; sped - the stupidly pointless editor
; written by pinosaur
-global main
+%include "fileutils.S"
+
extern printf
-extern malloc
-extern realloc
+extern fflush
+extern stdout
extern free
-extern memset
+
+global main
; macros
%macro write_str 2
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
- char_str db `read this char: %i\n`, 0x00
- printfint_str db `int: %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
+ buffer resb 4
+ buffer_lines resb 4
+ cur_line resb 4
section .text
main:
_main_existing:
mov ebx, DWORD [ebp+_ARGV]
- add ebx, 4
+ 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
_main_exit:
+
+ ; free string array
+
+
%undef _ARGC
%undef _ARGV
pop ebp
ret
+; prompt for user
+; no args - reads from globals
+repl:
-; reads file line by line
-; args: filename
-; return:
-; eax - pointer to mem
-; ecx - lines read
-readFile:
- %define _FILE_NAME 8
- %define FILE_HANDLE 4
- %define IS_EOF 8
- %define LINES_READ 12
- %define BUF_PTR 16 ; malloced array of strings
+ %define CMDSTR 4 ; the previous line read from user
push ebp
mov ebp, esp
+
+ sub esp, 4
+
+ _repl_loop:
- ; allocate vars
- sub esp, 16
- mov DWORD [ebp-FILE_HANDLE], 0x00
- mov DWORD [ebp-IS_EOF], 0x00
- mov DWORD [ebp-LINES_READ], 0x00
+ ; print the prompt
+ push prompt_str
+ call printf
+ push DWORD [stdout]
+ call fflush
+ ; read line from stdin
push 0
- call malloc
- mov [ebp-BUF_PTR], eax
-
- ; open existing file
- mov eax, 5
- mov ebx, [ebp+_FILE_NAME]
- mov ecx, 0
- mov edx, 0777
- int 0x80
- mov [ebp-FILE_HANDLE], eax
+ call readLine
- ; check if file was open successfully
- cmp eax, 0
- jge _readFile_loop
- push eax
- push wrongfile_str
+ 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_loop:
+ ; n prints the current line number =-=-=-=-=-=-=-=
+ mov eax, DWORD [ebp-CMDSTR]
+ cmp BYTE [eax], 'n'
+ jne _repl_cmd_number_end
- ; check if eof was reached
- cmp DWORD [ebp-IS_EOF], 1
- je _readFile_exit
+ push DWORD [cur_line]
+ push currentline_str
+ call printf
- push DWORD [ebp-FILE_HANDLE]
- call readLine
+ jmp _repl_continue
+ _repl_cmd_number_end:
- mov esi, eax
- mov [ebp-IS_EOF], ebx
+ ; - 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
- push esi
- call printf
+ 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 string buffer bigger
- mov eax, DWORD [ebp-LINES_READ]
+ ; make sure we are within bounds
+ mov eax, DWORD [cur_line]
add eax, 1
- mov ecx, 4
- mul ecx
- push eax
- push DWORD [ebp-BUF_PTR]
- call realloc
- mov DWORD [ebp-BUF_PTR], eax
+ cmp eax, [buffer_lines]
+ jge _repl_invalid_addr
+
+ add DWORD [cur_line], 1
- ; write string to buffer
- mov eax, DWORD [ebp-BUF_PTR]
- mov ecx, 4
- mul ecx
- mov eax, esi
+ jmp _repl_continue
+ _repl_cmd_incline_end:
- add DWORD [ebp-LINES_READ], 1
