win32: changes to user ids

Formalise the use of 0 as the uid of a process running with elevated
privileges:

- Rewrite getuid(2) to return DEFAULT_UID by default and 0 if the
  process has elevated privileges.
- geteuid(2) and the corresponding functions for groups are aliases
  for getuid(2).
- Change root's home directory to be whatever GetSystemDirectory()
  returns, probably C:/Windows/System32 in most cases.
- Remove the special handling of geteuid(2) in the line editing code.

With these changes the shell started by 'su' is a lot more like a
*nix root shell.

1 files changed, 5 insertions, 6 deletions

diff --git a/include/mingw.h b/include/mingw.h
index ead07ae82..7aa2d5cc9 100644
--- a/include/mingw.h
+++ b/include/mingw.h
@@ -9,7 +9,7 @@ typedef int gid_t;
 typedef int uid_t;
 
 #define DEFAULT_UID 4095
-#define DEFAULT_GID 4095
+#define DEFAULT_GID DEFAULT_UID
 
 /*
  * arpa/inet.h
@@ -388,13 +388,13 @@ char *mingw_getcwd(char *pointer, int len);
 off_t mingw_lseek(int fd, off_t offset, int whence);
 
 
-IMPL(getgid,int,DEFAULT_GID,void);
+int getuid(void);
+#define getgid getuid
+#define geteuid getuid
+#define getegid getuid
 int getgroups(int n, gid_t *groups);
 IMPL(getppid,int,1,void);
-IMPL(getegid,int,DEFAULT_GID,void);
-IMPL(geteuid,int,DEFAULT_UID,void);
 NOIMPL(getsid,pid_t pid UNUSED_PARAM);
-IMPL(getuid,int,DEFAULT_UID,void);
 int getlogin_r(char *buf, size_t len);
 int fcntl(int fd, int cmd, ...);
 int fsync(int fd);
@@ -521,4 +521,3 @@ ULONGLONG CompatGetTickCount64(void);
 ssize_t get_random_bytes(void *buf, ssize_t count);
 int enumerate_links(const char *file, char *name);
 void hide_console(void);
-int is_admin(void);