On Thu, Jul 11, 2019 at 01:24:28AM +0530, Bhupesh Sharma wrote:
> 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 <[email protected]>
> ---
> 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");
Does fp need to be closed somewhere to avoid a leak?
> + 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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