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qemu/tests/unit/test-xs-node.c

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hw/xen: Add basic XenStore tree walk and write/read/directory support This is a fairly simple implementation of a copy-on-write tree. The node walk function starts off at the root, with 'inplace == true'. If it ever encounters a node with a refcount greater than one (including the root node), then that node is shared with other trees, and cannot be modified in place, so the inplace flag is cleared and we copy on write from there on down. Xenstore write has 'mkdir -p' semantics and will create the intermediate nodes if they don't already exist, so in that case we flip the inplace flag back to true as we populate the newly-created nodes. We put a copy of the absolute path into the buffer in the struct walk_op, with *two* NUL terminators at the end. As xs_node_walk() goes down the tree, it replaces the next '/' separator with a NUL so that it can use the 'child name' in place. The next recursion down then puts the '/' back and repeats the exercise for the next path element... if it doesn't hit that *second* NUL termination which indicates the true end of the path. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-20 01:36:38 +00:00
/*
* QEMU XenStore XsNode testing
*
* Copyright © 2023 Amazon.com, Inc. or its affiliates. All Rights Reserved.
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "qapi/error.h"
#include "qemu/module.h"
static int nr_xs_nodes;
static GList *xs_node_list;
#define XS_NODE_UNIT_TEST
/*
* We don't need the core Xen definitions. And we *do* want to be able
* to run the unit tests even on architectures that Xen doesn't support
* (because life's too short to bother doing otherwise, and test coverage
* doesn't hurt).
*/
#define __XEN_PUBLIC_XEN_H__
#include "hw/i386/kvm/xenstore_impl.c"
#define DOMID_QEMU 0
#define DOMID_GUEST 1
/* This doesn't happen in qemu but we want to make valgrind happy */
static void xs_impl_delete(XenstoreImplState *s)
{
int err;
hw/xen: Implement XenStore watches Starts out fairly simple: a hash table of watches based on the path. Except there can be multiple watches on the same path, so the watch ends up being a simple linked list, and the head of that list is in the hash table. Which makes removal a bit of a PITA but it's not so bad; we just special-case "I had to remove the head of the list and now I have to replace it in / remove it from the hash table". And if we don't remove the head, it's a simple linked-list operation. We do need to fire watches on *deleted* nodes, so instead of just a simple xs_node_unref() on the topmost victim, we need to recurse down and fire watches on them all. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-22 18:38:23 +00:00
xs_impl_reset_watches(s, DOMID_GUEST);
g_assert(!s->nr_domu_watches);
hw/xen: Add basic XenStore tree walk and write/read/directory support This is a fairly simple implementation of a copy-on-write tree. The node walk function starts off at the root, with 'inplace == true'. If it ever encounters a node with a refcount greater than one (including the root node), then that node is shared with other trees, and cannot be modified in place, so the inplace flag is cleared and we copy on write from there on down. Xenstore write has 'mkdir -p' semantics and will create the intermediate nodes if they don't already exist, so in that case we flip the inplace flag back to true as we populate the newly-created nodes. We put a copy of the absolute path into the buffer in the struct walk_op, with *two* NUL terminators at the end. As xs_node_walk() goes down the tree, it replaces the next '/' separator with a NUL so that it can use the 'child name' in place. The next recursion down then puts the '/' back and repeats the exercise for the next path element... if it doesn't hit that *second* NUL termination which indicates the true end of the path. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-20 01:36:38 +00:00
err = xs_impl_rm(s, DOMID_QEMU, XBT_NULL, "/local");
g_assert(!err);
g_assert(s->nr_nodes == 1);
hw/xen: Implement XenStore watches Starts out fairly simple: a hash table of watches based on the path. Except there can be multiple watches on the same path, so the watch ends up being a simple linked list, and the head of that list is in the hash table. Which makes removal a bit of a PITA but it's not so bad; we just special-case "I had to remove the head of the list and now I have to replace it in / remove it from the hash table". And if we don't remove the head, it's a simple linked-list operation. We do need to fire watches on *deleted* nodes, so instead of just a simple xs_node_unref() on the topmost victim, we need to recurse down and fire watches on them all. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-22 18:38:23 +00:00
g_hash_table_unref(s->watches);
hw/xen: Implement XenStore transactions Given that the whole thing supported copy on write from the beginning, transactions end up being fairly simple. On starting a transaction, just take a ref of the existing root; swap it back in on a successful commit. The main tree has a transaction ID too, and we keep a record of the last transaction ID given out. if the main tree is ever modified when it isn't the latest, it gets a new transaction ID. A commit can only succeed if the main tree hasn't moved on since it was forked. Strictly speaking, the XenStore protocol allows a transaction to succeed as long as nothing *it* read or wrote has changed in the interim, but no implementations do that; *any* change is sufficient to abort a transaction. This does not yet fire watches on the changed nodes on a commit. That bit is more fun and will come in a follow-on commit. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-22 22:05:37 +00:00
