Dump and restore current work directory (v2)

CWD is saved as file descriptor with number -1.

v2: use dump_regular_file
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>

cr-dump.c

@@ -137,6 +137,21 @@ err:
 	return ret;
 }
 
+static int dump_cwd(char *path, struct cr_fdset *cr_fdset)
+{
+	int ret = -1;
+	int fd;
+
+	fd = open(path, O_RDONLY | O_DIRECTORY);
+	if (fd < 0) {
+		pr_perror("Failed to openat %s\n", path);
+		return -1;
+	}
+
+	return dump_one_reg_file(FDINFO_FD, ~0L, fd, 1, 0, 0, cr_fdset);
+}
+
+
 static int dump_pipe_and_data(int lfd, struct pipe_entry *e,
 			      struct cr_fdset *cr_fdset)
 {
@@ -306,6 +321,12 @@ static int dump_task_files(pid_t pid, struct cr_fdset *cr_fdset)
 	pr_info("Dumping opened files (pid: %d)\n", pid);
 	pr_info("----------------------------------------\n");
 
+	snprintf(pid_fd_dir, sizeof(pid_fd_dir), "/proc/%d/cwd", pid);
+	if (dump_cwd(pid_fd_dir, cr_fdset)) {
+		pr_perror("Can't dump cwd %s\n", pid_fd_dir);
+		return -1;
+	}
+
 	snprintf(pid_fd_dir, sizeof(pid_fd_dir), "/proc/%d/fd", pid);
 	fd_dir = opendir(pid_fd_dir);
 	if (!fd_dir) {

cr-restore.c

@@ -437,11 +437,8 @@ static struct fmap_fd *pop_fmap_fd(int pid, unsigned long start)
 	return NULL;
 }
 
-static int open_fe_fd(struct fdinfo_entry *fe, int fd)
+static int get_file_path(char *path, struct fdinfo_entry *fe, int fd)
 {
-	char path[PATH_MAX];
-	int tmp;
-
 	if (read(fd, path, fe->len) != fe->len) {
 		pr_err("Error reading path");
 		return -1;
@@ -449,6 +446,17 @@ static int open_fe_fd(struct fdinfo_entry *fe, int fd)
 
 	path[fe->len] = '\0';
 
+	return 0;
+}
+
+static int open_fe_fd(struct fdinfo_entry *fe, int fd)
+{
+	char path[PATH_MAX];
+	int tmp;
+
+	if (get_file_path(path, fe, fd))
+		return -1;
+
 	tmp = open(path, fe->flags);
 	if (tmp < 0) {
 		pr_perror("Can't open file %s\n", path);
@@ -460,6 +468,24 @@ static int open_fe_fd(struct fdinfo_entry *fe, int fd)
 	return tmp;
 }
 
+static int restore_cwd(struct fdinfo_entry *fe, int fd)
+{
+	char path[PATH_MAX];
+	int ret;
+
+	if (get_file_path(path, fe, fd))
+		return -1;
+
+	pr_info("Restore CWD %s\n", path);
+	ret = chdir(path);
+	if (ret < 0) {
+		pr_perror("Can't change dir %s\n", path);
+		return -1;
+	}
+
+	return 0;
+}
+
 static int open_fd(int pid, struct fdinfo_entry *fe, int *cfd)
 {
 	int fd, tmp;
@@ -474,6 +500,9 @@ static int open_fd(int pid, struct fdinfo_entry *fe, int *cfd)
 		*cfd = tmp;
 	}
 
+	if (fe->addr == ~0L)
+		return restore_cwd(fe, *cfd);
+
 	tmp = open_fe_fd(fe, *cfd);
 	if (tmp < 0)
 		return 1;