send_from_file(): Use sendfile() on Linux.

trunk/darkhttpd.c

@@ -28,6 +28,7 @@
 
 #ifdef __linux
 #define _GNU_SOURCE /* for strsignal() and vasprintf() */
+#include <sys/sendfile.h>
 #endif
 
 #include <sys/types.h>
@@ -1683,6 +1684,9 @@ static ssize_t send_from_file(int s, FILE *fp, long ofs, size_t size)
             return -1;
     }
     else return size;
+#else
+#ifdef __linux
+    return sendfile(s, fileno(fp), &ofs, size);
 #else
     #define BUFSIZE 20000
     char buf[BUFSIZE];
@@ -1693,6 +1697,7 @@ static ssize_t send_from_file(int s, FILE *fp, long ofs, size_t size)
     if (fread(buf, amount, 1, fp) != 1) return -2;
     return send(s, buf, amount, 0);
 #endif
+#endif
 }