g_hash_table_unref(s->transactions);
hw/xen: Add basic XenStore tree walk and write/read/directory support This is a fairly simple implementation of a copy-on-write tree. The node walk function starts off at the root, with 'inplace == true'. If it ever encounters a node with a refcount greater than one (including the root node), then that node is shared with other trees, and cannot be modified in place, so the inplace flag is cleared and we copy on write from there on down. Xenstore write has 'mkdir -p' semantics and will create the intermediate nodes if they don't already exist, so in that case we flip the inplace flag back to true as we populate the newly-created nodes. We put a copy of the absolute path into the buffer in the struct walk_op, with *two* NUL terminators at the end. As xs_node_walk() goes down the tree, it replaces the next '/' separator with a NUL so that it can use the 'child name' in place. The next recursion down then puts the '/' back and repeats the exercise for the next path element... if it doesn't hit that *second* NUL termination which indicates the true end of the path. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-20 01:36:38 +00:00
xs_node_unref(s->root);
g_free(s);
if (xs_node_list) {
GList *l;
for (l = xs_node_list; l; l = l->next) {
XsNode *n = l->data;
printf("Remaining node at %p name %s ref %u\n", n, n->name,
n->ref);
}
}
g_assert(!nr_xs_nodes);
}
static int write_str(XenstoreImplState *s, unsigned int dom_id,
unsigned int tx_id, const char *path,
const char *content)
{
GByteArray *d = g_byte_array_new();
int err;
g_byte_array_append(d, (void *)content, strlen(content));
err = xs_impl_write(s, dom_id, tx_id, path, d);
g_byte_array_unref(d);
return err;
}
hw/xen: Implement XenStore watches Starts out fairly simple: a hash table of watches based on the path. Except there can be multiple watches on the same path, so the watch ends up being a simple linked list, and the head of that list is in the hash table. Which makes removal a bit of a PITA but it's not so bad; we just special-case "I had to remove the head of the list and now I have to replace it in / remove it from the hash table". And if we don't remove the head, it's a simple linked-list operation. We do need to fire watches on *deleted* nodes, so instead of just a simple xs_node_unref() on the topmost victim, we need to recurse down and fire watches on them all. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-22 18:38:23 +00:00
static void watch_cb(void *_str, const char *path, const char *token)
{
GString *str = _str;
g_string_append(str, path);
g_string_append(str, token);
}
hw/xen: Add basic XenStore tree walk and write/read/directory support This is a fairly simple implementation of a copy-on-write tree. The node walk function starts off at the root, with 'inplace == true'. If it ever encounters a node with a refcount greater than one (including the root node), then that node is shared with other trees, and cannot be modified in place, so the inplace flag is cleared and we copy on write from there on down. Xenstore write has 'mkdir -p' semantics and will create the intermediate nodes if they don't already exist, so in that case we flip the inplace flag back to true as we populate the newly-created nodes. We put a copy of the absolute path into the buffer in the struct walk_op, with *two* NUL terminators at the end. As xs_node_walk() goes down the tree, it replaces the next '/' separator with a NUL so that it can use the 'child name' in place. The next recursion down then puts the '/' back and repeats the exercise for the next path element... if it doesn't hit that *second* NUL termination which indicates the true end of the path. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-20 01:36:38 +00:00
static XenstoreImplState *setup(void)
{
XenstoreImplState *s = xs_impl_create();
char *abspath;
int err;
abspath = g_strdup_printf("/local/domain/%u", DOMID_GUEST);
err = write_str(s, DOMID_QEMU, XBT_NULL, abspath, "");
g_assert(!err);
hw/xen: Implement XenStore watches Starts out fairly simple: a hash table of watches based on the path. Except there can be multiple watches on the same path, so the watch ends up being a simple linked list, and the head of that list is in the hash table. Which makes removal a bit of a PITA but it's not so bad; we just special-case "I had to remove the head of the list and now I have to replace it in / remove it from the hash table". And if we don't remove the head, it's a simple linked-list operation. We do need to fire watches on *deleted* nodes, so instead of just a simple xs_node_unref() on the topmost victim, we need to recurse down and fire watches on them all. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-22 18:38:23 +00:00
g_assert(s->nr_nodes == 4);