+ ; g goes to first line =-=-=-=-=-=-=-=-=-=-=-=-=
+ mov eax, DWORD [ebp-CMDSTR]
+ cmp BYTE [eax], 'g'
+ jne _repl_cmd_jumptop_end
- jmp _readFile_loop
+ mov DWORD [cur_line], 0x00
- _readFile_exit:
- ; close file
- mov eax, 6
- mov ebx, [ebp-FILE_HANDLE]
- int 0x80
+ jmp _repl_continue
+ _repl_cmd_jumptop_end:
- %undef _FILE_NAME
- %undef FILE_HANDLE
- %undef IS_EOF
- %undef LINES_READ
- %undef BUF_PTR
+ ; G goes to last line =-=-=-=-=-=-=-=-=-=-=-=-=
+ mov eax, DWORD [ebp-CMDSTR]
+ cmp BYTE [eax], 'G'
+ jne _repl_cmd_jumpbot_end
- mov esp, ebp
- pop ebp
- ret
+ mov eax, DWORD [buffer_lines]
+ sub eax, 1
+ mov DWORD [cur_line], eax
+ jmp _repl_continue
+ _repl_cmd_jumpbot_end:
-; reads a line until newline character is reached
-; args: file_handle
-; return:
-; eax: location to buffer
-; ebx: contains eof
-readLine:
- %define _FILE_HANDLE 8
- %define CHAR_COUNT 4 ; count number of characters read
- %define BLOCK_COUNT 8 ; number of 64 blocks we've read
- %define STR_PTR 12 ; malloced buffer to store read string
+ ; c changes the current line =-=-=-=-=-=-=-=-=-=
+ mov eax, DWORD [ebp-CMDSTR]
+ cmp BYTE [eax], 'c'
+ jne _repl_cmd_change_end
- push ebp
- mov ebp, esp
-
- ; allocate vars
- sub esp, 12
- mov DWORD [ebp-CHAR_COUNT], 0x00
- mov DWORD [ebp-BLOCK_COUNT], 0x00
-
- push 64
- call malloc
- mov [ebp-STR_PTR], eax
-
- push DWORD [ebp-STR_PTR]
- push 0x00
- push 64
-
- _readLine_loop:
- ; if buffer is full
- cmp BYTE [ebp-CHAR_COUNT], 63 ; leave one byte for null byte
- jne _readLine_notfull
- jmp _readLine_exit
-
- _readLine_notfull:
- ; read a single character
- mov eax, 3
- mov ebx, [ebp+_FILE_HANDLE]
- mov ecx, [ebp-STR_PTR]
- add ecx, [ebp-CHAR_COUNT]
- mov edx, 1
- int 0x80
+ ; read a new line to use
+ push 0
+ call readLine
- ; mov eax, 4
- ; mov ebx, 1
- ; mov ecx, [ebp-STR_PTR]
- ; add ecx, [ebp-CHAR_COUNT]
- ; mov edx, 1
- ; int 0x80
-
- ; check for eof
- cmp eax, 0 ; eax has zero on eof
- jne _readLine_not_eof
- mov ebx, 1
- jmp _readLine_exit
- _readLine_not_eof:
+ mov esi, eax
+
+ ; free old string
+ mov eax, [cur_line]
+ mov ecx, 4
+ mul ecx
+ add eax, [buffer]
+ push DWORD [eax]
+ call free
- ; check for newline
- mov eax, [ebp-STR_PTR]
- add eax, [ebp-CHAR_COUNT]
- cmp DWORD [eax], 0x0a
- jne _readLine_not_newline
- mov ebx, 0
- jmp _readLine_exit
- _readLine_not_newline:
+ ; insert new string
+ mov eax, [cur_line]
+ mov ecx, 4
+ mul ecx
+ add eax, DWORD [buffer]
+ mov [eax], esi
- add DWORD [ebp-CHAR_COUNT], 1
- jmp _readLine_loop
+ jmp _repl_continue
+ _repl_cmd_change_end:
- _readLine_exit:
- mov eax, DWORD [ebp-STR_PTR]
+ jmp _repl_invalid_cmd
- %undef _FILE_HANDLE
- %undef CHAR_COUNT
- %undef BLOCK_COUNT
- %undef STR_PTR
+ ; 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
-
+
