More comprehensible and rewrite-friendly software → More resilient society.

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author	Kartik Agaram <vc@akkartik.com>	2020-09-26 20:15:45 -0700
committer	Kartik Agaram <vc@akkartik.com>	2020-09-26 20:15:45 -0700
commit	42349345f4fcab2ce4db4ed25ce96745d938f47b (patch)
tree	8231ce7280c9f63a76f49a57696d733ff91798c9 /apps/ex5
parent	b8682e73495856e3a0759e9fb1ff60448caffbb1 (diff)
download	mu-42349345f4fcab2ce4db4ed25ce96745d938f47b.tar.gz

6866

Diffstat (limited to 'apps/ex5')

0 files changed, 0 insertions, 0 deletions

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <html> <head> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> <title>Mu - 020syscalls.cc</title> <meta name="Generator" content="Vim/8.1"> <meta name="plugin-version" content="vim8.1_v1"> <meta name="syntax" content="cpp"> <meta name="settings" content="number_lines,use_css,pre_wrap,no_foldcolumn,expand_tabs,line_ids,prevent_copy="> <meta name="colorscheme" content="minimal-light"> <style type="text/css">  </style> <script type='text/javascript'>  </script> </head> <body onload='JumpToLine();'> <a href='https://github.com/akkartik/mu/blob/master/020syscalls.cc'>https://github.com/akkartik/mu/blob/master/020syscalls.cc</a> <pre id='vimCodeElement'> 1 :(before "End Initialize Op Names") 2 <a href='001help.cc.html#L239'>put_new</a>(<a href='010---vm.cc.html#L342'>Name</a>, "cd", "software interrupt (int)"); 3 4 :(before "End Single-Byte Opcodes") 5 case 0xcd: { // int imm8 (software interrupt) 6 <a href='003trace.cc.html#L96'>trace</a>(Callstack_depth+1, "run") << "syscall" << end(); 7 uint8_t code = <a href='010---vm.cc.html#L325'>next</a>(); 8 if (code != 0x80) { 9 <a href='003trace.cc.html#L228'>raise</a> << "Unimplemented interrupt code " << <a href='010---vm.cc.html#L394'>HEXBYTE</a> << code << '\n' << end(); 10 <a href='003trace.cc.html#L228'>raise</a> << " Only `int 80h` supported for now.\n" << end(); 11 break; 12 } 13 <a href='020syscalls.cc.html#L18'>process_int80</a>(); 14 break; 15 } 16 17 :(code) 18 void <a href='020syscalls.cc.html#L18'>process_int80</a>() { 19 switch (<a href='010---vm.cc.html#L25'>Reg</a>[EAX].u) { 20 case 1: 21 exit(/*exit code*/<a href='010---vm.cc.html#L25'>Reg</a>[EBX].u); 22 break; 23 case 3: 24 <a href='003trace.cc.html#L96'>trace</a>(Callstack_depth+1, "run") << "read: " << <a href='010---vm.cc.html#L25'>Reg</a>[EBX].u << ' ' << <a href='010---vm.cc.html#L25'>Reg</a>[ECX].u << ' ' << <a href='010---vm.cc.html#L25'>Reg</a>[EDX].u << end(); 25 <a href='010---vm.cc.html#L25'>Reg</a>[EAX].i = read(/*file descriptor*/<a href='010---vm.cc.html#L25'>Reg</a>[EBX].u, /*memory buffer*/<a href='010---vm.cc.html#L180'>mem_addr_u8</a>(<a href='010---vm.cc.html#L25'>Reg</a>[ECX].u), /*size*/<a href='010---vm.cc.html#L25'>Reg</a>[EDX].u); 26 <a href='003trace.cc.html#L96'>trace</a>(Callstack_depth+1, "run") << "result: " << <a href='010---vm.cc.html#L25'>Reg</a>[EAX].i << end(); 27 if (<a href='010---vm.cc.html#L25'>Reg</a>[EAX].i == -1) <a href='003trace.cc.html#L228'>raise</a> << "read: " << strerror(errno) << '\n' << end(); 28 break; 29 case 4: 30 <a