Reduce strerror and errno usage

libkmod/libkmod-builtin.c

@@ -33,29 +33,27 @@
 	char *buf;
 };
 
-static bool kmod_builtin_info_init(struct kmod_builtin_info *info, struct kmod_ctx *ctx)
+static int kmod_builtin_info_init(struct kmod_builtin_info *info, struct kmod_ctx *ctx)
 {
 	char path[PATH_MAX];
 	FILE *fp = NULL;
 	const char *dirname = kmod_get_dirname(ctx);
 	size_t len = strlen(dirname);
 
-	if ((len + 1 + strlen(MODULES_BUILTIN_MODINFO) + 1) >= sizeof(path)) {
-		errno = ENAMETOOLONG;
-		return false;
-	}
+	if ((len + 1 + strlen(MODULES_BUILTIN_MODINFO) + 1) >= sizeof(path))
+		return -ENAMETOOLONG;
 	snprintf(path, sizeof(path), "%s/" MODULES_BUILTIN_MODINFO, dirname);
 
 	fp = fopen(path, "r");
 	if (fp == NULL)
-		return false;
+		return -errno;
 
 	info->ctx = ctx;
 	info->fp = fp;
 	info->bufsz = 0;
 	info->buf = NULL;
 
-	return true;
+	return 0;
 }
 
 static void kmod_builtin_info_release(struct kmod_builtin_info *info)
@@ -64,19 +62,6 @@
 	fclose(info->fp);
 }
 
-static ssize_t get_string(struct kmod_builtin_info *info)
-{
-	ssize_t len;
-
-	len = getdelim(&info->buf, &info->bufsz, '\0', info->fp);
-	if (len > 0 && info->buf[len] != '\0') {
-		errno = EINVAL;
-		len = -1;
-	}
-
-	return len;
-}
-
 static ssize_t get_strings(struct kmod_builtin_info *info, const char *modname,
 			   struct strbuf *buf)
 {
@@ -86,11 +71,11 @@
 	for (count = 0; count < INTPTR_MAX;) {
 		char *dot, *line;
 
-		n = get_string(info);
+		n = getdelim(&info->buf, &info->bufsz, '\0', info->fp);
 		if (n == -1) {
 			if (!feof(info->fp)) {
 				count = -errno;
-				ERR(info->ctx, "get_string: %s\n", strerror(errno));
+				ERR(info->ctx, "get_strings: %m\n");
 			}
 			break;
 		}
@@ -142,10 +127,8 @@
 	/* (string vector + NULL) * sizeof(char *) + strbuf_used() */
 	if (uaddsz_overflow(count, 1, &n) ||
 	    umulsz_overflow(sizeof(char *), n, &vec_size) ||
-	    uaddsz_overflow(strbuf_used(buf), vec_size, &total_size)) {
-		errno = ENOMEM;
+	    uaddsz_overflow(strbuf_used(buf), vec_size, &total_size))
 		return NULL;
-	}
 
 	vector = realloc(buf->bytes, total_size);
 	if (vector == NULL)
@@ -171,18 +154,20 @@
 	DECLARE_STRBUF(buf);
 	struct kmod_builtin_info info;
 	ssize_t count;
+	int ret;
 
-	if (!kmod_builtin_info_init(&info, ctx))
-		return -errno;
+	ret = kmod_builtin_info_init(&info, ctx);
+	if (ret < 0)
+		return ret;
 
 	count = get_strings(&info, modname, &buf);
 	if (count == 0)
 		*modinfo = NULL;
 	else if (count > 0) {
 		*modinfo = strbuf_to_vector(&buf, (size_t)count);
 		if (*modinfo == NULL) {
-			count = -errno;
-			ERR(ctx, "strbuf_to_vector: %s\n", strerror(errno));
+			count = -ENOMEM;
+			ERR(ctx, "strbuf_to_vector: %m\n");
 		}
 	}
 

libkmod/libkmod-elf.c

@@ -305,7 +305,7 @@
 	}
 }
 
-struct kmod_elf *kmod_elf_new(const void *memory, off_t size)
+int kmod_elf_new(const void *memory, off_t size, struct kmod_elf **out_elf)
 {
 	struct kmod_elf *elf;
 	size_t shdrs_size, shdr_size;
@@ -317,21 +317,14 @@
 	assert_cc(sizeof(uint32_t) == sizeof(Elf32_Word));
 	assert_cc(sizeof(uint32_t) == sizeof(Elf64_Word));
 
-	if (!memory) {
-		errno = -EINVAL;
-		return NULL;
-	}
-
 	elf = malloc(sizeof(struct kmod_elf));
-	if (elf == NULL) {
-		return NULL;
-	}
+	if (elf == NULL)
+		return -ENOMEM;
 
 	err = elf_identify(elf, memory, size);
 	if (err < 0) {
 		free(elf);
-		errno = -err;
-		return NULL;
+		return err;
 	}
 
 	elf->memory = memory;
@@ -393,12 +386,12 @@
 	}
 
 	kmod_elf_save_sections(elf);
-	return elf;
+	*out_elf = elf;
+	return 0;
 
 invalid:
 	free(elf);
-	errno = EINVAL;
-	return NULL;
+	return -EINVAL;
 }
 
 void kmod_elf_unref(struct kmod_elf *elf)
@@ -666,7 +659,7 @@
 	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 +668,27 @@
 