hw/xen: Add basic XenStore tree walk and write/read/directory support This is a fairly simple implementation of a copy-on-write tree. The node walk function starts off at the root, with 'inplace == true'. If it ever encounters a node with a refcount greater than one (including the root node), then that node is shared with other trees, and cannot be modified in place, so the inplace flag is cleared and we copy on write from there on down. Xenstore write has 'mkdir -p' semantics and will create the intermediate nodes if they don't already exist, so in that case we flip the inplace flag back to true as we populate the newly-created nodes. We put a copy of the absolute path into the buffer in the struct walk_op, with *two* NUL terminators at the end. As xs_node_walk() goes down the tree, it replaces the next '/' separator with a NUL so that it can use the 'child name' in place. The next recursion down then puts the '/' back and repeats the exercise for the next path element... if it doesn't hit that *second* NUL termination which indicates the true end of the path. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-20 01:36:38 +00:00
g_free(abspath);
abspath = g_strdup_printf("/local/domain/%u/some", DOMID_GUEST);
err = write_str(s, DOMID_QEMU, XBT_NULL, abspath, "");
g_assert(!err);
g_assert(s->nr_nodes == 5);
g_free(abspath);
return s;
}
static void test_xs_node_simple(void)
{
GByteArray *data = g_byte_array_new();
XenstoreImplState *s = setup();
hw/xen: Implement XenStore watches Starts out fairly simple: a hash table of watches based on the path. Except there can be multiple watches on the same path, so the watch ends up being a simple linked list, and the head of that list is in the hash table. Which makes removal a bit of a PITA but it's not so bad; we just special-case "I had to remove the head of the list and now I have to replace it in / remove it from the hash table". And if we don't remove the head, it's a simple linked-list operation. We do need to fire watches on *deleted* nodes, so instead of just a simple xs_node_unref() on the topmost victim, we need to recurse down and fire watches on them all. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-22 18:38:23 +00:00
GString *guest_watches = g_string_new(NULL);
GString *qemu_watches = g_string_new(NULL);
hw/xen: Add basic XenStore tree walk and write/read/directory support This is a fairly simple implementation of a copy-on-write tree. The node walk function starts off at the root, with 'inplace == true'. If it ever encounters a node with a refcount greater than one (including the root node), then that node is shared with other trees, and cannot be modified in place, so the inplace flag is cleared and we copy on write from there on down. Xenstore write has 'mkdir -p' semantics and will create the intermediate nodes if they don't already exist, so in that case we flip the inplace flag back to true as we populate the newly-created nodes. We put a copy of the absolute path into the buffer in the struct walk_op, with *two* NUL terminators at the end. As xs_node_walk() goes down the tree, it replaces the next '/' separator with a NUL so that it can use the 'child name' in place. The next recursion down then puts the '/' back and repeats the exercise for the next path element... if it doesn't hit that *second* NUL termination which indicates the true end of the path. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-20 01:36:38 +00:00
GList *items = NULL;
XsNode *old_root;
uint64_t gencnt;
int err;
g_assert(s);
hw/xen: Implement XenStore watches Starts out fairly simple: a hash table of watches based on the path. Except there can be multiple watches on the same path, so the watch ends up being a simple linked list, and the head of that list is in the hash table. Which makes removal a bit of a PITA but it's not so bad; we just special-case "I had to remove the head of the list and now I have to replace it in / remove it from the hash table". And if we don't remove the head, it's a simple linked-list operation. We do need to fire watches on *deleted* nodes, so instead of just a simple xs_node_unref() on the topmost victim, we need to recurse down and fire watches on them all. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-22 18:38:23 +00:00
err = xs_impl_watch(s, DOMID_GUEST, "some", "guestwatch",
watch_cb, guest_watches);
g_assert(!err);
g_assert(guest_watches->len == strlen("someguestwatch"));
g_assert(!strcmp(guest_watches->str, "someguestwatch"));
g_string_truncate(guest_watches, 0);
err = xs_impl_watch(s, 0, "/local/domain/1/some", "qemuwatch",
watch_cb, qemu_watches);
g_assert(!err);
g_assert(qemu_watches->len == strlen("/local/domain/1/someqemuwatch"));
g_assert(!strcmp(qemu_watches->str, "/local/domain/1/someqemuwatch"));
g_string_truncate(qemu_watches, 0);
hw/xen: Add basic XenStore tree walk and write/read/directory support This is a fairly simple implementation of a copy-on-write tree. The node walk function starts off at the root, with 'inplace == true'. If it ever encounters a node with a refcount greater than one (including the root node), then that node is shared with other trees, and cannot be modified in place, so the inplace flag is cleared and we copy on write from there on down. Xenstore write has 'mkdir -p' semantics and will create the intermediate nodes if they don't already exist, so in that case we flip the inplace flag back to true as we populate the newly-created nodes. We put a copy of the absolute path into the buffer in the struct walk_op, with *two* NUL terminators at the end. As xs_node_walk() goes down the tree, it replaces the next '/' separator with a NUL so that it can use the 'child name' in place. The next recursion down then puts the '/' back and repeats the exercise for the next path element... if it doesn't hit that *second* NUL termination which indicates the true end of the path. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-20 01:36:38 +00:00
