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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v2 07/18] tools/xenstore: add wrapper for tdb_fetch()
Add a wrapper function for tdb_fetch taking the name of the node in
the data base as a parameter. Let it return a data pointer and the
length of the data via a length pointer provided as additional
parameter.
Move logging of the TDB access from the callers into the wrapper.
This enables to make set_tdb_key() and tdb_ctx static.
This is in preparation to replace TDB with a more simple data storage.
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
V2:
- always set *size in db_fetch() (Julien Grall)
- change db_fetch() return type (Julien Grall)
- move logging
---
tools/xenstore/xenstored_core.c | 55 +++++++++++++++-----------
tools/xenstore/xenstored_core.h | 3 +-
tools/xenstore/xenstored_transaction.c | 31 ++++++---------
3 files changed, 44 insertions(+), 45 deletions(-)
diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c
index 170181d8e6..70db5265ad 100644
--- a/tools/xenstore/xenstored_core.c
+++ b/tools/xenstore/xenstored_core.c
@@ -85,7 +85,7 @@ bool keep_orphans = false;
static int reopen_log_pipe[2];
static int reopen_log_pipe0_pollfd_idx = -1;
char *tracefile = NULL;
-TDB_CONTEXT *tdb_ctx = NULL;
+static TDB_CONTEXT *tdb_ctx = NULL;
unsigned int trace_flags = TRACE_OBJ | TRACE_IO;
static const char *sockmsg_string(enum xsd_sockmsg_type type);
@@ -556,7 +556,7 @@ static void initialize_fds(int *p_sock_pollfd_idx, int
*ptimeout)
}
}
-void set_tdb_key(const char *name, TDB_DATA *key)
+static void set_tdb_key(const char *name, TDB_DATA *key)
{
/*
* Dropping const is fine here, as the key will never be modified
@@ -566,25 +566,39 @@ void set_tdb_key(const char *name, TDB_DATA *key)
key->dsize = strlen(name);
}
+struct xs_tdb_record_hdr *db_fetch(const char *db_name, size_t *size)
+{
+ TDB_DATA key, data;
+
+ set_tdb_key(db_name, &key);
+ data = tdb_fetch(tdb_ctx, key);
+ if (!data.dptr) {
+ errno = (tdb_error(tdb_ctx) == TDB_ERR_NOEXIST) ? ENOENT : EIO;
+ *size = 0;
+ } else {
+ *size = data.dsize;
+ trace_tdb("read %s size %zu\n", db_name,
+ *size + strlen(db_name));
+ }
+
+ return (struct xs_tdb_record_hdr *)data.dptr;
+}
+
static void get_acc_data(const char *name, struct node_account_data *acc)
{
- TDB_DATA key, old_data;
+ size_t size;
struct xs_tdb_record_hdr *hdr;
if (acc->memory < 0) {
- set_tdb_key(name, &key);
- old_data = tdb_fetch(tdb_ctx, key);
+ hdr = db_fetch(name, &size);
/* No check for error, as the node might not exist. */
- if (old_data.dptr == NULL) {
+ if (hdr == NULL) {
acc->memory = 0;
} else {
- trace_tdb("read %s size %zu\n", name,
- old_data.dsize + key.dsize);
- hdr = (void *)old_data.dptr;
- acc->memory = old_data.dsize;
+ acc->memory = size;
acc->domid = hdr->perms[0].id;
}
- talloc_free(old_data.dptr);
+ talloc_free(hdr);
}
}
@@ -698,7 +712,7 @@ int db_delete(struct connection *conn, const char *name,
struct node *read_node(struct connection *conn, const void *ctx,
const char *name)
{
- TDB_DATA key, data;
+ size_t size;
struct xs_tdb_record_hdr *hdr;
struct node *node;
const char *db_name;
@@ -717,29 +731,24 @@ struct node *read_node(struct connection *conn, const
void *ctx,
}
db_name = transaction_prepend(conn, name);
- set_tdb_key(db_name, &key);
+ hdr = db_fetch(db_name, &size);
- data = tdb_fetch(tdb_ctx, key);
-
- if (data.dptr == NULL) {
- if (tdb_error(tdb_ctx) == TDB_ERR_NOEXIST) {
+ if (hdr == NULL) {
+ if (errno == ENOENT) {
node->generation = NO_GENERATION;
