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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-17 02:20:36 +0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-17 02:20:36 +0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /include/linux/highuid.h | |
download | linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.xz |
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'include/linux/highuid.h')
-rw-r--r-- | include/linux/highuid.h | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/include/linux/highuid.h b/include/linux/highuid.h new file mode 100644 index 000000000000..53ecac3905e8 --- /dev/null +++ b/include/linux/highuid.h @@ -0,0 +1,98 @@ +#ifndef _LINUX_HIGHUID_H +#define _LINUX_HIGHUID_H + +#include <linux/config.h> +#include <linux/types.h> + +/* + * general notes: + * + * CONFIG_UID16 is defined if the given architecture needs to + * support backwards compatibility for old system calls. + * + * kernel code should use uid_t and gid_t at all times when dealing with + * kernel-private data. + * + * old_uid_t and old_gid_t should only be different if CONFIG_UID16 is + * defined, else the platform should provide dummy typedefs for them + * such that they are equivalent to __kernel_{u,g}id_t. + * + * uid16_t and gid16_t are used on all architectures. (when dealing + * with structures hard coded to 16 bits, such as in filesystems) + */ + + +/* + * 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; + +extern void __bad_uid(void); +extern void __bad_gid(void); + +#define DEFAULT_OVERFLOWUID 65534 +#define DEFAULT_OVERFLOWGID 65534 + +#ifdef CONFIG_UID16 + +/* prevent uid mod 65536 effect by returning a default value for high UIDs */ +#define high2lowuid(uid) ((uid) & ~0xFFFF ? (old_uid_t)overflowuid : (old_uid_t)(uid)) +#define high2lowgid(gid) ((gid) & ~0xFFFF ? (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)) + +#define __convert_uid(size, uid) \ + (size >= sizeof(uid) ? (uid) : high2lowuid(uid)) +#define __convert_gid(size, gid) \ + (size >= sizeof(gid) ? (gid) : high2lowgid(gid)) + + +#else + +#define __convert_uid(size, uid) (uid) +#define __convert_gid(size, gid) (gid) + +#endif /* !CONFIG_UID16 */ + +/* uid/gid input should be always 32bit uid_t */ +#define SET_UID(var, uid) do { (var) = __convert_uid(sizeof(var), (uid)); } while (0) +#define SET_GID(var, gid) do { (var) = __convert_gid(sizeof(var), (gid)); } while (0) + +/* + * 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) & ~0xFFFF ? (uid16_t)fs_overflowuid : (uid16_t)(uid)) +#define fs_high2lowgid(gid) ((gid) & ~0xFFFF ? (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 */ |