From: Emil Velikov <[email protected]> Since all the compression magic is always available now, we don't need to loop at runtime nor use alloca - latter of which comes with a handful of caveats.
Simply throw in a few assert_cc(), which will trigger at build-time. Signed-off-by: Emil Velikov <[email protected]> --- libkmod/libkmod-file.c | 22 ++++++++-------------- 1 file changed, 8 insertions(+), 14 deletions(-) diff --git a/libkmod/libkmod-file.c b/libkmod/libkmod-file.c index b69f1ef..5b88d6c 100644 --- a/libkmod/libkmod-file.c +++ b/libkmod/libkmod-file.c @@ -410,7 +410,6 @@ struct kmod_file *kmod_file_open(const struct kmod_ctx *ctx, { struct kmod_file *file = calloc(1, sizeof(struct kmod_file)); const struct comp_type *itr; - size_t magic_size_max = 0; int err = 0; if (file == NULL) @@ -422,22 +421,17 @@ struct kmod_file *kmod_file_open(const struct kmod_ctx *ctx, goto error; } - for (itr = comp_types; itr->load != NULL; itr++) { - if (magic_size_max < itr->magic_size) - magic_size_max = itr->magic_size; - } - - if (magic_size_max > 0) { - char *buf = alloca(magic_size_max + 1); + { + char buf[7]; ssize_t sz; - if (buf == NULL) { - err = -errno; - goto error; - } - sz = read_str_safe(file->fd, buf, magic_size_max + 1); + assert_cc(sizeof(magic_zstd) < sizeof(buf)); + assert_cc(sizeof(magic_xz) < sizeof(buf)); + assert_cc(sizeof(magic_zlib) < sizeof(buf)); + + sz = read_str_safe(file->fd, buf, sizeof(buf)); lseek(file->fd, 0, SEEK_SET); - if (sz != (ssize_t)magic_size_max) { + if (sz != (sizeof(buf) - 1)) { if (sz < 0) err = sz; else -- 2.43.0
