tdb: add overflow/ENOSPC handling to tdb_expand_file()
[obnox/samba/samba-obnox.git] / lib / tdb / common / io.c
index d549715f831b414fc098b334a97f6572c74ffc76..d17764008f613be9111411427d70f25c9a2dbf26 100644 (file)
@@ -1,4 +1,4 @@
- /* 
+ /*
    Unix SMB/CIFS implementation.
 
    trivial database library
@@ -6,11 +6,11 @@
    Copyright (C) Andrew Tridgell              1999-2005
    Copyright (C) Paul `Rusty' Russell             2000
    Copyright (C) Jeremy Allison                           2000-2003
-   
+
      ** NOTE! The following LGPL license applies to the tdb
      ** library. This does NOT imply that all of Samba is released
      ** under the LGPL
-   
+
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
 
 /* check for an out of bounds access - if it is out of bounds then
    see if the database has been expanded by someone else and expand
-   if necessary 
-   note that "len" is the minimum length needed for the db
+   if necessary
 */
-static int tdb_oob(struct tdb_context *tdb, tdb_off_t len, int probe)
+static int tdb_oob(struct tdb_context *tdb, tdb_off_t off, tdb_len_t len,
+                  int probe)
 {
        struct stat st;
-       if (len <= tdb->map_size)
+       if (len + off < len) {
+               if (!probe) {
+                       /* Ensure ecode is set for log fn. */
+                       tdb->ecode = TDB_ERR_IO;
+                       TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_oob off %u len %u wrap\n",
+                                off, len));
+               }
+               return -1;
+       }
+
+       if (off + len <= tdb->map_size)
                return 0;
        if (tdb->flags & TDB_INTERNAL) {
                if (!probe) {
                        /* Ensure ecode is set for log fn. */
                        tdb->ecode = TDB_ERR_IO;
-                       TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_oob len %d beyond internal malloc size %d\n",
-                                (int)len, (int)tdb->map_size));
+                       TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_oob len %u beyond internal malloc size %u\n",
+                                (int)(off + len), (int)tdb->map_size));
                }
                return -1;
        }
@@ -53,28 +63,44 @@ static int tdb_oob(struct tdb_context *tdb, tdb_off_t len, int probe)
                return -1;
        }
 
-       if (st.st_size < (size_t)len) {
-               if (!probe) {
-                       /* Ensure ecode is set for log fn. */
-                       tdb->ecode = TDB_ERR_IO;
-                       TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_oob len %d beyond eof at %d\n",
-                                (int)len, (int)st.st_size));
-               }
+       /* Beware >4G files! */
+       if ((tdb_off_t)st.st_size != st.st_size) {
+               /* Ensure ecode is set for log fn. */
+               tdb->ecode = TDB_ERR_IO;
+               TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_oob len %llu too large!\n",
+                        (long long)st.st_size));
                return -1;
        }
 
-       /* Unmap, update size, remap */
+       /* Unmap, update size, remap.  We do this unconditionally, to handle
+        * the unusual case where the db is truncated.
+        *
+        * This can happen to a child using tdb_reopen_all(true) on a
+        * TDB_CLEAR_IF_FIRST tdb whose parent crashes: the next
+        * opener will truncate the database. */
        if (tdb_munmap(tdb) == -1) {
                tdb->ecode = TDB_ERR_IO;
                return -1;
        }
        tdb->map_size = st.st_size;
-       tdb_mmap(tdb);
+       if (tdb_mmap(tdb) != 0) {
+               return -1;
+       }
+
+       if (st.st_size < (size_t)off + len) {
+               if (!probe) {
+                       /* Ensure ecode is set for log fn. */
+                       tdb->ecode = TDB_ERR_IO;
+                       TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_oob len %u beyond eof at %u\n",
+                                (int)(off + len), (int)st.st_size));
+               }
+               return -1;
+       }
        return 0;
 }
 
 /* write a lump of data at a specified offset */
-static int tdb_write(struct tdb_context *tdb, tdb_off_t off, 
+static int tdb_write(struct tdb_context *tdb, tdb_off_t off,
                     const void *buf, tdb_len_t len)
 {
        if (len == 0) {
@@ -86,19 +112,23 @@ static int tdb_write(struct tdb_context *tdb, tdb_off_t off,
                return -1;
        }
 
