libkmod: return the errno from kmod_elf_strip()

Rework the function signature and return the error code instead of the
stripped module. Thus we no longer explicitly set errno.

Reference: #244
Signed-off-by: Emil Velikov <[email protected]>
Link: #346
Signed-off-by: Lucas De Marchi <[email protected]>

Author: evelikov

libkmod/libkmod-elf.c

@@ -666,7 +666,7 @@ static int elf_strip_vermagic(const struct kmod_elf *elf, uint8_t *changed)
 	return -ENODATA;
 }
 
-const void *kmod_elf_strip(const struct kmod_elf *elf, unsigned int flags)
+int kmod_elf_strip(const struct kmod_elf *elf, unsigned int flags, const void **stripped)
 {
 	uint8_t *changed;
 	int err = 0;
@@ -675,30 +675,27 @@ const void *kmod_elf_strip(const struct kmod_elf *elf, unsigned int flags)
 
 	changed = memdup(elf->memory, elf->size);
 	if (changed == NULL)
-		return NULL;
+		return -errno;
 
 	ELFDBG(elf, "copied memory to allow writing.\n");
 
 	if (flags & KMOD_INSERT_FORCE_MODVERSION) {
 		err = elf_strip_versions_section(elf, changed);
-		if (err < 0) {
-			errno = -err;
+		if (err < 0)
 			goto fail;
-		}
 	}
 
 	if (flags & KMOD_INSERT_FORCE_VERMAGIC) {
 		err = elf_strip_vermagic(elf, changed);
-		if (err < 0) {
-			errno = -err;
+		if (err < 0)
 			goto fail;
-		}
 	}
 
-	return changed;
+	*stripped = changed;
+	return 0;
 fail:
 	free(changed);
-	return NULL;
+	return err;
 }
 
 static int kmod_elf_get_symbols_symtab(const struct kmod_elf *elf,

libkmod/libkmod-internal.h

@@ -159,7 +159,7 @@ _must_check_ _nonnull_all_ int kmod_elf_get_modinfo_strings(const struct kmod_el
 _must_check_ _nonnull_all_ int kmod_elf_get_modversions(const struct kmod_elf *elf, struct kmod_modversion **array);
 _must_check_ _nonnull_all_ int kmod_elf_get_symbols(const struct kmod_elf *elf, struct kmod_modversion **array);
 _must_check_ _nonnull_all_ int kmod_elf_get_dependency_symbols(const struct kmod_elf *elf, struct kmod_modversion **array);
-_must_check_ _nonnull_all_ const void *kmod_elf_strip(const struct kmod_elf *elf, unsigned int flags);
+_must_check_ _nonnull_all_ int kmod_elf_strip(const struct kmod_elf *elf, unsigned int flags, const void **stripped);
 
 /*
  * Debug mock lib need to find section ".gnu.linkonce.this_module" in order to

libkmod/libkmod-module.c

@@ -662,10 +662,11 @@ static int do_init_module(struct kmod_module *mod, unsigned int flags, const cha
 			return err;
 		}
 
-		stripped = kmod_elf_strip(elf, flags);
-		if (stripped == NULL) {
-			ERR(mod->ctx, "Failed to strip version information: %m\n");
-			return -errno;
+		err = kmod_elf_strip(elf, flags, &stripped);
+		if (err) {
+			ERR(mod->ctx, "Failed to strip version information: %s\n",
+			    strerror(-err));
+			return err;
 		}
 		mem = stripped;
 	} else {