Adds options --no-httpd and --exec

The option option --exec use the remaining arguments
of the command line (at the right of --exec) as a
command to launch with its arguments. Arguments can
use @p (for port), @t (for token) or @@ for @.

When the option --exec is given, the command is launched
as soon as afb-daemon is ready. When the command die,
afb-daemon exits and before exiting, afb-daemon kills
the launched command and its childs.

The option --no-http forbids the activation of
the HTTP server.

Change-Id: Icdd91d84c818796b5ac6ea5d33ff3549a2fe3c25
Signed-off-by: José Bollo <jose.bollo@iot.bzh>

4 files changed, 185 insertions, 26 deletions

diff --git a/doc/afb-overview.md b/doc/afb-overview.md
index c66f84ea..6272b5d2 100644
--- a/doc/afb-overview.md
+++ b/doc/afb-overview.md
@@ -232,6 +232,17 @@ The launch options for binder **afb-daemon** are:
 
 		Get all in background mode
 
+	  --no-httpd
+
+		Forbids HTTP serve
+
+	  --exec
+
+		Must be the last option for afb-daemon. The remaining
+		arguments define a command that afb-daemon will launch.
+		The sequences @p, @t and @@ of the arguments are replaced
+		with the port, the token and @.
+
 
 Future development of afb-daemon
 --------------------------------
diff --git a/src/afb-config.c b/src/afb-config.c
index 4754c958..e2fec3a0 100644
--- a/src/afb-config.c
+++ b/src/afb-config.c
@@ -88,7 +88,11 @@
 
 #define SET_TRACEREQ       27
 
-#define SHORTOPTS	"vqhV"
+#define SET_NO_HTTPD       28
+
+#define SET_EXEC           'e'
+
+#define SHORTOPTS	"vqhVe"
 
 // Command line structure hold cli --command + help text
 typedef struct {
@@ -120,7 +124,7 @@ static AFB_options cliOptions[] = {
 
 	{SET_SESSION_DIR,   1, "sessiondir",  "Sessions file path [default rootdir/sessions]"},
 
-	{SET_LDPATH,        1, "ldpaths",     "Load bindingss from dir1:dir2:... [default = " BINDING_INSTALL_DIR "]"},
+	{SET_LDPATH,        1, "ldpaths",     "Load bindings from dir1:dir2:... [default = " BINDING_INSTALL_DIR "]"},
 	{SET_AUTH_TOKEN,    1, "token",       "Initial Secret [default=no-session, --token= for session without authentication]"},
 
 	{DISPLAY_VERSION,   0, "version",     "Display version and copyright"},
@@ -139,6 +143,9 @@ static AFB_options cliOptions[] = {
 
 	{SET_TRACEREQ,      1, "tracereq",    "Log the requests: no, common, extra, all"},
 
+	{SET_NO_HTTPD,      0, "no-httpd",    "Forbids HTTP service"},
+	{SET_EXEC,          0, "exec",        "Execute the remaining arguments"},
+
 	{0, 0, NULL, NULL}
 /* *INDENT-ON* */
 };
@@ -447,6 +454,16 @@ static void parse_arguments(int argc, char **argv, struct afb_config *config)
 			config->tracereq = argvalenum(optionIndex, tracereq_desc);
 			break;
 
+		case SET_NO_HTTPD:
+			noarg(optionIndex);
+			config->noHttpd = 1;
+			break;
+
+		case SET_EXEC:
+			config->exec = &argv[optind];
+			optind = argc;
+			break;
+
 		case DISPLAY_VERSION:
 			noarg(optionIndex);
 			printVersion(stdout);
@@ -526,6 +543,7 @@ void afb_config_dump(struct afb_config *config)
 {
 	struct afb_config_list *l;
 	struct enumdesc *e;
+	char **v;
 
