[PATCHv4 3/8] kexec: Introduce a new image probe method 'probe2'

[Pingfan Liu]

As more complicated capsule kernel format occurs like zboot, where the
compressed kernel is stored as a payload. The straight forward
decompression can not meet the demand.

So introducing a new image probe interface -- probe2, which reads in the
kernel file and decides how to unfold the content by the method itself.

The interface probe and probe2 can not coexist

Signed-off-by: Pingfan Liu <piliu at redhat.com>
To: kexec at lists.infradead.org
Cc: horms at verge.net.au
Cc: ardb at kernel.org
Cc: jeremy.linton at arm.com
---
 kexec/kexec.c | 31 +++++++++++++++++++++++--------
 kexec/kexec.h |  9 +++++++++
 2 files changed, 32 insertions(+), 8 deletions(-)

diff --git a/kexec/kexec.c b/kexec/kexec.c
index d5e6dc0..5f75179 100644
--- a/kexec/kexec.c
+++ b/kexec/kexec.c
@@ -702,6 +702,9 @@ static int initialze_probe(const char *kern_fname,
 	if (probe_type >= 0)
 		return probe_type;
 
+	if (!file_type[0].probe)
+		goto type_probe2;
+
 	*kernel_fd = open(kern_fname, O_RDONLY);
 	if (*kernel_fd == -1) {
 		die("Failed to open file %s:%s\n", kern_fname,
@@ -712,27 +715,39 @@ static int initialze_probe(const char *kern_fname,
 	/* slurp in the input kernel */
 	*kernel_buf = slurp_decompress_file(kern_fname, kernel_size);
 	probe_type = 0;
+	return probe_type;
 
+type_probe2:
+	probe_type = 1;
 	return probe_type;
 }
 
 static int probe(struct file_type *ft, const char *kern_fname,
 		char **kernel_buf, off_t *kernel_size, int *kernel_fd)
 {
+	struct parsed_info info;
 	int ret;
 
-	initialze_probe(kern_fname, kernel_buf, kernel_size, kernel_fd);
+	ret = initialze_probe(kern_fname, kernel_buf, kernel_size, kernel_fd);
+	if (ret == 0) {
 #ifdef __aarch64__
-	/* handle Image.gz like cases */
-	if (is_zlib_file(kern_fname, &kernel_size)) {
-		if ((ret = ft->probe(kern_fname, *kernel_size)) >= 0)
-			*kernel_fd = ret;
-	} else {
-		ret = ft->probe(*kernel_buf, *kernel_size);
-	}
+		/* handle Image.gz like cases */
+		if (is_zlib_file(kern_fname, &kernel_size)) {
+			if ((ret = ft->probe(kern_fname, *kernel_size)) >= 0)
+				*kernel_fd = ret;
+		} else {
+			ret = ft->probe(*kernel_buf, *kernel_size);
+		}
 #else
 		ret = ft->probe(*kernel_buf, *kernel_size);
 #endif
+	} else if (ret == 1) {
+		ret = ft->probe2(kern_fname, &info);
+		*kernel_buf = info.kernel_buf;
+		*kernel_size = info.kernel_size;
+		*kernel_fd = info.fd;
+	}
+
 	return ret;
 }
 
diff --git a/kexec/kexec.h b/kexec/kexec.h
index 0d820ad..fbeee3d 100644
--- a/kexec/kexec.h
+++ b/kexec/kexec.h
@@ -176,6 +176,12 @@ struct arch_map_entry {
 	unsigned long arch;
 };
 
+struct parsed_info {
+	char *kernel_buf;
+	off_t kernel_size;
+	int fd;
+};
+
 extern const struct arch_map_entry arches[];
 long physical_arch(void);
 
@@ -192,6 +198,7 @@ unsigned long locate_hole(struct kexec_info *info,
 	int hole_end);
 
 typedef int (probe_t)(const char *kernel_buf, off_t kernel_size);
+typedef int (probe2_t)(const char *kern_fname, struct parsed_info *info);
 typedef int (load_t )(int argc, char **argv,
 	const char *kernel_buf, off_t kernel_size, 
 	struct kexec_info *info);
@@ -201,6 +208,8 @@ struct file_type {
 	probe_t *probe;
 	load_t  *load;
 	usage_t *usage;
+	/* Keep it as the last one so that by default it is NULL */
+	probe2_t *probe2;
 };
 
 extern struct file_type file_type[];
-- 
2.31.1