diff mbox series

[v7,01/12] tools: mkeficapsule: rework the code a little bit

Message ID 20211116043238.67226-2-takahiro.akashi@linaro.org
State Superseded
Headers show
Series efi_loader: capsule: improve capsule authentication support | expand

Commit Message

AKASHI Takahiro Nov. 16, 2021, 4:32 a.m. UTC
Abstract common routines to make the code easily understandable.
No functional change.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
---
 tools/mkeficapsule.c | 223 ++++++++++++++++++++++++++++++-------------
 1 file changed, 159 insertions(+), 64 deletions(-)

Comments

Heinrich Schuchardt Nov. 16, 2021, 12:19 p.m. UTC | #1
On 11/16/21 05:32, AKASHI Takahiro wrote:
> Abstract common routines to make the code easily understandable.
> No functional change.
>
> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> Reviewed-by: Simon Glass <sjg@chromium.org>
> ---
>   tools/mkeficapsule.c | 223 ++++++++++++++++++++++++++++++-------------
>   1 file changed, 159 insertions(+), 64 deletions(-)
>
> diff --git a/tools/mkeficapsule.c b/tools/mkeficapsule.c
> index 4995ba4e0c2a..afdcaf7e7933 100644
> --- a/tools/mkeficapsule.c
> +++ b/tools/mkeficapsule.c
> @@ -61,17 +61,122 @@ static void print_usage(void)
>   	       tool_name);
>   }
>
> +/**
> + * read_bin_file - read a firmware binary file
> + * @bin:	Path to a firmware binary file
> + * @data:	Pointer to pointer of allocated buffer
> + * @bin_size:	Size of allocated buffer
> + *
> + * Read out a content of binary, @bin, into @data.
> + * A caller should free @data.
> + *
> + * Return:
> + * * 0  - on success
> + * * -1 - on failure
> + */
> +static int read_bin_file(char *bin, void **data, off_t *bin_size)
> +{
> +	FILE *g;
> +	struct stat bin_stat;
> +	void *buf;
> +	size_t size;
> +	int ret = 0;
> +
> +	g = fopen(bin, "r");
> +	if (!g) {
> +		printf("cannot open %s\n", bin);

Error messages should be written to stderr. Use perror(bin) to get a
message like:

     <filename>: No such file or directory

Or use fprintf(stderr, ...).

> +		return -1;
> +	}
> +	if (stat(bin, &bin_stat) < 0) {
> +		printf("cannot determine the size of %s\n", bin);
> +		ret = -1;
> +		goto err;
> +	}
> +	if (bin_stat.st_size > (u32)~0U) {
> +		printf("file size is too large: %s\n", bin);
> +		ret = -1;
> +		goto err;
> +	}
> +	buf = malloc(bin_stat.st_size);

For a symbolic link st_size is the length of the pathname it contains.
So this function is of no help here.

> +	if (!buf) {
> +		printf("cannot allocate memory: %zx\n",
> +		       (size_t)bin_stat.st_size);
> +		ret = -1;
> +		goto err;
> +	}
> +
> +	size = fread(buf, 1, bin_stat.st_size, g);
> +	if (size < bin_stat.st_size) {

fread() reads from a stream which is not necessarily a file but can be a
named pipe. stat() does not indicate when the stream will end.

You have to run fread() in a loop until feof() or ferror() indicate that
there is nothing more to be read from the stream.

