#ifndef VLIBC_GRP_H
#define VLIBC_GRP_H

/*
 * vlibc — <grp.h>.
 *
 * The group database (todo 37). struct group mirrors /etc/group, whose
 * records are name:passwd:gid:member,member,... — the member list is a
 * comma-separated tail, empty when the group has no members. Everything
 * here is POSIX.1-2008 base (Level 1).
 *
 * The non-reentrant forms getgrnam/getgrgid/getgrent return a pointer to a
 * static structure whose contents — including the strings and the member
 * array it points at — are overwritten by the next call to any of the
 * three. getgrnam/getgrgid open and scan the whole file per call; getgrent
 * walks a cursor that setgrent rewinds and endgrent closes.
 *
 * The _r forms behave like their <pwd.h> counterparts: the entry is written
 * into caller storage (the gr_mem pointer array and the member name strings
 * both live inside the supplied buffer) and the return value is 0 on
 * success, ERANGE when the buffer is too small, or 0 with *result NULL when
 * no entry matches. errno is never touched: the error number IS the return
 * value.
 */

#include <vlibc/features.h>

#include <stddef.h>
#include <sys/types.h>

#ifdef __cplusplus
extern "C" {
#endif

/* One group database entry (/etc/group record). */
struct group
{
    char *gr_name;   /* group name */
    char *gr_passwd; /* encrypted password; usually empty */
    gid_t gr_gid;    /* numeric group id */
    char **gr_mem;   /* NULL-terminated member-name array */
};

/*
 * Look up the first entry whose name matches; NULL when absent. The result
 * points into shared static storage valid only until the next grp call.
 */
struct group *
getgrnam(const char *name);

/*
 * Look up the first entry whose gid matches; NULL when absent. Result
 * storage is shared with getgrnam/getgrent as described above.
 */
struct group *
getgrgid(gid_t gid);

/*
 * Return the next entry from the group stream, opening it on the first
 * call; NULL at end of file. The stream cursor advances per call.
 */
struct group *
getgrent(void);

/* Rewind the group stream to its first entry. */
void
setgrent(void);

/* Close the group stream; a later getgrent reopens from the start. */
void
endgrent(void);

int
getgrnam_r(const char *name, struct group *gr, char *buf, size_t bufsize, struct group **result);

int
getgrgid_r(gid_t gid, struct group *gr, char *buf, size_t bufsize, struct group **result);

int
getgrent_r(struct group *gr, char *buf, size_t bufsize, struct group **result);

#if VLIBC_LEVEL_GE(2)
/* Level 2 (muslmimic): XSI. */

#include <stdio.h> /* FILE */

/*
 * Return the next entry read from the given open stream, or NULL at end of
 * file or on a malformed/unopenable record; the entry is parsed as an
 * /etc/group record. Result storage is shared with getgrnam/getgrgid/
 * getgrent as described above, so the stream must not be closed until the
 * caller has copied the result. XSI.
 */
struct group *
fgetgrent(FILE *stream);

#endif /* VLIBC_LEVEL_GE(2) */

#ifdef __cplusplus
}
#endif

#endif /* VLIBC_GRP_H */