patch-2.3.39 linux/include/linux/highuid.h

• Lines: 105
• Date: Mon Jan 10 18:29:08 2000
• Orig file: v2.3.38/linux/include/linux/highuid.h
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.38/linux/include/linux/highuid.h linux/include/linux/highuid.h
@@ -0,0 +1,104 @@
+#ifndef _LINUX_HIGHUID_H
+#define _LINUX_HIGHUID_H
+
+#include <linux/types.h>
+
+/*
+ * general notes:
+ *
+ * UID16_COMPAT_NEEDED is defined in include/asm-{arch}/posix_types.h
+ * if the given architecture needs to support backwards compatibility
+ * for old system calls.
+ *
+ * old_uid_t and old_gid_t are only used if UID16_COMPAT_NEEDED
+ * is defined.
+ *
+ * uid16_t and gid16_t are used on all architectures. (when dealing
+ * with structures hard coded to 16 bits, such as in filesystems)
+ */
+
+
+#ifdef UID16_COMPAT_NEEDED
+
+/*
+ * This is the "overflow" UID and GID. They are used to signify uid/gid
+ * overflow to old programs when they request uid/gid information but are
+ * using the old 16 bit interfaces.
+ * When you run a libc5 program, it will think that all highuid files or
+ * processes are owned by this uid/gid.
+ * The idea is that it's better to do so than possibly return 0 in lieu of
+ * 65536, etc.
+ */
+
+extern int overflowuid;
+extern int overflowgid;
+
+#define DEFAULT_OVERFLOWUID	65534
+#define DEFAULT_OVERFLOWGID	65534
+
+
+/* prevent uid mod 65536 effect by returning a default value for high UIDs */
+#define high2lowuid(uid) ((uid) > 65535) ? (old_uid_t)overflowuid : (old_uid_t)(uid)
+#define high2lowgid(gid) ((gid) > 65535) ? (old_gid_t)overflowgid : (old_gid_t)(gid)
+/*
+ * -1 is different in 16 bits than it is in 32 bits
+ * these macros are used by chown(), setreuid(), ...,
+ */
+#define low2highuid(uid) ((uid) == (old_uid_t)-1) ? (uid_t)-1 : (uid_t)(uid)
+#define low2highgid(gid) ((gid) == (old_gid_t)-1) ? (gid_t)-1 : (gid_t)(gid)
+
+/* Avoid extra ifdefs with these macros */
+
+#define SET_UID16(var, uid)	var = high2lowuid(uid)
+#define SET_GID16(var, gid)	var = high2lowgid(gid)
+#define NEW_TO_OLD_UID(uid)	high2lowuid(uid)
+#define NEW_TO_OLD_GID(gid)	high2lowgid(gid)
+
+#define SET_OLDSTAT_UID(stat, uid)	(stat).st_uid = high2lowuid(uid)
+#define SET_OLDSTAT_GID(stat, gid)	(stat).st_gid = high2lowgid(gid)
+#define SET_STAT_UID(stat, uid)		(stat).st_uid = high2lowuid(uid)
+#define SET_STAT_GID(stat, gid)		(stat).st_gid = high2lowgid(gid)
+
+#else
+
+#define SET_UID16(var, uid)	do { ; } while (0)
+#define SET_GID16(var, gid)	do { ; } while (0)
+#define NEW_TO_OLD_UID(uid)	uid
+#define NEW_TO_OLD_GID(gid)	gid
+
+#define SET_OLDSTAT_UID(stat, uid)	(stat).st_uid = uid
+#define SET_OLDSTAT_GID(stat, gid)	(stat).st_gid = gid
+#define SET_STAT_UID(stat, uid)		(stat).st_uid = uid
+#define SET_STAT_GID(stat, gid)		(stat).st_gid = gid
+
+#define high2lowuid(x)		(x)
+
+#endif /* UID16_COMPAT_NEEDED */
+
+
+/*
+ * Everything below this line is needed on all architectures, to deal with
+ * filesystems that only store 16 bits of the UID/GID, etc.
+ */
+
+/*
+ * This is the UID and GID that will get written to disk if a filesystem
+ * only supports 16-bit UIDs and the kernel has a high UID/GID to write
+ */
+extern int fs_overflowuid;
+extern int fs_overflowgid;
+
+#define DEFAULT_FS_OVERFLOWUID	65534
+#define DEFAULT_FS_OVERFLOWGID	65534
+
+/*
+ * Since these macros are used in architectures that only need limited
+ * 16-bit UID back compatibility, we won't use old_uid_t and old_gid_t
+ */
+#define fs_high2lowuid(uid) (uid > 65535) ? (uid16_t)fs_overflowuid : (uid16_t)uid
+#define fs_high2lowgid(gid) (gid > 65535) ? (gid16_t)fs_overflowgid : (gid16_t)gid
+
+#define low_16_bits(x)	x & 0xFFFF
+#define high_16_bits(x)	(x & 0xFFFF0000) >> 16
+
+#endif /* _LINUX_HIGHUID_H */