NOTES-cross-layer.txt

uClibc has a difficult-to-parse macro declaration of getuid()

How to determine that getuid syscall in kernel has constant return code?
 * Can manually inspect, but that's hidden in macros in 3.5.
 * For any non-trivial code, you would need the output from the
   optimizer to determine constraints on the output from the syscall

== uClibc notes ==

  * There are only 5 references to getuid in uClibc
   * not much space savings there.
  * ld.so has it's own syscall definition called '_dl_getuid'

How to convert kernel constant constraint to getuid syscall
constraint, in the getuid declaration in uClibc?

Call is so thin in library, that changing the reference in the
header file is more effective.

== busybox notes ==
 * number of references to 'getuid(' in busybox (via grep)
   34

 * size difference with getuid redefined in /usr/include/unistd.h
   $ size-delta busybox.base busybox
busybox.base  =>  busybox
       baseline   other   change  percent
 text:   966906   965032    -1874   0%
 data:     4114     4098      -16   0%
  bss:     9536     9536        0   0%
total:   980556   978666    -1890   0%
 * 1890 bytes in busybox (default configuration)

=== Patch for /usr/include/unistd.h ===
--- unistd.h.save	2012-07-09 17:28:37.040324365 -0700
+++ unistd.h	2012-07-09 17:34:11.036314767 -0700
@@ -695,7 +695,8 @@
 #endif
 
 /* Get the real user ID of the calling process.  */
-extern __uid_t getuid (void) __THROW;
+#define getuid()	0
+//extern __uid_t getuid (void) __THROW;
 
 /* Get the effective user ID of the calling process.  */
 extern __uid_t geteuid (void) __THROW;
--------------------------

 * via header file macro?