X-Git-Url: https://git.jankratochvil.net/?p=inetdmx.git;a=blobdiff_plain;f=inetdmx.c;h=ebab3bf2b0a34bff752249f9b2b3fb23214d8fd7;hp=4029438cbef54c175131c596ef3b7f3576cfb392;hb=009beb6c39a09220131eed12a9d79a83e140e245;hpb=f692db7f13fda5aefb49fcde0caa34f96118e44a

diff --git a/inetdmx.c b/inetdmx.c
index 4029438..ebab3bf 100644
--- a/inetdmx.c
+++ b/inetdmx.c
@@ -18,15 +18,19 @@
 #include <sys/wait.h>
 #include <stdarg.h>
 #include <syslog.h>
+#include <sys/file.h>
+#include <utime.h>
+#include <time.h>
+#include <assert.h>
 
 
 #define CONNECT_RETRY_MSEC 100
-
-static long opt_start_timeout=60;
-static int opt_port;
-static int opt_syslog;
-static int opt_stderr;
-static const char *opt_lock;
+#define DEFAULT_START_COMMAND_TIMEOUT 60
+#define DEFAULT_IDLE_SERVER_TIMEOUT (90*60)
+#define FLOCK_TIMEOUT_OVER_START_TIMEOUT 2
+#define SESSION_BUFFER_SIZE 0x1000
+#define SYSTEM_CHECKED_BUFFER_SIZE_MIN 0x1000
+#define SYSTEM_CHECKED_BUFFER_SIZE (LINE_MAX > SYSTEM_CHECKED_BUFFER_SIZE_MIN ? LINE_MAX : SYSTEM_CHECKED_BUFFER_SIZE_MIN)
 
 
 /* /usr/include/glib-2.0/glib/gmacros.h */
@@ -59,55 +63,178 @@ static const char *opt_lock;
 
 static const char *program_name;
 
+static int opt_start;
+static int opt_stop;
+static long opt_start_command_timeout=DEFAULT_START_COMMAND_TIMEOUT;
+static long opt_idle_server_timeout=DEFAULT_IDLE_SERVER_TIMEOUT;
+static int opt_port;
+static int opt_syslog;
+static int opt_stderr;
+static const char *opt_lock;
+static int opt_ignore_spawned_command_output;
+static const char *opt_command;
+
+
 static void fatal(const char *fmt,...) G_GNUC_PRINTF(1,2) G_GNUC_NORETURN;
-static void fatal(const char *fmt,...)
+
+static void verror(const char *fmt,va_list ap) G_GNUC_PRINTF(1,0);
+static void verror(const char *fmt,va_list ap)
 {
 int use_syslog=opt_syslog,use_stderr=opt_stderr;
-va_list ap;
 char *string;
-const char *const error_error="Error printing error message";
+const char *const double_error="Error printing error message";
 
 	if (!use_syslog && !use_stderr)
 		use_stderr=1;
-	va_start(ap,fmt);
 	if (-1==vasprintf(&string,fmt,ap)) {
-		if (fmt==error_error)
+		if (fmt==double_error)
 			exit(EXIT_FAILURE);
-		fatal(error_error);
+		fatal(double_error);
 		}
 	if (use_stderr)
-		fprintf(stderr,"%s: %s!\n",program_name,string);
+		fprintf(stderr,"%s: %s\n",program_name,string);
 	if (use_syslog) {
 		openlog(program_name,LOG_PID,LOG_DAEMON);
-		syslog(LOG_DAEMON|LOG_ERR,"%s!",string);
+		syslog(LOG_DAEMON|LOG_ERR,"%s",string);
 		closelog();
 		}
+}
+
+static void error(const char *fmt,...) G_GNUC_PRINTF(1,2);
+static void error(const char *fmt,...)
+{
+va_list ap;
+
+	va_start(ap,fmt);
+	verror(fmt,ap);
+	va_end(ap);
+}
+
+static void fatal(const char *fmt,...)
+{
+va_list ap;
+
+	va_start(ap,fmt);
+	verror(fmt,ap);
 	va_end(ap);
 	exit(EXIT_FAILURE);
 }
 
