This patch adds 'is_zlib_file()' helper function which can be
used to quickly determine with the passed kernel image is a zlib
compressed kernel image.
This is specifically useful for arm64 zImage (or Image.gz) support,
which is introduced by later patches in this patchset.
Signed-off-by: Bhupesh Sharma <bhsharma@xxxxxxxxxx>
---
kexec/kexec-zlib.h | 1 +
kexec/zlib.c | 32 ++++++++++++++++++++++++++++++++
2 files changed, 33 insertions(+)
diff --git a/kexec/kexec-zlib.h b/kexec/kexec-zlib.h
index 43c107bf4a72..16300f294759 100644
--- a/kexec/kexec-zlib.h
+++ b/kexec/kexec-zlib.h
@@ -6,5 +6,6 @@
#include "config.h"
+int is_zlib_file(const char *filename, off_t *r_size);
char *zlib_decompress_file(const char *filename, off_t *r_size);
#endif /* __KEXEC_ZLIB_H */
diff --git a/kexec/zlib.c b/kexec/zlib.c
index 95b608059d41..34d5ca566769 100644
--- a/kexec/zlib.c
+++ b/kexec/zlib.c
@@ -23,6 +23,32 @@ static void _gzerror(gzFile fp, int *errnum, const char **errmsg)
}
}
+int is_zlib_file(const char *filename, off_t *r_size)
+{
+ gzFile fp;
+ int errnum;
+ const char *msg;
+
+ if (!filename)
+ goto out;
+
+ fp = gzopen(filename, "rb");
+ if (fp == 0) {
+ _gzerror(fp, &errnum, &msg);
+ dbgprintf("Cannot open `%s': %s\n", filename, msg);
+ goto out;
+ }
+
+ if (gzdirect(fp))
+ /* It's not in gzip format */
+ goto out;
+
+ /* It's in gzip format */
+ return 1;
+out:
+ return 0;
+}
+
char *zlib_decompress_file(const char *filename, off_t *r_size)
{
gzFile fp;
@@ -84,6 +110,12 @@ fail:
return buf;
}
#else
+
+int is_zlib_file(const char *filename, off_t *r_size)
+{
+ return 0;
+}
+
char *zlib_decompress_file(const char *UNUSED(filename), off_t *UNUSED(r_size))
{
return NULL;
--
2.7.4
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