 #define NN(x)   (x)?:""
 #define P(...)  fprintf(stderr, __VA_ARGS__)
@@ -534,10 +552,12 @@ void afb_config_dump(struct afb_config *config)
 #define S(x)	PF(x);P("%s",NN(config->x));PE;
 #define D(x)	PF(x);P("%d",config->x);PE;
 #define H(x)	PF(x);P("%x",config->x);PE;
+#define B(x)	PF(x);P("%s",config->x?"yes":"no");PE;
 #define L(x)	PF(x);l=config->x;if(l){P("%s\n",NN(l->value));for(l=l->next;l;l=l->next)P("-- %15s  %s\n","",NN(l->value));}else PE;
-#define E(x,d)	for(e=d;e->name&&e->value!=config->x;e++);PF(x);if(e->name)P("%s",e->name);else P("%d",config->x);PE;
+#define E(x,d)	for(e=d;e->name&&e->value!=config->x;e++);if(e->name){PF(x);P("%s",e->name);PE;}else{D(x);}
+#define V(x)	P("-- %15s:", #x);for(v=config->x;v&&*v;v++)P(" %s",*v); PE;
 
-	P("-- BEGIN OF CONFIG --\n");
+	P("---BEGIN-OF-CONFIG---\n");
 	S(console)
 	S(rootdir)
 	S(roothttp)
@@ -554,8 +574,10 @@ void afb_config_dump(struct afb_config *config)
 	L(so_bindings)
 	L(ldpaths)
 
+	V(exec)
+
 	D(httpdPort)
-	D(background)
+	B(background)
 	D(readyfd)
 	D(cacheTimeout)
 	D(apiTimeout)
@@ -563,10 +585,13 @@ void afb_config_dump(struct afb_config *config)
 	D(nbSessionMax)
 	E(mode,mode_desc)
 	E(tracereq,tracereq_desc)
-	P("-- END OF CONFIG --\n");
+	B(noHttpd)
+	P("---END-OF-CONFIG---\n");
 
+#undef V
 #undef E
 #undef L
+#undef B
 #undef H
 #undef D
 #undef S
diff --git a/src/afb-config.h b/src/afb-config.h
index 542a617e..eb76abe8 100644
--- a/src/afb-config.h
+++ b/src/afb-config.h
@@ -34,6 +34,7 @@ struct afb_config {
 	char *rootapi;		// Base URL for REST APIs
 	char *sessiondir;	// where to store mixer session files
 	char *token;		// initial authentication token [default NULL no session]
+
 	struct afb_config_list *aliases;
 	struct afb_config_list *dbus_clients;
 	struct afb_config_list *dbus_servers;
@@ -42,6 +43,8 @@ struct afb_config {
 	struct afb_config_list *so_bindings;
 	struct afb_config_list *ldpaths;
 
+	char **exec;
+
 	int httpdPort;
 	int background;		// run in backround mode
 	int readyfd;		// a #fd to signal when ready to serve
@@ -51,6 +54,7 @@ struct afb_config {
 	int nbSessionMax;	// max count of sessions
 	int mode;		// mode of listening
 	int tracereq;
+	int noHttpd;
 };
 
 extern struct afb_config *afb_config_parse_arguments(int argc, char **argv);
diff --git a/src/main.c b/src/main.c
index ac93de4f..9fbbb072 100644
--- a/src/main.c
+++ b/src/main.c
@@ -25,6 +25,7 @@
 #include <unistd.h>
 #include <fcntl.h>
 #include <sys/stat.h>
+#include <sys/wait.h>
 
 #include <systemd/sd-event.h>
 
@@ -46,6 +47,9 @@
 
 #include <afb/afb-binding.h>
 
+static struct afb_config *config;
+static pid_t childpid;
+
 /*----------------------------------------------------------
  |   helpers for handling list of arguments
  +--------------------------------------------------------- */
@@ -83,19 +87,21 @@ static void start_list(struct afb_config_list *list,
 }
 
