Sockets may never receive notification of some link errors, causing "git fetch" or similar processes to hang forever. Enabling keepalive messages allows hung processes to error out after a few minutes/hours depending on the keepalive settings of the system.
This is a problem noticed when running non-interactive cronjobs to mirror repositories using "git fetch".
Signed-off-by: Eric Wong <normalperson@yhbt.net> --- connect.c | 13 +++++++++++++ 1 files changed, 13 insertions(+), 0 deletions(-)
Show changes to connect.c +13 −0
diff --git a/connect.c b/connect.c index 51990fa..d0f59ef 100644 --- a/connect.c +++ b/connect.c @@ -175,6 +175,15 @@ static void get_host_and_port(char **host, const char **port) } } +static void enable_keepalive(int sockfd) +{ + int ka = 1; + + if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0) + fprintf(stderr, "unable to set SO_KEEPALIVE on socket: %s\n", + strerror(errno)); +} + #ifndef NO_IPV6 static const char *ai_name(const struct addrinfo *ai) @@ -239,6 +248,8 @@ static int git_tcp_connect_sock(char *host, int flags) if (sockfd < 0) die("unable to connect to %s:\n%s", host, error_message.buf); + enable_keepalive(sockfd); + if (flags & CONNECT_VERBOSE) fprintf(stderr, "done.\n"); @@ -312,6 +323,8 @@ static int git_tcp_connect_sock(char *host, int flags) if (sockfd < 0) die("unable to connect to %s:\n%s", host, error_message.buf); + enable_keepalive(sockfd); + if (flags & CONNECT_VERBOSE) fprintf(stderr, "done.\n");
-- Eric Wong