On Wed, 28 Sep 2022 14:33:18 +1000 David Gibson <david(a)gibson.dropbear.id.au> wrote:conf_runas() handles several of the different possible cases for the --runas argument in a slightly odd order. Although it can parse both numeric UIDs/GIDs and user/group names, it can't parse a numeric UID combined with a group name or vice versa. That's not obviously useful, but it's slightly surprising gap to have.Ah, actually, I had noticed that: I usually type my UID as number, but I can't remember GIDs... then I had half a mind of "fixing" that, and never got to it.[...] +++ b/conf.c @@ -859,46 +859,50 @@ dns6: * * Return: 0 on success, negative error code on failure */ -static int conf_runas(const char *opt, unsigned int *uid, unsigned int *gid) +static int conf_runas(char *opt, unsigned int *uid, unsigned int *gid)While I like your approach better than the existing one, I see one detail that, albeit minor, might drive somebody mad: if the UID is valid, but the GID isn't, we go back to conf_ugid(): if (ret) err("Invalid --runas option: %s", runas); and print the UID part, only, because we cut before the separator. Perhaps we could simply put the separator back before returning -EINVAL (instead of copying the buffer) -- we just have zero or one occurrences of ':'. -- Stefano