show: Filter -D output with --pid option

Show only image info relevant to given pid. Also reuse
the introduced --pid argument for exec action.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

cr-show.c

@@ -261,11 +261,28 @@ void show_creds(int fd, struct cr_options *o)
 	pb_show_vertical(fd, PB_CREDS);
 }
 
+static int pstree_item_from_pb(PstreeEntry *e, struct pstree_item *item)
+{
+	int i;
+
+	item->pid.virt = e->pid;
+	item->nr_threads = e->n_threads;
+	item->threads = xzalloc(sizeof(struct pid) * e->n_threads);
+	if (!item->threads) {
+		xfree(item);
+		return -1;
+	}
+
+	for (i = 0; i < item->nr_threads; i++)
+		item->threads[i].virt = e->threads[i];
+
+	return 0;
+}
+
 static void pstree_handler(int fd, void *obj, int collect)
 {
 	PstreeEntry *e = obj;
 	struct pstree_item *item = NULL;
-	int i;
 
 	if (!collect)
 		return;
@@ -274,17 +291,11 @@ static void pstree_handler(int fd, void *obj, int collect)
 	if (!item)
 		return;
 
-	item->pid.virt = e->pid;
-	item->nr_threads = e->n_threads;
-	item->threads = xzalloc(sizeof(struct pid) * e->n_threads);
-	if (!item->threads) {
+	if (pstree_item_from_pb(e, item)) {
 		xfree(item);
 		return;
 	}
 
-	for (i = 0; i < item->nr_threads; i++)
-		item->threads[i].virt = e->threads[i];
-
 	list_add_tail(&item->sibling, &pstree_list);
 }
 
@@ -428,30 +439,9 @@ err:
 	return ret;
 }
 
-static int cr_show_all(struct cr_options *opts)
+static int cr_show_pstree_item(struct cr_options *opts, struct pstree_item *item)
 {
-	struct pstree_item *item = NULL, *tmp;
-	int i, ret = -1, fd, pid;
-
-	fd = open_image_ro(CR_FD_PSTREE);
-	if (fd < 0)
-		goto out;
-	show_collect_pstree(fd, 1);
-	close(fd);
-
-	fd = open_image_ro(CR_FD_SK_QUEUES);
-	if (fd < 0)
-		goto out;
-
-	show_sk_queues(fd, opts);
-	close(fd);
-
-	pid = list_first_entry(&pstree_list, struct pstree_item, sibling)->pid.virt;
-	ret = try_show_namespaces(pid, opts);
-	if (ret)
-		goto out;
-
-	list_for_each_entry(item, &pstree_list, sibling) {
+	int ret = -1, i;
 	struct cr_fdset *cr_fdset = NULL;
 
 	cr_fdset = cr_task_fdset_open(item->pid.virt, O_SHOW);
@@ -473,7 +463,7 @@ static int cr_show_all(struct cr_options *opts)
 
 			fd_th = open_image_ro(CR_FD_CORE, item->threads[i].virt);
 			if (fd_th < 0)
-					goto out;
+				goto outc;
 
 			pr_msg("Thread %d.%d:\n", item->pid.virt, item->threads[i].virt);
 			pr_msg("----------------------------------------\n");
@@ -494,9 +484,70 @@ static int cr_show_all(struct cr_options *opts)
 		}
 	pr_msg("---[ end of task %d ]---\n", item->pid.virt);
 
+	ret = 0;
+outc:
 	close_cr_fdset(&cr_fdset);
+out:
+	return ret;
+}
+
+static int cr_show_pid(struct cr_options *opts, int pid)
+{
+	int fd, ret;
+	struct pstree_item item;
+
+	fd = open_image_ro(CR_FD_PSTREE);
+	if (fd < 0)
+		return -1;
+
+	while (1) {
+		PstreeEntry *pe;
+
+		ret = pb_read_one_eof(fd, &pe, PB_PSTREE);
+		if (ret <= 0)
+			return ret;
+
+		if (pe->pid == pid) {
+			pstree_item_from_pb(pe, &item);
+			pstree_entry__free_unpacked(pe, NULL);
+			break;
 		}
 
+		pstree_entry__free_unpacked(pe, NULL);
+	}
+
+	close(fd);
+
+	return cr_show_pstree_item(opts, &item);
+}
+
+static int cr_show_all(struct cr_options *opts)
+{
+	struct pstree_item *item = NULL, *tmp;
+	int ret = -1, fd, pid;
+
+	fd = open_image_ro(CR_FD_PSTREE);
+	if (fd < 0)
+		goto out;
+	show_collect_pstree(fd, 1);
+	close(fd);
+
+	fd = open_image_ro(CR_FD_SK_QUEUES);
+	if (fd < 0)
+		goto out;
+
+	show_sk_queues(fd, opts);
+	close(fd);
+
+	pid = list_first_entry(&pstree_list, struct pstree_item, sibling)->pid.virt;
+	ret = try_show_namespaces(pid, opts);
+	if (ret)
+		goto out;
+
+	list_for_each_entry(item, &pstree_list, sibling)
+		if (cr_show_pstree_item(opts, item))
+			break;
+
 out:
 	list_for_each_entry_safe(item, tmp, &pstree_list, sibling) {
 		list_del(&item->sibling);
@@ -506,10 +557,13 @@ out:
 	return ret;
 }
 