-       if (tdb->methods->tdb_oob(tdb, off + len, 0) != 0)
+       if (tdb->methods->tdb_oob(tdb, off, len, 0) != 0)
                return -1;
 
        if (tdb->map_ptr) {
                memcpy(off + (char *)tdb->map_ptr, buf, len);
        } else {
+#ifdef HAVE_INCOHERENT_MMAP
+               tdb->ecode = TDB_ERR_IO;
+               return -1;
+#else
                ssize_t written = pwrite(tdb->fd, buf, len, off);
                if ((written != (ssize_t)len) && (written != -1)) {
                        /* try once more */
                        tdb->ecode = TDB_ERR_IO;
                        TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_write: wrote only "
-                                "%d of %d bytes at %d, trying once more\n",
-                                (int)written, len, off));
+                                "%zi of %u bytes at %u, trying once more\n",
+                                written, len, off));
                        written = pwrite(tdb->fd, (const char *)buf+written,
                                         len-written,
                                         off+written);
@@ -106,16 +136,17 @@ static int tdb_write(struct tdb_context *tdb, tdb_off_t off,
                if (written == -1) {
                        /* Ensure ecode is set for log fn. */
                        tdb->ecode = TDB_ERR_IO;
-                       TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_write failed at %d "
-                                "len=%d (%s)\n", off, len, strerror(errno)));
+                       TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_write failed at %u "
+                                "len=%u (%s)\n", off, len, strerror(errno)));
                        return -1;
                } else if (written != (ssize_t)len) {
                        tdb->ecode = TDB_ERR_IO;
                        TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_write: failed to "
-                                "write %d bytes at %d in two attempts\n",
+                                "write %u bytes at %u in two attempts\n",
                                 len, off));
                        return -1;
                }
+#endif
        }
        return 0;
 }
@@ -131,26 +162,31 @@ void *tdb_convert(void *buf, uint32_t size)
 
 
 /* read a lump of data at a specified offset, maybe convert */
-static int tdb_read(struct tdb_context *tdb, tdb_off_t off, void *buf, 
+static int tdb_read(struct tdb_context *tdb, tdb_off_t off, void *buf,
                    tdb_len_t len, int cv)
 {
-       if (tdb->methods->tdb_oob(tdb, off + len, 0) != 0) {
+       if (tdb->methods->tdb_oob(tdb, off, len, 0) != 0) {
                return -1;
        }
 
        if (tdb->map_ptr) {
                memcpy(buf, off + (char *)tdb->map_ptr, len);
        } else {
+#ifdef HAVE_INCOHERENT_MMAP
+               tdb->ecode = TDB_ERR_IO;
+               return -1;
+#else
                ssize_t ret = pread(tdb->fd, buf, len, off);
                if (ret != (ssize_t)len) {
                        /* Ensure ecode is set for log fn. */
                        tdb->ecode = TDB_ERR_IO;
-                       TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_read failed at %d "
-                                "len=%d ret=%d (%s) map_size=%d\n",
-                                (int)off, (int)len, (int)ret, strerror(errno),
-                                (int)tdb->map_size));
+                       TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_read failed at %u "
+                                "len=%u ret=%zi (%s) map_size=%u\n",
+                                off, len, ret, strerror(errno),
+                                tdb->map_size));
                        return -1;
                }
+#endif
        }
        if (cv) {
                tdb_convert(buf, len);
@@ -163,19 +199,19 @@ static int tdb_read(struct tdb_context *tdb, tdb_off_t off, void *buf,
 /*
   do an unlocked scan of the hash table heads to find the next non-zero head. The value
   will then be confirmed with the lock held
-*/             
+*/
 static void tdb_next_hash_chain(struct tdb_context *tdb, uint32_t *chain)
 {
        uint32_t h = *chain;
        if (tdb->map_ptr) {
-               for (;h < tdb->header.hash_size;h++) {
+               for (;h < tdb->hash_size;h++) {
                        if (0 != *(uint32_t *)(TDB_HASH_TOP(h) + (unsigned char *)tdb->map_ptr)) {
                                break;
                        }
                }
        } else {
                uint32_t off=0;
-               for (;h < tdb->header.hash_size;h++) {
+               for (;h < tdb->hash_size;h++) {
                        if (tdb_ofs_read(tdb, TDB_HASH_TOP(h), &off) != 0 || off != 0) {
                                break;
                        }
@@ -203,15 +239,25 @@ int tdb_munmap(struct tdb_context *tdb)
        return 0;
 }
 
