From: Linda Knippers <linda.knippers@hpe.com>
To: Dan Williams <dan.j.williams@intel.com>, linux-nvdimm@lists.01.org
Subject: Re: [ndctl PATCH] util: distinguish error codes for sysfs_{read, write}_attr()
Date: Fri, 9 Jun 2017 16:09:48 -0400 [thread overview]
Message-ID: <593B008C.60502@hpe.com> (raw)
In-Reply-To: <149698606405.12023.3409783083697026090.stgit@dwillia2-desk3.amr.corp.intel.com>
On 06/09/2017 01:27 AM, Dan Williams wrote:
> There are occasions where it would be good to know the difference
> between a sysfs attribute failing to be accessed because we could not
> open versus could not read/write.
I think it would be really helpful if you returned the actual errno value
rather than something hard coded. The most common reason for not being able to write
something is that it requires running as root, in which case you should
get an EPERM. I think an accurate errno will help users figure out what's
gone wrong.
-- ljk
>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> ---
> util/sysfs.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/util/sysfs.c b/util/sysfs.c
> index 31d1a898eba2..7905455890dc 100644
> --- a/util/sysfs.c
> +++ b/util/sysfs.c
> @@ -34,13 +34,13 @@ int __sysfs_read_attr(struct log_ctx *ctx, const char *path, char *buf)
>
> if (fd < 0) {
> log_dbg(ctx, "failed to open %s: %s\n", path, strerror(errno));
> - return -1;
> + return -ENOENT;
> }
> n = read(fd, buf, SYSFS_ATTR_SIZE);
> close(fd);
> if (n < 0 || n >= SYSFS_ATTR_SIZE) {
> log_dbg(ctx, "failed to read %s: %s\n", path, strerror(errno));
> - return -1;
> + return -EIO;
> }
> buf[n] = 0;
> if (n && buf[n-1] == '\n')
> @@ -56,7 +56,7 @@ static int write_attr(struct log_ctx *ctx, const char *path,
>
> if (fd < 0) {
> log_dbg(ctx, "failed to open %s: %s\n", path, strerror(errno));
> - return -1;
> + return -ENOENT;
> }
> n = write(fd, buf, len);
> close(fd);
> @@ -64,7 +64,7 @@ static int write_attr(struct log_ctx *ctx, const char *path,
> if (!quiet)
> log_dbg(ctx, "failed to write %s to %s: %s\n", buf, path,
> strerror(errno));
> - return -1;
> + return -EIO;
> }
> return 0;
> }
>
> _______________________________________________
> Linux-nvdimm mailing list
> Linux-nvdimm@lists.01.org
> https://lists.01.org/mailman/listinfo/linux-nvdimm
>
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next prev parent reply other threads:[~2017-06-09 20:08 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-09 5:27 [ndctl PATCH] util: distinguish error codes for sysfs_{read, write}_attr() Dan Williams
2017-06-09 20:09 ` Linda Knippers [this message]
2017-06-09 20:53 ` Dan Williams
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