On Mon, Feb 12, 2024 at 05:23:09PM GMT, Emil Velikov via B4 Relay wrote:
From: Emil Velikov <emil.l.veli...@gmail.com>

Currently, when built w/o given compression we'll incorrectly report a
"compression_none".

As we reach do_finit_module(), we'll naively assume that the kernel can
handle the compressed module, yet omit the MODULE_INIT_COMPRESSED_FILE
flag.

As result the kernel will barf at us, do_finit_module will fail with non
-ENOSYS and we won't end in the do_init_module codepath (which will also
fail).

In other words: with this change, you can build kmod without zstd, xz
and zlib support and the kernel will load the modules, assuming it
supports the format \o/

Signed-off-by: Emil Velikov <emil.l.veli...@gmail.com>

nice.


Reviewed-by: Lucas De Marchi <lucas.demar...@intel.com>

Lucas De Marchi

---
libkmod/libkmod-file.c | 27 ++++++++++++++++++---------
1 file changed, 18 insertions(+), 9 deletions(-)

diff --git a/libkmod/libkmod-file.c b/libkmod/libkmod-file.c
index 3a79464..b69f1ef 100644
--- a/libkmod/libkmod-file.c
+++ b/libkmod/libkmod-file.c
@@ -174,9 +174,14 @@ out:
        free((void *)zst_outb.dst);
        return ret;
}
+#else
+static int load_zstd(struct kmod_file *file)
+{
+       return -ENOSYS;
+}
+#endif

static const char magic_zstd[] = {0x28, 0xB5, 0x2F, 0xFD};
-#endif

#ifdef ENABLE_XZ
static void xz_uncompress_belch(struct kmod_file *file, lzma_ret ret)
@@ -275,9 +280,14 @@ static int load_xz(struct kmod_file *file)
        lzma_end(&strm);
        return ret;
}
+#else
+static int load_xz(struct kmod_file *file)
+{
+       return -ENOSYS;
+}
+#endif

static const char magic_xz[] = {0xfd, '7', 'z', 'X', 'Z', 0};
-#endif

#ifdef ENABLE_ZLIB
#define READ_STEP (4 * 1024 * 1024)
@@ -339,9 +349,14 @@ error:
        gzclose(gzf); /* closes the gzfd */
        return err;
}
+#else
+static int load_zlib(struct kmod_file *file)
+{
+       return -ENOSYS;
+}
+#endif

static const char magic_zlib[] = {0x1f, 0x8b};
-#endif

static const struct comp_type {
        size_t magic_size;
@@ -349,15 +364,9 @@ static const struct comp_type {
        const char *magic_bytes;
        int (*load)(struct kmod_file *file);
} comp_types[] = {
-#ifdef ENABLE_ZSTD
        {sizeof(magic_zstd),    KMOD_FILE_COMPRESSION_ZSTD, magic_zstd, 
load_zstd},
-#endif
-#ifdef ENABLE_XZ
        {sizeof(magic_xz),      KMOD_FILE_COMPRESSION_XZ, magic_xz, load_xz},
-#endif
-#ifdef ENABLE_ZLIB
        {sizeof(magic_zlib),    KMOD_FILE_COMPRESSION_ZLIB, magic_zlib, 
load_zlib},
-#endif
        {0,                     KMOD_FILE_COMPRESSION_NONE, NULL, NULL}
};


--
2.43.0


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