libkmod: swap alloca usage for a few assert_cc

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 <emil.l.velikov@gmail.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Lucas De Marchi <lucas.de.marchi@gmail.com>
This commit is contained in:
Emil Velikov 2024-02-12 17:23:10 +00:00 committed by Lucas De Marchi
parent 0c12738807
commit 737744301a

View File

@ -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