+static char *asprintf_checked(const char *fmt,...) G_GNUC_PRINTF(1,2);
+static char *asprintf_checked(const char *fmt,...)
+{
+char *string;
+va_list ap;
+int rc;
+
+	va_start(ap,fmt);
+	rc=vasprintf(&string,fmt,ap);
+	va_end(ap);
+	if (rc==-1)
+		fatal("Error formatting string using formatstring: %s",fmt);
+	return string;
+}
+
 static void usage(void)
 {
 	fprintf(stderr,"\
-Syntax: %s [{-T|--start-timeout} <start-timeout] [-S|--syslog] [-e|--stderr]\n\
-        [{-l|--lock} <filename>]\n\
-        {-p|--port} <server-port> <start-server-command>\n\
+Syntax: %s {-1|--start} [{-T|--start-command-timeout} <start-command-timeout>]\n\
+        \t[{-l|--lock} <filename>] [-S|--syslog] [-e|--stderr]\n\
+        \t\[-I|--ignore-spawned-command-output]\n\
+        \t{-p|--port} <server-port> <start-server-command>\n\
+     or %s {-0|--stop}  [{-i|--idle-server-timeout} <idle-server-timeout>]\n\
+        \t[{-l|--lock} <filename>] [-S|--syslog] [-e|--stderr]\n\
+        \t\[-I|--ignore-spawned-command-output]\n\
+        \t<stop-server-command>\n\
 \n\
-Error messages out to stderr by default, -S|--syslog omits stderr output,\n\
-both -S|--syslog and -e|--stderr output the errors by both methods.\n\
-\n",program_name);
+Error messages are printed to stderr by default,\n\
+-S|--syslog omits stderr output, both -S|--syslog and -e|--stderr output\n\
+the errors by both methods.\n\
+-I|--ignore-spawned-command-output will no longer warn of any stdout/stderr\n\
+output of <*-server-command>s but it will no longer stuck if they held their\n\
+output descriptors open.\n\
+\n",program_name,program_name);
 	exit(EXIT_FAILURE);
 }
 
 static const struct option longopts[]={
-	{"start-timeout",1,0,'T'},
-	{"syslog"       ,0,0,'S'},
-	{"stderr"       ,0,0,'e'},
-	{"lock"         ,1,0,'l'},
-	{"port"         ,1,0,'p'},
-	{NULL           ,0,0,0  },
+	{"start"                        ,0,0,'1'},
+	{"stop"                         ,0,0,'0'},
+	{"start-command-timeout"        ,1,0,'T'},
+	{"idle-server-timeout"          ,1,0,'i'},
+	{"syslog"                       ,0,0,'S'},
+	{"stderr"                       ,0,0,'e'},
+	{"lock"                         ,1,0,'l'},
+	{"port"                         ,1,0,'p'},
+	{"ignore-spawned-command-output",0,0,'I'},
+	{"help"                         ,0,0,'h'},
+	{NULL                           ,0,0,0  },
 	};
 
+static int lock_fd=-1;
+
+static int sighandler_flock_timeout_hit;
+static void sighandler_flock_timeout(int signo)
+{
+	sighandler_flock_timeout_hit=1;
+}
+
+static int lock_create(int lock_mode)
+{
+int retries=3;
+sighandler_t sighandler_alrm_orig;
+int flock_rc;
+
+	if (!opt_lock)
+		return 1;
+	/* Never drop the lock if the lock is already being held. */
+	if (lock_fd!=-1)
+		retries=-1;
+retry:
+	if (lock_fd==-1) {
+		if (-1==(lock_fd=open(opt_lock,O_CREAT|O_RDWR,0600)))
+			fatal("Error creating lock file \"%s\": %m",opt_lock);
+		}
+	sighandler_alrm_orig=signal(SIGALRM,sighandler_flock_timeout);
+	alarm(opt_start_command_timeout+FLOCK_TIMEOUT_OVER_START_TIMEOUT);
+	flock_rc=flock(lock_fd,lock_mode);
+	alarm(0);
+	signal(SIGALRM,sighandler_alrm_orig);
+	if (sighandler_flock_timeout_hit)
+		fatal("Timeout locking lock file \"%s\": %m",opt_lock);
+	if (flock_rc) {
+		if (lock_mode&LOCK_NB && errno==EWOULDBLOCK)
+			return 0;
+		fatal("Error locking lock file \"%s\": %m",opt_lock);
+		}
+	if (access(opt_lock,R_OK|W_OK)) {
+		if (retries--<=0)
+			fatal("Racing for the lock file \"%s\", giving up",opt_lock);
+		if (close(lock_fd))
+			fatal("Error closing lock file \"%s\": %m",opt_lock);
+		lock_fd=-1;
+		goto retry;
+		}
+	return 1;
+}
+
+static void lock_touch(void)
+{
+	if (!opt_lock || lock_fd==-1)
+		return;
+	if (utime(opt_lock,NULL))
+		fatal("Error updating lock file \"%s\" timestamp: %m",opt_lock);
+}
+
+static void lock_close(void)
+{
+	if (lock_fd==-1)
+		return;
+	if (close(lock_fd))
+		fatal("Error closing lock file \"%s\": %m",opt_lock);
+	lock_fd=-1;
+}
+
 static int connect_try(void)
 {
 int fdtcp;
@@ -152,8 +279,10 @@ int fdi,fdo;
 		for (fdi=0;fdi<G_N_ELEMENTS(pollfdi);fdi++)
 			if (pollfdi[fdi].events)
 				break;
-		if (fdi>=G_N_ELEMENTS(pollfdi))
+		if (fdi>=G_N_ELEMENTS(pollfdi)) {
+			lock_close();
 			exit(EXIT_SUCCESS);
+			}
 		if (0>=poll(pollfdi,G_N_ELEMENTS(pollfdi),-1))
 			fatal("poll(%s socket,%s socket): %m",pollfdi_name[0],pollfdi_name[1]);
 		for (fdi=0;fdi<G_N_ELEMENTS(pollfdi);fdi++)
@@ -167,7 +296,7 @@ int fdi,fdo;
 		for (fdi=0;fdi<G_N_ELEMENTS(pollfdi);fdi++) {
 			for (;;) {
 				ssize_t got;
-				char buf[0x1000];
+				char buf[SESSION_BUFFER_SIZE];
 
