On Mon, Feb 12, 2024 at 05:23:10PM GMT, Emil Velikov via B4 Relay wrote:
From: Emil Velikov <emil.l.velikov@xxxxxxxxx>
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@xxxxxxxxx>
---
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));
../libkmod/libkmod-file.c: In function 'kmod_file_open':
../shared/macro.h:25:9: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement]
25 | _Static_assert((expr), #expr)
| ^~~~~~~~~~~~~~
../libkmod/libkmod-file.c:424:9: note: in expansion of macro 'assert_cc'
424 | assert_cc(sizeof(magic_zstd) < sizeof(buf));
| ^~~~~~~~~
So I'd go with this on top of this patch... I can squash it as needed
when applying:
|diff --git a/libkmod/libkmod-file.c b/libkmod/libkmod-file.c
|index f162a10..8baf12d 100644
|--- a/libkmod/libkmod-file.c
|+++ b/libkmod/libkmod-file.c
|@@ -408,10 +408,15 @@ struct kmod_elf *kmod_file_get_elf(struct kmod_file *file)
| struct kmod_file *kmod_file_open(const struct kmod_ctx *ctx,
| const char *filename)
| {
|- struct kmod_file *file = calloc(1, sizeof(struct kmod_file));
|+ struct kmod_file *file;
| char buf[7];
| ssize_t sz;
|
|+ assert_cc(sizeof(magic_zstd) < sizeof(buf));
|+ assert_cc(sizeof(magic_xz) < sizeof(buf));
|+ assert_cc(sizeof(magic_zlib) < sizeof(buf));
|+
|+ file = calloc(1, sizeof(struct kmod_file));
| if (file == NULL)
| return NULL;
|
|@@ -421,10 +426,6 @@ struct kmod_file *kmod_file_open(const struct kmod_ctx *ctx,
| return NULL;
| }
|
|- 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 != (sizeof(buf) - 1)) {
Lucas De Marchi