/* Read gives ENOENT when it should */
err = xs_impl_read(s, DOMID_GUEST, XBT_NULL, "foo", data);
g_assert(err == ENOENT);
/* Write works */
err = write_str(s, DOMID_GUEST, XBT_NULL, "some/relative/path",
"something");
g_assert(s->nr_nodes == 7);
g_assert(!err);
hw/xen: Implement XenStore watches Starts out fairly simple: a hash table of watches based on the path. Except there can be multiple watches on the same path, so the watch ends up being a simple linked list, and the head of that list is in the hash table. Which makes removal a bit of a PITA but it's not so bad; we just special-case "I had to remove the head of the list and now I have to replace it in / remove it from the hash table". And if we don't remove the head, it's a simple linked-list operation. We do need to fire watches on *deleted* nodes, so instead of just a simple xs_node_unref() on the topmost victim, we need to recurse down and fire watches on them all. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-22 18:38:23 +00:00
g_assert(!strcmp(guest_watches->str,
"some/relative/pathguestwatch"));
g_assert(!strcmp(qemu_watches->str,
"/local/domain/1/some/relative/pathqemuwatch"));
g_string_truncate(qemu_watches, 0);
g_string_truncate(guest_watches, 0);
xs_impl_reset_watches(s, 0);
hw/xen: Add basic XenStore tree walk and write/read/directory support This is a fairly simple implementation of a copy-on-write tree. The node walk function starts off at the root, with 'inplace == true'. If it ever encounters a node with a refcount greater than one (including the root node), then that node is shared with other trees, and cannot be modified in place, so the inplace flag is cleared and we copy on write from there on down. Xenstore write has 'mkdir -p' semantics and will create the intermediate nodes if they don't already exist, so in that case we flip the inplace flag back to true as we populate the newly-created nodes. We put a copy of the absolute path into the buffer in the struct walk_op, with *two* NUL terminators at the end. As xs_node_walk() goes down the tree, it replaces the next '/' separator with a NUL so that it can use the 'child name' in place. The next recursion down then puts the '/' back and repeats the exercise for the next path element... if it doesn't hit that *second* NUL termination which indicates the true end of the path. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-20 01:36:38 +00:00
/* Read gives back what we wrote */
err = xs_impl_read(s, DOMID_GUEST, XBT_NULL, "some/relative/path", data);
g_assert(!err);
g_assert(data->len == strlen("something"));
g_assert(!memcmp(data->data, "something", data->len));
/* Even if we use an abolute path */
g_byte_array_set_size(data, 0);
err = xs_impl_read(s, DOMID_GUEST, XBT_NULL,
"/local/domain/1/some/relative/path", data);
g_assert(!err);
g_assert(data->len == strlen("something"));
hw/xen: Implement XenStore watches Starts out fairly simple: a hash table of watches based on the path. Except there can be multiple watches on the same path, so the watch ends up being a simple linked list, and the head of that list is in the hash table. Which makes removal a bit of a PITA but it's not so bad; we just special-case "I had to remove the head of the list and now I have to replace it in / remove it from the hash table". And if we don't remove the head, it's a simple linked-list operation. We do need to fire watches on *deleted* nodes, so instead of just a simple xs_node_unref() on the topmost victim, we need to recurse down and fire watches on them all. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-22 18:38:23 +00:00
g_assert(!qemu_watches->len);
g_assert(!guest_watches->len);
hw/xen: Add basic XenStore tree walk and write/read/directory support This is a fairly simple implementation of a copy-on-write tree. The node walk function starts off at the root, with 'inplace == true'. If it ever encounters a node with a refcount greater than one (including the root node), then that node is shared with other trees, and cannot be modified in place, so the inplace flag is cleared and we copy on write from there on down. Xenstore write has 'mkdir -p' semantics and will create the intermediate nodes if they don't already exist, so in that case we flip the inplace flag back to true as we populate the newly-created nodes. We put a copy of the absolute path into the buffer in the struct walk_op, with *two* NUL terminators at the end. As xs_node_walk() goes down the tree, it replaces the next '/' separator with a NUL so that it can use the 'child name' in place. The next recursion down then puts the '/' back and repeats the exercise for the next path element... if it doesn't hit that *second* NUL termination which indicates the true end of the path. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-20 01:36:38 +00:00
/* Keep a copy, to force COW mode */
old_root = xs_node_ref(s->root);
/* Write works again */
err = write_str(s, DOMID_GUEST, XBT_NULL,
"/local/domain/1/some/relative/path2",
"something else");
g_assert(!err);
