uint16_t inet_cksum(uint16_t *addr, int len) FAST_FUNC;
+/* 0 if argv[0] is NULL: */
+unsigned string_array_len(char **argv) FAST_FUNC;
void overlapping_strcpy(char *dst, const char *src) FAST_FUNC;
char *safe_strncpy(char *dst, const char *src, size_t size) FAST_FUNC;
char *strncpy_IFNAMSIZ(char *dst, const char *src) FAST_FUNC;
#else
#define die_if_bad_username(name) ((void)(name))
#endif
+/*
+ * Returns (-1) terminated malloced result of getgroups().
+ * Reallocs group_array (useful for repeated calls).
+ * ngroups is an initial size of array. It is rounded up to 32 for realloc.
+ * ngroups is updated on return.
+ * ngroups can be NULL: bb_getgroups(NULL, NULL) is valid usage.
+ * Dies on errors (on Linux, only xrealloc can cause this, not internal getgroups call).
+ */
+gid_t *bb_getgroups(int *ngroups, gid_t *group_array) FAST_FUNC;
#if ENABLE_FEATURE_UTMP
void FAST_FUNC write_new_utmp(pid_t pid, int new_type, const char *tty_name, const char *username, const char *hostname);