For _fs_read(), @len == 0 means we read the whole file. And we just pass @len == 0 to make each filesystem to handle it.
In fact we have info->size() call to properly get the filesize.
So we can not only call info->size() to grab the file_size for len == 0 case, but also detect invalid @len (e.g. @len > file_size) in advance or truncate @len.
This behavior also allows us to handle unaligned better in the incoming patches.
Signed-off-by: Qu Wenruo wqu@suse.com --- fs/fs.c | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-)
diff --git a/fs/fs.c b/fs/fs.c index 6de1a3eb6d5d..d992cdd6d650 100644 --- a/fs/fs.c +++ b/fs/fs.c @@ -579,6 +579,7 @@ static int _fs_read(const char *filename, ulong addr, loff_t offset, loff_t len, { struct fstype_info *info = fs_get_info(fs_type); void *buf; + loff_t file_size; int ret;
#ifdef CONFIG_LMB @@ -589,10 +590,26 @@ static int _fs_read(const char *filename, ulong addr, loff_t offset, loff_t len, } #endif
- /* - * We don't actually know how many bytes are being read, since len==0 - * means read the whole file. - */ + ret = info->size(filename, &file_size); + if (ret < 0) { + log_err("** Unable to get file size for %s, %d **\n", + filename, ret); + return ret; + } + if (offset >= file_size) { + log_err( + "** Invalid offset, offset (%llu) >= file size (%llu)\n", + offset, file_size); + return -EINVAL; + + } + if (len == 0 || offset + len > file_size) { + if (len > file_size) + log_info( + "** Truncate read length from %llu to %llu, as file size is %llu **\n", + len, file_size, file_size); + len = file_size - offset; + } buf = map_sysmem(addr, len); ret = info->read(filename, buf, offset, len, actread); unmap_sysmem(buf);