 /*----------------------------------------------------------
- | closeSession
- |   try to close everything before leaving
+ | exit_handler
+ |   Handles on exit specific actions
  +--------------------------------------------------------- */
-static void closeSession(int status, void *data)
+static void exit_handler()
 {
-	/* struct afb_config *config = data; */
+	if (childpid > 0)
+		killpg(childpid, SIGKILL);
+		/* TODO: check whether using SIGHUP isn't better */
 }
 
 /*----------------------------------------------------------
  | daemonize
  |   set the process in background
  +--------------------------------------------------------- */
-static void daemonize(struct afb_config *config)
+static void daemonize()
 {
 	int consoleFD;
 	int pid;
@@ -155,7 +161,7 @@ static int init_alias(void *closure, char *spec)
 				  0, 0);
 }
 
-static int init_http_server(struct afb_hsrv *hsrv, struct afb_config *config)
+static int init_http_server(struct afb_hsrv *hsrv)
 {
 	if (!afb_hsrv_add_handler
 	    (hsrv, config->rootapi, afb_hswitch_websocket_switch, NULL, 20))
@@ -183,7 +189,7 @@ static int init_http_server(struct afb_hsrv *hsrv, struct afb_config *config)
 	return 1;
 }
 
-static struct afb_hsrv *start_http_server(struct afb_config *config)
+static struct afb_hsrv *start_http_server()
 {
 	int rc;
 	struct afb_hsrv *hsrv;
@@ -200,7 +206,7 @@ static struct afb_hsrv *start_http_server(struct afb_config *config)
 	}
 
 	if (!afb_hsrv_set_cache_timeout(hsrv, config->cacheTimeout)
-	    || !init_http_server(hsrv, config)) {
+	    || !init_http_server(hsrv)) {
 		ERROR("initialisation of httpd failed");
 		afb_hsrv_put(hsrv);
 		return NULL;
@@ -221,6 +227,114 @@ static struct afb_hsrv *start_http_server(struct afb_config *config)
 }
 
 /*---------------------------------------------------------
+ | execute_command
+ |   
+ +--------------------------------------------------------- */
+
+static void on_sigchld(int signum, siginfo_t *info, void *uctx)
+{
+	if (info->si_pid == childpid) {
+		switch (info->si_code) {
+		case CLD_EXITED:
+		case CLD_KILLED:
+		case CLD_DUMPED:
+			childpid = 0;
+			killpg(info->si_pid, SIGKILL);
+			waitpid(info->si_pid, NULL, 0);
+			exit(0);
+		}
+	}
+}
+
+/*
+# @@ @
+# @p port
+# @t token
+*/
+
+#define SUBST_CHAR  '@'
+#define SUBST_STR   "@"
+
+static int instanciate_command_args()
+{
+	char *orig, *repl, *sub, *val, port[20];
+	int i, rc, r;
+	size_t s, l;
+
+	rc = snprintf(port, sizeof port, "%d", config->httpdPort);
+	if (rc < 0 || rc >= (int)(sizeof port))
+		return -1;
+
+	for (i = 0 ; (orig = config->exec[i]) ; i++) {
+		repl = 0;
+		s = 0;
+		for(;;) {
+			sub = strchrnul(orig, SUBST_CHAR);
+			l = sub - orig;
+			if (repl)
+				repl = mempcpy(repl, orig, l);
+			else
+				s += l;
+			if (!*sub) {
+				/* at end */
+				if (repl || orig == config->exec[i])
+					break;
+				repl = malloc(1 + s);
+				if (!repl)
+					return -1;
+				orig = config->exec[i];
+				config->exec[i] = repl;
+				repl[s] = 0;
+			} else {
+				r = 2;
+				switch(sub[1]) {
+				case 'p': val = port;  break;
+				case 't': val = config->token ? : ""; break;
+				default: r = 1;
+				case SUBST_CHAR: val = SUBST_STR; break;
+				}
+				orig = &sub[r];
+				l = strlen(val);
+				if (repl)
+					repl = mempcpy(repl, val, l);
+				else
+					s += l;
+			}
+		}
+	}
+	return 0;
+}
+
+static int execute_command()
+{
+	struct sigaction siga;
+
+	/* check whether a command is to execute or not */
+	if (!config->exec || !config->exec[0])
+		return 0;
+
+	/* install signal handler */
+	memset(&siga, 0, sizeof siga);
+	siga.sa_sigaction = on_sigchld;
+	siga.sa_flags = SA_SIGINFO;
+	sigaction(SIGCHLD, &siga, NULL);
+
+	/* fork now */
+	childpid = fork();
+	if (childpid)
+		return 0;
+
+	/* makes arguments */
+	if (instanciate_command_args() >= 0) {
+		setpgid(0, 0);
+		execv(config->exec[0], config->exec);
+		ERROR("can't launch %s: %m", config->exec[0]);
+	}
+	exit(1);
+	return -1;
+}
+
+/*---------------------------------------------------------
  | main
  |   Parse option and launch action
  +--------------------------------------------------------- */
@@ -228,14 +342,13 @@ static struct afb_hsrv *start_http_server(struct afb_config *config)
 int main(int argc, char *argv[])
 {
 	struct afb_hsrv *hsrv;
-	struct afb_config *config;
 	struct sd_event *eventloop;
 