-int cr_show(struct cr_options *opts)
+int cr_show(struct cr_options *opts, int pid)
 {
 	if (opts->show_dump_file)
 		return cr_parse_file(opts);
 
+	if (pid)
+		return cr_show_pid(opts, pid);
+
 	return cr_show_all(opts);
 }

crtools.c

@@ -62,13 +62,13 @@ bad_ns:
 
 int main(int argc, char *argv[])
 {
-	pid_t pid = 0;
+	pid_t pid = 0, tree_id = 0;
 	int ret = -1;
 	int opt, idx;
 	int log_inited = 0;
 	int log_level = 0;
 
-	static const char short_opts[] = "dsf:t:hcD:o:n:vxVr:jl";
+	static const char short_opts[] = "dsf:t:p:hcD:o:n:vxVr:jl";
 
 	BUILD_BUG_ON(PAGE_SIZE != PAGE_IMAGE_SIZE);
 
@@ -88,6 +88,7 @@ int main(int argc, char *argv[])
 	while (1) {
 		static struct option long_opts[] = {
 			{ "tree", required_argument, 0, 't' },
+			{ "pid", required_argument, 0, 'p' },
 			{ "leave-stopped", no_argument, 0, 's' },
 			{ "restore-detached", no_argument, 0, 'd' },
 			{ "contents", no_argument, 0, 'c' },
@@ -126,9 +127,12 @@ int main(int argc, char *argv[])
 		case 'x':
 			opts.ext_unix_sk = true;
 			break;
-		case 't':
+		case 'p':
 			pid = atoi(optarg);
 			break;
+		case 't':
+			tree_id = atoi(optarg);
+			break;
 		case 'c':
 			opts.show_pages_content	= true;
 			break;
@@ -292,22 +296,24 @@ int main(int argc, char *argv[])
 
 	switch (argv[optind][0]) {
 	case 'd':
-		if (!pid)
+		if (!tree_id)
 			goto opt_pid_missing;
-		ret = cr_dump_tasks(pid, &opts);
+		ret = cr_dump_tasks(tree_id, &opts);
 		break;
 	case 'r':
-		if (!pid)
+		if (!tree_id)
 			goto opt_pid_missing;
-		ret = cr_restore_tasks(pid, &opts);
+		ret = cr_restore_tasks(tree_id, &opts);
 		break;
 	case 's':
-		ret = cr_show(&opts);
+		ret = cr_show(&opts, pid);
 		break;
 	case 'c':
 		ret = cr_check();
 		break;
 	case 'e':
+		if (!pid)
+			pid = tree_id; /* old usage */
 		if (!pid)
 			goto opt_pid_missing;
 		ret = cr_exec(pid, argv + optind + 1);
@@ -328,7 +334,7 @@ usage:
 	pr_msg("  %s restore -t pid [<options>]\n", argv[0]);
 	pr_msg("  %s show (-D dir)|(-f file) [<options>]\n", argv[0]);
 	pr_msg("  %s check\n", argv[0]);
-	pr_msg("  %s exec -t pid <syscall-string>\n", argv[0]);
+	pr_msg("  %s exec -p pid <syscall-string>\n", argv[0]);
 
 	pr_msg("\nCommands:\n");
 	pr_msg("  dump           checkpoint a process/tree identified by pid\n");
@@ -390,6 +396,7 @@ usage:
 	pr_msg("  -f|--file             show contents of a checkpoint file\n");
 	pr_msg("  -D|--images-dir       directory where to get images from\n");
 	pr_msg("  -c|--contents         show contents of pages dumped in hexdump format\n");
+	pr_msg("  -p|--pid <pid>        show files relevant to pid (filter -D flood)\n");
 
 	pr_msg("\nOther options:\n");
 	pr_msg("  -h|--help             show this text\n");

include/crtools.h

@@ -217,7 +217,7 @@ extern struct cr_options opts;
 
 int cr_dump_tasks(pid_t pid, const struct cr_options *opts);
 int cr_restore_tasks(pid_t pid, struct cr_options *opts);
-int cr_show(struct cr_options *opts);
+int cr_show(struct cr_options *opts, int pid);
 int convert_to_elf(char *elf_path, int fd_core);
 int cr_check(void);
 int cr_exec(int pid, char **opts);