/* Routines for vectors of uids/gids Copyright (C) 1995, 1996, 1997, 1998 Free Software Foundation, Inc. Written by Miles Bader This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include #include #include /* Return a new, empty, idvec, or NULL if there wasn't enough memory. */ struct idvec * make_idvec () { struct idvec *idvec = malloc (sizeof (struct idvec)); if (idvec) { idvec->alloced = idvec->num = 0; idvec->ids = 0; } return idvec; } /* Free's IDVEC, but not the storage pointed to by the IDS field. */ void idvec_free_wrapper (struct idvec *idvec) { free (idvec); } void idvec_free_contents (struct idvec *idvec) { if (idvec->alloced) free (idvec->ids); } void idvec_free (struct idvec *idvec) { idvec_free_contents (idvec); idvec_free_wrapper (idvec); } /* Ensure that IDVEC has enough spaced allocated to hold NUM ids, thus ensuring that any subsequent ids added won't return a memory allocation error unless it would result in more ids that NUM. ENOMEM is returned if a memory allocation error occurs. */ error_t idvec_ensure (struct idvec *idvec, unsigned num) { if (num > idvec->alloced) { uid_t *_ids = realloc (idvec->ids, num * sizeof (uid_t)); if (! _ids) return ENOMEM; idvec->ids = _ids; idvec->alloced = num; } return 0; } /* Like idvec_ensure(), but takes INC, the increment of the number of ids already in IDVEC as an argument. */ error_t idvec_grow (struct idvec *idvec, unsigned inc) { return idvec_ensure (idvec, idvec->num + inc); } /* Returns true if IDVEC contains ID, at or after position POS. */ int idvec_tail_contains (const struct idvec *idvec, unsigned pos, uid_t id) { uid_t *ids = idvec->ids, *end = ids + idvec->num, *p = ids + pos; while (p < end) if (*p++ == id) return 1; return 0; } /* Insert ID into IDVEC at position POS, returning ENOMEM if there wasn't enough memory, or 0. */ error_t idvec_insert (struct idvec *idvec, unsigned pos, uid_t id) { error_t err = 0; unsigned num = idvec->num; unsigned new_num = (pos < num ? num + 1 : pos + 1); if (idvec->alloced == num) /* If we seem to be growing by just one, actually prealloc some more. */ err = idvec_ensure (idvec, new_num + num); else err = idvec_ensure (idvec, new_num); if (! err) { uid_t *ids = idvec->ids; if (pos < num) bcopy (ids + pos, ids + pos + 1, (num - pos) * sizeof (uid_t)); else if (pos > num) bzero (ids + num, (pos - num) * sizeof (uid_t)); ids[pos] = id; idvec->num = new_num; } return err; } /* Add ID onto the end of IDVEC, returning ENOMEM if there's not enough memory, or 0. */ error_t idvec_add (struct idvec *idvec, uid_t id) { return idvec_insert (idvec, idvec->num, id); } /* If IDVEC doesn't contain ID, add it onto the end, returning ENOMEM if there's not enough memory; otherwise, do nothing. */ error_t idvec_add_new (struct idvec *idvec, uid_t id) { if (idvec_contains (idvec, id)) return 0; else return idvec_add (idvec, id); } /* If IDVEC doesn't contain ID at position POS or after, insert it at POS, returning ENOMEM if there's not enough memory; otherwise, do nothing. */ error_t idvec_insert_new (struct idvec *idvec, unsigned pos, uid_t id) { if (idvec_tail_contains (idvec, pos, id)) return 0; else return idvec_insert (idvec, pos, id); } /* Set the ids in IDVEC to IDS (NUM elements long); delete whatever the previous ids were. */ error_t idvec_set_ids (struct idvec *idvec, const uid_t *ids, unsigned num) { error_t err; err = idvec_ensure (idvec, num); if (!err) { bcopy (ids, idvec->ids, num * sizeof (uid_t)); idvec->num = num; } return err; } /* Like idvec_set_ids, but get the new ids from new. */ error_t idvec_set (struct idvec *idvec, const struct idvec *new) { return idvec_set_ids (idvec, new->ids, new->num); } /* Adds each id in the vector IDS (NUM elements long) to