RE: [PATCH] tools: hv: introduce -n/--no-daemon option

From: KY Srinivasan
Date: Wed Oct 22 2014 - 13:11:54 EST




> -----Original Message-----
> From: Vitaly Kuznetsov [mailto:vkuznets@xxxxxxxxxx]
> Sent: Wednesday, October 22, 2014 9:07 AM
> To: KY Srinivasan; Haiyang Zhang; devel@xxxxxxxxxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Subject: [PATCH] tools: hv: introduce -n/--no-daemon option
>
> All tools/hv daemons do mandatory daemon() on startup. However, no
> pidfile is created, this make it difficult for an init system to track such
> daemons.
> Modern linux distros use systemd as their init system. It can handle the
> daemonizing by itself, however, it requires a daemon to stay in foreground
> for that. Some distros already carry distro-specific patch for hv tools which
> switches off daemon().
>
> Introduce -n/--no-daemon option for all 3 daemons in hv/tools. Parse
> options with getopt() to make this part easily expandable.
>
> Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
You may want to include Greg KH in the "to" list.
Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>


> ---
> tools/hv/hv_fcopy_daemon.c | 33 +++++++++++++++++++++++++++++++-
> -
> tools/hv/hv_kvp_daemon.c | 34
> ++++++++++++++++++++++++++++++++--
> tools/hv/hv_vss_daemon.c | 33 +++++++++++++++++++++++++++++++--
> 3 files changed, 94 insertions(+), 6 deletions(-)
>
> diff --git a/tools/hv/hv_fcopy_daemon.c b/tools/hv/hv_fcopy_daemon.c
> index 8f96b3e..f437d73 100644
> --- a/tools/hv/hv_fcopy_daemon.c
> +++ b/tools/hv/hv_fcopy_daemon.c
> @@ -33,6 +33,7 @@
> #include <sys/stat.h>
> #include <fcntl.h>
> #include <dirent.h>
> +#include <getopt.h>
>
> static int target_fd;
> static char target_fname[W_MAX_PATH];
> @@ -126,15 +127,43 @@ static int hv_copy_cancel(void)
>
> }
>
> -int main(void)
> +void print_usage(char *argv[])
> +{
> + fprintf(stderr, "Usage: %s [options]\n"
> + "Options are:\n"
> + " -n, --no-daemon stay in foreground, don't
> daemonize\n"
> + " -h, --help print this help\n", argv[0]);
> +}
> +
> +int main(int argc, char *argv[])
> {
> int fd, fcopy_fd, len;
> int error;
> + int daemonize = 1, long_index = 0, opt;
> int version = FCOPY_CURRENT_VERSION;
> char *buffer[4096 * 2];
> struct hv_fcopy_hdr *in_msg;
>
> - if (daemon(1, 0)) {
> + static struct option long_options[] = {
> + {"help", no_argument, 0, 'h' },
> + {"no-daemon", no_argument, 0, 'n' },
> + {0, 0, 0, 0 }
> + };
> +
> + while ((opt = getopt_long(argc, argv, "hn", long_options,
> + &long_index)) != -1) {
> + switch (opt) {
> + case 'n':
> + daemonize = 0;
> + break;
> + case 'h':
> + default:
> + print_usage(argv);
> + exit(EXIT_FAILURE);
> + }
> + }
> +
> + if (daemonize && daemon(1, 0)) {
> syslog(LOG_ERR, "daemon() failed; error: %s",
> strerror(errno));
> exit(EXIT_FAILURE);
> }
> diff --git a/tools/hv/hv_kvp_daemon.c b/tools/hv/hv_kvp_daemon.c index
> 4088b81..22b0764 100644
> --- a/tools/hv/hv_kvp_daemon.c
> +++ b/tools/hv/hv_kvp_daemon.c
> @@ -43,6 +43,7 @@
> #include <fcntl.h>
> #include <dirent.h>
> #include <net/if.h>
> +#include <getopt.h>
>
> /*
> * KVP protocol: The user mode component first registers with the @@ -
> 1417,7 +1418,15 @@ netlink_send(int fd, struct cn_msg *msg)
> return sendmsg(fd, &message, 0);
> }
>
> -int main(void)
> +void print_usage(char *argv[])
> +{
> + fprintf(stderr, "Usage: %s [options]\n"
> + "Options are:\n"
> + " -n, --no-daemon stay in foreground, don't
> daemonize\n"
> + " -h, --help print this help\n", argv[0]);
> +}
> +
> +int main(int argc, char *argv[])
> {
> int fd, len, nl_group;
> int error;
> @@ -1435,9 +1444,30 @@ int main(void)
> struct hv_kvp_ipaddr_value *kvp_ip_val;
> char *kvp_recv_buffer;
> size_t kvp_recv_buffer_len;
> + int daemonize = 1, long_index = 0, opt;
> +
> + static struct option long_options[] = {
> + {"help", no_argument, 0, 'h' },
> + {"no-daemon", no_argument, 0, 'n' },
> + {0, 0, 0, 0 }
> + };
> +
> + while ((opt = getopt_long(argc, argv, "hn", long_options,
> + &long_index)) != -1) {
> + switch (opt) {
> + case 'n':
> + daemonize = 0;
> + break;
> + case 'h':
> + default:
> + print_usage(argv);
> + exit(EXIT_FAILURE);
> + }
> + }
>
> - if (daemon(1, 0))
> + if (daemonize && daemon(1, 0))
> return 1;
> +
> openlog("KVP", 0, LOG_USER);
> syslog(LOG_INFO, "KVP starting; pid is:%d", getpid());
>
> diff --git a/tools/hv/hv_vss_daemon.c b/tools/hv/hv_vss_daemon.c index
> 6a213b8..9ae2b6e 100644
> --- a/tools/hv/hv_vss_daemon.c
> +++ b/tools/hv/hv_vss_daemon.c
> @@ -36,6 +36,7 @@
> #include <linux/hyperv.h>
> #include <linux/netlink.h>
> #include <syslog.h>
> +#include <getopt.h>
>
> static struct sockaddr_nl addr;
>
> @@ -131,7 +132,15 @@ static int netlink_send(int fd, struct cn_msg *msg)
> return sendmsg(fd, &message, 0);
> }
>
> -int main(void)
> +void print_usage(char *argv[])
> +{
> + fprintf(stderr, "Usage: %s [options]\n"
> + "Options are:\n"
> + " -n, --no-daemon stay in foreground, don't
> daemonize\n"
> + " -h, --help print this help\n", argv[0]);
> +}
> +
> +int main(int argc, char *argv[])
> {
> int fd, len, nl_group;
> int error;
> @@ -143,8 +152,28 @@ int main(void)
> struct hv_vss_msg *vss_msg;
> char *vss_recv_buffer;
> size_t vss_recv_buffer_len;
> + int daemonize = 1, long_index = 0, opt;
> +
> + static struct option long_options[] = {
> + {"help", no_argument, 0, 'h' },
> + {"no-daemon", no_argument, 0, 'n' },
> + {0, 0, 0, 0 }
> + };
> +
> + while ((opt = getopt_long(argc, argv, "hn", long_options,
> + &long_index)) != -1) {
> + switch (opt) {
> + case 'n':
> + daemonize = 0;
> + break;
> + case 'h':
> + default:
> + print_usage(argv);
> + exit(EXIT_FAILURE);
> + }
> + }
>
> - if (daemon(1, 0))
> + if (daemonize && daemon(1, 0))
> return 1;
>
> openlog("Hyper-V VSS", 0, LOG_USER);
> --
> 1.9.3

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