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ITS#9916 liblmdb: use alternate MDB_page2 struct for some accesses

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fakepage pointers are only guaranteed to be 2-byte aligned. Use a
2-byte aligned struct definition when referencing 2-byte page members
if a page pointer possibly points to a fakepage.
This commit is contained in:
Howard Chu 2022-11-15 15:33:48 +00:00
parent 4031bdba88
commit 8e3cab0f63
1 changed files with 74 additions and 55 deletions
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129
libraries/liblmdb/mdb.c
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@ -1046,9 +1046,26 @@ typedef struct MDB_page {
#define mp_pad mp_hdr.mh_pad
#define mp_flags mp_hdr.mh_flags
#define mp_pb mp_hdr.mh_pb
indx_t mp_ptrs[1]; /**< dynamic size */
indx_t mp_ptrs[0]; /**< dynamic size */
} MDB_page;
/** Alternate page header, for 2-byte aligned access */
typedef struct MDB_page2 {
uint16_t mp2_p[(sizeof(pgno_t)+sizeof(txnid_t))/2];
uint16_t mp2_pad;
uint16_t mp2_flags;
indx_t mp2_lower;
indx_t mp2_upper;
indx_t mp2_ptrs[0];
} MDB_page2;
#define MP_PGNO(p) (((MDB_page2 *)(void *)(p))->mp2_p)
#define MP_PAD(p) (((MDB_page2 *)(void *)(p))->mp2_pad)
#define MP_FLAGS(p) (((MDB_page2 *)(void *)(p))->mp2_flags)
#define MP_LOWER(p) (((MDB_page2 *)(void *)(p))->mp2_lower)
#define MP_UPPER(p) (((MDB_page2 *)(void *)(p))->mp2_upper)
#define MP_PTRS(p) (((MDB_page2 *)(void *)(p))->mp2_ptrs)
/** Size of the page header, excluding dynamic data at the end */
#define PAGEHDRSZ ((unsigned)sizeof(MDB_page_header))
@ -1059,10 +1076,10 @@ typedef struct MDB_page {
#define PAGEBASE PAGEHDRSZ
/** Number of nodes on a page */
#define NUMKEYS(p) (((p)->mp_lower - (PAGEHDRSZ-PAGEBASE)) >> 1)
#define NUMKEYS(p) ((MP_LOWER(p) - (PAGEHDRSZ-PAGEBASE)) >> 1)
/** The amount of space remaining in the page */
#define SIZELEFT(p) (indx_t)((p)->mp_upper - (p)->mp_lower)
#define SIZELEFT(p) (indx_t)(MP_UPPER(p) - MP_LOWER(p))
/** The percentage of space used in the page, in tenths of a percent. */
#define PAGEFILL(env, p) (1000L * ((env)->me_psize - PAGEHDRSZ - SIZELEFT(p)) / \
@ -1073,15 +1090,15 @@ typedef struct MDB_page {
#define FILL_THRESHOLD 250
/** Test if a page is a leaf page */
#define IS_LEAF(p) F_ISSET((p)->mp_flags, P_LEAF)
#define IS_LEAF(p) F_ISSET(MP_FLAGS(p), P_LEAF)
/** Test if a page is a LEAF2 page */
#define IS_LEAF2(p) F_ISSET((p)->mp_flags, P_LEAF2)
#define IS_LEAF2(p) F_ISSET(MP_FLAGS(p), P_LEAF2)
/** Test if a page is a branch page */
#define IS_BRANCH(p) F_ISSET((p)->mp_flags, P_BRANCH)
#define IS_BRANCH(p) F_ISSET(MP_FLAGS(p), P_BRANCH)
/** Test if a page is an overflow page */
#define IS_OVERFLOW(p) F_ISSET((p)->mp_flags, P_OVERFLOW)
#define IS_OVERFLOW(p) F_ISSET(MP_FLAGS(p), P_OVERFLOW)
/** Test if a page is a sub page */
#define IS_SUBP(p) F_ISSET((p)->mp_flags, P_SUBP)
#define IS_SUBP(p) F_ISSET(MP_FLAGS(p), P_SUBP)
/** Test if (this non-sub page is dirty && env is non-#MDB_WRITEMAP) */
