X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Fshared%2Fmacro.h;h=58530a398089a1ff16b199111bde046659a3bf40;hp=5fa17ed2085cdc2fe3a7b992468f5917d6cd96b0;hb=ffc442ae487303626321ac0e3a5023d4c4a0944f;hpb=ab76853a4ca68ec371c971dfe2cc68f19fe07659

diff --git a/src/shared/macro.h b/src/shared/macro.h
index 5fa17ed20..58530a398 100644
--- a/src/shared/macro.h
+++ b/src/shared/macro.h
@@ -26,6 +26,7 @@
 #include <sys/types.h>
 #include <sys/uio.h>
 #include <inttypes.h>
+#include <stdbool.h>
 
 #define _printf_(a,b) __attribute__ ((format (printf, a, b)))
 #define _alloc_(...) __attribute__ ((alloc_size(__VA_ARGS__)))
@@ -461,6 +462,18 @@ do {                                                                    \
 #define GID_INVALID ((gid_t) -1)
 #define MODE_INVALID ((mode_t) -1)
 
+static inline bool UID_IS_INVALID(uid_t uid) {
+        /* We consider both the old 16bit -1 user and the newer 32bit
+         * -1 user invalid, since they are or used to be incompatible
+         * with syscalls such as setresuid() or chown(). */
+
+        return uid == (uid_t) ((uint32_t) -1) || uid == (uid_t) ((uint16_t) -1);
+}
+
+static inline bool GID_IS_INVALID(gid_t gid) {
+        return gid == (gid_t) ((uint32_t) -1) || gid == (gid_t) ((uint16_t) -1);
+}
+
 #define DEFINE_TRIVIAL_CLEANUP_FUNC(type, func)                 \
         static inline void func##p(type *p) {                   \
                 if (*p)                                         \