add strequals and startswith macros + add drop_privileges macro that drops the group before the user

Signed-off-by: Mattias Andrée <maandree@operamail.com>

1 files changed, 35 insertions, 0 deletions

diff --git a/src/libmdsserver/macros.h b/src/libmdsserver/macros.h
index 0c2a2e2..bb4e1c3 100644
--- a/src/libmdsserver/macros.h
+++ b/src/libmdsserver/macros.h
@@ -23,6 +23,7 @@
 #include <stdio.h>
 #include <unistd.h>
 #include <pthread.h>
+#include <string.h>
 */
 
 
@@ -180,5 +181,39 @@
   buf_next(buffer, type, 1)
 
 
+/**
+ * Check whether two strings are equal
+ * 
+ * @param   a:char*  One of the strings
+ * @param   b:char*  The other of the strings
+ * @return  :int     Whether the strings are equal
+ */
+#define strequals(a, b)  \
+  (strcmp(a, b) == 0)
+
+
+/**
+ * Check whether a string starts with another string
+ * 
+ * @param   haystack:char*  The string to inspect
+ * @param   needle:char*    The string `haystack` should start with
+ * @return  :int            Whether `haystack` starts with `needle`
+ */
+#define startswith(haystack, needle)  \
+  (strstr(haystack, needle) == haystack)
+
+
+/**
+ * Set effective user and the effective group to the
+ * real user and the real group, respectively. If the
+ * group cannot be set, the user till not be set either.
+ * 
+ * @return  :int  Non-zero on error
+ */
+#define drop_privileges()                              \
+  ((getegid() == getgid() ? 0 : setegid(getgid())) ||  \
+   (geteuid() == getuid() ? 0 : seteuid(getuid())))
+
+
 #endif