config: allow a chdir at the time a new configuration file is loaded

If a directory name/path prefix is appended to a loaded configuration
file, do a chdir at that point.  We finally have all the mechanism to
do this right.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

13 files changed, 98 insertions, 39 deletions

diff --git a/core/cmdline.inc b/core/cmdline.inc
index 8b84f48d..d860ac70 100644
--- a/core/cmdline.inc
+++ b/core/cmdline.inc
@@ -37,6 +37,7 @@ make_plain_cmdline:
 
 		dec di
 		mov [CmdLinePtr],di
+		mov byte [es:di],0		; Null-terminate
 
 		pop es
 		ret
diff --git a/core/comboot.inc b/core/comboot.inc
index e271b9ec..25c4e186 100644
--- a/core/comboot.inc
+++ b/core/comboot.inc
@@ -517,7 +517,7 @@ comapi_open:
 		mov ds,P_ES
 		mov si,P_SI
 		mov di,InitRD
-		pm_call mangle_name
+		pm_call pm_mangle_name
 		pop ds
 		pm_call pm_searchdir
 		jz comapi_err
@@ -749,7 +749,7 @@ comapi_runkernel:
 		mov ds,P_DS
 		mov si,P_SI
 		mov di,KernelName
-		pm_call mangle_name
+		pm_call pm_mangle_name
 		pop ds
 		pm_call pm_searchdir
 		jz comapi_err
diff --git a/core/conio.inc b/core/conio.inc
index 835359fb..60d1fcb2 100644
--- a/core/conio.inc
+++ b/core/conio.inc
@@ -207,7 +207,7 @@ msg_viewimage:
 		mov byte [si],0			; Zero-terminate filename
 		mov si,VGAFileBuf
 		mov di,VGAFileMBuf
-		pm_call mangle_name
+		pm_call pm_mangle_name
 		call core_open
 		jz msg_putcharnext		; Not there
 		call vgadisplayfile
diff --git a/core/extern.inc b/core/extern.inc
index da6c675b..3e25226a 100644
--- a/core/extern.inc
+++ b/core/extern.inc
@@ -13,14 +13,18 @@
 	extern hello
 
 	; fs.c
-	extern fs_init, pm_searchdir, getfssec, mangle_name, load_config
-        extern unmangle_name, close_file
+	extern fs_init, pm_searchdir, getfssec, pm_mangle_name, load_config
+        extern pm_unmangle_name, close_file
 
 	; chdir.c
 	extern pm_realpath
 
         ; readdir.c
         extern opendir, readdir, closedir
+
+	; newconfig.c
+	extern pm_is_config_file
+
 %if IS_PXELINUX
 	; pxe.c
 	extern unload_pxe, reset_pxe
diff --git a/core/fs.c b/core/fs.c
index 6acfd3be..c53636f2 100644
--- a/core/fs.c
+++ b/core/fs.c
@@ -70,26 +70,39 @@ void load_config(void)
 	printf("ERROR: No configuration file found\n");
 }
 
-void mangle_name(com32sys_t *regs)
+void pm_mangle_name(com32sys_t *regs)
 {
     const char *src = MK_PTR(regs->ds, regs->esi.w[0]);
     char       *dst = MK_PTR(regs->es, regs->edi.w[0]);
-    
-    this_fs->fs_ops->mangle_name(dst, src);
+
+    mangle_name(dst, src);
 }
 
+void mangle_name(char *dst, const char *src)
+{
+    this_fs->fs_ops->mangle_name(dst, src);
+}
 
-void unmangle_name(com32sys_t *regs)
+/*
+ * XXX: current unmangle_name() is stpcpy() on all filesystems; consider
+ * eliminating it as a method.
+ */
+void pm_unmangle_name(com32sys_t *regs)
 {
     const char *src = MK_PTR(regs->ds, regs->esi.w[0]);
     char       *dst = MK_PTR(regs->es, regs->edi.w[0]);
     
-    dst = this_fs->fs_ops->unmangle_name(dst, src);
+    dst = unmangle_name(dst, src);
 
     /* Update the di register to point to the last null char */
     regs->edi.w[0] = OFFS_WRT(dst, regs->es);
 }
 
+char *unmangle_name(char *dst, const char *src)
+{
+    return this_fs->fs_ops->unmangle_name(dst, src);
+}
+
 void getfssec(com32sys_t *regs)
 {
     int sectors;
diff --git a/core/include/core.h b/core/include/core.h
index 88ced70d..c955e730 100644
--- a/core/include/core.h
+++ b/core/include/core.h
@@ -11,6 +11,9 @@ extern char CurrentDirName[];
 extern char SubvolName[];
 extern char ConfigName[];
 extern char KernelName[];
+extern char cmd_line[];
+extern char ConfigFile[];
+extern char KernelCName[];
 
