drivers/firmware/efi/libstub/file.c

Source file repositories/reference/linux-study-clean/drivers/firmware/efi/libstub/file.c

File Facts

System
Linux kernel
Corpus path
drivers/firmware/efi/libstub/file.c
Extension
.c
Size
8982 bytes
Lines
332
Domain
Driver Families
Bucket
drivers/firmware
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct finfo {
	efi_file_info_t info;
	efi_char16_t	filename[MAX_FILENAME_SIZE];
};

static efi_status_t efi_open_file(efi_file_protocol_t *volume,
				  struct finfo *fi,
				  efi_file_protocol_t **handle,
				  unsigned long *file_size)
{
	efi_guid_t info_guid = EFI_FILE_INFO_ID;
	efi_file_protocol_t *fh;
	unsigned long info_sz;
	efi_status_t status;
	efi_char16_t *c;

	/* Replace UNIX dir separators with EFI standard ones */
	for (c = fi->filename; *c != L'\0'; c++) {
		if (*c == L'/')
			*c = L'\\';
	}

	status = efi_call_proto(volume, open, &fh, fi->filename,
				EFI_FILE_MODE_READ, 0);
	if (status != EFI_SUCCESS) {
		efi_err("Failed to open file: %ls\n", fi->filename);
		return status;
	}

	info_sz = sizeof(struct finfo);
	status = efi_call_proto(fh, get_info, &info_guid, &info_sz, fi);
	if (status != EFI_SUCCESS) {
		efi_err("Failed to get file info\n");
		efi_call_proto(fh, close);
		return status;
	}

	*handle = fh;
	*file_size = fi->info.file_size;
	return EFI_SUCCESS;
}

static efi_status_t efi_open_volume(efi_loaded_image_t *image,
				    efi_file_protocol_t **fh)
{
	efi_guid_t fs_proto = EFI_FILE_SYSTEM_GUID;
	efi_simple_file_system_protocol_t *io;
	efi_status_t status;

	status = efi_bs_call(handle_protocol, efi_table_attr(image, device_handle),
			     &fs_proto, (void **)&io);
	if (status != EFI_SUCCESS) {
		efi_err("Failed to handle fs_proto\n");
		return status;
	}

	status = efi_call_proto(io, open_volume, fh);
	if (status != EFI_SUCCESS)
		efi_err("Failed to open volume\n");

	return status;
}

static int find_file_option(const efi_char16_t *cmdline, int cmdline_len,
			    const efi_char16_t *prefix, int prefix_size,
			    efi_char16_t *result, int result_len)
{
	int prefix_len = prefix_size / 2;
	bool found = false;
	int i;

	for (i = prefix_len; i < cmdline_len; i++) {
		if (!memcmp(&cmdline[i - prefix_len], prefix, prefix_size)) {
			found = true;
			break;
		}
	}

	if (!found)
		return 0;

	/* Skip any leading slashes */
	while (i < cmdline_len && (cmdline[i] == L'/' || cmdline[i] == L'\\'))
		i++;

	while (--result_len > 0 && i < cmdline_len) {
		efi_char16_t c = cmdline[i++];

		if (c == L'\0' || c == L'\n' || c == L' ')
			break;

Annotation

Implementation Notes