teliva - Fork of Lua 5.1 to encourage end-user programming

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Diffstat (limited to 'break.tlv')

-rw-r--r--

1 files changed, 11 insertions, 0 deletions

:(before "End Initialize Op Names") put_new(Name, "cd", "software interrupt (int)"); :(before "End Single-Byte Opcodes") case 0xcd: { // int imm8 (software interrupt) trace(Callstack_depth+1, "run") << "syscall" << end(); uint8_t code = next(); if (code != 0x80) { raise << "Unimplemented interrupt code " << HEXBYTE << code << '\n' << end(); raise << " Only `int 80h` supported for now.\n" << end(); break; } process_int80(); break; } :(code) void process_int80() { switch (Reg[EAX].u) { case 1: exit(/*exit code*/Reg[EBX].u); break; case 3: trace(Callstack_depth+1, "run") << "read: " << Reg[EBX].u << ' ' << Reg[ECX].u << ' ' << Reg[EDX].u << end(); Reg[EAX].i = read(/*file descriptor*/Reg[EBX].u, /*memory buffer*/mem_addr_u8(Reg[ECX].u), /*size*/Reg[EDX].u); trace(Callstack_depth+1, "run") << "result: " << Reg[EAX].i << end(); if (Reg[EAX].i == -1) raise << "read: " << strerror(errno) << '\n' << end(); break; case 4: trace(Callstack_depth+1, "run") << "write: " << Reg[EBX].u << ' ' << Reg[ECX].u << ' ' << Reg[EDX].u << end(); trace(Callstack_depth+1, "run") << Reg[ECX].u << " => " << mem_addr_string(Reg[ECX].u, Reg[EDX].u) << end(); Reg[EAX].i = write(/*file descriptor*/Reg[EBX].u, /*memory buffer*/mem_addr_u8(Reg[ECX].u), /*size*/Reg[EDX].u); trace(Callstack_depth+1, "run") << "result: " << Reg[EAX].i << end(); if (Reg[EAX].i == -1) raise << "write: " << strerror(errno) << '\n' << end(); break; case 5: { check_flags(ECX); check_mode(EDX); trace(Callstack_depth+1, "run") << "open: " << Reg[EBX].u << ' ' << Reg[ECX].u << end(); trace(Callstack_depth+1, "run") << Reg[EBX].u << " => " << mem_addr_kernel_string(Reg[EBX].u) << end(); Reg[EAX].i = open(/*filename*/mem_addr_kernel_string(Reg[EBX].u), /*flags*/Reg[ECX].u, /*mode*/0640); trace(Callstack_depth+1, "run") << "result: " << Reg[EAX].i << end(); if (Reg[EAX].i == -1) raise << "open: " << strerror(errno) << '\n' << end(); break; } case 6: trace(Callstack_depth+1, "run") << "close: " << Reg[EBX].u << end(); Reg[EAX].i = close(/*file descriptor*/Reg[EBX].u); trace(Callstack_depth+1, "run") << "result: " << Reg[EAX].i << end(); if (Reg[EAX].i == -1) raise << "close: " << strerror(errno) << '\n' << end(); break; case 8: check_mode(ECX); trace(Callstack_depth+1, "run") << "creat: " << Reg[EBX].u << end(); trace(Callstack_depth+1, "run") << Reg[EBX].u << " => " << mem_addr_kernel_string(Reg[EBX].u) << end(); Reg[EAX].i = creat(/*filename*/mem_addr_kernel_string(Reg[EBX].u), /*mode*/0640); trace(Callstack_depth+1, "run") << "result: " << Reg[EAX].i << end(); if (Reg[EAX].i == -1) raise << "creat: " << strerror(errno) << '\n' << end(); break; case 10: trace(Callstack_depth+1, "run") << "unlink: " << Reg[EBX].u << end(); trace(Callstack_depth+1, "run") << Reg[EBX].u << " => " << mem_addr_kernel_string(Reg[EBX].u) << end(); Reg[EAX].i = unlink(/*filename*/mem_addr_kernel_string(Reg[EBX].u)); trace(Callstack_depth+1, "run") << "result: " << Reg[EAX].i << end(); if (Reg[EAX].i == -1) raise << "unlink: " << strerror(errno) << '\n' << end(); break; case 38: trace(Callstack_depth+1, "run") << "rename: " << Reg[EBX].u << " -> " << Reg[ECX].u << end(); trace(Callstack_depth+1, "run") << Reg[EBX].u << " => " << mem_addr_kernel_string(Reg[EBX].u) << end(); trace(Callstack_depth+1, "run") << Reg[ECX].u << " => " << mem_addr_kernel_string(Reg[ECX].u) << end(); Reg[EAX].i = rename(/*old filename*/mem_addr_kernel_string(Reg[EBX].u), /*new filename*/mem_addr_kernel_string(Reg[ECX].u)); trace(Callstack_depth+1, "run") << "result: " << Reg[EAX].i << end(); if (Reg[EAX].i == -1) raise << "rename: " << strerror(errno) << '\n' << end(); break; case 45: // brk: modify size of data segment trace(Callstack_depth+1, "run") << "grow data segment to " << Reg[EBX].u << end(); grow_data_segment(/*new end address*/Reg[EBX].u); break; case 90: // mmap: allocate memory outside existing segment allocations trace(Callstack_depth+1, "run") << "mmap: allocate new segment" << end(); // Ignore most arguments for now: address hint, protection flags, sharing flags, fd, offset. // We only support anonymous maps. Reg[EAX].u = new_segment(/*length*/read_mem_u32(Reg[EBX].u+0x4)); trace(Callstack_depth+1, "run") << "result: " << Reg[EAX].u << end(); break; default: raise << HEXWORD << EIP << ": unimplemented syscall " << Reg[EAX].u << '\n' << end(); } } // SubX is oblivious to file permissions, directories, symbolic links, terminals, and much else besides. // Also ignoring any concurrency considerations for now. void check_flags(int reg) { uint32_t flags = Reg[reg].u; if (flags != ((flags & O_RDONLY) | (flags & O_WRONLY))) { cerr << HEXWORD << EIP << ": most POSIX flags to the open() syscall are not supported. Just O_RDONLY and O_WRONLY for now. Zero concurrent access support.\n"; exit(1); } if ((flags & O_RDONLY) && (flags & O_WRONLY)) { cerr << HEXWORD << EIP << ": can't open a file for both reading and writing at once. See http://man7.org/linux/man-pages/man2/open.2.html.\n"; exit(1); } } void check_mode(int reg) { if (Reg[reg].u != 0600) { cerr << HEXWORD << EIP << ": SubX is oblivious to file permissions; register " << reg << " must be 0.\n"; exit(1); } } :(before "End Globals") // Very primitive/fixed/insecure mmap segments for now. uint32_t Segments_allocated_above = END_HEAP; const uint32_t SPACE_FOR_SEGMENT = 0x01000000; :(code) // always allocate multiples of the segment size uint32_t new_segment(uint32_t length) { assert(length > 0); uint32_t result = (Segments_allocated_above - length) & 0xff000000; if (result <= START_HEAP) { raise << "Allocated too many segments; the VM ran out of memory. " << "Maybe SPACE_FOR_SEGMENT can be smaller?\n" << end(); exit(1); } Mem.push_back(vma(result, result+length)); Segments_allocated_above = result; return result; }


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