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
+
+; section .bss
section .text
main:
; read command line args
mov ecx, [ebp+8]
-
cmp ecx, 1
- jg .readFile
+ jg .main_existing
; display error msg if no file
push nofile_str
call printf
mov eax, 1
- jmp .exit
-
-.readFile:
+ jmp .main_exit
+.main_existing:
mov ebx, DWORD [ebp+12]
add ebx, 4
push DWORD [ebx]
- push readfile_str
- call printf
+ ; push readfile_str
+ ; call printf
+
+ call readFile
mov eax, 0
- jmp .exit
+ jmp .main_exit
+
+.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
+
+ push ebp
+ mov ebp, esp
+
+ ; allocate vars
+ sub esp, 4
+ mov DWORD [ebp-FILE_HANDLE], 0x00
+
+ ; open existing file
+ mov eax, 5
+ mov ebx, [ebp+_FILE_NAME]
+ mov ecx, 0
+ mov edx, 0700
+ int 0x80
+ mov [ebp-FILE_HANDLE], eax
+
+ ; check if file was open successfully
+ cmp eax, 0
+ jge .readFile_noerror
+ push eax
+ push wrongfile_str
+ call printf
+ jmp .readFile_exit
+
+.readFile_noerror:
+
+ jmp .readFile_exit
+
+.readFile_exit:
+
+ ; close file
+ mov eax, 6
+ mov ebx, [ebp-FILE_HANDLE]
+ int 0x80
+
+ %undef _FILE_NAME
+ %undef FILE_HANDLE
+
+ mov esp, ebp
+ pop ebp
+ ret
+
+
+; reads a line until newline character is reached
+; args: file_handle
+; return: location to buffer
+readLine:
+
+ %define _FILE_HANDLE 8
+
+ push ebp
+ mov ebp, esp
+
+.readLine_loop:
+
+ ; read a single character
+ mov eax, 3
+ mov ebx, [ebp+_FILE_HANDLE]
+ ; mov ecx,
+ mov edx, 1
+ int 0x80
+
+ jmp .readLine_loop
-.exit:
mov esp, ebp
pop ebp
ret