 /* diskstart.inc isolinux.asm*/
 extern void getlinsec(void);
diff --git a/core/include/fs.h b/core/include/fs.h
index 124a8161..49026141 100644
--- a/core/include/fs.h
+++ b/core/include/fs.h
@@ -166,8 +166,11 @@ static inline struct file *handle_to_file(uint16_t handle)
 }
 
 /* fs.c */
-void mangle_name(com32sys_t *);
+void pm_mangle_name(com32sys_t *);
+void pm_unmangle_name(com32sys_t *);
 void pm_searchdir(com32sys_t *);
+void mangle_name(char *, const char *);
+char *unmangle_name(char *, const char *);
 int searchdir(const char *name);
 void _close_file(struct file *);
 
diff --git a/core/kernel.inc b/core/kernel.inc
index 5e1c7a39..3ac5af1c 100644
--- a/core/kernel.inc
+++ b/core/kernel.inc
@@ -62,6 +62,9 @@ linux_fdctab	resb 12
 cmd_line_here	equ $			; F800 Should be out of the way
 		endstruc
 
+		global cmd_line
+cmd_line	equ (real_mode_seg << 4) + cmd_line_here
+
 ;
 ; Old kernel command line signature
 ;
diff --git a/core/newconfig.c b/core/newconfig.c
new file mode 100644
index 00000000..08027a39
--- /dev/null
+++ b/core/newconfig.c
@@ -0,0 +1,41 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2010 Intel Corporation; author: H. Peter Anvin
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ *   Boston MA 02110-1301, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * newconfig.c
+ *
+ * Load a new configuration file
+ */
+
+#include "core.h"
+#include "fs.h"
+
+void pm_is_config_file(com32sys_t *regs)
+{
+    char target_cwd[FILENAME_MAX];
+    const char *p;
+
+    (void)regs;
+
+    /* Save configuration file as an absolute path for posterity */
+    realpath(ConfigName, KernelCName, FILENAME_MAX);
+
+    /* If we got anything on the command line, do a chdir */
+    p = cmd_line;
+    while (*p && !not_whitespace(*p))
+	p++;
+
+    if (*p) {
+	mangle_name(target_cwd, p);
+	chdir(target_cwd);
+    }
+}
diff --git a/core/parsecmd.inc b/core/parsecmd.inc
index ab5a7df9..b6a2c829 100644
--- a/core/parsecmd.inc
+++ b/core/parsecmd.inc
@@ -122,17 +122,11 @@ Onerror		resb max_cmd_len+1	; onerror
 		section .bss16
 KbdMap		resb 256		; Keyboard map
 FKeyName	resb MAX_FKEYS*FILENAME_MAX	; File names for F-key help
-KernelCNameLen	resw 1			; Length of unmangled kernel name
 InitRDCNameLen	resw 1			; Length of unmangled initrd name
-%if IS_SYSLINUX
-KernelName      resb FILENAME_MAX+1	; Mangled name for kernel
-KernelCName     resb FILENAME_MAX+2	; Unmangled kernel name
-InitRDCName     resb FILENAME_MAX+2	; Unmangled initrd name
-%else
+		global KernelName, KernelCName
 KernelName      resb FILENAME_MAX	; Mangled name for kernel
 KernelCName     resb FILENAME_MAX	; Unmangled kernel name
 InitRDCName     resb FILENAME_MAX	; Unmangled initrd name
-%endif
 MNameBuf        resb FILENAME_MAX
 InitRD          resb FILENAME_MAX
 
diff --git a/core/parseconfig.inc b/core/parseconfig.inc
index ad89f58d..b30dbc2a 100644
--- a/core/parseconfig.inc
+++ b/core/parseconfig.inc
@@ -104,7 +104,7 @@ pc_kernel:	cmp byte [VKernel],0
 		mov [VKernelBuf+vk_type],al
 		call pc_getline
 		mov di,VKernelBuf+vk_rname
-		pm_call mangle_name
+		pm_call pm_mangle_name
 .err:		ret
 
 ;
@@ -147,7 +147,7 @@ pc_setint16:
 pc_filecmd:	push ax				; Function to tailcall
 		call pc_getline
 		mov di,MNameBuf
-		pm_call mangle_name
+		pm_call pm_mangle_name
 		pm_call pm_searchdir
 		jnz .ok
 		pop ax				; Drop the successor function
@@ -160,7 +160,7 @@ pc_filecmd:	push ax				; Function to tailcall
 pc_opencmd:	push ax				; Function to tailcall
 		call pc_getline
 		mov di,MNameBuf
-		pm_call mangle_name
+		pm_call pm_mangle_name
 		call core_open
 		jnz .ok
 		pop ax				; Drop the successor function
@@ -289,7 +289,7 @@ pc_serial:	call getint
 pc_filename:	push ax
 		call pc_getline
 		pop di
-		pm_call mangle_name		; Mangle file name
+		pm_call pm_mangle_name		; Mangle file name
 		ret
 