 				if (fcntl(pollfdi[fdi].fd,F_SETFL,O_NONBLOCK))
 					fatal("fcntl(%s socket,F_SETFL,O_NONBLOCK): %m",pollfdi_name[fdi]);
@@ -205,74 +334,157 @@ int fdtcp;
 	session_transfer("remote",STDIN_FILENO,STDOUT_FILENO,"local",fdtcp,fdtcp);
 }
 
+static int popen_pclose_checked(const char *command)
+{
+FILE *f;
+char buf[SYSTEM_CHECKED_BUFFER_SIZE];
+size_t got;
+
+	if (!(f=popen(command,"r")))
+		fatal("Error opening spawned command \"%s\": %m",command);
+	setlinebuf(f);
+	while ((got=fread(buf,1,sizeof(buf)-1,f))) {
+char *s,*s_next;
+
+		assert(got<sizeof(buf));
+		buf[got]=0;
+		for (s=buf;*s;s=s_next) {
+			if ((s_next=strchr(s,'\n'))) {
+				*s_next++=0;
+				error("Error line of spawned \"%s\": %s",command,s);
+				}
+			else {
+				s_next=s+strlen(s);
+				error("Error line of spawned \"%s\" too long, string cut: %s",command,s);
+				}
+			}
+		}
+	if (ferror(f))
+		fatal("Error reading output of spawned \"%s\"",command);
+	if (!feof(f))
+		fatal("Error reaching end-of-file of messages of spawned \"%s\"",command);
+	return pclose(f);
+}
+
 static void system_checked(const char *command)
 {
 int rc;
 
-	rc=system(command);
+	if (!opt_ignore_spawned_command_output)
+		rc=popen_pclose_checked(opt_stderr
+				? command	/* differentiate ourself-dumped stdout from stderr */
+				: asprintf_checked("(%s) 2>&1",command)
+				);
+	else
+		rc=system(opt_stderr
+				? asprintf_checked("(%s) >&2",command)
+				: asprintf_checked("(%s) &>/dev/null",command)
+				);
 	if (WIFEXITED(rc) && !WEXITSTATUS(rc))
 		return;
 	if (WIFEXITED(rc))
-		fatal("Error spawning command \"%s\": return code %d!",
+		fatal("Error spawning command \"%s\": return code %d",
 				command,WEXITSTATUS(rc));
 #ifdef WCOREDUMP
 	if (WIFSIGNALED(rc) && WCOREDUMP(rc))
-		fatal("Error spawning command \"%s\": dumped core (terminating signal %d)!",
+		fatal("Error spawning command \"%s\": dumped core (terminating signal %d)",
 				command,WTERMSIG(rc));
 #endif /* WCOREDUMP */
 	if (WIFSIGNALED(rc))
-		fatal("Error spawning command \"%s\": terminating signal %d!",
+		fatal("Error spawning command \"%s\": terminating signal %d",
 				command,WTERMSIG(rc));
 	if (WIFSTOPPED(rc))
-		fatal("Error spawning command \"%s\": stopping signal %d!",
+		fatal("Error spawning command \"%s\": stopping signal %d",
 				command,WSTOPSIG(rc));
 #ifdef WIFCONTINUED
 	if (WIFCONTINUED(rc))
-		fatal("Error spawning command \"%s\": resumed by SIGCONT!",
+		fatal("Error spawning command \"%s\": resumed by SIGCONT",
 				command);
 #endif /* WIFCONTINUED */
-	fatal("Error spawning command \"%s\": unknown reason!",
+	fatal("Error spawning command \"%s\": unknown reason",
 			command);
 }
 
