kvm tools: Add option to list rootfs in 'kvm list'

Previously we would only list running instances, now that we create
rootfs instances it's appropriate to add a method to list them as
well.

Suggested-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

builtin-list.c

@@ -4,6 +4,7 @@
 #include <kvm/kvm.h>
 #include <kvm/parse-options.h>
 
+#include <dirent.h>
 #include <stdio.h>
 #include <string.h>
 #include <signal.h>
@@ -11,12 +12,18 @@
 
 #define PROCESS_NAME "kvm"
 
+static bool run;
+static bool rootfs;
+
 static const char * const list_usage[] = {
 	"kvm list",
 	NULL
 };
 
 static const struct option list_options[] = {
+	OPT_GROUP("General options:"),
+	OPT_BOOLEAN('i', "run", &run, "List running instances"),
+	OPT_BOOLEAN('r', "rootfs", &rootfs, "List rootfs instances"),
 	OPT_END()
 };
 
@@ -58,9 +65,66 @@ cleanup:
 	return 0;
 }
 
-int kvm_cmd_list(int argc, const char **argv, const char *prefix)
+static int kvm_list_running_instances(void)
 {
 	printf("  PID GUEST\n");
 
 	return kvm__enumerate_instances(print_guest);
 }
+
+static int kvm_list_rootfs(void)
+{
+	char name[PATH_MAX];
+	DIR *dir;
+	struct dirent *dirent;
+
+	snprintf(name, PATH_MAX, "%s%s", HOME_DIR, KVM_PID_FILE_PATH);
+	dir = opendir(name);
+	if (dir == NULL)
+		return -1;
+
+	printf("  ROOTFS\n");
+
+	while ((dirent = readdir(dir))) {
+		if (dirent->d_type == DT_DIR &&
+			strcmp(dirent->d_name, ".") &&
+			strcmp(dirent->d_name, ".."))
+			printf("%s\n", dirent->d_name);
+	}
+
+	return 0;
+}
+
+static void parse_setup_options(int argc, const char **argv)
+{
+	while (argc != 0) {
+		argc = parse_options(argc, argv, list_options, list_usage,
+				PARSE_OPT_STOP_AT_NON_OPTION);
+		if (argc != 0)
+			kvm_list_help();
+	}
+}
+
+int kvm_cmd_list(int argc, const char **argv, const char *prefix)
+{
+	int r;
+
+	parse_setup_options(argc, argv);
+
+	if (!run && !rootfs)
+		kvm_list_help();
+
+	if (run) {
+		r = kvm_list_running_instances();
+		if (r < 0)
+			perror("Error listing instances");
+	}
+
+	if (rootfs) {
+		r = kvm_list_rootfs();
+		if (r < 0)
+			perror("Error listing rootfs");
+	}
+
+	return 0;
+}