 ;
@@ -314,7 +314,7 @@ pc_label:	call commit_vk			; Commit any current vkernel
 		mov byte [VKernel],1		; We've seen a "label" statement
 		mov si,VKernelBuf+vk_vname	; By default, rname == mangled vname
 		mov di,VKernelBuf+vk_rname
-		pm_call mangle_name
+		pm_call pm_mangle_name
 		mov si,AppendBuf		; Default append==global append
 		mov di,VKernelBuf+vk_append
 		mov cx,[AppendLen]
@@ -409,7 +409,7 @@ commit_vk:
 		mov cx,7	; "initrd="
 		rep movsb
 		mov si,InitRD
-		pm_call unmangle_name
+		pm_call pm_unmangle_name
 		mov al,' '
 		stosb
 
diff --git a/core/runkernel.inc b/core/runkernel.inc
index f07c70f6..30177e80 100644
--- a/core/runkernel.inc
+++ b/core/runkernel.inc
@@ -78,10 +78,8 @@ construct_cmdline:
                 mov cx,boot_image_len
                 rep movsb
                 mov si,KernelCName		; Unmangled kernel name
-                mov cx,[KernelCNameLen]
-                rep movsb
-                mov al,' '                      ; Space
-                stosb
+		call strcpy
+		mov byte [es:di-1],' '		; Follow by space
 
 		call do_ip_append		; Handle IPAppend
 
@@ -546,7 +544,7 @@ parse_load_initrd:
 
 		push di
 		mov di,InitRD		; Target buffer for mangled name
-		pm_call mangle_name
+		pm_call pm_mangle_name
 		pop di
 		call loadinitrd
 
@@ -593,7 +591,7 @@ loadinitrd:
 		push edi
                 mov si,InitRD
                 mov di,InitRDCName
-                pm_call unmangle_name             ; Create human-readable name
+                pm_call pm_unmangle_name             ; Create human-readable name
                 sub di,InitRDCName
                 mov [InitRDCNameLen],di
                 mov di,InitRD
diff --git a/core/ui.inc b/core/ui.inc
index 827710f2..5fe3e539 100644
--- a/core/ui.inc
+++ b/core/ui.inc
@@ -333,11 +333,11 @@ load_kernel:					; Load the kernel now
 		mov si,command_line
                 mov di,KernelName
                 push si
-		pm_call mangle_name
+		pm_call pm_mangle_name
                 pop si
 ;
 ; Fast-forward to first option (we start over from the beginning, since
-; mangle_name doesn't necessarily return a consistent ending state.)
+; pm_mangle_name doesn't necessarily return a consistent ending state.)
 ;
 clin_non_wsp:   lodsb
                 cmp al,' '
@@ -400,6 +400,7 @@ vk_check:
 		mov si,VKernelBuf+vk_append
 		mov cx,[VKernelBuf+vk_appendlen]
 		rep movsb
+		mov byte [es:di],cl		; Null-terminate
 		mov [CmdLinePtr],di		; Where to add rest of cmd
 		pop es
 		mov di,KernelName
@@ -440,6 +441,7 @@ vk_check:
                 mov di,cmd_line_here
                 mov cx,[AppendLen]
                 rep movsb
+		mov byte [es:di],cl		; Null-terminate
                 mov [CmdLinePtr],di
                 pop di
                 pop si
@@ -487,7 +489,7 @@ bad_kernel:
 		mov si,KernelName
                 mov di,KernelCName
 		push di
-                pm_call unmangle_name              ; Get human form
+                pm_call pm_unmangle_name              ; Get human form
 		mov si,err_notfound		; Complain about missing kernel
 		call writestr
 		pop si				; KernelCName
@@ -616,9 +618,7 @@ kernel_good:
 
 		mov si,KernelName
 		mov di,KernelCName
-		pm_call unmangle_name
-		sub di,KernelCName
-		mov [KernelCNameLen],di
+		pm_call pm_unmangle_name
 
 		; Default memory limit, can be overridden by image loaders
 		mov eax,[HighMemRsvd]
@@ -675,9 +675,8 @@ is_unknown_filetype:
 
 is_config_file:
 		push si
-		mov si,KernelCName		; Save the config file name, for posterity
-		mov di,ConfigName
-		pm_call pm_realpath
+		call make_plain_cmdline
+		pm_call pm_is_config_file
 		pop si
 		call openfd
 		call reset_config