-static int lock_fd=-1;
+static void start(void) G_GNUC_NORETURN;
+static void start(void)
+{
+int retry;
+
+	if (!opt_port)
+		fatal("-p|--port is a required argument for -1|--start");
+	if (opt_idle_server_timeout!=DEFAULT_IDLE_SERVER_TIMEOUT)
+		fatal("-i|--idle-server-timeout is a forbidden argument for -1|--start");
 
-static void lock_create(void)
+	lock_create(LOCK_SH);
+	lock_touch();
+	session_try();
+	lock_close();
+
+	lock_create(LOCK_EX);
+	system_checked(opt_command);
+	lock_create(LOCK_SH);
+
+	for (retry=0;retry*CONNECT_RETRY_MSEC/1000<opt_start_command_timeout;retry++) {
+		lock_touch();
+		session_try();
+		if (poll(NULL,0,CONNECT_RETRY_MSEC))
+			fatal("poll(timeout %dmsec): %m",CONNECT_RETRY_MSEC);
+		}
+	fatal("Timed out after %ld seconds connecting to port %d after spawned: %s",
+			opt_start_command_timeout,opt_port,opt_command);
+}
+
+/* Returns: Is fresh? */
+static int lock_create_and_time_check(int lock_mode)
 {
-int retries=3;
+struct stat statbuf;
 
 	if (!opt_lock)
-		return;
-retry:
-	if (-1==(lock_fd=open(opt_lock,O_CREAT|O_RDWR,0600)))
-		fatal("Error creating lock file \"%s\": %m",opt_lock);
-	if (flock(lock_fd,LOCK_EX))
-		fatal("Error locking lock file \"%s\": %m",opt_lock);
-	if (!access(opt_lock,O_RD|O_WR)) {
-		if (retries--<=0)
-			fatal("Racing for the lock file \"%s\", giving up");
-		if (close(lock_fd))
-			fatal("Error closing lock file \"%s\": %m",opt_lock);
-		lock_fd=-1;
-		goto retry;
-		}
-	if (utime(opt_lock,NULL))
-		fatal("Error updating lock file \"%s\" timestamp: %m",opt_lock);
+		return 0;
+
+	if (!lock_create(lock_mode|LOCK_NB))
+		exit(EXIT_SUCCESS);
+	if (lock_fd==-1 || fstat(lock_fd,&statbuf))
+		fatal("Error fstat(2)ting lock file \"%s\": %m",opt_lock);
+	return statbuf.st_mtime>=time(NULL)-opt_idle_server_timeout;
 }
 
-static void lock_close(void)
+static void lock_delete_and_close(void)
 {
-	if (lock_fd==-1)
-		return;
-	if (close(lock_fd))
-		fatal("Error closing lock file \"%s\": %m",opt_lock);
-	lock_fd=-1;
+	if (opt_lock && lock_fd!=-1)
+		if (unlink(opt_lock))
+			fatal("Error deleting no longer used lock file \"%s\": %m",opt_lock);
+	lock_close();
+}
+
+static void stop(void) G_GNUC_NORETURN;
+static void stop(void)
+{
+int is_fresh;
+
+	/* Lock still being held! */
+	if (opt_port)
+		fatal("-p|--port is a forbidden argument for -0|--stop");
+	if (opt_start_command_timeout!=DEFAULT_START_COMMAND_TIMEOUT)
+		fatal("-T|--start-command-timeout is a forbidden argument for -0|--stop");
+	if (opt_idle_server_timeout!=DEFAULT_IDLE_SERVER_TIMEOUT && !opt_lock)
+		fatal("-l|--lock is a required argument for -i|--idle-server-timeout of -1|--start");
+
+	is_fresh=lock_create_and_time_check(LOCK_SH);
+	lock_close();
+	if (is_fresh)
+		exit(EXIT_SUCCESS);
+
+	lock_create_and_time_check(LOCK_EX);
+	system_checked(opt_command);
+	lock_delete_and_close();
+
+	exit(EXIT_SUCCESS);
 }
 