err = access_node(conn, node, NODE_ACCESS_READ, NULL);
errno = err ? : ENOENT;
} else {
- log("TDB error on read: %s", tdb_errorstr(tdb_ctx));
+ log("DB error on read: %s", strerror(errno));
errno = EIO;
}
goto error;
}
- trace_tdb("read %s size %zu\n", key.dptr, data.dsize + key.dsize);
-
node->parent = NULL;
- talloc_steal(node, data.dptr);
+ talloc_steal(node, hdr);
/* Datalen, childlen, number of permissions */
- hdr = (void *)data.dptr;
node->generation = hdr->generation;
node->perms.num = hdr->num_perms;
node->datalen = hdr->datalen;
@@ -748,7 +757,7 @@ struct node *read_node(struct connection *conn, const void
*ctx,
/* Permissions are struct xs_permissions. */
node->perms.p = hdr->perms;
node->acc.domid = get_node_owner(node);
- node->acc.memory = data.dsize;
+ node->acc.memory = size;
if (domain_adjust_node_perms(node))
goto error;
diff --git a/tools/xenstore/xenstored_core.h b/tools/xenstore/xenstored_core.h
index 3074f14511..590d1b0a1f 100644
--- a/tools/xenstore/xenstored_core.h
+++ b/tools/xenstore/xenstored_core.h
@@ -314,7 +314,6 @@ do { \
trace("tdb: " __VA_ARGS__); \
} while (0)
-extern TDB_CONTEXT *tdb_ctx;
extern int dom0_domid;
extern int dom0_event;
extern int priv_domid;
@@ -363,7 +362,7 @@ extern xengnttab_handle **xgt_handle;
int remember_string(struct hashtable *hash, const char *str);
/* Data base access functions. */
-void set_tdb_key(const char *name, TDB_DATA *key);
+struct xs_tdb_record_hdr *db_fetch(const char *db_name, size_t *size);
int db_write(struct connection *conn, const char *db_name, void *data,
size_t size, struct node_account_data *acc,
enum write_node_mode mode, bool no_quota_check);
diff --git a/tools/xenstore/xenstored_transaction.c
b/tools/xenstore/xenstored_transaction.c
index 6e06634807..7d8c0afc6a 100644
--- a/tools/xenstore/xenstored_transaction.c
+++ b/tools/xenstore/xenstored_transaction.c
@@ -356,26 +356,22 @@ static int finalize_transaction(struct connection *conn,
struct transaction *trans, bool *is_corrupt)
{
struct accessed_node *i, *n;
- TDB_DATA key, ta_key, data;
+ size_t size;
struct xs_tdb_record_hdr *hdr;
uint64_t gen;
int flag;
list_for_each_entry_safe(i, n, &trans->accessed, list) {
if (i->check_gen) {
- set_tdb_key(i->node, &key);
- data = tdb_fetch(tdb_ctx, key);
- hdr = (void *)data.dptr;
- if (!data.dptr) {
- if (tdb_error(tdb_ctx) != TDB_ERR_NOEXIST)
- return EIO;
+ hdr = db_fetch(i->node, &size);
+ if (!hdr) {
+ if (errno != ENOENT)
+ return errno;
gen = NO_GENERATION;
} else {
- trace_tdb("read %s size %zu\n", key.dptr,
- key.dsize + data.dsize);
gen = hdr->generation;
}
- talloc_free(data.dptr);
+ talloc_free(hdr);
if (i->generation != gen)
return EAGAIN;
}
@@ -393,19 +389,14 @@ static int finalize_transaction(struct connection *conn,
while ((i = list_top(&trans->accessed, struct accessed_node, list))) {
if (i->ta_node) {
- set_tdb_key(i->trans_name, &ta_key);
- data = tdb_fetch(tdb_ctx, ta_key);
- if (data.dptr) {
- trace_tdb("read %s size %zu\n", ta_key.dptr,
- ta_key.dsize + data.dsize);
- hdr = (void *)data.dptr;
+ hdr = db_fetch(i->trans_name, &size);
+ if (hdr) {
hdr->generation = ++generation;
flag = (i->generation == NO_GENERATION)
? NODE_CREATE : NODE_MODIFY;
- *is_corrupt |= db_write(conn, i->node,
- data.dptr, data.dsize,
- NULL, flag, true);
- talloc_free(data.dptr);
+ *is_corrupt |= db_write(conn, i->node, hdr,
+ size, NULL, flag, true);
+ talloc_free(hdr);
if (db_delete(conn, i->trans_name, NULL))
*is_corrupt = true;
} else {
--
2.35.3
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