From 0e709571bfe7e3b8160044970e2084194f9a963b Mon Sep 17 00:00:00 2001 From: Bhupesh Sharma Date: Mon, 15 Jul 2019 11:32:55 +0530 Subject: [PATCH 3/5] kexec/kexec-zlib.h: Add 'is_zlib_file()' helper function 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 Signed-off-by: Simon Horman --- kexec/kexec-zlib.h | 1 + kexec/zlib.c | 38 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 39 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..9bc340d85001 100644 --- a/kexec/zlib.c +++ b/kexec/zlib.c @@ -23,6 +23,38 @@ 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; + int is_zlib_file = 0; /* default: It's not in gzip format */ + const char *msg; + ssize_t result; + + 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 in gzip format */ + is_zlib_file = 1; + + result = gzclose(fp); + if (result != Z_OK) { + _gzerror(fp, &errnum, &msg); + dbgprintf(" Close of %s failed: %s\n", filename, msg); + } + +out: + return is_zlib_file; +} + char *zlib_decompress_file(const char *filename, off_t *r_size) { gzFile fp; @@ -84,6 +116,12 @@ 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