vm+dom0/filecopy-unpacker: send errors to qfile-agent istead of local message (#239)

Because unpacker no longer require GUI access, there is no need for separate
process for error reporting. Which greatly simplify the code.

dom0/qubes_rpc/qfile-dom0-unpacker.c

@@ -52,12 +52,11 @@ void wait_for_child(int statusfd)
 	}
 }
 
-extern void do_unpack(int);
+extern int do_unpack(void);
 
 int main(int argc, char ** argv)
 {
 	char *incoming_dir;
-	int pipefds[2];
 	int uid;
 	char *var;
 	long long files_limit = DEFAULT_MAX_UPDATES_FILES;
@@ -73,32 +72,15 @@ int main(int argc, char ** argv)
 	if ((var=getenv("UPDATES_MAX_FILES")))
 		files_limit = atoll(var);
 
-	pipe(pipefds);
-
 	uid = prepare_creds_return_uid(argv[1]);
 
 	incoming_dir = argv[2];
 	mkdir(incoming_dir, 0700);
 	if (chdir(incoming_dir))
 		gui_fatal("Error chdir to %s", incoming_dir); 
-	switch (fork()) {
+	if (chroot(incoming_dir)) //impossible
-	case -1:
+		gui_fatal("Error chroot to %s", incoming_dir);
-		perror("fork");
-		exit(1);
-	case 0:
-		if (chroot(incoming_dir)) //impossible
-			gui_fatal("Error chroot to %s", incoming_dir);
-		setuid(uid);
-		close(pipefds[0]);
-		set_size_limit(bytes_limit, files_limit);
-		do_unpack(pipefds[1]);
-		exit(0);
-	default:;
-	}
-
 	setuid(uid);
-	close(pipefds[1]);
+	set_size_limit(bytes_limit, files_limit);
-	wait_for_child(pipefds[0]);
+	return do_unpack();
-
-	return 0;
 }

qubes_rpc/qfile-unpacker.c

@@ -29,32 +29,14 @@ int prepare_creds_return_uid(char *username)
 	return pwd->pw_uid;
 }
 
-void wait_for_child(int statusfd)
+extern int do_unpack(void);
-{
-	int status;
-	if (read(statusfd, &status, sizeof status)!=sizeof status)
-		gui_fatal("File copy error: Internal error reading status from unpacker");
-	errno = status;
-	switch (status) {
-	case LEGAL_EOF: break;
-	case 0: gui_fatal("File copy: Connection terminated unexpectedly"); break;
-	case EINVAL: gui_fatal("File copy: Corrupted data from packer"); break;
-	case EEXIST: gui_fatal("File copy: not overwriting existing file. Clean ~/incoming, and retry copy"); break;
-	default: gui_fatal("File copy"); 
-	}
-}
-
-extern void do_unpack(int);
 
 int main(int argc, char ** argv)
 {
 	char *incoming_dir;
-	int pipefds[2];
 	int uid;
 	char *remote_domain;
 
-	pipe(pipefds);
-
 	uid = prepare_creds_return_uid("user");
 
 	remote_domain = getenv("QREXEC_REMOTE_DOMAIN");
@@ -67,25 +49,8 @@ int main(int argc, char ** argv)
 	mkdir(incoming_dir, 0700);
 	if (chdir(incoming_dir))
 		gui_fatal("Error chdir to %s", incoming_dir); 
-	switch (fork()) {
+	if (chroot(incoming_dir)) //impossible
-	case -1:
+		gui_fatal("Error chroot to %s", incoming_dir);
-		perror("fork");
-		exit(1);
-	case 0:
-		if (chroot(incoming_dir)) //impossible
-			gui_fatal("Error chroot to %s", incoming_dir);
-		setuid(uid);
-		close(pipefds[0]);
-		do_unpack(pipefds[1]);
-		exit(0);
-	default:;
-	}
-
-	close(0);
-	close(1);
 	setuid(uid);
-	close(pipefds[1]);
+	return do_unpack();
-	wait_for_child(pipefds[0]);
-
-	return 0;
 }

qubes_rpc/unpack.c

@@ -35,14 +35,22 @@ int read_all_with_crc(int fd, void *buf, int size) {
 	return ret;
 }
 
-int global_status_fd;
+void send_status_and_crc(int code) {
-void do_exit(int code)
+	struct result_header hdr;
-{
+	int saved_errno;
-	int codebuf = code;
+
-	write(global_status_fd, &codebuf, sizeof codebuf);
+	saved_errno = errno;
-	exit(0);
+	hdr.error_code = code;
+	hdr.crc32 = crc32_sum;
+	write_all(1, &hdr, sizeof(hdr));
+	errno = saved_errno;
 }
 
+void do_exit(int code)
+{
+	send_status_and_crc(code);
+	exit(code);
+}
 
 void fix_times_and_perms(struct file_header *untrusted_hdr,
 			 char *untrusted_name)
@@ -130,20 +138,8 @@ void process_one_file(struct file_header *untrusted_hdr)
 		do_exit(EINVAL);
 }
 
-void send_status_and_crc() {
+int do_unpack()
-	struct result_header hdr;
-	int saved_errno;
-
-	saved_errno = errno;
-	hdr.error_code = errno;
-	hdr.crc32 = crc32_sum;
-	write_all(1, &hdr, sizeof(hdr));
-	errno = saved_errno;
-}
-
-void do_unpack(int fd)
 {
-	global_status_fd = fd;
 	struct file_header untrusted_hdr;
 	/* initialize checksum */
 	crc32_sum = 0;
@@ -158,9 +154,6 @@ void do_unpack(int fd)
 		if (files_limit && total_files > files_limit)
 			do_exit(EDQUOT);
 	}
-	send_status_and_crc();
+	send_status_and_crc(errno);
-	if (errno)
+	return errno;
-		do_exit(errno);
-	else
-		do_exit(LEGAL_EOF);
 }