g_assert(s->nr_nodes == 8);
hw/xen: Implement XenStore watches Starts out fairly simple: a hash table of watches based on the path. Except there can be multiple watches on the same path, so the watch ends up being a simple linked list, and the head of that list is in the hash table. Which makes removal a bit of a PITA but it's not so bad; we just special-case "I had to remove the head of the list and now I have to replace it in / remove it from the hash table". And if we don't remove the head, it's a simple linked-list operation. We do need to fire watches on *deleted* nodes, so instead of just a simple xs_node_unref() on the topmost victim, we need to recurse down and fire watches on them all. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-22 18:38:23 +00:00
g_assert(!qemu_watches->len);
g_assert(!strcmp(guest_watches->str, "some/relative/path2guestwatch"));
g_string_truncate(guest_watches, 0);
hw/xen: Add basic XenStore tree walk and write/read/directory support This is a fairly simple implementation of a copy-on-write tree. The node walk function starts off at the root, with 'inplace == true'. If it ever encounters a node with a refcount greater than one (including the root node), then that node is shared with other trees, and cannot be modified in place, so the inplace flag is cleared and we copy on write from there on down. Xenstore write has 'mkdir -p' semantics and will create the intermediate nodes if they don't already exist, so in that case we flip the inplace flag back to true as we populate the newly-created nodes. We put a copy of the absolute path into the buffer in the struct walk_op, with *two* NUL terminators at the end. As xs_node_walk() goes down the tree, it replaces the next '/' separator with a NUL so that it can use the 'child name' in place. The next recursion down then puts the '/' back and repeats the exercise for the next path element... if it doesn't hit that *second* NUL termination which indicates the true end of the path. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-20 01:36:38 +00:00
/* Overwrite an existing node */
err = write_str(s, DOMID_GUEST, XBT_NULL, "some/relative/path",
"another thing");
g_assert(!err);
g_assert(s->nr_nodes == 8);
hw/xen: Implement XenStore watches Starts out fairly simple: a hash table of watches based on the path. Except there can be multiple watches on the same path, so the watch ends up being a simple linked list, and the head of that list is in the hash table. Which makes removal a bit of a PITA but it's not so bad; we just special-case "I had to remove the head of the list and now I have to replace it in / remove it from the hash table". And if we don't remove the head, it's a simple linked-list operation. We do need to fire watches on *deleted* nodes, so instead of just a simple xs_node_unref() on the topmost victim, we need to recurse down and fire watches on them all. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-22 18:38:23 +00:00
g_assert(!qemu_watches->len);
g_assert(!strcmp(guest_watches->str, "some/relative/pathguestwatch"));
g_string_truncate(guest_watches, 0);
hw/xen: Add basic XenStore tree walk and write/read/directory support This is a fairly simple implementation of a copy-on-write tree. The node walk function starts off at the root, with 'inplace == true'. If it ever encounters a node with a refcount greater than one (including the root node), then that node is shared with other trees, and cannot be modified in place, so the inplace flag is cleared and we copy on write from there on down. Xenstore write has 'mkdir -p' semantics and will create the intermediate nodes if they don't already exist, so in that case we flip the inplace flag back to true as we populate the newly-created nodes. We put a copy of the absolute path into the buffer in the struct walk_op, with *two* NUL terminators at the end. As xs_node_walk() goes down the tree, it replaces the next '/' separator with a NUL so that it can use the 'child name' in place. The next recursion down then puts the '/' back and repeats the exercise for the next path element... if it doesn't hit that *second* NUL termination which indicates the true end of the path. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-20 01:36:38 +00:00
/* We can list the two files we wrote */
err = xs_impl_directory(s, DOMID_GUEST, XBT_NULL, "some/relative", &gencnt,
&items);
g_assert(!err);
g_assert(items);
g_assert(gencnt == 2);
g_assert(!strcmp(items->data, "path"));
g_assert(items->next);
g_assert(!strcmp(items->next->data, "path2"));
g_assert(!items->next->next);
g_list_free_full(items, g_free);
hw/xen: Implement XenStore watches Starts out fairly simple: a hash table of watches based on the path. Except there can be multiple watches on the same path, so the watch ends up being a simple linked list, and the head of that list is in the hash table. Which makes removal a bit of a PITA but it's not so bad; we just special-case "I had to remove the head of the list and now I have to replace it in / remove it from the hash table". And if we don't remove the head, it's a simple linked-list operation. We do need to fire watches on *deleted* nodes, so instead of just a simple xs_node_unref() on the topmost victim, we need to recurse down and fire watches on them all. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-22 18:38:23 +00:00
err = xs_impl_unwatch(s, DOMID_GUEST, "some", "guestwatch",
