diff options
Diffstat (limited to 'src/basic/user-util.h')
| -rw-r--r-- | src/basic/user-util.h | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/src/basic/user-util.h b/src/basic/user-util.h index 36f71fb004..f569363811 100644 --- a/src/basic/user-util.h +++ b/src/basic/user-util.h @@ -20,6 +20,7 @@ ***/ #include <stdbool.h> +#include <stdint.h> #include <sys/types.h> #include <unistd.h> @@ -57,8 +58,19 @@ int take_etc_passwd_lock(const char *root); #define UID_INVALID ((uid_t) -1) #define GID_INVALID ((gid_t) -1) -/* The following macros add 1 when converting things, since UID 0 is a - * valid UID, while the pointer NULL is special */ +/* Let's pick a UIDs within the 16bit range, so that we are compatible with containers using 16bit + * user namespacing. At least on Fedora normal users are allocated until UID 60000, hence do not + * allocate from below this. Also stay away from the upper end of the range as that is often used + * for overflow/nobody users. */ +#define DYNAMIC_UID_MIN ((uid_t) UINT32_C(0x0000EF00)) +#define DYNAMIC_UID_MAX ((uid_t) UINT32_C(0x0000FFEF)) + +static inline bool uid_is_dynamic(uid_t uid) { + return DYNAMIC_UID_MIN <= uid && uid <= DYNAMIC_UID_MAX; +} + +/* The following macros add 1 when converting things, since UID 0 is a valid UID, while the pointer + * NULL is special */ #define PTR_TO_UID(p) ((uid_t) (((uintptr_t) (p))-1)) #define UID_TO_PTR(u) ((void*) (((uintptr_t) (u))+1)) |