X-Git-Url: https://git.danieliu.xyz/?a=blobdiff_plain;f=sped.asm;h=d7dcb8de8a7a55ed4bddc4917be6192cc886f130;hb=aab6303fb9c43a2d727774c25b3c50a4b1fcae8d;hp=a76e7de3e1477462a30d83093a8f33d011c6923a;hpb=a7e38d5436df06ef83114adbcd3ee8c89d609b16;p=sped.git diff --git a/sped.asm b/sped.asm index a76e7de..d7dcb8d 100644 --- a/sped.asm +++ b/sped.asm @@ -1,6 +1,14 @@ +; sped - the stupidly pointless editor +; written by pinosaur + +%include "fileutils.S" -global main extern printf +extern fflush +extern stdout +extern free + +global main ; macros %macro write_str 2 @@ -13,119 +21,242 @@ extern printf section .data banner_str db `SPED - the stupidly pointless editor\n`, 0x00 - readfile_str db `reading file %s\n`, 0x00 nofile_str db `no file provided\n`, 0x00 - argcount_str db `there are %d args\n`, 0x00 - wrongfile_str db `unable to open file, error code: %i\n`, 0x00 + readlines_str db `opened file with %i lines\n`, 0x00 + prompt_str db `sped > `, 0x00 + invalidcmd_str db `invalid command\n`, 0x00 + invalidaddr_str db `invalid address\n`, 0x00 + charcount_str db `read %i chars\n`, 0x00 + currentline_str db `current line: %i\n`, 0x00 + echo_str db `%s`, 0x00 ; print strings without format exploit -; section .bss +section .bss + buffer resb 4 + buffer_lines resb 4 + cur_line resb 4 section .text main: + %define _ARGC 8 + %define _ARGV 12 + push ebp mov ebp, esp ; read command line args - mov ecx, [ebp+8] + mov ecx, [ebp+_ARGC] cmp ecx, 1 - jg .main_existing + jg _main_existing ; display error msg if no file push nofile_str call printf mov eax, 1 - jmp .main_exit + jmp _main_exit -.main_existing: - mov ebx, DWORD [ebp+12] - add ebx, 4 + _main_existing: + mov ebx, DWORD [ebp+_ARGV] + add ebx, 4 ; first user arg is filename push DWORD [ebx] - ; push readfile_str - ; call printf - call readFile + mov [buffer], eax + mov [buffer_lines], ecx + mov DWORD [cur_line], 0x00 + + push DWORD [buffer_lines] + push readlines_str + call printf + + call repl + mov eax, 0 - jmp .main_exit + jmp _main_exit + + _main_exit: + + ; free string array + + + %undef _ARGC + %undef _ARGV -.main_exit: mov esp, ebp pop ebp ret -; reads file line by line -; args: filename -; return: -; eax - pointer to mem -; ecx - lines read -readFile: - %define _FILE_NAME 8 - %define FILE_HANDLE 4 +; prompt for user +; no args - reads from globals +repl: + + %define CMDSTR 4 ; the previous line read from user push ebp mov ebp, esp - - ; allocate vars + sub esp, 4 - mov DWORD [ebp-FILE_HANDLE], 0x00 + + _repl_loop: - ; open existing file - mov eax, 5 - mov ebx, [ebp+_FILE_NAME] - mov ecx, 0 - mov edx, 0700 - int 0x80 - mov [ebp-FILE_HANDLE], eax + ; print the prompt + push prompt_str + call printf + push DWORD [stdout] + call fflush - ; check if file was open successfully - cmp eax, 0 - jge .readFile_noerror - push eax - push wrongfile_str + ; read line from stdin + push 0 + call readLine + + mov DWORD [ebp-CMDSTR], eax + + ; commands are single char for now + cmp ecx, 1 + jne _repl_invalid_cmd + + ; parse commands + mov eax, DWORD [ebp-CMDSTR] + mov eax, [eax] + + ; q exists program =-=-=-=-=-=-=-=-=-=-=-=-= + mov eax, DWORD [ebp-CMDSTR] + cmp BYTE [eax], 'q' + jne _repl_cmd_quit_end + jmp _repl_exit + _repl_cmd_quit_end: + + ; p prints current line =-=-=-=-=-=-=-=-=-=-= + mov eax, DWORD [ebp-CMDSTR] + cmp BYTE [eax], 'p' + jne _repl_cmd_print_end + + mov eax, DWORD [cur_line] + mov ecx, 4 + mul ecx + add eax, [buffer] + push DWORD [eax] + push echo_str call printf - jmp .readFile_exit + jmp _repl_continue + _repl_cmd_print_end: -.readFile_noerror: + ; n prints the current line number =-=-=-=-=-=-=-= + mov eax, DWORD [ebp-CMDSTR] + cmp BYTE [eax], 'n' + jne _repl_cmd_number_end - jmp .readFile_exit + push DWORD [cur_line] + push currentline_str + call printf -.readFile_exit: + jmp _repl_continue + _repl_cmd_number_end: - ; close file - mov eax, 6 - mov ebx, [ebp-FILE_HANDLE] - int 0x80 + ; - goes to prev line =-=-=-=-=-=-=-=-=-=-=-=-= + mov eax, DWORD [ebp-CMDSTR] + cmp BYTE [eax], '-' + jne _repl_cmd_decline_end - %undef _FILE_NAME - %undef FILE_HANDLE + ; make sure we are within bounds + mov eax, DWORD [cur_line] + sub eax, 1 + cmp eax, 0 + jl _repl_invalid_addr + + sub DWORD [cur_line], 1 - mov esp, ebp - pop ebp - ret + jmp _repl_continue + _repl_cmd_decline_end: + ; + goes to next line =-=-=-=-=-=-=-=-=-=-=-=-= + mov eax, DWORD [ebp-CMDSTR] + cmp BYTE [eax], '+' + jne _repl_cmd_incline_end -; reads a line until newline character is reached -; args: file_handle -; return: location to buffer -readLine: + ; make sure we are within bounds + mov eax, DWORD [cur_line] + add eax, 1 + cmp eax, [buffer_lines] + jge _repl_invalid_addr - %define _FILE_HANDLE 8 + add DWORD [cur_line], 1 - push ebp - mov ebp, esp + jmp _repl_continue + _repl_cmd_incline_end: -.readLine_loop: + ; g goes to first line =-=-=-=-=-=-=-=-=-=-=-=-= + mov eax, DWORD [ebp-CMDSTR] + cmp BYTE [eax], 'g' + jne _repl_cmd_jumptop_end - ; read a single character - mov eax, 3 - mov ebx, [ebp+_FILE_HANDLE] - ; mov ecx, - mov edx, 1 - int 0x80 + mov DWORD [cur_line], 0x00 + + jmp _repl_continue + _repl_cmd_jumptop_end: + + ; G goes to last line =-=-=-=-=-=-=-=-=-=-=-=-= + mov eax, DWORD [ebp-CMDSTR] + cmp BYTE [eax], 'G' + jne _repl_cmd_jumpbot_end + + mov eax, DWORD [buffer_lines] + sub eax, 1 + mov DWORD [cur_line], eax + + jmp _repl_continue + _repl_cmd_jumpbot_end: + + ; c changes the current line =-=-=-=-=-=-=-=-=-= + mov eax, DWORD [ebp-CMDSTR] + cmp BYTE [eax], 'c' + jne _repl_cmd_change_end + + ; read a new line to use + push 0 + call readLine - jmp .readLine_loop + mov esi, eax + + ; free old string + mov eax, [cur_line] + mov ecx, 4 + mul ecx + add eax, [buffer] + push DWORD [eax] + call free + + ; insert new string + mov eax, [cur_line] + mov ecx, 4 + mul ecx + add eax, DWORD [buffer] + mov [eax], esi + + jmp _repl_continue + _repl_cmd_change_end: + + + jmp _repl_invalid_cmd + + ; some error messages + _repl_invalid_cmd: + push invalidcmd_str + call printf + jmp _repl_continue + + _repl_invalid_addr: + push invalidaddr_str + call printf + jmp _repl_continue + + _repl_continue: + jmp _repl_loop + + _repl_exit: + + %undef CMDSTR mov esp, ebp pop ebp ret - +