IDVEC, as long as it wasn't previously in IDVEC. */ error_t idvec_merge_ids (struct idvec *idvec, const uid_t *ids, unsigned num) { error_t err = 0; unsigned num_old = idvec->num; while (num-- > 0 && !err) { int i; for (i = 0; i < num_old; i++) if (idvec->ids[i] == *ids) break; if (i == num_old) err = idvec_add (idvec, *ids); ids++; } return err; } /* Adds each id from NEW to IDVEC, as if with idvec_add_new(). */ error_t idvec_merge (struct idvec *idvec, const struct idvec *new) { return idvec_merge_ids (idvec, new->ids, new->num); } /* Remove any occurances of ID in IDVEC after position POS. Returns true if anything was done. */ int idvec_remove (struct idvec *idvec, unsigned pos, uid_t id) { if (pos < idvec->num) { int left = idvec->num - pos; uid_t *ids = idvec->ids + pos, *targ = ids; while (left--) { if (*ids != id) { if (ids != targ) *targ = *ids; targ++; } ids++; } if (ids == targ) return 0; idvec->num = targ - idvec->ids; return 1; } else return 0; } /* Remove all ids in SUB from IDVEC, returning true if anything was done. */ int idvec_subtract (struct idvec *idvec, const struct idvec *sub) { int i; int done = 0; for (i = 0; i < sub->num; i++) done |= idvec_remove (idvec, 0, sub->ids[i]); return done; } /* Remove all ids from IDVEC that are *not* in KEEP, returning true if anything was changed. */ int idvec_keep (struct idvec *idvec, const struct idvec *keep) { uid_t *old = idvec->ids, *new = old, *end = old + idvec->num; while (old < end) { uid_t id = *old++; if (idvec_contains (keep, id)) { if (old != new) *new = id; new++; } } if (old != new) { idvec->num = new - idvec->ids; return 1; } else return 0; } /* Deleted the id at position POS in IDVEC. */ void idvec_delete (struct idvec *idvec, unsigned pos) { unsigned num = idvec->num; if (pos < num) { uid_t *ids = idvec->ids; idvec->num = --num; if (num > pos) bcopy (ids + pos + 1, ids + pos, (num - pos) * sizeof (uid_t)); } } /* Insert ID at position POS in IDVEC, remoint any instances of ID previously present at POS or after. ENOMEM is returned if there's not enough memory, otherwise 0. */ error_t idvec_insert_only (struct idvec *idvec, unsigned pos, uid_t id) { if (idvec->num > pos && idvec->ids[pos] == id) return 0; else { idvec_remove (idvec, pos, id); return idvec_insert (idvec, pos, id); } } /* EFF and AVAIL should be idvec's corresponding to a processes effective and available ids. ID replaces the first id in EFF, and what it replaces is preserved by adding it to AVAIL (if not already present). If SECURE is non-NULL, and ID was not previously present in either EFF or AVAIL, then *SECURE is set to true. ENOMEM is returned if a malloc fails, otherwise 0. The return parameters are only touched if this call succeeds. */ error_t idvec_setid (struct idvec *eff, struct idvec *avail, uid_t id, int *secure) { error_t err; /* True if ID was not previously present in either EFF or AVAIL. */ int _secure = !idvec_contains (eff, id) && !idvec_contains (avail, id); if (eff->num > 0) /* If there are any old effective ids, we replace eff[0] with ID, and try to preserve the old eff[0] by putting it in AVAIL list if necessary. */ { if (avail->num == 0) /* The old eff[0] becomes avail[0] (the posix real id). */ err = idvec_add (avail, eff->ids[0]); else /* We preserve the old real id, and add eff[0] to the list of saved ids (if necessary). Inserting it means that the latest id saved will correspond to the (single) posix saved id. */ err = idvec_insert_only (avail, 1, eff->ids[0]); /* Replace eff[0] with the new id. */ eff->ids[0] = id; } else /* No previous effective ids, just make ID the first one. */ err = idvec_add (eff, id); if (err) return err; if (_secure && secure && !*secure) *secure = 1; return 0; }