sk-unix: dump/restore a file permissions

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

protobuf/sk-unix.proto

 import "fown.proto";
 import "sk-opts.proto";
 
+message file_perms_entry {
+	required uint32			mode		= 1;
+	required uint32			uid		= 2;
+	required uint32			gid		= 3;
+}
+
 message unix_sk_entry {
 	/*
 	 * Few words about why we need both -- id and ino.
@@ -31,4 +37,6 @@ message unix_sk_entry {
 	required bytes			name		= 11;
 
 	optional sk_shutdown		shutdown	= 12;
+
+	optional file_perms_entry	file_perms	= 13;
 }

sk-unix.c

@@ -37,6 +37,11 @@ struct unix_sk_desc {
 	unsigned int		nr_icons;
 	unsigned int		*icons;
 	unsigned char		shutdown;
+
+	mode_t			mode;
+	uid_t			uid;
+	gid_t			gid;
+
 	struct list_head	list;
 };
 
@@ -108,6 +113,7 @@ static int dump_one_unix_fd(int lfd, u32 id, const struct fd_parms *p)
 	struct unix_sk_desc *sk;
 	UnixSkEntry ue = UNIX_SK_ENTRY__INIT;
 	SkOptsEntry skopts = SK_OPTS_ENTRY__INIT;
+	FilePermsEntry perms = FILE_PERMS_ENTRY__INIT;
 
 	sk = (struct unix_sk_desc *)lookup_socket(p->stat.st_ino, PF_UNIX);
 	if (!sk)
@@ -132,6 +138,14 @@ static int dump_one_unix_fd(int lfd, u32 id, const struct fd_parms *p)
 	ue.opts		= &skopts;
 	ue.uflags	= 0;
 
+	if (sk->namelen && *sk->name) {
+		ue.file_perms = &perms;
+
+		perms.mode	= sk->mode;
+		perms.uid	= sk->uid;
+		perms.gid	= sk->gid;
+	}
+
 	sk_encode_shutdown(&ue, sk->shutdown);
 
 	if (ue.peer) {
@@ -323,6 +337,10 @@ static int unix_collect_one(const struct unix_diag_msg *m,
 				len = 0;
 				name = NULL;
 			}
+
+			d->mode = st.st_mode;
+			d->uid	= st.st_uid;
+			d->gid	= st.st_gid;
 		}
 
 		d->namelen = len;
@@ -564,6 +582,29 @@ static int bind_unix_sk(int sk, struct unix_sk_info *ui)
 		return -1;
 	}
 
+	if (ui->ue->name.len && *ui->name && ui->ue->file_perms) {
+		FilePermsEntry *perms = ui->ue->file_perms;
+		char fname[PATH_MAX];
+
+		if (ui->ue->name.len >= sizeof(fname)) {
+			pr_err("The file name is too long\n");
+			return -1;
+		}
+
+		memcpy(fname, ui->name, ui->ue->name.len);
+		fname[ui->ue->name.len] = '\0';
+
+		if (chown(fname, perms->uid, perms->gid) == -1) {
+			pr_perror("Unable to change file owner and group");
+			return -1;
+		}
+
+		if (chmod(fname, perms->mode) == -1) {
+			pr_perror("Unable to change file mode bits");
+			return -1;
+		}
+	}
+
 	futex_set_and_wake(&ui->bound, 1);
 done:
 	return 0;