href='003trace.cc.html#L96'>trace</a>(Callstack_depth+1, "run") << "write: " << <a href='010---vm.cc.html#L25'>Reg</a>[EBX].u << ' ' << <a href='010---vm.cc.html#L25'>Reg</a>[ECX].u << ' ' << <a href='010---vm.cc.html#L25'>Reg</a>[EDX].u << end(); 31 <a href='003trace.cc.html#L96'>trace</a>(Callstack_depth+1, "run") << <a href='010---vm.cc.html#L25'>Reg</a>[ECX].u << " => " << <a href='010---vm.cc.html#L223'>mem_addr_string</a>(<a href='010---vm.cc.html#L25'>Reg</a>[ECX].u, <a href='010---vm.cc.html#L25'>Reg</a>[EDX].u) << end(); 32 <a href='010---vm.cc.html#L25'>Reg</a>[EAX].i = write(/*file descriptor*/<a href='010---vm.cc.html#L25'>Reg</a>[EBX].u, /*memory buffer*/<a href='010---vm.cc.html#L180'>mem_addr_u8</a>(<a href='010---vm.cc.html#L25'>Reg</a>[ECX].u), /*size*/<a href='010---vm.cc.html#L25'>Reg</a>[EDX].u); 33 <a href='003trace.cc.html#L96'>trace</a>(Callstack_depth+1, "run") << "result: " << <a href='010---vm.cc.html#L25'>Reg</a>[EAX].i << end(); 34 if (<a href='010---vm.cc.html#L25'>Reg</a>[EAX].i == -1) <a href='003trace.cc.html#L228'>raise</a> << "write: " << strerror(errno) << '\n' << end(); 35 break; 36 case 5: { 37 <a href='020syscalls.cc.html#L89'>check_flags</a>(<a href='010---vm.cc.html#L11'>ECX</a>); 38 <a href='020syscalls.cc.html#L101'>check_mode</a>(<a href='010---vm.cc.html#L12'>EDX</a>); 39 <a href='003trace.cc.html#L96'>trace</a>(Callstack_depth+1, "run") << "open: " << <a href='010---vm.cc.html#L25'>Reg</a>[EBX].u << ' ' << <a href='010---vm.cc.html#L25'>Reg</a>[ECX].u << end(); 40 <a href='003trace.cc.html#L96'>trace</a>(Callstack_depth+1, "run") << <a href='010---vm.cc.html#L25'>Reg</a>[EBX].u << " => " << <a href='010---vm.cc.html#L220'>mem_addr_kernel_string</a>(<a href='010---vm.cc.html#L25'>Reg</a>[EBX].u) << end(); 41 <a href='010---vm.cc.html#L25'>Reg</a>[EAX].i = open(/*filename*/<a href='010---vm.cc.html#L220'>mem_addr_kernel_string</a>(<a href='010---vm.cc.html#L25'>Reg</a>[EBX].u), /*flags*/<a href='010---vm.cc.html#L25'>Reg</a>[ECX].u, /*mode*/0640); 42 <a href='003trace.cc.html#L96'>trace</a>(Callstack_depth+1, "run") << "result: " << <a href='010---vm.cc.html#L25'>Reg</a>[EAX].i << end(); 43 if (<a href='010---vm.cc.html#L25'>Reg</a>[EAX].i == -1) <a href='003trace.cc.html#L228'>raise</a> << "open: " << strerror(errno) << '\n' << end(); 44 break; 45 } 46 case 6: 47 <a href='003trace.cc.html#L96'>trace</a>(Callstack_depth+1, "run") << "close: " << <a href='010---vm.cc.html#L25'>Reg</a>[EBX].u << end(); 48 <a href='010---vm.cc.html#L25'>Reg</a>[EAX].i = close(/*file descriptor*/<a href='010---vm.cc.html#L25'>Reg</a>[EBX].u); 49 <a href='003trace.cc.html#L96'>trace</a>(Callstack_depth+1, "run") << "result: " << <a href='010---vm.cc.html#L25'>Reg</a>[EAX].i << end(); 50 if (<a href='010---vm.cc.html#L25'>Reg</a>[EAX].i == -1) <a href='003trace.cc.html#L228'>raise</a> << "close: " << strerror(errno) << '\n' << end(); 51 break; 52 case 8: 53 <a href='020syscalls.cc.html#L101'>check_mode</a>(<a href='010---vm.cc.html#L11'>ECX</a>); 54 <a href='003trace.cc.html#L96'>trace</a>(Callstack_depth+1, "run") << "creat: " << <a href='010---vm.cc.html#L25'>Reg</a>[EBX].u << end(); 