crtools: cleanup fdset initalization

v2: wrappers names become less obfuscating

This patch:
1) Updates function cr_fdset_open() to be suitable for handling fdset creation
for dump and show stages.
2) Replaces cr_fdset_open() by new wrapper function cr_fdset_dump().
3) Replaces prep_cr_fdset_for_restore() by new wrapper function cr_fdset_show().
Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>

cr-dump.c

@@ -1187,7 +1187,7 @@ static int dump_one_zombie(struct pstree_item *item, struct proc_pid_stat *pps,
 {
 	struct core_entry *core;
 
-	cr_fdset = cr_fdset_open(item->pid, CR_FD_DESC_CORE, cr_fdset);
+	cr_fdset = cr_dump_fdset_open(item->pid, CR_FD_DESC_CORE, cr_fdset);
 	if (cr_fdset == NULL)
 		return -1;
 
@@ -1216,7 +1216,7 @@ static int dump_task_threads(struct pstree_item *item)
 		if (item->pid == item->threads[i])
 			continue;
 
-		cr_fdset_thread = cr_fdset_open(item->threads[i], CR_FD_DESC_CORE, NULL);
+		cr_fdset_thread = cr_dump_fdset_open(item->threads[i], CR_FD_DESC_CORE, NULL);
 		if (!cr_fdset_thread)
 			goto err;
 
@@ -1266,7 +1266,7 @@ static int dump_one_task(struct pstree_item *item, struct cr_fdset *cr_fdset)
 		return dump_one_zombie(item, &pps_buf, cr_fdset);
 
 	ret = -1;
-	if (!cr_fdset_open(item->pid, CR_FD_DESC_TASK, cr_fdset))
+	if (!cr_dump_fdset_open(item->pid, CR_FD_DESC_TASK, cr_fdset))
 		goto err;
 
 	ret = collect_mappings(pid, pid_dir, &vma_area_list);
@@ -1383,12 +1383,12 @@ 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);
+		cr_fdset = cr_dump_fdset_open(item->pid, CR_FD_DESC_NONE, NULL);
 		if (!cr_fdset)
 			goto err;
 
 		if (item->pid == pid) {
-			if (!cr_fdset_open(item->pid, CR_FD_DESC_USE(CR_FD_PSTREE), cr_fdset))
+			if (!cr_dump_fdset_open(item->pid, CR_FD_DESC_USE(CR_FD_PSTREE), cr_fdset))
 				goto err;
 			if (dump_pstree(pid, &pstree_list, cr_fdset))
 				goto err;

cr-show.c

@@ -535,7 +535,7 @@ static int cr_show_all(unsigned long pid, struct cr_options *opts)
 	LIST_HEAD(pstree_list);
 	int i, ret = -1;
 
-	cr_fdset = prep_cr_fdset_for_restore(pid, CR_FD_DESC_PSTREE);
+	cr_fdset = cr_show_fdset_open(pid, CR_FD_DESC_PSTREE);
 	if (!cr_fdset)
 		goto out;
 
@@ -551,7 +551,7 @@ static int cr_show_all(unsigned long pid, struct cr_options *opts)
 
 	list_for_each_entry(item, &pstree_list, list) {
 
-		cr_fdset = prep_cr_fdset_for_restore(item->pid, CR_FD_DESC_TASK);
+		cr_fdset = cr_show_fdset_open(item->pid, CR_FD_DESC_TASK);
 		if (!cr_fdset)
 			goto out;
 
@@ -566,7 +566,7 @@ static int cr_show_all(unsigned long pid, struct cr_options *opts)
 				if (item->threads[i] == item->pid)
 					continue;
 
-				cr_fdset_th = prep_cr_fdset_for_restore(item->threads[i], CR_FD_DESC_CORE);
+				cr_fdset_th = cr_show_fdset_open(item->threads[i], CR_FD_DESC_CORE);
 				if (!cr_fdset_th)
 					goto out;
 

crtools.c

@@ -157,7 +157,8 @@ void close_cr_fdset(struct cr_fdset **cr_fdset)
 	*cr_fdset = NULL;
 }
 