Best regards

Heinrich

> +		printf("read failed (%zx)\n", size);
> +		ret = -1;
> +		goto err;
> +	}
> +
> +	*data = buf;
> +	*bin_size = bin_stat.st_size;
> +err:
> +	fclose(g);
> +
> +	return ret;
> +}
> +
> +/**
> + * write_capsule_file - write a capsule file
> + * @bin:	FILE stream
> + * @data:	Pointer to data
> + * @bin_size:	Size of data
> + *
> + * Write out data, @data, with the size @bin_size.
> + *
> + * Return:
> + * * 0  - on success
> + * * -1 - on failure
> + */
> +static int write_capsule_file(FILE *f, void *data, size_t size, const char *msg)
> +{
> +	size_t size_written;
> +
> +	size_written = fwrite(data, 1, size, f);
> +	if (size_written < size) {
> +		printf("%s: write failed (%zx != %zx)\n", msg,
> +		       size_written, size);
> +		return -1;
> +	}
> +
> +	return 0;
> +}
> +
> +/**
> + * create_fwbin - create an uefi capsule file
> + * @path:	Path to a created capsule file
> + * @bin:	Path to a firmware binary to encapsulate
> + * @guid:	GUID of related FMP driver
> + * @index:	Index number in capsule
> + * @instance:	Instance number in capsule
> + * @mcount:	Monotonic count in authentication information
> + * @private_file:	Path to a private key file
> + * @cert_file:	Path to a certificate file
> + *
> + * This function actually does the job of creating an uefi capsule file.
> + * All the arguments must be supplied.
> + * If either @private_file ror @cert_file is NULL, the capsule file
> + * won't be signed.
> + *
> + * Return:
> + * * 0  - on success
> + * * -1 - on failure
> + */
>   static int create_fwbin(char *path, char *bin, efi_guid_t *guid,
>   			unsigned long index, unsigned long instance)
>   {
>   	struct efi_capsule_header header;
>   	struct efi_firmware_management_capsule_header capsule;
>   	struct efi_firmware_management_capsule_image_header image;
> -	FILE *f, *g;
> -	struct stat bin_stat;
> -	u8 *data;
> -	size_t size;
> +	FILE *f;
> +	void *data;
> +	off_t bin_size;
>   	u64 offset;
> +	int ret;
>
>   #ifdef DEBUG
>   	printf("For output: %s\n", path);
> @@ -79,25 +184,28 @@ static int create_fwbin(char *path, char *bin, efi_guid_t *guid,
>   	printf("\tindex: %ld\n\tinstance: %ld\n", index, instance);
>   #endif
>
> -	g = fopen(bin, "r");
> -	if (!g) {
> -		printf("cannot open %s\n", bin);
> -		return -1;
> -	}
> -	if (stat(bin, &bin_stat) < 0) {
> -		printf("cannot determine the size of %s\n", bin);
> -		goto err_1;
> -	}
> -	data = malloc(bin_stat.st_size);
> -	if (!data) {
> -		printf("cannot allocate memory: %zx\n", (size_t)bin_stat.st_size);
> -		goto err_1;
> -	}
> +	f = NULL;
> +	data = NULL;
> +	ret = -1;
> +
> +	/*
> +	 * read a firmware binary
> +	 */
> +	if (read_bin_file(bin, &data, &bin_size))
> +		goto err;
> +
> +	/*
> +	 * write a capsule file
> +	 */
>   	f = fopen(path, "w");
>   	if (!f) {
>   		printf("cannot open %s\n", path);
> -		goto err_2;
> +		goto err;
>   	}
> +
> +	/*
> +	 * capsule file header
> +	 */
>   	header.capsule_guid = efi_guid_fm_capsule;
>   	header.header_size = sizeof(header);
>   	/* TODO: The current implementation ignores flags */
> @@ -105,70 +213,57 @@ static int create_fwbin(char *path, char *bin, efi_guid_t *guid,
>   	header.capsule_image_size = sizeof(header)
>   					+ sizeof(capsule) + sizeof(u64)
>   					+ sizeof(image)
> -					+ bin_stat.st_size;
> -
> -	size = fwrite(&header, 1, sizeof(header), f);
> -	if (size < sizeof(header)) {
> -		printf("write failed (%zx)\n", size);
> -		goto err_3;
> -	}
> +					+ bin_size;
> +	if (write_capsule_file(f, &header, sizeof(header),
> +			       "Capsule header"))
> +		goto err;
>
> +	/*
> +	 * firmware capsule header
> +	 * This capsule has only one firmware capsule image.
> +	 */