-void tdb_mmap(struct tdb_context *tdb)
+/* If mmap isn't coherent, *everyone* must always mmap. */
+static bool should_mmap(const struct tdb_context *tdb)
+{
+#ifdef HAVE_INCOHERENT_MMAP
+       return true;
+#else
+       return !(tdb->flags & TDB_NOMMAP);
+#endif
+}
+
+int tdb_mmap(struct tdb_context *tdb)
 {
        if (tdb->flags & TDB_INTERNAL)
-               return;
+               return 0;
 
 #ifdef HAVE_MMAP
-       if (!(tdb->flags & TDB_NOMMAP)) {
-               tdb->map_ptr = mmap(NULL, tdb->map_size, 
-                                   PROT_READ|(tdb->read_only? 0:PROT_WRITE), 
+       if (should_mmap(tdb)) {
+               tdb->map_ptr = mmap(NULL, tdb->map_size,
+                                   PROT_READ|(tdb->read_only? 0:PROT_WRITE),
                                    MAP_SHARED|MAP_FILE, tdb->fd, 0);
 
                /*
@@ -220,8 +266,12 @@ void tdb_mmap(struct tdb_context *tdb)
 
                if (tdb->map_ptr == MAP_FAILED) {
                        tdb->map_ptr = NULL;
-                       TDB_LOG((tdb, TDB_DEBUG_WARNING, "tdb_mmap failed for size %d (%s)\n", 
+                       TDB_LOG((tdb, TDB_DEBUG_WARNING, "tdb_mmap failed for size %u (%s)\n",
                                 tdb->map_size, strerror(errno)));
+#ifdef HAVE_INCOHERENT_MMAP
+                       tdb->ecode = TDB_ERR_IO;
+                       return -1;
+#endif
                }
        } else {
                tdb->map_ptr = NULL;
@@ -229,6 +279,7 @@ void tdb_mmap(struct tdb_context *tdb)
 #else
        tdb->map_ptr = NULL;
 #endif
+       return 0;
 }
 
 /* expand a file.  we prefer to use ftruncate, as that is what posix
@@ -236,26 +287,37 @@ void tdb_mmap(struct tdb_context *tdb)
 static int tdb_expand_file(struct tdb_context *tdb, tdb_off_t size, tdb_off_t addition)
 {
        char buf[8192];
+       tdb_off_t new_size;
 
        if (tdb->read_only || tdb->traverse_read) {
                tdb->ecode = TDB_ERR_RDONLY;
                return -1;
        }
 