-struct cr_fdset *cr_fdset_open(int pid, unsigned long use_mask, struct cr_fdset *cr_fdset)
+static struct cr_fdset *cr_fdset_open(int pid, unsigned long use_mask,
+			       unsigned long flags, struct cr_fdset *cr_fdset)
 {
 	struct cr_fdset *fdset;
 	unsigned int i;
@@ -186,23 +187,39 @@ struct cr_fdset *cr_fdset_open(int pid, unsigned long use_mask, struct cr_fdset
 		if (ret)
 			goto err;
 
+		if (flags & O_EXCL) {
 			ret = unlink(path);
 			if (ret && errno != ENOENT) {
 				pr_perror("Unable to unlink %s", path);
 				goto err;
 			}
+		}
 
-		ret = open(path, O_RDWR | O_CREAT | O_EXCL, CR_FD_PERM);
+		ret = open(path, flags, CR_FD_PERM);
 		if (ret < 0) {
+			if (!(flags & O_CREAT))
+				/* caller should check himself */
+				continue;
 			pr_perror("Unable to open %s", path);
 			goto err;
 		}
 		fdset->fds[i] = ret;
 
 		pr_debug("Opened %s with %d\n", path, ret);
+		if (flags == O_RDONLY) {
+			u32 magic;
+
+			if (read_img(ret, &magic) < 0)
+				goto err;
+			if (magic != fdset_template[i].magic) {
+				pr_err("Magic doesn't match for %s\n", path);
+				goto err;
+			}
+		} else {
 			if (write_img(ret, &fdset_template[i].magic))
 				goto err;
 		}
+	}
 
 	return fdset;
 
@@ -214,49 +231,16 @@ err:
 	return NULL;
 }
 
-struct cr_fdset *prep_cr_fdset_for_restore(int pid, unsigned long use_mask)
+struct cr_fdset *cr_dump_fdset_open(int pid, unsigned long use_mask,
+				     struct cr_fdset *cr_fdset)
 {
-	unsigned int i;
-	int ret = -1;
-	char path[PATH_MAX];
-	u32 magic;
-	struct cr_fdset *cr_fdset;
-
-	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;
-
-		ret = get_image_path(path, sizeof(path),
-				fdset_template[i].fmt, pid);
-		if (ret)
-			goto err;
-
-		ret = open(path, O_RDWR, CR_FD_PERM);
-		if (ret < 0) {
-			pr_perror("Unable to open %s", path);
-			goto err;
-		}
-		cr_fdset->fds[i] = ret;
-
-		pr_debug("Opened %s with %d\n", path, ret);
-		if (read_img(ret, &magic) < 0)
-			goto err;
-		if (magic != fdset_template[i].magic) {
-			pr_err("Magic doesn't match for %s\n", path);
-			goto err;
-		}
-
-	}
-
-	return cr_fdset;
+	return cr_fdset_open(pid, use_mask, O_RDWR | O_CREAT | O_EXCL,
+			     cr_fdset);
+}
 
-err:
-	close_cr_fdset(&cr_fdset);
-	return NULL;
+struct cr_fdset *cr_show_fdset_open(int pid, unsigned long use_mask)
+{
+	return cr_fdset_open(pid, use_mask, O_RDONLY, NULL);
 }
 
 static int parse_ns_string(const char *ptr, unsigned int *flags)

include/crtools.h

@@ -119,8 +119,8 @@ 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 *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);
+struct cr_fdset *cr_dump_fdset_open(int pid, unsigned long use_mask, struct cr_fdset *);
+struct cr_fdset *cr_show_fdset_open(int pid, unsigned long use_mask);
 void close_cr_fdset(struct cr_fdset **cr_fdset);
 
 void free_mappings(struct list_head *vma_area_list);

namespaces.c

@@ -33,7 +33,7 @@ static int do_dump_namespaces(int ns_pid, unsigned int ns_flags)
 	struct cr_fdset *fdset;
 	int ret = 0;
 
-	fdset = cr_fdset_open(ns_pid, CR_FD_DESC_NS, NULL);
+	fdset = cr_dump_fdset_open(ns_pid, CR_FD_DESC_NS, NULL);
 	if (fdset == NULL)
 		return -1;
 
@@ -118,7 +118,7 @@ int try_show_namespaces(int ns_pid)
 {
 	struct cr_fdset *fdset;
 
-	fdset = prep_cr_fdset_for_restore(ns_pid, CR_FD_DESC_NS);
+	fdset = cr_show_fdset_open(ns_pid, CR_FD_DESC_NS);
 	if (!fdset)
 		return -1;