>   	capsule.version = 0x00000001;
>   	capsule.embedded_driver_count = 0;
>   	capsule.payload_item_count = 1;
> -	size = fwrite(&capsule, 1, sizeof(capsule), f);
> -	if (size < (sizeof(capsule))) {
> -		printf("write failed (%zx)\n", size);
> -		goto err_3;
> -	}
> +	if (write_capsule_file(f, &capsule, sizeof(capsule),
> +			       "Firmware capsule header"))
> +		goto err;
> +
>   	offset = sizeof(capsule) + sizeof(u64);
> -	size = fwrite(&offset, 1, sizeof(offset), f);
> -	if (size < sizeof(offset)) {
> -		printf("write failed (%zx)\n", size);
> -		goto err_3;
> -	}
> +	if (write_capsule_file(f, &offset, sizeof(offset),
> +			       "Offset to capsule image"))
> +		goto err;
>
> +	/*
> +	 * firmware capsule image header
> +	 */
>   	image.version = 0x00000003;
>   	memcpy(&image.update_image_type_id, guid, sizeof(*guid));
>   	image.update_image_index = index;
>   	image.reserved[0] = 0;
>   	image.reserved[1] = 0;
>   	image.reserved[2] = 0;
> -	image.update_image_size = bin_stat.st_size;
> +	image.update_image_size = bin_size;
>   	image.update_vendor_code_size = 0; /* none */
>   	image.update_hardware_instance = instance;
>   	image.image_capsule_support = 0;
> +	if (write_capsule_file(f, &image, sizeof(image),
> +			       "Firmware capsule image header"))
> +		goto err;
>
> -	size = fwrite(&image, 1, sizeof(image), f);
> -	if (size < sizeof(image)) {
> -		printf("write failed (%zx)\n", size);
> -		goto err_3;
> -	}
> -	size = fread(data, 1, bin_stat.st_size, g);
> -	if (size < bin_stat.st_size) {
> -		printf("read failed (%zx)\n", size);
> -		goto err_3;
> -	}
> -	size = fwrite(data, 1, bin_stat.st_size, f);
> -	if (size < bin_stat.st_size) {
> -		printf("write failed (%zx)\n", size);
> -		goto err_3;
> -	}
> -
> -	fclose(f);
> -	fclose(g);
> -	free(data);
> -
> -	return 0;
> +	/*
> +	 * firmware binary
> +	 */
> +	if (write_capsule_file(f, data, bin_size, "Firmware binary"))
> +		goto err;
>
> -err_3:
> -	fclose(f);
> -err_2:
> +	ret = 0;
> +err:
> +	if (f)
> +		fclose(f);
>   	free(data);
> -err_1:
> -	fclose(g);
>
> -	return -1;
> +	return ret;
>   }
>
>   /*
>
AKASHI Takahiro Nov. 17, 2021, 1:20 a.m. UTC | #2
On Tue, Nov 16, 2021 at 01:19:10PM +0100, Heinrich Schuchardt wrote:
> On 11/16/21 05:32, AKASHI Takahiro wrote:
> > Abstract common routines to make the code easily understandable.
> > No functional change.
> > 
> > Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> > Reviewed-by: Simon Glass <sjg@chromium.org>
> > ---
> >   tools/mkeficapsule.c | 223 ++++++++++++++++++++++++++++++-------------
> >   1 file changed, 159 insertions(+), 64 deletions(-)
> > 
> > diff --git a/tools/mkeficapsule.c b/tools/mkeficapsule.c
> > index 4995ba4e0c2a..afdcaf7e7933 100644
> > --- a/tools/mkeficapsule.c
> > +++ b/tools/mkeficapsule.c
> > @@ -61,17 +61,122 @@ static void print_usage(void)
> >   	       tool_name);
> >   }
> > 
> > +/**
> > + * read_bin_file - read a firmware binary file
> > + * @bin:	Path to a firmware binary file
> > + * @data:	Pointer to pointer of allocated buffer
> > + * @bin_size:	Size of allocated buffer
> > + *
> > + * Read out a content of binary, @bin, into @data.
> > + * A caller should free @data.
> > + *
> > + * Return:
> > + * * 0  - on success
> > + * * -1 - on failure
> > + */
> > +static int read_bin_file(char *bin, void **data, off_t *bin_size)
> > +{
> > +	FILE *g;
> > +	struct stat bin_stat;
> > +	void *buf;
> > +	size_t size;
> > +	int ret = 0;
> > +
> > +	g = fopen(bin, "r");
> > +	if (!g) {
> > +		printf("cannot open %s\n", bin);
> 
> Error messages should be written to stderr. Use perror(bin) to get a
> message like:
> 
>     <filename>: No such file or directory
> 
> Or use fprintf(stderr, ...).

