; sped - the stupidly pointless editor
; written by pinosaur
+; sped.asm: main file
-%include "fileutils.S"
+%include "macros.S"
extern printf
-extern fflush
-extern stdout
-extern free
-global main
+extern readFile
+extern repl
-; macros
-%macro write_str 2
- mov eax, 4
- mov ebx, 1
- mov ecx, %1
- mov edx, %2
- int 0x80
-%endmacro
+global main
section .data
banner_str db `SPED - the stupidly pointless editor\n`, 0x00
- nofile_str db `no file provided\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
- buffer resb 4
- buffer_lines resb 4
- buffer_filename resb 4
- cur_line resb 4
+ nofile_str db `no file provided.\n`, 0x00
+ readlines_str db `opened file with %i lines.\n`, 0x00
section .text
main:
%define _ARGC 8
%define _ARGV 12
+ %define BUFFER 4
+ %define BUFFER_LINES 8
+ %define BUFFER_FILENAME 12
+
push ebp
mov ebp, esp
+ sub esp, 12
+
; read command line args
mov ecx, [ebp+_ARGC]
cmp ecx, 1
mov ebx, DWORD [ebp+_ARGV]
add ebx, 4 ; first user arg is filename
mov ebx, [ebx]
- mov [buffer_filename], ebx
+ mov [ebp-BUFFER_FILENAME], ebx
- push DWORD [buffer_filename]
+ push DWORD [ebp-BUFFER_FILENAME]
call readFile
- mov [buffer], eax
- mov [buffer_lines], ecx
- mov DWORD [cur_line], 0x00
+ mov [ebp-BUFFER], eax
+ mov [ebp-BUFFER_LINES], ecx
- push DWORD [buffer_lines]
+ push DWORD [ebp-BUFFER_LINES]
push readlines_str
call printf
+ push DWORD [ebp-BUFFER]
+ push DWORD [ebp-BUFFER_LINES]
+ push DWORD [ebp-BUFFER_FILENAME]
call repl
mov eax, 0
; free string array
-
%undef _ARGC
%undef _ARGV
+ %undef BUFFER
+ %undef BUFFER_LINES
+ %undef BUFFER_FILENAME
mov esp, ebp
pop ebp
ret
-; prompt for user
-; no args - reads from globals
-repl:
-
- %define CMDSTR 4 ; the previous line read from user
-
- push ebp
- mov ebp, esp
-
- sub esp, 4
-
- _repl_loop:
-
- ; print the prompt
- push prompt_str
- call printf
- push DWORD [stdout]
- call fflush
-
- ; 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 _repl_continue
- _repl_cmd_print_end:
-
- ; n prints the current line number =-=-=-=-=-=-=-=
- mov eax, DWORD [ebp-CMDSTR]
- cmp BYTE [eax], 'n'
- jne _repl_cmd_number_end
-
- push DWORD [cur_line]
- push currentline_str
- call printf
-
- jmp _repl_continue
- _repl_cmd_number_end:
-
- ; - goes to prev line =-=-=-=-=-=-=-=-=-=-=-=-=
- mov eax, DWORD [ebp-CMDSTR]
- cmp BYTE [eax], '-'
- jne _repl_cmd_decline_end
-
- ; 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
-
- jmp _repl_continue
- _repl_cmd_decline_end:
-
- ; + goes to next line =-=-=-=-=-=-=-=-=-=-=-=-=
- mov eax, DWORD [ebp-CMDSTR]
- cmp BYTE [eax], '+'
- jne _repl_cmd_incline_end
-
- ; make sure we are within bounds
- mov eax, DWORD [cur_line]
- add eax, 1
- cmp eax, [buffer_lines]
- jge _repl_invalid_addr
-
- add DWORD [cur_line], 1
-
- jmp _repl_continue
- _repl_cmd_incline_end:
-
- ; g goes to first line =-=-=-=-=-=-=-=-=-=-=-=-=
- mov eax, DWORD [ebp-CMDSTR]
- cmp BYTE [eax], 'g'
- jne _repl_cmd_jumptop_end
-
- 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
-
- 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:
-
- ; w writes file =-=-=-=-=-=-=-=-=-=-=-=-=
- mov eax, DWORD [ebp-CMDSTR]
- cmp BYTE [eax], 'w'
- jne _repl_cmd_write_end
-
- push DWORD [buffer_filename]
- push DWORD [buffer]
- push DWORD [buffer_lines]
- call writeFile
-
- jmp _repl_continue
- _repl_cmd_write_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
-
