From: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> fstat() is used to determine the filesize before read() and it requires a filesystem. That means that 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 | 23 +++++++++++++++++++++-- 1 files changed, 21 insertions(+), 2 deletions(-) diff --git a/kexec/kexec.c b/kexec/kexec.c index a1cec86..6baa2d8 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 +486,26 @@ 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)); + } else { + size = stats.st_size; + } + *r_size = size; buf = xmalloc(size); progress = 0; -- 1.6.5.2