[v2] systemd support

Enable support for systemd's start-up completion notification
and, optionally, socket-based activation.

Signed-off-by: Christian Storm <christian.storm@siemens.com>
---
 Kconfig                   |  7 ++++++
 Makefile.flags            |  4 ++++
 core/swupdate.c           | 10 ++++++++
 corelib/network_thread.c  | 54 +++++++++++++++++++++++++++++++++---------
 corelib/progress_thread.c | 13 ++++++++++
 doc/source/swupdate.rst   | 60 +++++++++++++++++++++++++++++++++++++++++++++++
 6 files changed, 137 insertions(+), 11 deletions(-)

On 22/09/2017 16:42, Christian Storm wrote:
> Enable support for systemd's start-up completion notification
> and, optionally, socket-based activation.
> 
> Signed-off-by: Christian Storm <christian.storm@siemens.com>
> ---
>  Kconfig                   |  7 ++++++
>  Makefile.flags            |  4 ++++
>  core/swupdate.c           | 10 ++++++++
>  corelib/network_thread.c  | 54 +++++++++++++++++++++++++++++++++---------
>  corelib/progress_thread.c | 13 ++++++++++
>  doc/source/swupdate.rst   | 60 +++++++++++++++++++++++++++++++++++++++++++++++
>  6 files changed, 137 insertions(+), 11 deletions(-)
> 
> diff --git a/Kconfig b/Kconfig
> index f90d218..c6dde7f 100644
> --- a/Kconfig
> +++ b/Kconfig
> @@ -61,6 +61,13 @@ menu "Swupdate Settings"
>  
>  menu "General Configuration"
>  
> +config SYSTEMD
> +	bool "enable systemd support"
> +	default n
> +	help
> +	  Enable support for systemd's start-up completion
> +	  notification and socket-based activation features.
> +
>  config SCRIPTS
>  	bool "enable pre and postinstall scripts"
>  	default y
> diff --git a/Makefile.flags b/Makefile.flags
> index 391fc7f..3dbf379 100644
> --- a/Makefile.flags
> +++ b/Makefile.flags
> @@ -165,6 +165,10 @@ ifeq ($(CONFIG_UBOOT),y)
>  LDLIBS += z ubootenv
>  endif
>  
> +ifeq ($(CONFIG_SYSTEMD),y)
> +LDLIBS += systemd
> +endif
> +
>  # suricatta
>  ifneq ($(CONFIG_SURICATTA),)
>  ifneq ($(CONFIG_SURICATTA_SSL),)
> diff --git a/core/swupdate.c b/core/swupdate.c
> index e35289e..ef94bd9 100644
> --- a/core/swupdate.c
> +++ b/core/swupdate.c
> @@ -59,6 +59,10 @@
>  #include "pctl.h"
>  #include "bootloader.h"
>  
> +#ifdef CONFIG_SYSTEMD
> +#include <systemd/sd-daemon.h>
> +#endif
> +
>  #define MODULE_NAME	"swupdate"
>  
>  static pthread_t network_daemon;
> @@ -864,6 +868,12 @@ int main(int argc, char **argv)
>  		}
>  	}
>  
> +#ifdef CONFIG_SYSTEMD
> +	if (sd_booted()) {
> +		sd_notify(0, "READY=1");
> +	}
> +#endif
> +
>  	/*
>  	 * Install a handler for SIGTERM that cancels
>  	 * the network_daemon thread to allow atexit()
> diff --git a/corelib/network_thread.c b/corelib/network_thread.c
> index 5ed516e..747ee1b 100644
> --- a/corelib/network_thread.c
> +++ b/corelib/network_thread.c
> @@ -44,6 +44,10 @@
>  #include "pctl.h"
>  #include "generated/autoconf.h"
>  
> +#ifdef CONFIG_SYSTEMD
> +#include <systemd/sd-daemon.h>
> +#endif
> +
>  #define LISTENQ	1024
>  
>  #define NUM_CACHED_MESSAGES 100
> @@ -109,20 +113,39 @@ static void network_notifier(RECOVERY_STATUS status, int error, const char *msg)
>  int listener_create(const char *path, int type)
>  {
>  	struct sockaddr_un servaddr;
> -	int listenfd;
> -
> -	listenfd = socket(AF_LOCAL, type, 0);
> -	unlink(path);
> -	bzero(&servaddr, sizeof(servaddr));
> -	servaddr.sun_family = AF_LOCAL;
> -	strcpy(servaddr.sun_path, path);
> +	int listenfd = -1;
>  
> -	if (bind(listenfd,  (struct sockaddr *) &servaddr, sizeof(servaddr)) < 0) {
> -		close(listenfd);
> -		return -1;
> +#ifdef CONFIG_SYSTEMD
> +	if (sd_booted()) {
> +		for (int fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + sd_listen_fds(0); fd++) {
> +			if (sd_is_socket_unix(fd, SOCK_STREAM, 1, path, 0)) {
> +				listenfd = fd;
> +				break;
> +			}
> +		}
> +		if (listenfd == -1) {
> +			TRACE("got no socket at %s from systemd", path);
> +		} else {
> +			TRACE("got socket fd=%d at %s from systemd", listenfd, path);
> +		}
>  	}
> +#endif
> +
> +	if (listenfd == -1) {
> +		TRACE("creating socket at %s", path);
> +		listenfd = socket(AF_LOCAL, type, 0);
> +		unlink(path);
> +		bzero(&servaddr, sizeof(servaddr));
