1 ;; -----------------------------------------------------------------------
3 ;; Copyright 1994-2005 H. Peter Anvin - All Rights Reserved
5 ;; This program is free software; you can redistribute it and/or modify
6 ;; it under the terms of the GNU General Public License as published by
7 ;; the Free Software Foundation, Inc., 53 Temple Place Ste 330,
8 ;; Boston MA 02111-1307, USA; either version 2 of the License, or
9 ;; (at your option) any later version; incorporated herein by reference.
11 ;; -----------------------------------------------------------------------
14 ; This file should be entered with the config file open (for getc)
17 call parse_config ; Parse configuration file
21 ; Check whether or not we are supposed to display the boot prompt.
24 cmp word [ForcePrompt],0 ; Force prompt?
26 test byte [KbdFlags],5Bh ; Shift Alt Caps Scroll
27 jz auto_boot ; If neither, default boot
30 cmp word [NoEscape],0 ; If NOESCAPE, no prompt,
31 jne auto_boot ; always run default cmd
36 mov byte [FuncFlag],0 ; <Ctrl-F> not pressed
40 ; get the very first character -- we can either time
41 ; out, or receive a character press at this time. Some dorky BIOSes stuff
42 ; a return in the buffer on bootup, so wipe the keyboard buffer first.
44 clear_buffer: mov ah,11h ; Check for pending char
49 jmp short clear_buffer
51 ; For the first character, both KbdTimeout and
52 ; TotalTimeout apply; after that, only TotalTimeout.
55 mov eax,[TotalTimeout]
62 and dword [ThisKbdTo],0 ; For the next time...
67 got_ascii: cmp al,7Fh ; <DEL> == <BS>
72 cmp di,command_line ; Space must not be first
74 enter_char: test byte [FuncFlag],1
82 .not_ctrl_f: cmp di,max_cmd_len+command_line ; Check there's space
85 call writechr ; Echo to screen
87 not_ascii: mov byte [FuncFlag],0
90 cmp al,'F' & 1Fh ; <Ctrl-F>
92 cmp al,'U' & 1Fh ; <Ctrl-U>
93 je kill_command ; Kill input line
94 cmp al,'V' & 1Fh ; <Ctrl-V>
96 cmp al,'X' & 1Fh ; <Ctrl-X>
98 cmp al,08h ; Backspace
100 backspace: cmp di,command_line ; Make sure there is anything
101 je get_char ; to erase
102 dec di ; Unstore one character
103 mov si,wipe_char ; and erase it from the screen
116 mov byte [FuncFlag],1
120 ctrl_f_0: add al,10 ; <Ctrl-F>0 == F10
126 ; AL = 0 if we get here
132 show_help: ; AX = func key # (0 = F1, 9 = F10)
133 push di ; Save end-of-cmdline pointer
134 shl ax,FILENAME_MAX_LG2 ; Convert to pointer
137 cmp byte [di+NULLOFFSET],NULLFILE
138 je short fk_nofile ; Undefined F-key
140 jz short fk_nofile ; File not found
148 push di ; Command line write pointer
149 mov si,syslinux_banner
158 ; ... fall through ...
160 ; Write the boot prompt and command line again and
161 ; wait for input. Note that this expects the cursor
162 ; to already have been CRLF'd, and that the old value
163 ; of DI (the command line write pointer) is on the stack.
167 pop di ; Command line write pointer
169 mov byte [di],0 ; Null-terminate command line
171 call cwritestr ; Write command line so far
176 ; Jump here to run the default command line
181 mov cx,(max_cmd_len+4) >> 2
183 jmp short load_kernel
186 ; Jump here when the command line is completed
190 cmp di,command_line ; Did we just hit return?
192 xor al,al ; Store a final null
195 load_kernel: ; Load the kernel now
197 ; First we need to mangle the kernel name the way DOS would...
207 ; Fast-forward to first option (we start over from the beginning, since
208 ; mangle_name doesn't necessarily return a consistent ending state.)
213 clin_is_wsp: and al,al
218 clin_opt_ptr: dec si ; Point to first nonblank
219 mov [CmdOptPtr],si ; Save ptr to first option
221 ; If "allowoptions 0", put a null character here in order to ignore any
222 ; user-specified options.
224 mov ax,[AllowOptions]
231 ; Now check if it is a "virtual kernel"
234 xor si,si ; Beginning of vk_seg
236 cmp si,[VKernelBytes]
246 ; SI updated on return
248 sub di,cx ; Return to beginning of buf
258 ; We *are* using a "virtual kernel"
262 push word real_mode_seg
265 mov si,VKernelBuf+vk_append
266 mov cx,[VKernelBuf+vk_appendlen]
268 mov [CmdLinePtr],di ; Where to add rest of cmd
272 mov si,VKernelBuf+vk_rname
273 mov cx,FILENAME_MAX ; We need ECX == CX later
277 mov al,[VKernelBuf+vk_ipappend]
280 xor bx,bx ; Try only one version
282 mov al, [VKernelBuf+vk_type]
285 %if IS_PXELINUX || IS_ISOLINUX
286 ; Is this a "localboot" pseudo-kernel?
288 cmp byte [VKernelBuf+vk_rname+4], 0
290 cmp byte [VKernelBuf+vk_rname], 0
292 jne get_kernel ; No, it's real, go get it
294 mov ax, [VKernelBuf+vk_rname+1]
303 ; Not a "virtual kernel" - check that's OK and construct the command line
305 cmp word [AllowImplicit],byte 0
321 mov [KernelType], cl ; CL == 0 here
324 ; Find the kernel on disk
326 get_kernel: mov byte [KernelName+FILENAME_MAX],0 ; Zero-terminate filename/extension
327 %if IS_SYSLINUX || IS_MDSLINUX ; SYSLINUX has to deal with DOS mangled names...