watch_cb, guest_watches);
g_assert(!err);
err = xs_impl_unwatch(s, DOMID_GUEST, "some", "guestwatch",
watch_cb, guest_watches);
g_assert(err == ENOENT);
err = xs_impl_watch(s, DOMID_GUEST, "some/relative/path2", "watchp2",
watch_cb, guest_watches);
g_assert(!err);
g_assert(guest_watches->len == strlen("some/relative/path2watchp2"));
g_assert(!strcmp(guest_watches->str, "some/relative/path2watchp2"));
g_string_truncate(guest_watches, 0);
err = xs_impl_watch(s, DOMID_GUEST, "/local/domain/1/some/relative",
"watchrel", watch_cb, guest_watches);
g_assert(!err);
g_assert(guest_watches->len ==
strlen("/local/domain/1/some/relativewatchrel"));
g_assert(!strcmp(guest_watches->str,
"/local/domain/1/some/relativewatchrel"));
g_string_truncate(guest_watches, 0);
hw/xen: Add basic XenStore tree walk and write/read/directory support This is a fairly simple implementation of a copy-on-write tree. The node walk function starts off at the root, with 'inplace == true'. If it ever encounters a node with a refcount greater than one (including the root node), then that node is shared with other trees, and cannot be modified in place, so the inplace flag is cleared and we copy on write from there on down. Xenstore write has 'mkdir -p' semantics and will create the intermediate nodes if they don't already exist, so in that case we flip the inplace flag back to true as we populate the newly-created nodes. We put a copy of the absolute path into the buffer in the struct walk_op, with *two* NUL terminators at the end. As xs_node_walk() goes down the tree, it replaces the next '/' separator with a NUL so that it can use the 'child name' in place. The next recursion down then puts the '/' back and repeats the exercise for the next path element... if it doesn't hit that *second* NUL termination which indicates the true end of the path. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-20 01:36:38 +00:00
/* Write somewhere else which already existed */
err = write_str(s, DOMID_GUEST, XBT_NULL, "some/relative", "moredata");
g_assert(!err);
hw/xen: Implement XenStore watches Starts out fairly simple: a hash table of watches based on the path. Except there can be multiple watches on the same path, so the watch ends up being a simple linked list, and the head of that list is in the hash table. Which makes removal a bit of a PITA but it's not so bad; we just special-case "I had to remove the head of the list and now I have to replace it in / remove it from the hash table". And if we don't remove the head, it's a simple linked-list operation. We do need to fire watches on *deleted* nodes, so instead of just a simple xs_node_unref() on the topmost victim, we need to recurse down and fire watches on them all. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-22 18:38:23 +00:00
g_assert(s->nr_nodes == 8);
g_assert(!strcmp(guest_watches->str,
"/local/domain/1/some/relativewatchrel"));
g_string_truncate(guest_watches, 0);
hw/xen: Add basic XenStore tree walk and write/read/directory support This is a fairly simple implementation of a copy-on-write tree. The node walk function starts off at the root, with 'inplace == true'. If it ever encounters a node with a refcount greater than one (including the root node), then that node is shared with other trees, and cannot be modified in place, so the inplace flag is cleared and we copy on write from there on down. Xenstore write has 'mkdir -p' semantics and will create the intermediate nodes if they don't already exist, so in that case we flip the inplace flag back to true as we populate the newly-created nodes. We put a copy of the absolute path into the buffer in the struct walk_op, with *two* NUL terminators at the end. As xs_node_walk() goes down the tree, it replaces the next '/' separator with a NUL so that it can use the 'child name' in place. The next recursion down then puts the '/' back and repeats the exercise for the next path element... if it doesn't hit that *second* NUL termination which indicates the true end of the path. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-20 01:36:38 +00:00
g_byte_array_set_size(data, 0);
err = xs_impl_read(s, DOMID_GUEST, XBT_NULL, "some/relative", data);
g_assert(!err);
g_assert(data->len == strlen("moredata"));
g_assert(!memcmp(data->data, "moredata", data->len));
/* Overwrite existing data */
err = write_str(s, DOMID_GUEST, XBT_NULL, "some/relative", "otherdata");
g_assert(!err);
hw/xen: Implement XenStore watches Starts out fairly simple: a hash table of watches based on the path. Except there can be multiple watches on the same path, so the watch ends up being a simple linked list, and the head of that list is in the hash table. Which makes removal a bit of a PITA but it's not so bad; we just special-case "I had to remove the head of the list and now I have to replace it in / remove it from the hash table". And if we don't remove the head, it's a simple linked-list operation. We do need to fire watches on *deleted* nodes, so instead of just a simple xs_node_unref() on the topmost victim, we need to recurse down and fire watches on them all. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-22 18:38:23 +00:00
g_string_truncate(guest_watches, 0);