55 <a href='003trace.cc.html#L96'>trace</a>(Callstack_depth+1, "run") << <a href='010---vm.cc.html#L25'>Reg</a>[EBX].u << " => " << <a href='010---vm.cc.html#L220'>mem_addr_kernel_string</a>(<a href='010---vm.cc.html#L25'>Reg</a>[EBX].u) << end(); 56 <a href='010---vm.cc.html#L25'>Reg</a>[EAX].i = creat(/*filename*/<a href='010---vm.cc.html#L220'>mem_addr_kernel_string</a>(<a href='010---vm.cc.html#L25'>Reg</a>[EBX].u), /*mode*/0640); 57 <a href='003trace.cc.html#L96'>trace</a>(Callstack_depth+1, "run") << "result: " << <a href='010---vm.cc.html#L25'>Reg</a>[EAX].i << end(); 58 if (<a href='010---vm.cc.html#L25'>Reg</a>[EAX].i == -1) <a href='003trace.cc.html#L228'>raise</a> << "creat: " << strerror(errno) << '\n' << end(); 59 break; 60 case 10: 61 <a href='003trace.cc.html#L96'>trace</a>(Callstack_depth+1, "run") << "unlink: " << <a href='010---vm.cc.html#L25'>Reg</a>[EBX].u << end(); 62 <a href='003trace.cc.html#L96'>trace</a>(Callstack_depth+1, "run") << <a href='010---vm.cc.html#L25'>Reg</a>[EBX].u << " => " << <a href='010---vm.cc.html#L220'>mem_addr_kernel_string</a>(<a href='010---vm.cc.html#L25'>Reg</a>[EBX].u) << end(); 63 <a href='010---vm.cc.html#L25'>Reg</a>[EAX].i = unlink(/*filename*/<a href='010---vm.cc.html#L220'>mem_addr_kernel_string</a>(<a href='010---vm.cc.html#L25'>Reg</a>[EBX].u)); 64 <a href='003trace.cc.html#L96'>trace</a>(Callstack_depth+1, "run") << "result: " << <a href='010---vm.cc.html#L25'>Reg</a>[EAX].i << end(); 65 if (<a href='010---vm.cc.html#L25'>Reg</a>[EAX].i == -1) <a href='003trace.cc.html#L228'>raise</a> << "unlink: " << strerror(errno) << '\n' << end(); 66 break; 67 case 38: 68 <a href='003trace.cc.html#L96'>trace</a>(Callstack_depth+1, "run") << "rename: " << <a href='010---vm.cc.html#L25'>Reg</a>[EBX].u << " -> " << <a href='010---vm.cc.html#L25'>Reg</a>[ECX].u << end(); 69 <a href='003trace.cc.html#L96'>trace</a>(Callstack_depth+1, "run") << <a href='010---vm.cc.html#L25'>Reg</a>[EBX].u << " => " << <a href='010---vm.cc.html#L220'>mem_addr_kernel_string</a>(<a href='010---vm.cc.html#L25'>Reg</a>[EBX].u) << end(); 70 <a href='003trace.cc.html#L96'>trace</a>(Callstack_depth+1, "run") << <a href='010---vm.cc.html#L25'>Reg</a>[ECX].u << " => " << <a href='010---vm.cc.html#L220'>mem_addr_kernel_string</a>(<a href='010---vm.cc.html#L25'>Reg</a>[ECX].u) << end(); 71 <a href='010---vm.cc.html#L25'>Reg</a>[EAX].i = rename(/*old filename*/<a href='010---vm.cc.html#L220'>mem_addr_kernel_string</a>(<a href='010---vm.cc.html#L25'>Reg</a>[EBX].u), /*new filename*/<a href='010---vm.cc.html#L220'>mem_addr_kernel_string</a>(<a href='010---vm.cc.html#L25'>Reg</a>[ECX].u)); 72 <a href='003trace.cc.html#L96'>trace</a>(Callstack_depth+1, "run") << "result: " << <a href='010---vm.cc.html#L25'>Reg</a>[EAX].i << end(); 73 if (<a href='010---vm.cc.html#L25'>Reg</a>[EAX].i == -1) <a href='003trace.cc.html#L228'>raise</a> << "rename: " << strerror(errno) << '\n' << end(); 74 break; 75 case 90: // mmap: allocate memory outside existing segment allocations 76 <a href='003trace.cc.html#L96'>trace</a>(Callstack_depth+1, "run") << "mmap: allocate new segment" << end(); 77 // Ignore most arguments for now: address hint, protection flags, sharing flags, fd, offset. 