1 files changed, 167 insertions, 0 deletions
diff --git a/helper/helper_proto.c b/helper/helper_proto.c
new file mode 100644
index 0000000..3abe263
--- /dev/null
+++ b/helper/helper_proto.c
@@ -0,0 +1,167 @@
+/* Part of mate-screensaver.
+ *
+ * Copyright (c) 2019-2021 Paul Wolneykien <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+/* Provides functions for two-way communication between the screensaver
+ * and the helper program. The idea of helper program is to be able to
+ * run mate-screensaver-dialog without any setuid bits.
+ */
+
+#include "config.h"
+
+#include <stdlib.h>
+#ifdef HAVE_UNISTD_H
+# include <unistd.h>
+#endif
+
+#include "helper_proto.h"
+
+static ssize_t
+read_all (int fd, void *buf, size_t count)
+{
+ ssize_t rd, t_rd = 0;
+
+ if (0 == count)
+ return 0;
+
+ while (t_rd < count)
+ {
+ rd = read (fd, buf + t_rd, count - t_rd);
+ if (0 == rd)
+ break;
+ if (rd < 0)
+ return rd;
+ t_rd += rd;
+ }
+
+ return t_rd;
+}
+
+ssize_t
+read_msg (int fd, char *buf, size_t length)
+{
+ size_t msg_len;
+ ssize_t rd;
+
+ rd = read_all (fd, &msg_len, sizeof msg_len);
+ if (rd < 0)
+ return HELPER_IO_ERR;
+ if (rd > 0 && rd != sizeof msg_len)
+ return HELPER_LENGTH_READ_ERR;
+
+ if (msg_len >= length)
+ return HELPER_TOO_LONG_ERR;
+
+ if (msg_len > 0)
+ {
+ rd = read_all (fd, buf, msg_len);
+ if (rd < 0)
+ return HELPER_IO_ERR;
+ if (rd != msg_len)
+ return HELPER_MSG_READ_ERR;
+ }
+ else
+ rd = 0;
+ buf[rd] = '\0';
+
+ return rd;
+}
+
+int
+read_prompt (int fd, char *buf, size_t *length)
+{
+ int msg_type, rd;
+
+ rd = read_all (fd, &msg_type, sizeof msg_type);
+ if (0 == rd)
+ return 0;
+ if (rd < 0)
+ return HELPER_IO_ERR;
+ if (rd > 0 && rd != sizeof msg_type)
+ return HELPER_TYPE_READ_ERR;
+
+ rd = read_msg (fd, buf, *length);
+ if (rd < 0)
+ return rd;
+
+ *length = rd;
+ return msg_type;
+}
+
+static ssize_t
+write_all (int fd, const void *buf, size_t count)
+{
+ ssize_t wt, t_wt = 0;
+
+ if (0 == count)
+ return 0;
+
+ while (t_wt < count)
+ {
+ wt = write (fd, buf + t_wt, count - t_wt);
+ if (0 == wt)
+ break;
+ if (wt < 0)
+ return wt;
+ t_wt += wt;
+ }
+
+ return t_wt;
+}
+
+ssize_t
+write_msg (int fd, const void *buf, size_t length)
+{
+ ssize_t wt;
+
+ wt = write_all (fd, &length, sizeof length);
+ if (wt < 0)
+ return HELPER_IO_ERR;
+ if (wt > 0 && wt != sizeof length)
+ return HELPER_LENGTH_WRITE_ERR;
+
+ if (length > 0)
+ {
+ wt = write_all (fd, buf, length);
+ if (wt < 0)
+ return HELPER_IO_ERR;
+ if (wt != length)
+ return HELPER_MSG_WRITE_ERR;
+ }
+ else
+ wt = 0;
+
+ return wt;
+}
+
+int
+write_prompt (int fd, int msg_type, const void *buf, size_t length)
+{
+ ssize_t wt;
+
+ wt = write_all (fd, &msg_type, sizeof msg_type);
+ if (wt < 0)
+ return HELPER_IO_ERR;
+ if (wt > 0 && wt != sizeof msg_type)
+ return HELPER_TYPE_WRITE_ERR;
+
+ wt = write_msg (fd, buf, length);
+
+ return wt;
+}