common: New function gnupg_usleep.

* configure.ac (HAVE_NANOSLEEP): Test for nanosleep.
* common/sysutils.c: Always include time.h.
(gnupg_usleep): New.
--

This function has been compiled from nPth and Libassuan.

Signed-off-by: Werner Koch <wk@gnupg.org>

common/sysutils.c

@@ -49,8 +49,8 @@
 # include <asm/sysinfo.h>
 # include <asm/unistd.h>
 #endif
+#include <time.h>
 #ifdef HAVE_SETRLIMIT
-# include <time.h>
 # include <sys/time.h>
 # include <sys/resource.h>
 #endif
@@ -307,6 +307,50 @@ gnupg_sleep (unsigned int seconds)
 }
 
 
+/* Wrapper around the platforms usleep function.  This one won't wake
+ * up before the sleep time has really elapsed.  When build with nPth
+ * it merely calls npth_usleep and thus suspends only the current
+ * thread. */
+void
+gnupg_usleep (unsigned int usecs)
+{
+#if defined(USE_NPTH)
+
+  npth_usleep (usecs);
+
+#elif defined(HAVE_W32_SYSTEM)
+
+  Sleep ((usecs + 999) / 1000);
+
+#elif defined(HAVE_NANOSLEEP)
+
+  if (usecs)
+    {
+      struct timespec req;
+      struct timespec rem;
+
+      req.tv_sec = 0;
+      req.tv_nsec = usecs * 1000;
+
+      while (nanosleep (&req, &rem) < 0 && errno == EINTR)
+        req = rem;
+    }
+
+#else /*Standard Unix*/
+
+  if (usecs)
+    {
+      struct timeval tv;
+
+      tv.tv_sec  = usecs / 1000000;
+      tv.tv_usec = usecs % 1000000;
+      select (0, NULL, NULL, NULL, &tv);
+    }
+
+#endif
+}
+
+
 /* This function is a NOP for POSIX systems but required under Windows
    as the file handles as returned by OS calls (like CreateFile) are
    different from the libc file descriptors (like open). This function

common/sysutils.h

@@ -54,6 +54,7 @@ const unsigned char *get_session_marker (size_t *rlen);
 unsigned int get_uint_nonce (void);
 /*int check_permissions (const char *path,int extension,int checkonly);*/
 void gnupg_sleep (unsigned int seconds);
+void gnupg_usleep (unsigned int usecs);
 int translate_sys2libc_fd (gnupg_fd_t fd, int for_write);
 int translate_sys2libc_fd_int (int fd, int for_write);
 FILE *gnupg_tmpfile (void);

configure.ac

@@ -1387,6 +1387,16 @@ AC_CHECK_FUNCS([memicmp stpcpy strsep strlwr strtoul memmove stricmp strtol \
                 flockfile funlockfile getpwnam getpwuid \
                 getenv inet_pton strpbrk])
 
+# On some systems (e.g. Solaris) nanosleep requires linking to librl.
+# Given that we use nanosleep only as an optimization over a select
+# based wait function we want it only if it is available in libc.
+_save_libs="$LIBS"
+AC_SEARCH_LIBS([nanosleep], [],
+               [AC_DEFINE(HAVE_NANOSLEEP,1,
+                [Define to 1 if you have the `nanosleep' function in libc.])])
+LIBS="$_save_libs"
+
+
 # See whether libc supports the Linux inotify interface
 case "${host}" in
     *-*-linux*)