diff options
| -rw-r--r-- | libshouldbeinlibc/idvec.c | 44 |
1 files changed, 41 insertions, 3 deletions
diff --git a/libshouldbeinlibc/idvec.c b/libshouldbeinlibc/idvec.c index 01eabdd6..b89adab1 100644 --- a/libshouldbeinlibc/idvec.c +++ b/libshouldbeinlibc/idvec.c @@ -131,7 +131,7 @@ idvec_add (struct idvec *idvec, id_t id) return idvec_insert (idvec, idvec->num, id); } -/* IF IDVEC doesn't contain ID, add it onto the end, returning ENOMEM if +/* 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, id_t id) @@ -142,7 +142,7 @@ idvec_add_new (struct idvec *idvec, id_t id) return idvec_add (idvec, id); } -/* IF IDVEC doesn't contain ID at position POS or after, insert it at POS, +/* 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, id_t id) @@ -164,6 +164,44 @@ idvec_merge_ids (struct idvec *idvec, id_t *ids, unsigned num) return err; } +/* Remove any occurances of ID in IDVEC after position POS> Returns true if + anything was done. */ +int +idvec_remove (struct idvec *idvec, unsigned pos, id_t id) +{ + int left = idvec->num - pos; + id_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; +} + +/* 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, id_t id) +{ + if (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 @@ -188,7 +226,7 @@ idvec_setid (struct idvec *eff, struct idvec *avail, id_t id, int *secure) /* 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_new (avail, 1, eff->ids[0]); + err = idvec_insert_only (avail, 1, eff->ids[0]); /* Replace eff[0] with the new id. */ eff->ids[0] = id; |