#define IS_DIRTY_NW(txn, p) ((p)->mp_txnid > (txn)->mt_txnid)
@ -1192,7 +1209,7 @@ typedef struct MDB_node {
#define LEAFSIZE(k, d) (NODESIZE + (k)->mv_size + (d)->mv_size)
/** Address of node \b i in page \b p */
#define NODEPTR(p, i) ((MDB_node *)((char *)(p) + (p)->mp_ptrs[i] + PAGEBASE))
#define NODEPTR(p, i) ((MDB_node *)((char *)(p) + MP_PTRS(p)[i] + PAGEBASE))
/** Address of the key for the node */
#define NODEKEY(node) (void *)((node)->mn_data)
@ -1220,6 +1237,8 @@ typedef struct MDB_node {
/** Copy a page number from src to dst */
#ifdef MISALIGNED_OK
#define COPY_PGNO(dst,src) dst = src
#undef MP_PGNO
#define MP_PGNO(p) ((p)->mp_pgno)
#else
#if MDB_SIZE_MAX > 0xffffffffU
#define COPY_PGNO(dst,src) do { \
@ -1923,7 +1942,7 @@ static pgno_t
mdb_dbg_pgno(MDB_page *mp)
{
pgno_t ret;
COPY_PGNO(ret, mp->mp_pgno);
COPY_PGNO(ret, MP_PGNO(mp));
return ret;
}
@ -1976,7 +1995,7 @@ mdb_page_list(MDB_page *mp)
MDB_val key;
DKBUF;
switch (mp->mp_flags & (P_BRANCH|P_LEAF|P_LEAF2|P_META|P_OVERFLOW|P_SUBP)) {
switch (MP_FLAGS(mp) & (P_BRANCH|P_LEAF|P_LEAF2|P_META|P_OVERFLOW|P_SUBP)) {
case P_BRANCH: type = "Branch page"; break;
case P_LEAF: type = "Leaf page"; break;
case P_LEAF|P_SUBP: type = "Sub-page"; break;
@ -1990,7 +2009,7 @@ mdb_page_list(MDB_page *mp)
pgno, ((MDB_meta *)METADATA(mp))->mm_txnid);
return;
default:
fprintf(stderr, "Bad page %"Yu" flags 0x%X\n", pgno, mp->mp_flags);
fprintf(stderr, "Bad page %"Yu" flags 0x%X\n", pgno, MP_FLAGS(mp));
return;
}
@ -2026,7 +2045,7 @@ mdb_page_list(MDB_page *mp)
total = EVEN(total);
}
fprintf(stderr, "Total: header %d + contents %d + unused %d\n",
IS_LEAF2(mp) ? PAGEHDRSZ : PAGEBASE + mp->mp_lower, total, SIZELEFT(mp));
IS_LEAF2(mp) ? PAGEHDRSZ : PAGEBASE + MP_LOWER(mp), total, SIZELEFT(mp));
}
void
@ -7744,7 +7763,7 @@ mdb_cursor_set(MDB_cursor *mc, MDB_val *key, MDB_val *data,
mc->mc_ki[mc->mc_top] = 0;
return MDB_NOTFOUND;
}
if (mp->mp_flags & P_LEAF2) {
if (MP_FLAGS(mp) & P_LEAF2) {
nodekey.mv_size = mc->mc_db->md_pad;
nodekey.mv_data = LEAF2KEY(mp, 0, nodekey.mv_size);
} else {
@ -7765,7 +7784,7 @@ mdb_cursor_set(MDB_cursor *mc, MDB_val *key, MDB_val *data,
unsigned int i;
unsigned int nkeys = NUMKEYS(mp);
if (nkeys > 1) {
if (mp->mp_flags & P_LEAF2) {
if (MP_FLAGS(mp) & P_LEAF2) {
nodekey.mv_data = LEAF2KEY(mp,
nkeys-1, nodekey.mv_size);
} else {
@ -7783,7 +7802,7 @@ mdb_cursor_set(MDB_cursor *mc, MDB_val *key, MDB_val *data,
if (rc < 0) {
if (mc->mc_ki[mc->mc_top] < NUMKEYS(mp)) {
/* This is definitely the right page, skip search_page */
if (mp->mp_flags & P_LEAF2) {
if (MP_FLAGS(mp) & P_LEAF2) {
nodekey.mv_data = LEAF2KEY(mp,
mc->mc_ki[mc->mc_top], nodekey.mv_size);
} else {
@ -8348,7 +8367,7 @@ mdb_cursor_put(MDB_cursor *mc, MDB_val *key, MDB_val *data,
*mc->mc_dbflag |= DB_DIRTY;
if ((mc->mc_db->md_flags & (MDB_DUPSORT|MDB_DUPFIXED))
== MDB_DUPFIXED)
np->mp_flags |= P_LEAF2;
MP_FLAGS(np) |= P_LEAF2;
mc->mc_flags |= C_INITIALIZED;
} else {
/* make sure all cursor pages are writable */