 	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-file-zlib.c

@@ -60,7 +60,6 @@ int kmod_file_load_zlib(struct kmod_file *file)
 		return -EINVAL;
 	}
 
-	errno = 0;
 	gzfd = fcntl(file->fd, F_DUPFD_CLOEXEC, 3);
 	if (gzfd < 0)
 		return -errno;

libkmod/libkmod-file.c

@@ -58,53 +58,53 @@
 	// clang-format on
 };
 
-struct kmod_elf *kmod_file_get_elf(struct kmod_file *file)
+int kmod_file_get_elf(struct kmod_file *file, struct kmod_elf **elf)
 {
-	int err;
-
-	if (file->elf)
-		return file->elf;
-
-	err = kmod_file_load_contents(file);
-	if (err) {
-		errno = -err;
-		return NULL;
+	if (!file->elf) {
+		int err = kmod_file_load_contents(file);
+		if (err)
+			return err;
+
+		err = kmod_elf_new(file->memory, file->size, &file->elf);
+		if (err)
+			return err;
 	}
 
-	file->elf = kmod_elf_new(file->memory, file->size);
-	return file->elf;
+	*elf = file->elf;
+	return 0;
 }
 
-struct kmod_file *kmod_file_open(const struct kmod_ctx *ctx, const char *filename)
+int kmod_file_open(const struct kmod_ctx *ctx, const char *filename,
+		   struct kmod_file **out_file)
 {
-	struct kmod_file *file;
+	_cleanup_free_ struct kmod_file *file;
 	char buf[7];
 	ssize_t sz;
+	int ret;
 
 	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;
+	if (file == NULL) {
+		file = NULL;
+		return -ENOMEM;
+	}
 
 	file->fd = open(filename, O_RDONLY | O_CLOEXEC);
-	if (file->fd < 0) {
-		free(file);
-		return NULL;
-	}
+	if (file->fd < 0)
+		return -errno;
 
 	sz = pread_str_safe(file->fd, buf, sizeof(buf), 0);
 	if (sz != (sizeof(buf) - 1)) {
 		if (sz < 0)
-			errno = -sz;
+			ret = (int)sz;
 		else
-			errno = EINVAL;
+			ret = -EINVAL;
 
 		close(file->fd);
-		free(file);
-		return NULL;
+		return ret;
 	}
 
 	for (unsigned int i = 0; i < ARRAY_SIZE(comp_types); i++) {
@@ -120,7 +120,9 @@
 
 	file->ctx = ctx;
 
-	return file;
+	*out_file = file;
+	file = NULL;
+	return 0;
 }
 
 /*
@@ -135,7 +137,7 @@
 	return file->load(file);
 }
 
-void *kmod_file_get_contents(const struct kmod_file *file)
+const void *kmod_file_get_contents(const struct kmod_file *file)
 {
 	return file->memory;
 }

libkmod/libkmod-internal.h

@@ -135,31 +135,32 @@ _nonnull_(1) void kmod_module_set_required(struct kmod_module *mod, bool require
 _nonnull_all_ bool kmod_module_is_builtin(struct kmod_module *mod);
 
 /* libkmod-file.c */
-_must_check_ _nonnull_all_ struct kmod_file *kmod_file_open(const struct kmod_ctx *ctx, const char *filename);
-_nonnull_all_ struct kmod_elf *kmod_file_get_elf(struct kmod_file *file);
+struct kmod_file;
+struct kmod_elf;
+_must_check_ _nonnull_all_ int kmod_file_open(const struct kmod_ctx *ctx, const char *filename, struct kmod_file **file);
+_must_check_ _nonnull_all_ int kmod_file_get_elf(struct kmod_file *file, struct kmod_elf **elf);
 _nonnull_all_ int kmod_file_load_contents(struct kmod_file *file);
-_must_check_ _nonnull_all_ void *kmod_file_get_contents(const struct kmod_file *file);
+_must_check_ _nonnull_all_ const void *kmod_file_get_contents(const struct kmod_file *file);
 _must_check_ _nonnull_all_ off_t kmod_file_get_size(const struct kmod_file *file);
 _must_check_ _nonnull_all_ enum kmod_file_compression_type kmod_file_get_compression(const struct kmod_file *file);
 _must_check_ _nonnull_all_ int kmod_file_get_fd(const struct kmod_file *file);
 _nonnull_all_ void kmod_file_unref(struct kmod_file *file);
 
 /* libkmod-elf.c */
-struct kmod_elf;
 struct kmod_modversion {
 	uint64_t crc;
 	enum kmod_symbol_bind bind;
 	const char *symbol;
 };
 
-struct kmod_elf *kmod_elf_new(const void *memory, off_t size);
+_must_check_ _nonnull_all_ int kmod_elf_new(const void *memory, off_t size, struct kmod_elf **elf);
 _nonnull_all_ void kmod_elf_unref(struct kmod_elf *elf);
 _must_check_ _nonnull_all_ const void *kmod_elf_get_memory(const struct kmod_elf *elf);
 _must_check_ _nonnull_all_ int kmod_elf_get_modinfo_strings(const struct kmod_elf *elf, char ***array);
 _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