Declare (and simplify) uid_from_user.

uid_from_user doesn't need to cope with numeric ids in the BSD code
like it did with the old Android code; the caller now handles those.

Also explain what SUPPORT_DOT is for.

Change-Id: I185c9f02b7039795069aa30545563b8a6ef54cd5

toolbox/Android.mk

@@ -96,7 +96,7 @@ LOCAL_C_INCLUDES := bionic/libc/bionic
 
 LOCAL_CFLAGS += \
     -Wno-unused-parameter \
-    -DSUPPORT_DOT \
+    -include bsd-compatibility.h \
 
 LOCAL_SHARED_LIBRARIES := \
 	libcutils \

toolbox/bsd-compatibility.h

@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) 2014, The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/types.h>
+
+/* We want chown to support user.group as well as user:group. */
+#define SUPPORT_DOT
+
+__BEGIN_DECLS
+
+extern int uid_from_user(const char* name, uid_t* uid);
+
+__END_DECLS

toolbox/uid_from_user.c

@@ -26,23 +26,14 @@
  * SUCH DAMAGE.
  */
 
-#include <limits.h>
 #include <pwd.h>
-#include <stdlib.h>
 #include <sys/types.h>
 
 int uid_from_user(const char* name, uid_t* uid) {
   struct passwd* pw = getpwnam(name);
-  if (pw != NULL) {
-    *uid = pw->pw_uid;
-    return 0;
-  }
-  // Try to parse as an integer.
-  char* end_ptr;
-  unsigned long number = strtoul(name, &end_ptr, 0);
-  if (end_ptr == name || *end_ptr != '\0' || number > INT_MAX) {
+  if (pw == NULL) {
     return -1;
   }
-  *uid = (int) number;
+  *uid = pw->pw_uid;
   return 0;
 }