> +		servaddr.sun_family = AF_LOCAL;
> +		strcpy(servaddr.sun_path, path);
>  
> -	chmod(path,  S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH);
> +		if (bind(listenfd,  (struct sockaddr *) &servaddr, sizeof(servaddr)) < 0) {
> +			close(listenfd);
> +			return -1;
> +		}
> +
> +		chmod(path,  S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH);
> +	}
>  
>  	if (type == SOCK_STREAM)
>  		if (listen(listenfd, LISTENQ) < 0) {
> @@ -173,6 +196,15 @@ static void empty_pipe(int fd)
>  
>  static void unlink_socket(void)
>  {
> +#ifdef CONFIG_SYSTEMD
> +	if (sd_booted() && sd_listen_fds(0) > 0) {
> +		/*
> +		 * There were socket fds handed-over by systemd,
> +		 * so don't delete the socket file.
> +		 */
> +		return;
> +	}
> +#endif
>  	unlink((char*)CONFIG_SOCKET_CTRL_PATH);
>  }
>  
> diff --git a/corelib/progress_thread.c b/corelib/progress_thread.c
> index e0a11fe..d215166 100644
> --- a/corelib/progress_thread.c
> +++ b/corelib/progress_thread.c
> @@ -43,6 +43,10 @@
>  #include <progress.h>
>  #include "generated/autoconf.h"
>  
> +#ifdef CONFIG_SYSTEMD
> +#include <systemd/sd-daemon.h>
> +#endif
> +
>  struct progress_conn {
>  	SIMPLEQ_ENTRY(progress_conn) next;
>  	int sockfd;
> @@ -185,6 +189,15 @@ void swupdate_progress_done(const char *info)
>  
>  static void unlink_socket(void)
>  {
> +#ifdef CONFIG_SYSTEMD
> +	if (sd_booted() && sd_listen_fds(0) > 0) {
> +		/*
> +		 * There were socket fds handed-over by systemd,
> +		 * so don't delete the socket file.
> +		 */
> +		return;
> +	}
> +#endif
>  	unlink((char*)CONFIG_SOCKET_PROGRESS_PATH);
>  }
>  
> diff --git a/doc/source/swupdate.rst b/doc/source/swupdate.rst
> index 4df0b6b..5302e04 100644
> --- a/doc/source/swupdate.rst
> +++ b/doc/source/swupdate.rst
> @@ -504,6 +504,66 @@ Command line parameters
>  |             |          | downloading                                |
>  +-------------+----------+--------------------------------------------+
>  
> +
> +systemd Integration
> +-------------------
> +
> +SWUpdate has optional systemd_ support via the compile-time
> +configuration switch ``CONFIG_SYSTEMD``. If enabled, SWUpdate
> +signals systemd about start-up completion and can make optional
> +use of systemd's socket-based activation feature.
> +
> +A sample systemd service unit file ``/etc/systemd/system/swupdate.service``
> +may look like the following starting SWUpdate in suricatta daemon mode:
> +
> +::
> +
> +	[Unit]
> +	Description=SWUpdate daemon
> +	Documentation=https://github.com/sbabic/swupdate
> +	Documentation=https://sbabic.github.io/swupdate
> +
> +	[Service]
> +	Type=notify
> +	ExecStart=/usr/bin/swupdate -u '-t default -u http://localhost -i 25'
> +
> +	[Install]
> +	WantedBy=multi-user.target
> +
> +Started via ``systemctl start swupdate.service``, SWUpdate
> +(re)creates its sockets on startup. For using socket-based
> +activation, an accompanying systemd socket unit file
> +``/etc/systemd/system/swupdate.socket`` is required:
> +
> +::
> +
> +	[Unit]
> +	Description=SWUpdate socket listener
> +	Documentation=https://github.com/sbabic/swupdate
> +	Documentation=https://sbabic.github.io/swupdate
> +
> +	[Socket]
> +	ListenStream=/tmp/sockinstctrl
> +	ListenStream=/tmp/swupdateprog
> +
> +	[Install]
> +	WantedBy=sockets.target
> +
> +On ``swupdate.socket`` being started, systemd creates the socket
> +files and hands them over to SWUpdate when it starts. So, for
> +example, when talking to ``/tmp/swupdateprog``, systemd starts
> +``swupdate.service`` and hands-over the socket files. The socket
> +files are also handed over on a "regular" start of SWUpdate via
> +``systemctl start swupdate.service``.
> +
> +Note that the socket paths in the two ``ListenStream=`` directives
> +have to match the socket paths ``CONFIG_SOCKET_CTRL_PATH`` and 
> +``CONFIG_SOCKET_PROGRESS_PATH`` in SWUpdate's configuration.
> +Here, the default socket path configuration is depicted.
> +
> +.. _systemd: https://www.freedesktop.org/wiki/Software/systemd/
> +
> +
>  Changes in boot-loader code
>  ===========================
>  
> 

Reviewed-by: Stefano Babic <sbabic@denx.de>

Best regards,
Stefano Babic