OK.
But remember that I have used printf() throughout mkeficapsule.c
even before this patch.
So I will add similar changes in patch#1 for consistency. 

> > +		return -1;
> > +	}
> > +	if (stat(bin, &bin_stat) < 0) {
> > +		printf("cannot determine the size of %s\n", bin);
> > +		ret = -1;
> > +		goto err;
> > +	}
> > +	if (bin_stat.st_size > (u32)~0U) {
> > +		printf("file size is too large: %s\n", bin);
> > +		ret = -1;
> > +		goto err;
> > +	}
> > +	buf = malloc(bin_stat.st_size);
> 
> For a symbolic link st_size is the length of the pathname it contains.
> So this function is of no help here.

Not true.
According to stat() manpage,

"lstat() is identical to stat(), except that if pathname is  a  symbolic
 link,  then  it returns information about the link itself, not the file
 that it refers to."

So stat() is a right system call.


> > +	if (!buf) {
> > +		printf("cannot allocate memory: %zx\n",
> > +		       (size_t)bin_stat.st_size);
> > +		ret = -1;
> > +		goto err;
> > +	}
> > +
> > +	size = fread(buf, 1, bin_stat.st_size, g);
> > +	if (size < bin_stat.st_size) {
> 
> fread() reads from a stream which is not necessarily a file but can be a
> named pipe. stat() does not indicate when the stream will end.
> 
> You have to run fread() in a loop until feof() or ferror() indicate that
> there is nothing more to be read from the stream.

No.
"a stream which is not necessarily a file but can be a named pipe"
may be true, but we don't handle such a use case with this tool.

