Sorry, forgot to attach
phcoder wrote:
> Hello, again
> I had a look at your patch. In some mail it was suggested that kernel
> patch should be split from module that uses it. So I resend the kernel
> part of my patch. Another question is whether we need some kind of
> abortion procedure (like in your patch) if a preboot hook fails.
> Javier Martín wrote:
>> An interface like this is implemented in another patch in "discussion",
>> my drivemap patch (see the August list archives). As yours, it is
>> linked-list based and very similar in the prototypes. I haven't checked
>> if your code has any kind of errors/corner cases,
>
> I checked and found that I didn't check if grub_malloc succeeded
>
>> but it seems terser
>> than mine even though it's a bit more difficult to understand because
>> you use double pointers to avoid my handling of the head case. I don't
>> understand the purpose of doubly-linking the list though...
>>
> The goal is to avoid walking through list when deleting an entry from it.
>>> Whether we need also interface for adding "postboot" commands? (in case
>>> boot_function returns)
>> I don't think it would offer a lot of functionality because most loaders
>> don't return on failure, they just get stuck or their payload
>> triple-faults and reboots.
>
> It's the case for i386-pc loaders but not the case of some other targets
> (e.g. EFI). So the question remains.
>
> Vladimir Serbinenko
Index: kern/loader.c
===================================================================
--- kern/loader.c (revision 1845)
+++ kern/loader.c (working copy)
@@ -22,12 +22,46 @@
#include <grub/err.h>
#include <grub/kernel.h>
+
static grub_err_t (*grub_loader_boot_func) (void);
static grub_err_t (*grub_loader_unload_func) (void);
static int grub_loader_noreturn;
static int grub_loader_loaded;
+static struct grub_preboot_t *grub_loader_preboots=0;
+
+struct grub_preboot_t *
+grub_loader_add_preboot (grub_err_t (*preboot_func) (int))
+{
+ struct grub_preboot_t **cur=&grub_loader_preboots;
+ if (!preboot_func)
+ return 0;
+ while (*cur)
+ cur=&((*cur)->next);
+ *cur=(struct grub_preboot_t *)grub_malloc (sizeof (struct grub_preboot_t));
+ if (!*cur)
+ {
+ grub_error (GRUB_ERR_OUT_OF_MEMORY, "hook not added");
+ return 0;
+ }
+ (*cur)->prev_pointer=cur;
+ (*cur)->next=0;
+ (*cur)->preboot_func=preboot_func;
+ return *cur;
+}
+
+void
+grub_loader_remove_preboot (struct grub_preboot_t *p)
+{
+ if (!p)
+ return;
+ *(p->prev_pointer)=p->next;
+ if (p->next)
+ (p->next)->prev_pointer=p->prev_pointer;
+ grub_free (p);
+}
+
int
grub_loader_is_loaded (void)
{
@@ -64,11 +98,19 @@
grub_err_t
grub_loader_boot (void)
{
+ struct grub_preboot_t *iter=grub_loader_preboots;
if (! grub_loader_loaded)
return grub_error (GRUB_ERR_NO_KERNEL, "no loaded kernel");
if (grub_loader_noreturn)
grub_machine_fini ();
+
+ while (iter)
+ {
+ if (iter->preboot_func)
+ iter->preboot_func (grub_loader_noreturn);
+ iter=iter->next;
+ }
return (grub_loader_boot_func) ();
}
Index: include/grub/loader.h
===================================================================
--- include/grub/loader.h (revision 1845)
+++ include/grub/loader.h (working copy)
@@ -25,6 +25,14 @@
#include <grub/err.h>
#include <grub/types.h>
+struct grub_preboot_t
+{
+ grub_err_t (*preboot_func) (int);
+ struct grub_preboot_t *next;
+ struct grub_preboot_t **prev_pointer;
+};
+
+
/* Check if a loader is loaded. */
int EXPORT_FUNC(grub_loader_is_loaded) (void);
@@ -37,6 +45,12 @@
/* Unset current loader, if any. */
void EXPORT_FUNC(grub_loader_unset) (void);
+/*Add a preboot function*/
+struct grub_preboot_t *EXPORT_FUNC(grub_loader_add_preboot) (grub_err_t (*preboot_func) (int noreturn));
+
+/*Remove given preboot function*/
+void EXPORT_FUNC(grub_loader_remove_preboot) (struct grub_preboot_t *p);
+
/* Call the boot hook in current loader. This may or may not return,
depending on the setting by grub_loader_set. */
grub_err_t EXPORT_FUNC(grub_loader_boot) (void);
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