 	LOGAUTH("afb-daemon");
 
 	// ------------- Build session handler & init config -------
 	config = afb_config_parse_arguments(argc, argv);
-	on_exit(closeSession, config);
+	atexit(exit_handler);
 
 	// ------------------ sanity check ----------------------------------------
 	if (config->httpdPort <= 0) {
@@ -243,8 +356,7 @@ int main(int argc, char *argv[])
 		exit(1);
 	}
 
-	afb_session_init(config->nbSessionMax, config->cntxTimeout,
-			 config->token, afb_apis_count());
+	afb_session_init(config->nbSessionMax, config->cntxTimeout, config->token, afb_apis_count());
 
 	afb_api_so_set_timeout(config->apiTimeout);
 	start_list(config->dbus_clients, afb_api_dbus_add_client, "the afb-dbus client");
@@ -254,8 +366,7 @@ int main(int argc, char *argv[])
 	start_list(config->dbus_servers, afb_api_dbus_add_server, "the afb-dbus service");
 	start_list(config->ws_servers, afb_api_ws_add_server, "the afb-websocket service");
 
-	if (!afb_hreq_init_cookie
-	    (config->httpdPort, config->rootapi, config->cntxTimeout)) {
+	if (!afb_hreq_init_cookie(config->httpdPort, config->rootapi, config->cntxTimeout)) {
 		ERROR("initialisation of cookies failed");
 		exit(1);
 	}
@@ -288,7 +399,7 @@ int main(int argc, char *argv[])
 	if (config->background) {
 		// --------- in background mode -----------
 		INFO("entering background mode");
-		daemonize(config);
+		daemonize();
 	} else {
 		// ---- in foreground mode --------------------
 		INFO("entering foreground mode");
@@ -301,20 +412,28 @@ int main(int argc, char *argv[])
 	if (config->tracereq)
 		afb_hook_req_create(NULL, NULL, NULL, config->tracereq, NULL, NULL);
 
-	/* start the HTTP server */
-	hsrv = start_http_server(config);
-	if (hsrv == NULL)
-		exit(1);
-
 	/* start the services */
 	if (afb_apis_start_all_services(1) < 0)
 		exit(1);
 
+	/* start the HTTP server */
+	if (!config->noHttpd) {
+		hsrv = start_http_server();
+		if (hsrv == NULL)
+			exit(1);
+	}
+
+	/* run the command */
+	if (execute_command() < 0)
+		exit(1);
+
+	/* signal that ready */
 	if (config->readyfd != 0) {
 		static const char readystr[] = "READY=1";
 		write(config->readyfd, readystr, sizeof(readystr) - 1);
 		close(config->readyfd);
 	}
+
 	// infinite loop
 	eventloop = afb_common_get_event_loop();
 	for (;;)