@ -8370,7 +8389,7 @@ mdb_cursor_put(MDB_cursor *mc, MDB_val *key, MDB_val *data,
fp_flags = P_LEAF;
fp = env->me_pbuf;
fp->mp_pad = data->mv_size; /* used if MDB_DUPFIXED */
fp->mp_lower = fp->mp_upper = (PAGEHDRSZ-PAGEBASE);
MP_LOWER(fp) = MP_UPPER(fp) = (PAGEHDRSZ-PAGEBASE);
olddata.mv_size = PAGEHDRSZ;
goto prep_subDB;
}
@ -8445,18 +8464,18 @@ more:
dkey.mv_data = memcpy(fp+1, olddata.mv_data, olddata.mv_size);
/* Make sub-page header for the dup items, with dummy body */
fp->mp_flags = P_LEAF|P_SUBP;
fp->mp_lower = (PAGEHDRSZ-PAGEBASE);
MP_FLAGS(fp) = P_LEAF|P_SUBP;
MP_LOWER(fp) = (PAGEHDRSZ-PAGEBASE);
xdata.mv_size = PAGEHDRSZ + dkey.mv_size + data->mv_size;
if (mc->mc_db->md_flags & MDB_DUPFIXED) {
fp->mp_flags |= P_LEAF2;
MP_FLAGS(fp) |= P_LEAF2;
fp->mp_pad = data->mv_size;
xdata.mv_size += 2 * data->mv_size; /* leave space for 2 more */
} else {
xdata.mv_size += 2 * (sizeof(indx_t) + NODESIZE) +
(dkey.mv_size & 1) + (data->mv_size & 1);
}
fp->mp_upper = xdata.mv_size - PAGEBASE;
MP_UPPER(fp) = xdata.mv_size - PAGEBASE;
olddata.mv_size = xdata.mv_size; /* pretend olddata is fp */
} else if (leaf->mn_flags & F_SUBDATA) {
/* Data is on sub-DB, just store it */
@ -8479,7 +8498,7 @@ more:
}
/* FALLTHRU */ /* Big enough MDB_DUPFIXED sub-page */
case MDB_CURRENT:
COPY_PGNO(fp->mp_pgno, mp->mp_pgno);
COPY_PGNO(MP_PGNO(fp), MP_PGNO(mp));
mc->mc_xcursor->mx_cursor.mc_pg[0] = fp;
flags |= F_DUPDATA;
goto put_sub;
@ -8487,7 +8506,7 @@ more:
xdata.mv_size = olddata.mv_size + offset;
}
fp_flags = fp->mp_flags;
fp_flags = MP_FLAGS(fp);
if (NODESIZE + NODEKSZ(leaf) + xdata.mv_size > env->me_nodemax) {
/* Too big for a sub-page, convert to sub-DB */
fp_flags &= ~P_SUBP;
@ -8518,16 +8537,16 @@ prep_subDB:
sub_root = mp;
}
if (mp != fp) {
mp->mp_flags = fp_flags;
mp->mp_pad = fp->mp_pad;
mp->mp_lower = fp->mp_lower;
mp->mp_upper = fp->mp_upper + offset;
MP_FLAGS(mp) = fp_flags;
MP_PAD(mp) = MP_PAD(fp);
MP_LOWER(mp) = MP_LOWER(fp);
MP_UPPER(mp) = MP_UPPER(fp) + offset;
if (fp_flags & P_LEAF2) {
memcpy(METADATA(mp), METADATA(fp), NUMKEYS(fp) * fp->mp_pad);
} else {
memcpy((char *)mp + mp->mp_upper + PAGEBASE, (char *)fp + fp->mp_upper + PAGEBASE,
olddata.mv_size - fp->mp_upper - PAGEBASE);
memcpy((char *)(&mp->mp_ptrs), (char *)(&fp->mp_ptrs), NUMKEYS(fp) * sizeof(mp->mp_ptrs[0]));
memcpy((char *)mp + MP_UPPER(mp) + PAGEBASE, (char *)fp + MP_UPPER(fp) + PAGEBASE,
olddata.mv_size - MP_UPPER(fp) - PAGEBASE);
memcpy((char *)MP_PTRS(mp), (char *)MP_PTRS(fp), NUMKEYS(fp) * sizeof(mp->mp_ptrs[0]));
for (i=0; i<NUMKEYS(fp); i++)
mp->mp_ptrs[i] += offset;
}
@ -8975,7 +8994,7 @@ mdb_node_add(MDB_cursor *mc, indx_t indx,
void *ndata;
DKBUF;
mdb_cassert(mc, mp->mp_upper >= mp->mp_lower);
mdb_cassert(mc, MP_UPPER(mp) >= MP_LOWER(mp));
DPRINTF(("add to %s %spage %"Yu" index %i, data size %"Z"u key size %"Z"u [%s]",
IS_LEAF(mp) ? "leaf" : "branch",
@ -8994,8 +9013,8 @@ mdb_node_add(MDB_cursor *mc, indx_t indx,
memcpy(ptr, key->mv_data, ksize);
/* Just using these for counting */
mp->mp_lower += sizeof(indx_t);
