Re: [PATCH 1/4] strbuf.c: keep errno in strbuf_read_file()
- From
Michael Haggerty <mhagger@alum.mit.edu>
- Date
- Sep 26, 2014, 10:30 UTC
- Message-ID
- <5425404E.7050100@alum.mit.edu>
- In-Reply-To
- <1406285039-22469-2-git-send-email-pclouds@gmail.com>
On 07/25/2014 12:43 PM, Nguyễn Thái Ngọc Duy wrote:
Show 25 quoted lines
> This function is used to replaced some code in the next patch that
> does this (i.e. keep the errno when read() fails)
>
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
> strbuf.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/strbuf.c b/strbuf.c
> index 33018d8..61d685d 100644
> --- a/strbuf.c
> +++ b/strbuf.c
> @@ -454,15 +454,18 @@ int strbuf_getwholeline_fd(struct strbuf *sb, int fd, int term)
>
> int strbuf_read_file(struct strbuf *sb, const char *path, size_t hint)
> {
> - int fd, len;
> + int fd, len, saved_errno;
>
> fd = open(path, O_RDONLY);
> if (fd < 0)
> return -1;
> len = strbuf_read(sb, fd, hint);
> + saved_errno = errno;
> close(fd);Theoretically close() can fail, though it seems a little far-fetched (and also uninteresting) if it fails for a file opened read-only. But if it did, you would not notice the error.
So I grepped through our code to see whether we typically bother to check the return value when close()ing a read-only file. And I found that we rarely even check its return value when *writing* to a file. (Many of those places are probably bugs.)
So, carry on and forget I said anything :-)
Show 9 quoted lines
> - if (len < 0)
> + if (len < 0) {
> + errno = saved_errno;
> return -1;
> + }
>
> return len;
> }
> Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Michael
-- Michael Haggerty mhagger@alum.mit.edu http://softwareswirl.blogspot.com/