-Takahiro Akashi

> Best regards
> 
> Heinrich
> 
> > +		printf("read failed (%zx)\n", size);
> > +		ret = -1;
> > +		goto err;
> > +	}
> > +
> > +	*data = buf;
> > +	*bin_size = bin_stat.st_size;
> > +err:
> > +	fclose(g);
> > +
> > +	return ret;
> > +}
> > +
> > +/**
> > + * write_capsule_file - write a capsule file
> > + * @bin:	FILE stream
> > + * @data:	Pointer to data
> > + * @bin_size:	Size of data
> > + *
> > + * Write out data, @data, with the size @bin_size.
> > + *
> > + * Return:
> > + * * 0  - on success
> > + * * -1 - on failure
> > + */
> > +static int write_capsule_file(FILE *f, void *data, size_t size, const char *msg)
> > +{
> > +	size_t size_written;
> > +
> > +	size_written = fwrite(data, 1, size, f);
> > +	if (size_written < size) {
> > +		printf("%s: write failed (%zx != %zx)\n", msg,
> > +		       size_written, size);
> > +		return -1;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +/**
> > + * create_fwbin - create an uefi capsule file
> > + * @path:	Path to a created capsule file
> > + * @bin:	Path to a firmware binary to encapsulate
> > + * @guid:	GUID of related FMP driver
> > + * @index:	Index number in capsule
> > + * @instance:	Instance number in capsule
> > + * @mcount:	Monotonic count in authentication information
> > + * @private_file:	Path to a private key file
> > + * @cert_file:	Path to a certificate file
> > + *
> > + * This function actually does the job of creating an uefi capsule file.
> > + * All the arguments must be supplied.
> > + * If either @private_file ror @cert_file is NULL, the capsule file
> > + * won't be signed.
> > + *
> > + * Return:
> > + * * 0  - on success
> > + * * -1 - on failure
> > + */
> >   static int create_fwbin(char *path, char *bin, efi_guid_t *guid,
> >   			unsigned long index, unsigned long instance)
> >   {
> >   	struct efi_capsule_header header;
> >   	struct efi_firmware_management_capsule_header capsule;
> >   	struct efi_firmware_management_capsule_image_header image;
> > -	FILE *f, *g;
> > -	struct stat bin_stat;
> > -	u8 *data;
> > -	size_t size;
> > +	FILE *f;
> > +	void *data;
> > +	off_t bin_size;
> >   	u64 offset;
> > +	int ret;
> > 
> >   #ifdef DEBUG
> >   	printf("For output: %s\n", path);
> > @@ -79,25 +184,28 @@ static int create_fwbin(char *path, char *bin, efi_guid_t *guid,
> >   	printf("\tindex: %ld\n\tinstance: %ld\n", index, instance);
> >   #endif
> > 
> > -	g = fopen(bin, "r");
> > -	if (!g) {
> > -		printf("cannot open %s\n", bin);
> > -		return -1;
> > -	}
> > -	if (stat(bin, &bin_stat) < 0) {
> > -		printf("cannot determine the size of %s\n", bin);
> > -		goto err_1;
> > -	}
> > -	data = malloc(bin_stat.st_size);
> > -	if (!data) {
> > -		printf("cannot allocate memory: %zx\n", (size_t)bin_stat.st_size);
> > -		goto err_1;
> > -	}
> > +	f = NULL;
> > +	data = NULL;
> > +	ret = -1;
> > +
> > +	/*
> > +	 * read a firmware binary
> > +	 */
> > +	if (read_bin_file(bin, &data, &bin_size))
> > +		goto err;
> > +
> > +	/*
> > +	 * write a capsule file
> > +	 */
> >   	f = fopen(path, "w");
> >   	if (!f) {
> >   		printf("cannot open %s\n", path);
> > -		goto err_2;
> > +		goto err;
> >   	}
> > +
> > +	/*
> > +	 * capsule file header
> > +	 */
> >   	header.capsule_guid = efi_guid_fm_capsule;
> >   	header.header_size = sizeof(header);
> >   	/* TODO: The current implementation ignores flags */
> > @@ -105,70 +213,57 @@ static int create_fwbin(char *path, char *bin, efi_guid_t *guid,
> >   	header.capsule_image_size = sizeof(header)
> >   					+ sizeof(capsule) + sizeof(u64)
> >   					+ sizeof(image)
> > -					+ bin_stat.st_size;
> > -
> > -	size = fwrite(&header, 1, sizeof(header), f);
> > -	if (size < sizeof(header)) {
> > -		printf("write failed (%zx)\n", size);
> > -		goto err_3;
> > -	}
> > +					+ bin_size;
> > +	if (write_capsule_file(f, &header, sizeof(header),
> > +			       "Capsule header"))
> > +		goto err;
> > 
> > +	/*
> > +	 * firmware capsule header
> > +	 * This capsule has only one firmware capsule image.
> > +	 */
> >   	capsule.version = 0x00000001;
> >   	capsule.embedded_driver_count = 0;
> >   	capsule.payload_item_count = 1;
> > -	size = fwrite(&capsule, 1, sizeof(capsule), f);
> > -	if (size < (sizeof(capsule))) {
> > -		printf("write failed (%zx)\n", size);
> > -		goto err_3;
> > -	}
> > +	if (write_capsule_file(f, &capsule, sizeof(capsule),
> > +			       "Firmware capsule header"))
> > +		goto err;
> > +
> >   	offset = sizeof(capsule) + sizeof(u64);
> > -	size = fwrite(&offset, 1, sizeof(offset), f);
> > -	if (size < sizeof(offset)) {
> > -		printf("write failed (%zx)\n", size);
> > -		goto err_3;
> > -	}
> > +	if (write_capsule_file(f, &offset, sizeof(offset),
> > +			       "Offset to capsule image"))
> > +		goto err;
> > 
> > +	/*
> > +	 * firmware capsule image header
> > +	 */
> >   	image.version = 0x00000003;
> >   	memcpy(&image.update_image_type_id, guid, sizeof(*guid));
> >   	image.update_image_index = index;
> >   	image.reserved[0] = 0;
> >   	image.reserved[1] = 0;
> >   	image.reserved[2] = 0;
> > -	image.update_image_size = bin_stat.st_size;
> > +	image.update_image_size = bin_size;
> >   	image.update_vendor_code_size = 0; /* none */
> >   	image.update_hardware_instance = instance;
> >   	image.image_capsule_support = 0;
> > +	if (write_capsule_file(f, &image, sizeof(image),
> > +			       "Firmware capsule image header"))
> > +		goto err;
> > 
> > -	size = fwrite(&image, 1, sizeof(image), f);
> > -	if (size < sizeof(image)) {
> > -		printf("write failed (%zx)\n", size);
> > -		goto err_3;
> > -	}
> > -	size = fread(data, 1, bin_stat.st_size, g);
> > -	if (size < bin_stat.st_size) {
> > -		printf("read failed (%zx)\n", size);
> > -		goto err_3;
> > -	}
> > -	size = fwrite(data, 1, bin_stat.st_size, f);
> > -	if (size < bin_stat.st_size) {
> > -		printf("write failed (%zx)\n", size);
> > -		goto err_3;
> > -	}
> > -
> > -	fclose(f);
> > -	fclose(g);
> > -	free(data);
> > -
> > -	return 0;
> > +	/*
> > +	 * firmware binary
> > +	 */
> > +	if (write_capsule_file(f, data, bin_size, "Firmware binary"))
> > +		goto err;
> > 
> > -err_3:
> > -	fclose(f);
> > -err_2:
> > +	ret = 0;
> > +err:
> > +	if (f)
> > +		fclose(f);
> >   	free(data);
> > -err_1:
> > -	fclose(g);
> > 
> > -	return -1;
> > +	return ret;
> >   }
> > 
> >   /*
> > 
>
diff mbox series

