dump: Images opening rework

Rename prep_cr_fdset_for_dump into cr_fdset_open and make it reentable, i.e.
every next enter will open more files in the same fdset. Required for zombies
and makes the code cleaner.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>

cr-dump.c

@@ -1035,7 +1035,7 @@ static int dump_task_threads(struct pstree_item *item)
 		if (item->pid == item->threads[i])
 			continue;
 
-		cr_fdset_thread = prep_cr_fdset_for_dump(item->threads[i], CR_FD_DESC_CORE);
+		cr_fdset_thread = cr_fdset_open(item->threads[i], CR_FD_DESC_CORE, NULL);
 		if (!cr_fdset_thread)
 			goto err;
 
@@ -1075,6 +1075,10 @@ static int dump_one_task(struct pstree_item *item, struct cr_fdset *cr_fdset)
 	if (ret < 0)
 		goto err;
 
+	cr_fdset = cr_fdset_open(item->pid, CR_FD_DESC_NOPSTREE, cr_fdset);
+	if (!cr_fdset)
+		goto err;
+
 	ret = collect_mappings(pid, pid_dir, &vma_area_list);
 	if (ret) {
 		pr_err("Collect mappings (pid: %d) failed with %d\n", pid, ret);
@@ -1178,16 +1182,17 @@ int cr_dump_tasks(pid_t pid, struct cr_options *opts)
 	collect_sockets();
 
 	list_for_each_entry(item, &pstree_list, list) {
+		cr_fdset = cr_fdset_open(item->pid, CR_FD_DESC_NONE, NULL);
+		if (!cr_fdset)
+			goto err;
+
 		if (item->pid == pid) {
-			cr_fdset = prep_cr_fdset_for_dump(item->pid, CR_FD_DESC_ALL);
+			cr_fdset = cr_fdset_open(item->pid,
+					CR_FD_DESC_USE(CR_FD_PSTREE), cr_fdset);
 			if (!cr_fdset)
 				goto err;
 			if (dump_pstree(pid, &pstree_list, cr_fdset))
 				goto err;
-		} else {
-			cr_fdset = prep_cr_fdset_for_dump(item->pid, CR_FD_DESC_NOPSTREE);
-			if (!cr_fdset)
-				goto err;
 		}
 
 		if (dump_one_task(item, cr_fdset))

crtools.c

@@ -106,20 +106,23 @@ static struct cr_fdset *alloc_cr_fdset(void)
 	return cr_fdset;
 }
 
-struct cr_fdset *prep_cr_fdset_for_dump(int pid, unsigned long use_mask)
+struct cr_fdset *cr_fdset_open(int pid, unsigned long use_mask, struct cr_fdset *cr_fdset)
 {
 	unsigned int i;
 	int ret = -1;
 	char path[PATH_MAX];
-	struct cr_fdset *cr_fdset;
 
+	if (cr_fdset == NULL) {
 		cr_fdset = alloc_cr_fdset();
 		if (!cr_fdset)
 			goto err;
+	}
 
 	for (i = 0; i < CR_FD_MAX; i++) {
 		if (!(use_mask & CR_FD_DESC_USE(i)))
 			continue;
+		if (cr_fdset->fds[i] != -1)
+			continue;
 
 		ret = get_image_path(path, sizeof(path),
 				fdset_template[i].fmt, pid);

include/crtools.h

@@ -88,7 +88,7 @@ int cr_restore_tasks(pid_t pid, struct cr_options *opts);
 int cr_show(unsigned long pid, struct cr_options *opts);
 int convert_to_elf(char *elf_path, int fd_core);
 
-struct cr_fdset *prep_cr_fdset_for_dump(int pid, unsigned long use_mask);
+struct cr_fdset *cr_fdset_open(int pid, unsigned long use_mask, struct cr_fdset *);
 struct cr_fdset *prep_cr_fdset_for_restore(int pid, unsigned long use_mask);
 void close_cr_fdset(struct cr_fdset **cr_fdset);