+int main(int argc,char **argv) G_GNUC_NORETURN;
 int main(int argc,char **argv)
 {
-int retry;
-const char *command;
 char optc;
 
 	if ((program_name=strrchr(argv[0],'/')))
@@ -281,15 +493,30 @@ char optc;
 		program_name=argv[0];
 
 	optarg=NULL; optind=0;	/* FIXME: Possible portability problem. */
-	while ((optc=getopt_long(argc,argv,"c:d:L:l:b:xCM:P:s:m:r:t:T:w:fvhV",longopts,NULL))!=EOF) switch (optc) {
+	while ((optc=getopt_long(argc,argv,"01T:i:Sel:p:Ih",longopts,NULL))!=EOF) switch (optc) {
 long l;
 char *endptr;
 
-		case 'T':	/* -T|--start-timeout */
+		case '1':	/* -1|--start */
+			opt_start=1;
+			break;
+
+		case '0':	/* -0|--stop */
+			opt_stop=1;
+			break;
+
+		case 'T':	/* -T|--start-command-timeout */
+			l=strtol(optarg,&endptr,0);
+			if (l<=0 || l>=LONG_MAX-FLOCK_TIMEOUT_OVER_START_TIMEOUT || (endptr && *endptr))
+				fatal("Invalid -T|--start-command-timeout value: %s",optarg);
+			opt_start_command_timeout=l;
+			break;
+
+		case 'i':	/* -i|--idle-server-timeout */
 			l=strtol(optarg,&endptr,0);
 			if (l<=0 || l>=LONG_MAX || (endptr && *endptr))
-				fatal("Invalid -T|--start-timeout values: %s",optarg);
-			opt_start_timeout=l;
+				fatal("Invalid -i|--idle-server-timeout value: %s",optarg);
+			opt_idle_server_timeout=l;
 			break;
 
 		case 'S':	/* -S|--syslog */
@@ -302,6 +529,11 @@ char *endptr;
 
 		case 'l':	/* -l|--lock */
 			opt_lock=optarg;
+			break;
+
+		case 'I':	/* -I|--ignore-spawned-command-output */
+			opt_ignore_spawned_command_output=1;
+			break;
 
 		case 'p':	/* -p|--port */
 			l=strtol(optarg,&endptr,0);
@@ -312,28 +544,28 @@ char *endptr;
 
 		default:
 			if (optc!='h')
-				fatal("Error parsing commandline!");
+				fatal("Error parsing commandline");
 			usage();
 			break;
 		}
 
-	if (!opt_port)
-		fatal("-p|--port is a required argument!");
+	if (!opt_start && !opt_stop)
+		fatal("At least one of -1|--start or -0|--stop is required");
+	if ( opt_start &&  opt_stop)
+		fatal("Both modes -1|--start and -0|--stop can never be specified simultaneously");
+
 	if (optind>=argc)
-		fatal("<start-server-command> is a required argument!");
+		fatal("<start-server-command/stop-server-command> is a required argument");
 	if (optind+1<argc)
-		fatal("Too many arguments, <start-server-command> needs quoting?");
-	command=argv[optind];
+		fatal("Too many arguments, <start-server-command/stop-server-command> may need quoting");
+	opt_command=argv[optind];
 
-	lock_create();
-	session_try();
-	system_checked(command);
+	if (!opt_syslog && !opt_stderr)
+		opt_stderr=1;
 
-	for (retry=0;retry*CONNECT_RETRY_MSEC/1000<opt_start_timeout;retry++) {
-		session_try();
-		if (poll(NULL,0,CONNECT_RETRY_MSEC))
-			fatal("poll(timeout %dmsec): %m",CONNECT_RETRY_MSEC);
-		}
-	fatal("Timed out after %ld seconds connecting to port %d after spawned: %s",
-			opt_start_timeout,opt_port,command);
+	if (opt_start)
+		start();
+	if (opt_stop)
+		stop();
+	assert(0);
 }