Patch

diff --git a/tools/mkeficapsule.c b/tools/mkeficapsule.c
index 4995ba4e0c2a..afdcaf7e7933 100644
--- a/tools/mkeficapsule.c
+++ b/tools/mkeficapsule.c
@@ -61,17 +61,122 @@  static void print_usage(void)
 	       tool_name);
 }
 
+/**
+ * read_bin_file - read a firmware binary file
+ * @bin:	Path to a firmware binary file
+ * @data:	Pointer to pointer of allocated buffer
+ * @bin_size:	Size of allocated buffer
+ *
+ * Read out a content of binary, @bin, into @data.
+ * A caller should free @data.
+ *
+ * Return:
+ * * 0  - on success
+ * * -1 - on failure
+ */
+static int read_bin_file(char *bin, void **data, off_t *bin_size)
+{
+	FILE *g;
+	struct stat bin_stat;
+	void *buf;
+	size_t size;
+	int ret = 0;
+
+	g = fopen(bin, "r");
+	if (!g) {
+		printf("cannot open %s\n", bin);
+		return -1;
+	}
+	if (stat(bin, &bin_stat) < 0) {
+		printf("cannot determine the size of %s\n", bin);
+		ret = -1;
+		goto err;
+	}
+	if (bin_stat.st_size > (u32)~0U) {
+		printf("file size is too large: %s\n", bin);
+		ret = -1;
+		goto err;
+	}
+	buf = malloc(bin_stat.st_size);
+	if (!buf) {
+		printf("cannot allocate memory: %zx\n",
+		       (size_t)bin_stat.st_size);
+		ret = -1;
+		goto err;
+	}
+
+	size = fread(buf, 1, bin_stat.st_size, g);
+	if (size < bin_stat.st_size) {
+		printf("read failed (%zx)\n", size);
+		ret = -1;
+		goto err;
+	}
+
+	*data = buf;
+	*bin_size = bin_stat.st_size;
+err:
+	fclose(g);
+
+	return ret;
+}
+
+/**
+ * write_capsule_file - write a capsule file
+ * @bin:	FILE stream
+ * @data:	Pointer to data
+ * @bin_size:	Size of data
+ *
+ * Write out data, @data, with the size @bin_size.
+ *
+ * Return:
+ * * 0  - on success
+ * * -1 - on failure
+ */
+static int write_capsule_file(FILE *f, void *data, size_t size, const char *msg)
+{
+	size_t size_written;
+
+	size_written = fwrite(data, 1, size, f);
+	if (size_written < size) {
+		printf("%s: write failed (%zx != %zx)\n", msg,
+		       size_written, size);
+		return -1;
+	}
+
+	return 0;
+}
+
+/**
+ * create_fwbin - create an uefi capsule file
+ * @path:	Path to a created capsule file
+ * @bin:	Path to a firmware binary to encapsulate
+ * @guid:	GUID of related FMP driver
+ * @index:	Index number in capsule
+ * @instance:	Instance number in capsule
+ * @mcount:	Monotonic count in authentication information
+ * @private_file:	Path to a private key file
+ * @cert_file:	Path to a certificate file
+ *
+ * This function actually does the job of creating an uefi capsule file.
+ * All the arguments must be supplied.
+ * If either @private_file ror @cert_file is NULL, the capsule file
+ * won't be signed.
+ *
+ * Return:
+ * * 0  - on success
+ * * -1 - on failure
+ */
 static int create_fwbin(char *path, char *bin, efi_guid_t *guid,
 			unsigned long index, unsigned long instance)
 {
 	struct efi_capsule_header header;
 	struct efi_firmware_management_capsule_header capsule;
 	struct efi_firmware_management_capsule_image_header image;
-	FILE *f, *g;
-	struct stat bin_stat;
-	u8 *data;
-	size_t size;
+	FILE *f;
+	void *data;
+	off_t bin_size;
 	u64 offset;
+	int ret;
 
 #ifdef DEBUG
 	printf("For output: %s\n", path);
@@ -79,25 +184,28 @@  static int create_fwbin(char *path, char *bin, efi_guid_t *guid,
 	printf("\tindex: %ld\n\tinstance: %ld\n", index, instance);
 #endif
 