-       if (ftruncate(tdb->fd, size+addition) == -1) {
+       if (!tdb_add_off_t(size, addition, &new_size)) {
+               tdb->ecode = TDB_ERR_OOM;
+               TDB_LOG((tdb, TDB_DEBUG_FATAL, "expand_file write "
+                       "overflow detected current size[%u] addition[%u]!\n",
+                       (unsigned)size, (unsigned)addition));
+               errno = ENOSPC;
+               return -1;
+       }
+
+       if (ftruncate(tdb->fd, new_size) == -1) {
                char b = 0;
-               ssize_t written = pwrite(tdb->fd,  &b, 1, (size+addition) - 1);
+               ssize_t written = pwrite(tdb->fd,  &b, 1, new_size - 1);
                if (written == 0) {
                        /* try once more, potentially revealing errno */
-                       written = pwrite(tdb->fd,  &b, 1, (size+addition) - 1);
+                       written = pwrite(tdb->fd,  &b, 1, new_size - 1);
                }
                if (written == 0) {
                        /* again - give up, guessing errno */
                        errno = ENOSPC;
                }
                if (written != 1) {
-                       TDB_LOG((tdb, TDB_DEBUG_FATAL, "expand_file to %d failed (%s)\n", 
-                                size+addition, strerror(errno)));
+                       tdb->ecode = TDB_ERR_OOM;
+                       TDB_LOG((tdb, TDB_DEBUG_FATAL, "expand_file to %u failed (%s)\n",
+                                (unsigned)new_size, strerror(errno)));
                        return -1;
                }
        }
@@ -273,19 +335,23 @@ static int tdb_expand_file(struct tdb_context *tdb, tdb_off_t size, tdb_off_t ad
                }
                if (written == 0) {
                        /* give up, trying to provide a useful errno */
+                       tdb->ecode = TDB_ERR_OOM;
                        TDB_LOG((tdb, TDB_DEBUG_FATAL, "expand_file write "
                                "returned 0 twice: giving up!\n"));
                        errno = ENOSPC;
                        return -1;
-               } else if (written == -1) {
+               }
+               if (written == -1) {
+                       tdb->ecode = TDB_ERR_OOM;
                        TDB_LOG((tdb, TDB_DEBUG_FATAL, "expand_file write of "
-                                "%d bytes failed (%s)\n", (int)n,
+                                "%u bytes failed (%s)\n", (int)n,
                                 strerror(errno)));
                        return -1;
-               } else if (written != n) {
+               }
+               if (written != n) {
                        TDB_LOG((tdb, TDB_DEBUG_WARNING, "expand_file: wrote "
-                                "only %d of %d bytes - retrying\n", (int)written,
-                                (int)n));
+                                "only %zu of %zi bytes - retrying\n", written,
+                                n));
                }
                addition -= written;
                size += written;
@@ -294,12 +360,39 @@ static int tdb_expand_file(struct tdb_context *tdb, tdb_off_t size, tdb_off_t ad
 }
 
 
+/* You need 'size', this tells you how much you should expand by. */
+tdb_off_t tdb_expand_adjust(tdb_off_t map_size, tdb_off_t size, int page_size)
+{
+       tdb_off_t new_size, top_size;
+
+       /* limit size in order to avoid using up huge amounts of memory for
+        * in memory tdbs if an oddball huge record creeps in */
+       if (size > 100 * 1024) {
+               top_size = map_size + size * 2;
+       } else {
+               top_size = map_size + size * 100;
+       }
+
+       /* always make room for at least top_size more records, and at
+          least 25% more space. if the DB is smaller than 100MiB,
+          otherwise grow it by 10% only. */
+       if (map_size > 100 * 1024 * 1024) {
+               new_size = map_size * 1.10;
+       } else {
+               new_size = map_size * 1.25;
+       }
+
+       /* Round the database up to a multiple of the page size */
+       new_size = MAX(top_size, new_size);
+       return TDB_ALIGN(new_size, page_size) - map_size;
+}
+
 /* expand the database at least size bytes by expanding the underlying
    file and doing the mmap again if necessary */
 int tdb_expand(struct tdb_context *tdb, tdb_off_t size)
 {
        struct tdb_record rec;
-       tdb_off_t offset, new_size;     
+       tdb_off_t offset;
 
        if (tdb_lock(tdb, -1, F_WRLCK) == -1) {
                TDB_LOG((tdb, TDB_DEBUG_ERROR, "lock failed in tdb_expand\n"));
@@ -307,22 +400,9 @@ int tdb_expand(struct tdb_context *tdb, tdb_off_t size)
        }
 
        /* must know about any previous expansions by another process */
-       tdb->methods->tdb_oob(tdb, tdb->map_size + 1, 1);
-
-       /* always make room for at least 100 more records, and at
-           least 25% more space. Round the database up to a multiple
-           of the page size */
-       new_size = MAX(tdb->map_size + size*100, tdb->map_size * 1.25);
-       size = TDB_ALIGN(new_size, tdb->page_size) - tdb->map_size;
-
-       if (!(tdb->flags & TDB_INTERNAL))
-               tdb_munmap(tdb);
+       tdb->methods->tdb_oob(tdb, tdb->map_size, 1, 1);
 
