[PATCH] read_file: Make it work on tftp servers which do not pass size

[Jan Weitzel]

Am Mittwoch, den 19.06.2013, 22:58 +0200 schrieb Sascha Hauer:
> Some tftp servers (for example netkit-tftp) do not pass the filesize.
> Add a workaround for read_file which reads the file into a temporary
> file which then is copied to a buffer.
> 
> Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
> ---
>  fs/fs.c      | 18 ++++++++++++++++++
>  fs/tftp.c    |  5 ++++-
>  include/fs.h |  2 ++
>  3 files changed, 24 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/fs.c b/fs/fs.c
> index dc3a6e3..7046f2c 100644
> --- a/fs/fs.c
> +++ b/fs/fs.c
> @@ -38,10 +38,21 @@ void *read_file(const char *filename, size_t *size)
>  	int fd;
>  	struct stat s;
>  	void *buf = NULL;
> +	const char *tmpfile = "/.read_file_tmp";
> +	int ret;
>  
> +again:
>  	if (stat(filename, &s))
>  		return NULL;
>  
> +	if (s.st_size == FILESIZE_MAX) {
> +		ret = copy_file(filename, tmpfile, 0);
> +		if (ret)
> +			return NULL;
> +		filename = tmpfile;
> +		goto again;
> +	}
> +
>  	buf = xzalloc(s.st_size + 1);
>  
>  	fd = open(filename, O_RDONLY);
> @@ -56,12 +67,19 @@ void *read_file(const char *filename, size_t *size)
>  	if (size)
>  		*size = s.st_size;
>  
> +	if (filename == tmpfile)
> +		unlink(tmpfile);
> +
>  	return buf;
>  
>  err_out1:
>  	close(fd);
>  err_out:
>  	free(buf);
> +
> +	if (filename == tmpfile)
> +		unlink(tmpfile);
> +
>  	return NULL;
>  }
>  
> diff --git a/fs/tftp.c b/fs/tftp.c
> index 98cbb37..1c37acf 100644
> --- a/fs/tftp.c
> +++ b/fs/tftp.c
> @@ -597,7 +597,10 @@ static int tftp_stat(struct device_d *dev, const char *filename, struct stat *s)
>  		return PTR_ERR(priv);
>  
>  	s->st_mode = S_IFREG | S_IRWXU | S_IRWXG | S_IRWXO;
> -	s->st_size = priv->filesize;
> +	if (priv->filesize)
> +		s->st_size = priv->filesize;
> +	else
> +		s->st_size = FILESIZE_MAX;
Maybe we can determine the size here? Commands like "ls -l" and
"ubiformat" asks about the filesize via stat. I'm not sure how much
overheat it will be.

Jan
>  
>  	tftp_do_close(priv);
>  
> diff --git a/include/fs.h b/include/fs.h
> index 8ff7300..fa6a8da 100644
> --- a/include/fs.h
> +++ b/include/fs.h
> @@ -147,6 +147,8 @@ int protect(int fd, size_t count, unsigned long offset, int prot);
>  int protect_file(const char *file, int prot);
>  void *memmap(int fd, int flags);
>  
> +#define FILESIZE_MAX	((size_t)-1)
> +
>  #define PROT_READ	1
>  #define PROT_WRITE	2
>