-	g = fopen(bin, "r");
-	if (!g) {
-		printf("cannot open %s\n", bin);
-		return -1;
-	}
-	if (stat(bin, &bin_stat) < 0) {
-		printf("cannot determine the size of %s\n", bin);
-		goto err_1;
-	}
-	data = malloc(bin_stat.st_size);
-	if (!data) {
-		printf("cannot allocate memory: %zx\n", (size_t)bin_stat.st_size);
-		goto err_1;
-	}
+	f = NULL;
+	data = NULL;
+	ret = -1;
+
+	/*
+	 * read a firmware binary
+	 */
+	if (read_bin_file(bin, &data, &bin_size))
+		goto err;
+
+	/*
+	 * write a capsule file
+	 */
 	f = fopen(path, "w");
 	if (!f) {
 		printf("cannot open %s\n", path);
-		goto err_2;
+		goto err;
 	}
+
+	/*
+	 * capsule file header
+	 */
 	header.capsule_guid = efi_guid_fm_capsule;
 	header.header_size = sizeof(header);
 	/* TODO: The current implementation ignores flags */
@@ -105,70 +213,57 @@  static int create_fwbin(char *path, char *bin, efi_guid_t *guid,
 	header.capsule_image_size = sizeof(header)
 					+ sizeof(capsule) + sizeof(u64)
 					+ sizeof(image)
-					+ bin_stat.st_size;
-
-	size = fwrite(&header, 1, sizeof(header), f);
-	if (size < sizeof(header)) {
-		printf("write failed (%zx)\n", size);
-		goto err_3;
-	}
+					+ bin_size;
+	if (write_capsule_file(f, &header, sizeof(header),
+			       "Capsule header"))
+		goto err;
 
+	/*
+	 * firmware capsule header
+	 * This capsule has only one firmware capsule image.
+	 */
 	capsule.version = 0x00000001;
 	capsule.embedded_driver_count = 0;
 	capsule.payload_item_count = 1;
-	size = fwrite(&capsule, 1, sizeof(capsule), f);
-	if (size < (sizeof(capsule))) {
-		printf("write failed (%zx)\n", size);
-		goto err_3;
-	}
+	if (write_capsule_file(f, &capsule, sizeof(capsule),
+			       "Firmware capsule header"))
+		goto err;
+
 	offset = sizeof(capsule) + sizeof(u64);
-	size = fwrite(&offset, 1, sizeof(offset), f);
-	if (size < sizeof(offset)) {
-		printf("write failed (%zx)\n", size);
-		goto err_3;
-	}
+	if (write_capsule_file(f, &offset, sizeof(offset),
+			       "Offset to capsule image"))
+		goto err;
 
+	/*
+	 * firmware capsule image header
+	 */
 	image.version = 0x00000003;
 	memcpy(&image.update_image_type_id, guid, sizeof(*guid));
 	image.update_image_index = index;
 	image.reserved[0] = 0;
 	image.reserved[1] = 0;
 	image.reserved[2] = 0;
-	image.update_image_size = bin_stat.st_size;
+	image.update_image_size = bin_size;
 	image.update_vendor_code_size = 0; /* none */
 	image.update_hardware_instance = instance;
 	image.image_capsule_support = 0;
+	if (write_capsule_file(f, &image, sizeof(image),
+			       "Firmware capsule image header"))
+		goto err;
 
-	size = fwrite(&image, 1, sizeof(image), f);
-	if (size < sizeof(image)) {
-		printf("write failed (%zx)\n", size);
-		goto err_3;
-	}
-	size = fread(data, 1, bin_stat.st_size, g);
-	if (size < bin_stat.st_size) {
-		printf("read failed (%zx)\n", size);
-		goto err_3;
-	}
-	size = fwrite(data, 1, bin_stat.st_size, f);
-	if (size < bin_stat.st_size) {
-		printf("write failed (%zx)\n", size);
-		goto err_3;
-	}
-
-	fclose(f);
-	fclose(g);
-	free(data);
-
-	return 0;
+	/*
+	 * firmware binary
+	 */
+	if (write_capsule_file(f, data, bin_size, "Firmware binary"))
+		goto err;
 
-err_3:
-	fclose(f);
-err_2:
+	ret = 0;
+err:
+	if (f)
+		fclose(f);
 	free(data);
-err_1:
-	fclose(g);
 
-	return -1;
+	return ret;
 }
 
 /*