server: Introduce privilege separation.

[tripe] / priv / comm.c

diff --git a/priv/comm.c b/priv/comm.c
new file mode 100644 (file)
index 0000000..ad2e518
--- /dev/null
+++ b/priv/comm.c
@@ -0,0 +1,174 @@
+/* -*-c-*-
+ *
+ * Communication between server and helper
+ *
+ * (c) 2008 Straylight/Edgeware
+ */
+
+/*----- Licensing notice --------------------------------------------------*
+ *
+ * This file is part of Trivial IP Encryption (TrIPE).
+ *
+ * TrIPE 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.
+ *
+ * TrIPE 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 TrIPE; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+/*----- Header files ------------------------------------------------------*/
+
+#include "priv.h"
+
+/*----- Global variables --------------------------------------------------*/
+
+int pc_fd = 0;                         /* File descriptor for comms */
+
+/*----- Main code ---------------------------------------------------------*/
+
+/* --- @pc_put@ --- *
+ *
+ * Arguments:  @const void *p@ = pointer to buffer
+ *             @size_t sz@ = size of the buffer
+ *
+ * Returns:    Zero on success, @-1@ on error (and @errno@ set).
+ *
+ * Use:                Writes a buffer, handling short writes and other bogosity.
+ */
+
+int pc_put(const void *p, size_t sz)
+{
+  ssize_t n;
+  const unsigned char *pp = p;
+
+  while (sz) {
+    n = write(pc_fd, pp, sz);
+    if (n < 0) {
+      if (errno == EINTR)
+       continue;
+      return (-1);
+    }
+    if (n == 0) {
+      errno = EIO;
+      return (-1);
+    }
+    pp += n; sz -= n;
+  }
+  return (0);
+}
+
+/* --- @pc_puterr@, @pc_putuint@, @pc_putsz@, @pc_puttops@ --- *
+ *
+ * Arguments:  @int err@ = error number to write
+ *             @uint u@ = unsigned integer to write
+ *             @size_t sz@ = size to write
+ *             @const tunnel_ops *tops@ = tunnel pointer to write
+ *
+ * Returns:    Zero on success, @-1@ on error (and @errno@ set).
+ *
+ * Use:                Sends an error/integer/size/tunnel-ops pointer.
+ */
+
+#define PUT(abbr, type)                                                \
+  int pc_put##abbr(type x) { return (pc_put(&x, sizeof(x))); }
+COMM_TYPES(PUT)
+
+/* --- @pc_putstring@ --- *
+ *
+ * Arguments:  @const char *s@ = pointer to string to write
+ *
+ * Returns:    Zero on success, @-1@ on error (and @errno@ set).
+ *
+ * Use:                Sends a string/error/integer/tunnel-ops pointer.
+ */
+
+int pc_putstring(const char *s)
+{
+  size_t sz = strlen(s);
+
+  if (pc_putsz(sz) || pc_put(s, sz))
+    return (-1);
+  return (0);
+}
+
+/* --- @pc_get@ --- *
+ *
+ * Arguments:  @void *p@ = pointer to buffer
+ *             @size_t sz@ = size of the buffer
+ *
+ * Returns:    Zero on success, @-1@ on error (and @errno@ set).
+ *
+ * Use:                Receives a buffer, handling short reads and other bogosity.
+ */
+
+int pc_get(void *p, size_t sz)
+{
+  ssize_t n;
+  unsigned char *pp = p;
+
+  while (sz) {
+    n = read(pc_fd, pp, sz);
+    if (n < 0) {
+      if (errno == EINTR)
+       continue;
+      else if (errno == ECONNRESET)
+       errno = -1;
+      return (-1);
+    }
+    if (n == 0) {
+      errno = -1;
+      return (-1);
+    }
+    pp += n; sz -= n;
+  }
+  return (0);
+}
+
+/* --- @pc_geterr@, @pc_getuint@, @pc_getsz@, @pc_getops@ --- *
+ *
+ * Arguments:  @int *err@ = where to put the error number
+ *             @uint *u@ = where to put the unsigned integer
+ *             @size_t *sz@ = where to put the size
+ *             @const tunnel_ops **tops@ = where to put the tunnel pointer
+ *
+ * Returns:    Zero on success, @-1@ on error (and @errno@ set).
+ *
+ * Use:                Receives an error/integer/size/tunnel-ops pointer.
+ */
+
+#define GET(abbr, type)                                                        \
+  int pc_get##abbr(type *x) { return (pc_get(x, sizeof(*x))); }
+COMM_TYPES(GET)
+
+/* --- @pc_gettring@ --- *
+ *
+ * Arguments:  @dstr *d@ = where to pc_put the string
+ *
+ * Returns:    Zero on success, @-1@ on error (and @errno@ set).
+ *
+ * Use:                Receives a string.
+ */
+
+int pc_getstring(dstr *d)
+{
+  size_t sz;
+
+  if (pc_getsz(&sz))
+    return (-1);
+  DENSURE(d, sz + 1);
+  if (pc_get(d->buf + d->len, sz))
+    return (-1);
+  d->len += sz;
+  d->buf[d->len] = 0;
+  return (0);
+}
+
+/*----- That's all, folks -------------------------------------------------*/