HW2: 修正 judge 使第一輪可以正常執行、修正輸出結果、處理 zombie child

2 files changed, 42 insertions, 34 deletions

diff --git a/hw2/judge.c b/hw2/judge.c
index 02b513a..9c707a0 100644
--- a/hw2/judge.c
+++ b/hw2/judge.c
@@ -18,6 +18,7 @@
 #include <sys/stat.h>
 #include <sys/time.h>
 #include <sys/types.h>
+#include <sys/wait.h>
 #include <time.h>
 #include <unistd.h>
 
@@ -39,6 +40,10 @@ static void player_tle_setter (int signo) {
 	player_tle = 1;
 }
 
+static void cleanup_child (int signo) {
+	waitpid (-1, NULL, WUNTRACED | WNOHANG);
+}
+
 static void fdata_clear (FData* d) {
 	d->last = 0;
 	d->score = 0;
@@ -87,6 +92,11 @@ int main (int argc, char* argv[]) {
 	};
 
 	for (int i = 0; i < ARRAY_LEN (ffd, FData); i++) {
+		struct stat st;
+		if (stat (ffd[i].fname, &st) >= 0 && S_ISFIFO (st.st_mode)) {
+			unlink (ffd[i].fname);
+		}
+
 		if (mkfifo (ffd[i].fname, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP) < 0) {
 			fprintf (stderr, "%s: cannot create FIFO `%s\': %s\n",
 				argv[0], ffd[i].fname, strerror (errno));
@@ -132,18 +142,14 @@ int main (int argc, char* argv[]) {
 	};
 	sigemptyset (&sa.sa_mask);
 	sigaction (SIGALRM, &sa, NULL);
+	sa.sa_handler = cleanup_child;
+	sigaction (SIGCHLD, &sa, NULL);
 	sa.sa_handler = SIG_IGN;
 	sigaction (SIGPIPE, &sa, NULL);
 
 	char *linestr = NULL;
 	size_t linelen = 0;
 	bool request_exit = false;
-	fd_set rset;
-	int nfds;
-
-	FD_ZERO (&rset);
-	FD_SET (ffd[0].fd, &rset);
-	nfds = ffd[0].fd + 1;
 
 	comp135_log (comp, "Waiting for initial request from big_judge");
 	while (!request_exit && getline (&linestr, &linelen, stdin) >= 0) {
@@ -168,33 +174,13 @@ int main (int argc, char* argv[]) {
 			goto new_loop_end;
 		}
 
-		for (i = 1, c = 'A'; i <= 4; i++, c++) {
-			fdata_clear (&ffd[i]);
-			ffd[i].key = random ();
-			ffd[i].pid = fork ();
-			if (ffd[i].pid < 0) {
-				fprintf (stderr, "Cannot fork: %s\n", strerror (errno));
-				break;
-			} else if (ffd[i].pid == 0) {
-				char* plname = xstrcat ("player_", pl[i - 1], NULL);
-				char* plthis = xgetres (plname);
-				char* plkey = xsprintf ("%ld", ffd[i].key);
-				char plid[2] = { c, '\0' };
-				execl (plthis, plname, judgename, plid, plkey, (char*)NULL);
-				fprintf (stderr, "Cannot execl `%s\': %s\n",
-					plthis, strerror (errno));
-				_exit (127);
-			}
-		}
-
-		if (i <= 4 && ffd[i].pid) {
-			for (int j = 1; j < i; j++) {
-				kill (ffd[i].pid, SIGKILL);
-			}
-			goto new_loop_end;
-		}
+		char trash_buf[512];
+		xfaddfl (ffd[0].fd, O_NONBLOCK);
+		while (read (ffd[0].fd, trash_buf, 512) > 0);
+		xfdelfl (ffd[0].fd, O_NONBLOCK);
 
 		for (int t = 0; t < 20; t++) {
+
 			char lastmsg[20];
 			int lastlen;
 
@@ -203,11 +189,33 @@ int main (int argc, char* argv[]) {
 			lastmsg[lastlen - 1] = '\0';
 			comp135_log (comp, "Previous round: %s", lastmsg);
 			lastmsg[lastlen - 1] = '\n';
+
 			comp135_log (comp, "This is round %d", t + 1);
 
 			for (i = 1, c = 'A'; i <= 4; i++, c++) {
 				if (t) {
 					write (ffd[i].fd, lastmsg, lastlen);
+				} else {
+					fdata_clear (&ffd[i]);
+					ffd[i].key = random ();
+					ffd[i].pid = fork ();
+					if (ffd[i].pid < 0) {
+						fprintf (stderr, "Cannot fork: %s\n", strerror (errno));
+						for (int j = 1; j < i; j++) {
+							kill (ffd[i].pid, SIGKILL);
+						}
+						goto new_loop_end;
+					} else if (ffd[i].pid == 0) {
+						char* plname = xstrcat ("player_", pl[i - 1], NULL);
+						char* plthis = xgetres (plname);
+						char* plkey = xsprintf ("%ld", ffd[i].key);
+						char plid[2] = { c, '\0' };
+						execl (plthis, plname, judgename, plid, plkey, (char*)NULL);
+						fprintf (stderr, "Cannot execl `%s\': %s\n",
+							plthis, strerror (errno));
+						_exit (127);
+					}
+					comp135_log (comp, "Player %c has PID %u", c, ffd[i].pid);
 				}
 
 				if (ffd[i].ignore) {
@@ -344,8 +352,8 @@ int main (int argc, char* argv[]) {
 
 		for (int j = 0; j < 4; j++) {
 			comp135_log (comp, "Send %s %d to big_judge",
-				pl[j], ffd[rank[j]].rank);
-			printf ("%s %d\n", pl[j], ffd[rank[j]].rank);
+				pl[rank[j] - 1], ffd[rank[j]].rank);
+			printf ("%s %d\n", pl[rank[j] - 1], ffd[rank[j]].rank);
 		}
 		fflush (stdout);
 
diff --git a/hw2/logger.c b/hw2/logger.c
index e8c2cbf..53e6a40 100644
--- a/hw2/logger.c
+++ b/hw2/logger.c
@@ -74,7 +74,7 @@ void comp135_init (Comp135* comp, const char* static_name, bool no_init) {
 		return;
 	}
 
-	setvbuf (fp, NULL, _IONBF, 0);
+	setvbuf (fp, NULL, _IOLBF, 0);
 	comp->log = xstrdup (comp135_logfile);
 	comp->log_fd = fd;
 	comp->log_file = fp;