Re: [PATCH 08/17] netlink: Treat send() or recv() errors as fatal

On Mon, 24 Jul 2023 16:09:27 +1000 David Gibson wrote:

Errors on send() or recv() calls on a netlink socket don't indicate errors with the netlink operations we're attempting, but rather that something's gone wrong with the mechanics of netlink itself. We don't really expect this to ever happen, and if it does, it's not clear what we could to to recover.

So, treat errors from these calls as fatal, rather than returning the error up the stack. This makes handling failures in the callers of nl_req() simpler.

Signed-off-by: David Gibson --- netlink.c | 36 +++++++++++++++++------------------- 1 file changed, 17 insertions(+), 19 deletions(-)

diff --git a/netlink.c b/netlink.c index 3620fd6..826c926 100644 --- a/netlink.c +++ b/netlink.c @@ -103,9 +103,9 @@ fail: * @req: Request with netlink header * @len: Request length * - * Return: received length on success, negative error code on failure + * Return: received length on success, terminates on error */ -static int nl_req(int s, char *buf, const void *req, ssize_t len) +static ssize_t nl_req(int s, char *buf, const void *req, ssize_t len) { char flush[NLBUFSIZ]; int done = 0; @@ -124,11 +124,17 @@ static int nl_req(int s, char *buf, const void *req, ssize_t len) } }

- if ((send(s, req, len, 0) < len) || - (len = recv(s, buf, NLBUFSIZ, 0)) < 0) - return -errno; + n = send(s, req, len, 0); + if (n < 0) + die("netlink: Failed to send(): %s", strerror(errno)); + else if (n < len) + die("netlink: Short send");

If you respin, probably worth doing: die("netlink: Short send (%li out of %li bytes)", n, len); -- Stefano