On Mon, Nov 03, 2008 at 10:59:00PM +0100, Sebastian Andrzej Siewior wrote:
> From: Sebastian Andrzej Siewior <bigeasy at linutronix.de>
>
> fstat() is used to determine the filesize before read() and
> it requires a filesystem. That it means it can not be used
> on character nodes. This makes it impossible to obtains the
> kernel from a char node like mtd or more likely ubi.
> We can't use this in every case because files in /proc don't
> support lseek(). This is required by the powerpc part to read
> some device-tree entries.
>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy at linutronix.de>
> ---
> kexec/kexec.c | 22 ++++++++++++++++++++--
> 1 files changed, 20 insertions(+), 2 deletions(-)
>
> diff --git a/kexec/kexec.c b/kexec/kexec.c
> index 0616091..3c3f73e 100644
> --- a/kexec/kexec.c
> +++ b/kexec/kexec.c
> @@ -467,7 +467,7 @@ char *slurp_file(const char *filename, off_t *r_size)
> {
> int fd;
> char *buf;
> - off_t size, progress;
> + off_t size, progress, err;
> ssize_t result;
> struct stat stats;
>
> @@ -486,7 +486,25 @@ char *slurp_file(const char *filename, off_t *r_size)
> die("Cannot stat: %s: %s\n",
> filename, strerror(errno));
> }
> - size = stats.st_size;
> + /*
> + * Seek in case the kernel is a character node like /dev/ubi0_0.
> + * This does not work on regular files which live in /proc and
> + * we need this for some /proc/device-tree entries
> + */
> + if (S_ISCHR(stats.st_mode)) {
> +
> + size = lseek(fd, 0, SEEK_END);
> + if (size < 0)
> + die("Can not seek file %s: %s\n", filename, strerror(errno));
> +
> + err = lseek(fd, 0, SEEK_SET);
> + if (err < 0)
> + die("Can not seek to the begin of file %s: %s\n", filename,
> + strerror(errno));
Please reformat these lines so they are <= 80 columns wide.
> + } else {
> + size = stats.st_size;
> + }
> +
> *r_size = size;
> buf = xmalloc(size);
> progress = 0;
> --
> 1.6.0.2
>
>
> _______________________________________________
> kexec mailing list
> kexec at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec
--
Simon Horman
VA Linux Systems Japan K.K., Sydney, Australia Satellite Office
H: www.vergenet.net/~horms/ W: www.valinux.co.jp/en
