crtools: make to be able to split messages by pid

If the option --log-pid is set, each process will have an own log file.
Otherwise PID is added to each log message.

A message can't be bigger than one page minus some bytes for pid.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

cr-restore.c

@@ -605,6 +605,10 @@ static int restore_task_with_children(void *_arg)
 		exit(-1);
 	}
 
+	ret = log_init_by_pid();
+	if (ret < 0)
+		exit(1);
+
 	list_for_each_entry(me, &tasks, list)
 		if (me->pid == pid)
 			break;

crtools.c

@@ -395,6 +395,7 @@ int main(int argc, char *argv[])
 			{ "help", no_argument, 0, 'h' },
 			{ SK_EST_PARAM, no_argument, 0, 42 },
 			{ "close", required_argument, 0, 43 },
+			{ "log-pid", no_argument, 0, 44},
 			{ },
 		};
 
@@ -434,6 +435,7 @@ int main(int argc, char *argv[])
 			}
 			break;
 		case 'o':
+			opts.output = strdup(optarg);
 			if (log_init(optarg))
 				return -1;
 			log_inited = 1;
@@ -470,6 +472,9 @@ int main(int argc, char *argv[])
 			close(fd);
 			break;
 		}
+		case 44:
+			opts.log_file_per_pid = 1;
+			break;
 		case 'h':
 		default:
 			goto usage;
@@ -553,7 +558,9 @@ usage:
 	pr_msg("     --%s  checkpoint/restore established TCP connections\n", SK_EST_PARAM);
 
 	pr_msg("\n* Logging:\n");
-	pr_msg("  -o|--log-file         log file name (relative path is relative to --images-dir)\n");
+	pr_msg("  -o|--log-file [NAME]  log file name (relative path is relative to --images-dir)\n");
+	pr_msg("     --log-pid		if the -o option is in effect, each restored processes is\n");
+	pr_msg("			written to the [NAME].pid file\n");
 	pr_msg("  -v [num]              set logging level\n");
 	pr_msg("                          0 - silent (only error messages)\n");
 	pr_msg("                          1 - informative (default)\n");

include/crtools.h

@@ -74,6 +74,8 @@ struct cr_options {
 	bool			ext_unix_sk;
 	bool			tcp_established_ok;
 	unsigned int		namespaces_flags;
+	bool			log_file_per_pid;
+	char			*output;
 };
 
 extern struct cr_options opts;

include/log.h

@@ -3,6 +3,7 @@
 
 extern int log_init(const char *output);
 extern void log_fini(void);
+extern int log_init_by_pid(void);
 
 extern int log_get_fd(void);
 

log.c

@@ -23,6 +23,9 @@
 static unsigned int current_loglevel = DEFAULT_LOGLEVEL;
 static int current_logfd = DEFAULT_LOGFD;
 
+static char buffer[PAGE_SIZE];
+static char buf_off = 0;
+
 int log_get_fd(void)
 {
 	return current_logfd;
@@ -67,6 +70,23 @@ err:
 	return -1;
 }
 
+int log_init_by_pid(void)
+{
+	char path[PATH_MAX];
+
+	if (!opts.log_file_per_pid) {
+		buf_off = snprintf(buffer, PAGE_SIZE, "%6d: ", getpid());
+		return 0;
+	}
+
+	if (!opts.output)
+		return 0;
+
+	snprintf(path, PATH_MAX, "%s.%d", opts.output, getpid());
+
+	return log_init(path);
+}
+
 void log_fini(void)
 {
 	if (current_logfd > 2)
@@ -86,7 +106,7 @@ void log_set_loglevel(unsigned int level)
 void print_on_level(unsigned int loglevel, const char *format, ...)
 {
 	va_list params;
-	int fd;
+	int fd, size, ret, off;
 
 	if (unlikely(loglevel == LOG_MSG)) {
 		fd = STDOUT_FILENO;
@@ -97,6 +117,16 @@ void print_on_level(unsigned int loglevel, const char *format, ...)
 	}
 
 	va_start(params, format);
-	vdprintf(fd, format, params);
+	size = vsnprintf(buffer + buf_off, PAGE_SIZE - buf_off, format, params);
 	va_end(params);
+
+	size += buf_off;
+
+	off = 0;
+	while (off < size) {
+		ret = write(fd, buffer + off, size - off);
+		if (ret <= 0)
+			break;
+		off += ret;
+	}
 }

test/zdtm.sh

@@ -113,7 +113,7 @@ run_test()
 		done
 
 		echo Restore $pid
-		setsid $CRTOOLS restore -D $ddump -o restore.log -v 4 -d -t $pid $args || return 2
+		setsid $CRTOOLS restore --log-pid -D $ddump -o restore.log -v 4 -d -t $pid $args || return 2
 
 		save_fds $pid  $ddump/restore.fd
 		diff_fds $ddump/dump.fd $ddump/restore.fd || return 2