hw/xen: Add basic XenStore tree walk and write/read/directory support This is a fairly simple implementation of a copy-on-write tree. The node walk function starts off at the root, with 'inplace == true'. If it ever encounters a node with a refcount greater than one (including the root node), then that node is shared with other trees, and cannot be modified in place, so the inplace flag is cleared and we copy on write from there on down. Xenstore write has 'mkdir -p' semantics and will create the intermediate nodes if they don't already exist, so in that case we flip the inplace flag back to true as we populate the newly-created nodes. We put a copy of the absolute path into the buffer in the struct walk_op, with *two* NUL terminators at the end. As xs_node_walk() goes down the tree, it replaces the next '/' separator with a NUL so that it can use the 'child name' in place. The next recursion down then puts the '/' back and repeats the exercise for the next path element... if it doesn't hit that *second* NUL termination which indicates the true end of the path. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-20 01:36:38 +00:00
g_byte_array_set_size(data, 0);
err = xs_impl_read(s, DOMID_GUEST, XBT_NULL, "some/relative", data);
g_assert(!err);
g_assert(data->len == strlen("otherdata"));
g_assert(!memcmp(data->data, "otherdata", data->len));
/* Remove the subtree */
err = xs_impl_rm(s, DOMID_GUEST, XBT_NULL, "some/relative");
g_assert(!err);
g_assert(s->nr_nodes == 5);
hw/xen: Implement XenStore watches Starts out fairly simple: a hash table of watches based on the path. Except there can be multiple watches on the same path, so the watch ends up being a simple linked list, and the head of that list is in the hash table. Which makes removal a bit of a PITA but it's not so bad; we just special-case "I had to remove the head of the list and now I have to replace it in / remove it from the hash table". And if we don't remove the head, it's a simple linked-list operation. We do need to fire watches on *deleted* nodes, so instead of just a simple xs_node_unref() on the topmost victim, we need to recurse down and fire watches on them all. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-22 18:38:23 +00:00
/* Each watch fires with the least specific relevant path */
g_assert(strstr(guest_watches->str,
"some/relative/path2watchp2"));
g_assert(strstr(guest_watches->str,
"/local/domain/1/some/relativewatchrel"));
g_string_truncate(guest_watches, 0);
hw/xen: Add basic XenStore tree walk and write/read/directory support This is a fairly simple implementation of a copy-on-write tree. The node walk function starts off at the root, with 'inplace == true'. If it ever encounters a node with a refcount greater than one (including the root node), then that node is shared with other trees, and cannot be modified in place, so the inplace flag is cleared and we copy on write from there on down. Xenstore write has 'mkdir -p' semantics and will create the intermediate nodes if they don't already exist, so in that case we flip the inplace flag back to true as we populate the newly-created nodes. We put a copy of the absolute path into the buffer in the struct walk_op, with *two* NUL terminators at the end. As xs_node_walk() goes down the tree, it replaces the next '/' separator with a NUL so that it can use the 'child name' in place. The next recursion down then puts the '/' back and repeats the exercise for the next path element... if it doesn't hit that *second* NUL termination which indicates the true end of the path. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-20 01:36:38 +00:00
g_byte_array_set_size(data, 0);
err = xs_impl_read(s, DOMID_GUEST, XBT_NULL, "some/relative", data);
g_assert(err == ENOENT);
g_byte_array_unref(data);
hw/xen: Implement XenStore watches Starts out fairly simple: a hash table of watches based on the path. Except there can be multiple watches on the same path, so the watch ends up being a simple linked list, and the head of that list is in the hash table. Which makes removal a bit of a PITA but it's not so bad; we just special-case "I had to remove the head of the list and now I have to replace it in / remove it from the hash table". And if we don't remove the head, it's a simple linked-list operation. We do need to fire watches on *deleted* nodes, so instead of just a simple xs_node_unref() on the topmost victim, we need to recurse down and fire watches on them all. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-22 18:38:23 +00:00
xs_impl_reset_watches(s, DOMID_GUEST);
g_string_free(qemu_watches, true);
g_string_free(guest_watches, true);
hw/xen: Add basic XenStore tree walk and write/read/directory support This is a fairly simple implementation of a copy-on-write tree. The node walk function starts off at the root, with 'inplace == true'. If it ever encounters a node with a refcount greater than one (including the root node), then that node is shared with other trees, and cannot be modified in place, so the inplace flag is cleared and we copy on write from there on down. Xenstore write has 'mkdir -p' semantics and will create the intermediate nodes if they don't already exist, so in that case we flip the inplace flag back to true as we populate the newly-created nodes. We put a copy of the absolute path into the buffer in the struct walk_op, with *two* NUL terminators at the end. As xs_node_walk() goes down the tree, it replaces the next '/' separator with a NUL so that it can use the 'child name' in place. The next recursion down then puts the '/' back and repeats the exercise for the next path element... if it doesn't hit that *second* NUL termination which indicates the true end of the path. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-20 01:36:38 +00:00