328 mov eax,[KernelName+8] ; Save initial extension
329 mov [exten_table_end],eax ; Last case == initial ext.
331 mov di,KernelName+4*IS_PXELINUX
333 mov cx,FILENAME_MAX-5 ; Need 4 chars + null
334 repne scasb ; Scan for final null
336 dec di ; Point to final null
337 .no_skip: mov [KernelExtPtr],di
340 .search_loop: push bx
341 mov di,KernelName ; Search on disk
345 mov eax,[bx] ; Try a different extension
346 %if IS_SYSLINUX || IS_MDSLINUX
347 mov [KernelName+8],eax
349 mov si,[KernelExtPtr]
354 cmp bx,exten_table_end
355 jna .search_loop ; allow == case (final case)
356 ; Fall into bad_kernel
358 ; bad_kernel: Kernel image not found
359 ; bad_implicit: The user entered a nonvirtual kernel name, with "implicit 0"
370 call unmangle_name ; Get human form
371 mov si,err_notfound ; Complain about missing kernel
376 jmp abort_load ; Ask user for clue
379 ; on_error: bad kernel, but we have onerror set
390 pop di ; <E> di == command_line
391 pop bx ; <D> bx == [OnerrorLen]
392 je bad_kernel.really ; Onerror matches command_line already
393 neg bx ; bx == -[OnerrorLen]
394 lea cx,[max_cmd_len+bx]
395 ; CX == max_cmd_len-[OnerrorLen]
396 mov di,command_line+max_cmd_len-1
397 mov byte [di+1],0 ; Enforce null-termination
400 rep movsb ; Make space in command_line
402 pop cx ; <C> cx == [OnerrorLen]
403 pop di ; <B> di == command_line
404 pop si ; <A> si == Onerror
409 ; kernel_corrupt: Called if the kernel file does not seem healthy
411 kernel_corrupt: mov si,err_notkernel
415 ; Get a key, observing ThisKbdTO and ThisTotalTO -- those are timeouts
416 ; which can be adjusted by the caller based on the corresponding
417 ; master variables; on return they're updated.
419 ; This cheats. If we say "no timeout" we actually get a timeout of
427 push word [BIOS_timer]
431 cmp ax,[BIOS_timer] ; Has the timer advanced?
435 dec dword [ThisKbdTo]
437 dec dword [ThisTotalTo]
442 pop cx ; Discard return address
444 mov si,Ontimeout ; Copy ontimeout command
446 mov cx,[OntimeoutLen] ; if we have one...
457 ; This is it! We have a name (and location on the disk)... let's load
458 ; that sucker!! First we have to decide what kind of file this is; base
459 ; that decision on the file extension. The following extensions are
460 ; recognized; case insensitive:
462 ; .com - COMBOOT image
463 ; .cbt - COMBOOT image
466 ; .0 - PXE bootstrap program (PXELINUX only)
468 ; .bss - Boot sector, but transfer over DOS superblock (SYSLINUX only)
469 ; .img - Floppy image (ISOLINUX only)
471 ; Anything else is assumed to be a Linux kernel.
480 ; Alternate entry point for which the return from
481 ; searchdir is stored in memory. This is used for
482 ; COMBOOT function INT 22h, AX=0016h.
485 mov dx,[Kernel_EAX+2]
493 mov [KernelCNameLen],di
496 %if IS_SYSLINUX || IS_MDSLINUX
497 mov ecx,[KernelName+7]
502 mov di,KernelName+4*IS_PXELINUX
508 .one_step: mov ecx,[di-4] ; 4 bytes before end
514 ; At this point, DX:AX contains the size of the kernel, SI contains
515 ; the file handle/cluster pointer, and ECX contains the extension (if any.)
517 movzx di,byte [KernelType]
519 jmp [kerneltype_table+di]
522 or ecx,20202000h ; Force lower case (except dot)
538 %if IS_SYSLINUX || IS_MDSLINUX
551 ; Otherwise Linux kernel
559 ; This is an image type we can't deal with
565 %if IS_SYSLINUX || IS_MDSLINUX
568 is_bss_sector equ is_bad_image
573 is_disk_image equ is_bad_image
577 err_badimage db 'Invalid image type for this media type!', CR, LF, 0
581 dw is_unknown_filetype ; VK_KERNEL
582 dw is_linux_kernel ; VK_LINUX
583 dw is_bootsector ; VK_BOOT
584 dw is_bss_sector ; VK_BSS
585 dw is_disk_image ; VK_FDIMAGE
586 dw is_comboot_image ; VK_COMBOOT
587 dw is_com32_image ; VK_COM32
588 dw is_config_file ; VK_CONFIG
592 ThisKbdTo resd 1 ; Temporary holder for KbdTimeout
593 ThisTotalTo resd 1 ; Temporary holder for TotalTimeout
594 KernelExtPtr resw 1 ; During search, final null pointer
595 CmdOptPtr resw 1 ; Pointer to first option on cmd line
596 KbdFlags resb 1 ; Check for keyboard escapes
597 FuncFlag resb 1 ; Escape sequences received from keyboard
598 KernelType resb 1 ; Kernel type, from vkernel, if known