mp->mp_upper -= ksize - sizeof(indx_t);
MP_LOWER(mp) += sizeof(indx_t);
MP_UPPER(mp) -= ksize - sizeof(indx_t);
return MDB_SUCCESS;
}
@ -9032,14 +9051,14 @@ mdb_node_add(MDB_cursor *mc, indx_t indx,
update:
/* Move higher pointers up one slot. */
for (i = NUMKEYS(mp); i > indx; i--)
mp->mp_ptrs[i] = mp->mp_ptrs[i - 1];
MP_PTRS(mp)[i] = MP_PTRS(mp)[i - 1];
/* Adjust free space offsets. */
ofs = mp->mp_upper - node_size;
mdb_cassert(mc, ofs >= mp->mp_lower + sizeof(indx_t));
mp->mp_ptrs[indx] = ofs;
mp->mp_upper = ofs;
mp->mp_lower += sizeof(indx_t);
ofs = MP_UPPER(mp) - node_size;
mdb_cassert(mc, ofs >= MP_LOWER(mp) + sizeof(indx_t));
MP_PTRS(mp)[indx] = ofs;
MP_UPPER(mp) = ofs;
MP_LOWER(mp) += sizeof(indx_t);
/* Write the node data. */
node = NODEPTR(mp, indx);
@ -9081,7 +9100,7 @@ update:
full:
DPRINTF(("not enough room in page %"Yu", got %u ptrs",
mdb_dbg_pgno(mp), NUMKEYS(mp)));
DPRINTF(("upper-lower = %u - %u = %"Z"d", mp->mp_upper,mp->mp_lower,room));
DPRINTF(("upper-lower = %u - %u = %"Z"d", MP_UPPER(mp),MP_LOWER(mp),room));
DPRINTF(("node size = %"Z"u", node_size));
mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
return MDB_PAGE_FULL;
@ -9112,8 +9131,8 @@ mdb_node_del(MDB_cursor *mc, int ksize)
base = LEAF2KEY(mp, indx, ksize);
if (x)
memmove(base, base + ksize, x * ksize);
mp->mp_lower -= sizeof(indx_t);
mp->mp_upper += ksize - sizeof(indx_t);
MP_LOWER(mp) -= sizeof(indx_t);
MP_UPPER(mp) += ksize - sizeof(indx_t);
return;
}
@ -9127,21 +9146,21 @@ mdb_node_del(MDB_cursor *mc, int ksize)
}
sz = EVEN(sz);
ptr = mp->mp_ptrs[indx];
ptr = MP_PTRS(mp)[indx];
for (i = j = 0; i < numkeys; i++) {
if (i != indx) {
mp->mp_ptrs[j] = mp->mp_ptrs[i];
if (mp->mp_ptrs[i] < ptr)
mp->mp_ptrs[j] += sz;
MP_PTRS(mp)[j] = MP_PTRS(mp)[i];
if (MP_PTRS(mp)[i] < ptr)
MP_PTRS(mp)[j] += sz;
j++;
}
}
base = (char *)mp + mp->mp_upper + PAGEBASE;
memmove(base + sz, base, ptr - mp->mp_upper);
base = (char *)mp + MP_UPPER(mp) + PAGEBASE;
memmove(base + sz, base, ptr - MP_UPPER(mp));
mp->mp_lower -= sizeof(indx_t);
mp->mp_upper += sz;
MP_LOWER(mp) -= sizeof(indx_t);
MP_UPPER(mp) += sz;
}
/** Compact the main page after deleting a node on a subpage.
@ -9170,11 +9189,11 @@ mdb_node_shrink(MDB_page *mp, indx_t indx)
} else {
xp = (MDB_page *)((char *)sp + delta); /* destination subpage */
for (i = NUMKEYS(sp); --i >= 0; )
xp->mp_ptrs[i] = sp->mp_ptrs[i] - delta;
MP_PTRS(xp)[i] = MP_PTRS(sp)[i] - delta;
len = PAGEHDRSZ;
}
sp->mp_upper = sp->mp_lower;
COPY_PGNO(sp->mp_pgno, mp->mp_pgno);
MP_UPPER(sp) = MP_LOWER(sp);
COPY_PGNO(MP_PGNO(sp), mp->mp_pgno);
SETDSZ(node, nsize);
/* Shift <lower nodes...initial part of subpage> upward */
@ -9246,7 +9265,7 @@ mdb_xcursor_init1(MDB_cursor *mc, MDB_node *node)
mx->mx_db.md_leaf_pages = 1;
mx->mx_db.md_overflow_pages = 0;
mx->mx_db.md_entries = NUMKEYS(fp);
COPY_PGNO(mx->mx_db.md_root, fp->mp_pgno);
COPY_PGNO(mx->mx_db.md_root, MP_PGNO(fp));
mx->mx_cursor.mc_snum = 1;
mx->mx_cursor.mc_top = 0;
mx->mx_cursor.mc_flags |= C_INITIALIZED;