Security fix! Correct handling of seteuid() return value See Debian bug #638002, reported by John Lightsey. When possible the (already available) set_euidgid() function is used. Additionally, it is unnecessary to change the identity when writing into an already open file descriptor. This should fix the problem.

FILE *peopen(const char *command, const char *type, char *const envp[], int *ret_pid);

FILE *peidopen(const char *command, const char *type, char *const envp[], int *ret_pid, uid_t uid, gid_t gid);