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;
+}