-       /*
-        * We must ensure the file is unmapped before doing this
-        * to ensure consistency with systems like OpenBSD where
-        * writes and mmaps are not consistent.
-        */
+       size = tdb_expand_adjust(tdb->map_size, size, tdb->page_size);
 
        /* expand the file itself */
        if (!(tdb->flags & TDB_INTERNAL)) {
@@ -330,33 +410,30 @@ int tdb_expand(struct tdb_context *tdb, tdb_off_t size)
                        goto fail;
        }
 
-       tdb->map_size += size;
+       /* form a new freelist record */
+       offset = tdb->map_size;
+       memset(&rec,'\0',sizeof(rec));
+       rec.rec_len = size - sizeof(rec);
 
        if (tdb->flags & TDB_INTERNAL) {
                char *new_map_ptr = (char *)realloc(tdb->map_ptr,
-                                                   tdb->map_size);
+                                                   tdb->map_size + size);
                if (!new_map_ptr) {
-                       tdb->map_size -= size;
                        goto fail;
                }
                tdb->map_ptr = new_map_ptr;
+               tdb->map_size += size;
        } else {
-               /*
-                * We must ensure the file is remapped before adding the space
-                * to ensure consistency with systems like OpenBSD where
-                * writes and mmaps are not consistent.
-                */
-
-               /* We're ok if the mmap fails as we'll fallback to read/write */
-               tdb_mmap(tdb);
+               /* Explicitly remap: if we're in a transaction, this won't
+                * happen automatically! */
+               tdb_munmap(tdb);
+               tdb->map_size += size;
+               if (tdb_mmap(tdb) != 0) {
+                       goto fail;
+               }
        }
 
-       /* form a new freelist record */
-       memset(&rec,'\0',sizeof(rec));
-       rec.rec_len = size - sizeof(rec);
-
        /* link it into the free list */
-       offset = tdb->map_size - size;
        if (tdb_free(tdb, offset, &rec) == -1)
                goto fail;
 
@@ -390,7 +467,7 @@ unsigned char *tdb_alloc_read(struct tdb_context *tdb, tdb_off_t offset, tdb_len
        if (!(buf = (unsigned char *)malloc(len ? len : 1))) {
                /* Ensure ecode is set for log fn. */
                tdb->ecode = TDB_ERR_OOM;
-               TDB_LOG((tdb, TDB_DEBUG_ERROR,"tdb_alloc_read malloc failed len=%d (%s)\n",
+               TDB_LOG((tdb, TDB_DEBUG_ERROR,"tdb_alloc_read malloc failed len=%u (%s)\n",
                           len, strerror(errno)));
                return NULL;
        }
@@ -419,7 +496,7 @@ int tdb_parse_data(struct tdb_context *tdb, TDB_DATA key,
                 * Optimize by avoiding the malloc/memcpy/free, point the
                 * parser directly at the mmap area.
                 */
-               if (tdb->methods->tdb_oob(tdb, offset+len, 0) != 0) {
+               if (tdb->methods->tdb_oob(tdb, offsetlen, 0) != 0) {
                        return -1;
                }
                data.dptr = offset + (unsigned char *)tdb->map_ptr;
@@ -443,10 +520,10 @@ int tdb_rec_read(struct tdb_context *tdb, tdb_off_t offset, struct tdb_record *r
        if (TDB_BAD_MAGIC(rec)) {
                /* Ensure ecode is set for log fn. */
                tdb->ecode = TDB_ERR_CORRUPT;
-               TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_rec_read bad magic 0x%x at offset=%d\n", rec->magic, offset));
+               TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_rec_read bad magic 0x%x at offset=%u\n", rec->magic, offset));
                return -1;
        }
-       return tdb->methods->tdb_oob(tdb, rec->next+sizeof(*rec), 0);
+       return tdb->methods->tdb_oob(tdb, rec->nextsizeof(*rec), 0);
 }
 
 int tdb_rec_write(struct tdb_context *tdb, tdb_off_t offset, struct tdb_record *rec)
@@ -461,7 +538,6 @@ static const struct tdb_methods io_methods = {
        tdb_next_hash_chain,
        tdb_oob,
        tdb_expand_file,
-       tdb_brlock
 };
 
 /*