util: follow_symlinks() for windows.

[sliver-openvswitch.git] / lib / util.c

diff --git a/lib/util.c b/lib/util.c
index 0ebf085..45efdb7 100644 (file)
--- a/lib/util.c
+++ b/lib/util.c
@@ -55,6 +55,8 @@ DEFINE_STATIC_PER_THREAD_DATA(struct { char s[128]; },
                               strerror_buffer,
                               { "" });
 
+static char *xreadlink(const char *filename);
+
 void
 ovs_assert_failure(const char *where, const char *function,
                    const char *condition)
@@ -323,6 +325,10 @@ ovs_retval_to_string(int retval)
             : ovs_strerror(retval));
 }
 
+/* This function returns the string describing the error number in 'error'
+ * for POSIX platforms.  For Windows, this function can be used for C library
+ * calls.  For socket calls that are also used in Windows, use sock_strerror()
+ * instead.  For WINAPI calls, look at ovs_lasterror_to_string(). */
 const char *
 ovs_strerror(int error)
 {
@@ -376,6 +382,10 @@ set_program_name__(const char *argv0, const char *version, const char *date,
 #ifdef _WIN32
     char *basename;
     size_t max_len = strlen(argv0) + 1;
+
+    if (program_name) {
+        return;
+    }
     basename = xmalloc(max_len);
     _splitpath_s(argv0, NULL, 0, NULL, 0, basename, max_len, NULL, 0);
     assert_single_threaded();
@@ -737,7 +747,7 @@ abs_file_name(const char *dir, const char *file_name)
 /* Like readlink(), but returns the link name as a null-terminated string in
  * allocated memory that the caller must eventually free (with free()).
  * Returns NULL on error, in which case errno is set appropriately. */
-char *
+static char *
 xreadlink(const char *filename)
 {
     size_t size;
@@ -769,10 +779,14 @@ xreadlink(const char *filename)
  *
  *     - Only symlinks in the final component of 'filename' are dereferenced.
  *
+ * For Windows platform, this function returns a string that has the same
+ * value as the passed string.
+ *
  * The caller must eventually free the returned string (with free()). */
 char *
 follow_symlinks(const char *filename)
 {
+#ifndef _WIN32
     struct stat s;
     char *fn;
     int i;
@@ -817,6 +831,7 @@ follow_symlinks(const char *filename)
 
     VLOG_WARN("%s: too many levels of symlinks", filename);
     free(fn);
+#endif
     return xstrdup(filename);
 }
 
@@ -1649,3 +1664,19 @@ exit:
     return ok;
 }
 
+#ifdef _WIN32
+\f
+/* Calls FormatMessage() with GetLastError() as an argument. Returns
+ * pointer to a buffer that receives the null-terminated string that specifies
+ * the formatted message and that has to be freed by the caller with
+ * LocalFree(). */
+char *
+ovs_lasterror_to_string(void)
+{
+    char *buffer;
+    FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM
+                  | FORMAT_MESSAGE_IGNORE_INSERTS, NULL, GetLastError(), 0,
+                  (char *)&buffer, 0, NULL);
+    return buffer;
+}
+#endif