78 // We only support anonymous maps. 79 <a href='010---vm.cc.html#L25'>Reg</a>[EAX].u = <a href='020syscalls.cc.html#L113'>new_segment</a>(/*length*/<a href='010---vm.cc.html#L172'>read_mem_u32</a>(<a href='010---vm.cc.html#L25'>Reg</a>[EBX].u+0x4)); 80 <a href='003trace.cc.html#L96'>trace</a>(Callstack_depth+1, "run") << "result: " << <a href='010---vm.cc.html#L25'>Reg</a>[EAX].u << end(); 81 break; 82 default: 83 <a href='003trace.cc.html#L228'>raise</a> << <a href='010---vm.cc.html#L395'>HEXWORD</a> << <a href='010---vm.cc.html#L26'>EIP</a> << ": unimplemented syscall " << <a href='010---vm.cc.html#L25'>Reg</a>[EAX].u << '\n' << end(); 84 } 85 } 86 87 // SubX is oblivious to file permissions, directories, symbolic links, terminals, and much else besides. 88 // Also ignoring any concurrency considerations for now. 89 void <a href='020syscalls.cc.html#L89'>check_flags</a>(int <a href='010---vm.cc.html#L20'>reg</a>) { 90 uint32_t flags = <a href='010---vm.cc.html#L25'>Reg</a>[reg].u; 91 if (flags != ((flags & O_RDONLY) | (flags & O_WRONLY))) { 92 cerr << <a href='010---vm.cc.html#L395'>HEXWORD</a> << <a href='010---vm.cc.html#L26'>EIP</a> << ": most POSIX flags to the open() syscall are not supported. Just O_RDONLY and O_WRONLY for now. Zero concurrent access support.\n"; 93 exit(1); 94 } 95 if ((flags & O_RDONLY) && (flags & O_WRONLY)) { 96 cerr << <a href='010---vm.cc.html#L395'>HEXWORD</a> << <a href='010---vm.cc.html#L26'>EIP</a> << ": 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"; 97 exit(1); 98 } 99 } 100 101 void <a href='020syscalls.cc.html#L101'>check_mode</a>(int <a href='010---vm.cc.html#L20'>reg</a>) { 102 if (<a href='010---vm.cc.html#L25'>Reg</a>[reg].u != 0600) { 103 cerr << <a href='010---vm.cc.html#L395'>HEXWORD</a> << <a href='010---vm.cc.html#L26'>EIP</a> << ": SubX is oblivious to file permissions; register " << <a href='010---vm.cc.html#L20'>reg</a> << " must be 0.\n"; 104 exit(1); 105 } 106 } 107 108 :(before "End Globals") 109 // Very primitive/fixed/insecure mmap segments for now. 110 uint32_t <a href='020syscalls.cc.html#L110'>Segments_allocated_above</a> = <a href='012elf.cc.html#L151'>END_HEAP</a>; 111 :(code) 112 // always allocate multiples of the segment size 113 uint32_t <a href='020syscalls.cc.html#L113'>new_segment</a>(uint32_t length) { 114 assert(length > 0); 115 uint32_t result = (<a href='020syscalls.cc.html#L110'>Segments_allocated_above</a> - length) & 0xff000000; // same number of zeroes as SEGMENT_ALIGNMENT 116 if (result <= <a href='012elf.cc.html#L150'>START_HEAP</a>) { 117 <a href='003trace.cc.html#L228'>raise</a> << "Allocated too many segments; the VM ran out of memory. " 118 << "Maybe <a href='010---vm.cc.html#L89'>SEGMENT_ALIGNMENT</a> can be smaller?\n" << <a href='003trace.cc.html#L173'>die</a>(); 119 } 120 <a href='010---vm.cc.html#L154'>Mem</a>.push_back(vma(result, result+length)); 121 <a href='020syscalls.cc.html#L110'>Segments_allocated_above</a> = result; 122 return result; 123 } </pre> </body> </html>


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