Files
klibc/src/file.asm

100 lines
2.5 KiB
NASM

%include "src/constants.asm"
extern umask_get
section .rodata
; Open flags
O_ACCMODE equ 00000003q
O_RDONLY equ 00000000q
O_WRONLY equ 00000001q
O_RDWR equ 00000002q
O_CREAT equ 00000100q ;create if not exist
O_EXCL equ 00000200q ;fail if file exists and O_EXCL+O_CREAT set
O_NOCTTY equ 00000400q
O_TRUNC equ 00001000q
O_APPEND equ 00002000q
O_NONBLOCK equ 00004000q
O_DSYNC equ 00010000q
FASYNC equ 00020000q
O_DIRECT equ 00040000q
O_LARGEFILE equ 00100000q
O_DIRECTORY equ 00200000q
O_NOFOLLOW equ 00400000q
O_NOATIME equ 01000000q
O_CLOEXEC equ 02000000q
__O_SYNC equ 04000000q
O_SYNC equ (__O_SYNC | O_DSYNC)
O_PATH equ 01000000q
__O_TMPFILE equ 02000000q
O_TMPFILE equ (__O_TMPFILE | O_DIRECTORY)
O_NDELAY equ O_NONBLOCK
; Permission flags
S_IXOTH equ 00001q ;o=x
S_IWOTH equ 00002q ;o=w
S_IROTH equ 00004q ;o=r
S_IRWXO equ 00007q ;o=rwx
S_IXGRP equ 00010q ;g=x
S_IWGRP equ 00020q ;g=w
S_IRGRP equ 00040q ;g=r
S_IRWXG equ 00070q ;g=rwx
S_IXUSR equ 00100q ;u=x
S_IWUSR equ 00200q ;u=w
S_IRUSR equ 00400q ;u=r
S_IRWXU equ 00700q ;u=rwx
S_ISVIX equ 0001000q ;sticky bit
S_ISGID equ 0002000q ;set-group-ID bit
S_ISUID equ 0004000q ;set-user-ID bit
section .bss
section .text
global fopen
global fclose
global fexist
;----- fopen(*file[], char mode) -----;
; Opens a file
; Return value: Pointer to opened file pointer, 0 (EOS) otherwise.
; Possible modes:
; 'r' Read-only, file must exist
; 'w' Write-only. Creates empty file or truncates an existing file
; 'a' Append. Creates file if it does not exist
; 'R' Read+write, file must exist
; 'W' Read+write. Creates empty file or truncates an existing file
; 'A' Read+append. Creates file if it does not exist
; <!> Invalid mode will also return 0 (EOS)
; Used registers:
; rax* (ret)
; rdi (arg) Pointer to string holding (path+)file name
; rsi Mode to open the file with (see description above)
fopen:
ret
;----- fclose(file) -----;
; Closes an opened file
; Return value: 0 if file closed. Negative error number if an error occured
; Used registers:
; rax* (ret)
; rdi (arg) Pointer to opened file
fclose:
cmp rdi, 3
jl .invalid_fd ;disallow closing stdin,stdout,stderr
mov rax, NR_close
syscall
jmp .quit
.invalid_fd:
mov rax, -EINVAL
.quit:
ret
;----- fexist(*file[]) -----;
; Checks if given file exists (attempts to open the file)
; Return value: 0- File closed succesfully. -errno (negative error number) if an error occured
; Used registers:
; rax* (ret)
; rdi (arg) Pointer to string holding (path+)file name
fexist:
ret