xs_node_unref(old_root);
xs_impl_delete(s);
}
hw/xen: Implement XenStore transactions Given that the whole thing supported copy on write from the beginning, transactions end up being fairly simple. On starting a transaction, just take a ref of the existing root; swap it back in on a successful commit. The main tree has a transaction ID too, and we keep a record of the last transaction ID given out. if the main tree is ever modified when it isn't the latest, it gets a new transaction ID. A commit can only succeed if the main tree hasn't moved on since it was forked. Strictly speaking, the XenStore protocol allows a transaction to succeed as long as nothing *it* read or wrote has changed in the interim, but no implementations do that; *any* change is sufficient to abort a transaction. This does not yet fire watches on the changed nodes on a commit. That bit is more fun and will come in a follow-on commit. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-22 22:05:37 +00:00
static void do_test_xs_node_tx(bool fail, bool commit)
{
XenstoreImplState *s = setup();
GString *watches = g_string_new(NULL);
GByteArray *data = g_byte_array_new();
unsigned int tx_id = XBT_NULL;
int err;
g_assert(s);
/* Set a watch */
err = xs_impl_watch(s, DOMID_GUEST, "some", "watch",
watch_cb, watches);
g_assert(!err);
g_assert(watches->len == strlen("somewatch"));
g_assert(!strcmp(watches->str, "somewatch"));
g_string_truncate(watches, 0);
/* Write something */
err = write_str(s, DOMID_GUEST, XBT_NULL, "some/relative/path",
"something");
g_assert(s->nr_nodes == 7);
g_assert(!err);
g_assert(!strcmp(watches->str,
"some/relative/pathwatch"));
g_string_truncate(watches, 0);
/* Create a transaction */
err = xs_impl_transaction_start(s, DOMID_GUEST, &tx_id);
g_assert(!err);
if (fail) {
/* Write something else in the root */
err = write_str(s, DOMID_GUEST, XBT_NULL, "some/relative/path",
"another thing");
g_assert(!err);
g_assert(s->nr_nodes == 7);
g_assert(!strcmp(watches->str,
"some/relative/pathwatch"));
g_string_truncate(watches, 0);
}
g_assert(!watches->len);
/* Perform a write in the transaction */
err = write_str(s, DOMID_GUEST, tx_id, "some/relative/path",
"something else");
g_assert(!err);
g_assert(s->nr_nodes == 7);
g_assert(!watches->len);
err = xs_impl_read(s, DOMID_GUEST, XBT_NULL, "some/relative/path", data);
g_assert(!err);
if (fail) {
g_assert(data->len == strlen("another thing"));
g_assert(!memcmp(data->data, "another thing", data->len));
} else {
g_assert(data->len == strlen("something"));
g_assert(!memcmp(data->data, "something", data->len));
}
g_byte_array_set_size(data, 0);
err = xs_impl_read(s, DOMID_GUEST, tx_id, "some/relative/path", data);
g_assert(!err);
g_assert(data->len == strlen("something else"));
g_assert(!memcmp(data->data, "something else", data->len));
g_byte_array_set_size(data, 0);
/* Attempt to commit the transaction */
err = xs_impl_transaction_end(s, DOMID_GUEST, tx_id, commit);
if (commit && fail) {
g_assert(err == EAGAIN);
} else {
g_assert(!err);
}
g_assert(!watches->len);
g_assert(s->nr_nodes == 7);
err = xs_impl_unwatch(s, DOMID_GUEST, "some", "watch",
watch_cb, watches);
g_assert(!err);
err = xs_impl_read(s, DOMID_GUEST, XBT_NULL, "some/relative/path", data);
g_assert(!err);
if (fail) {
g_assert(data->len == strlen("another thing"));
g_assert(!memcmp(data->data, "another thing", data->len));
} else if (commit) {
g_assert(data->len == strlen("something else"));
g_assert(!memcmp(data->data, "something else", data->len));
} else {
g_assert(data->len == strlen("something"));
g_assert(!memcmp(data->data, "something", data->len));
}
g_byte_array_unref(data);
g_string_free(watches, true);
xs_impl_delete(s);
}
static void test_xs_node_tx_fail(void)
{
do_test_xs_node_tx(true, true);
}
static void test_xs_node_tx_abort(void)
{
do_test_xs_node_tx(false, false);
do_test_xs_node_tx(true, false);
}
static void test_xs_node_tx_succeed(void)
{
do_test_xs_node_tx(false, true);
}
hw/xen: Add basic XenStore tree walk and write/read/directory support This is a fairly simple implementation of a copy-on-write tree. The node walk function starts off at the root, with 'inplace == true'. If it ever encounters a node with a refcount greater than one (including the root node), then that node is shared with other trees, and cannot be modified in place, so the inplace flag is cleared and we copy on write from there on down. Xenstore write has 'mkdir -p' semantics and will create the intermediate nodes if they don't already exist, so in that case we flip the inplace flag back to true as we populate the newly-created nodes. We put a copy of the absolute path into the buffer in the struct walk_op, with *two* NUL terminators at the end. As xs_node_walk() goes down the tree, it replaces the next '/' separator with a NUL so that it can use the 'child name' in place. The next recursion down then puts the '/' back and repeats the exercise for the next path element... if it doesn't hit that *second* NUL termination which indicates the true end of the path. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-20 01:36:38 +00:00
int main(int argc, char **argv)
{
g_test_init(&argc, &argv, NULL);
module_call_init(MODULE_INIT_QOM);
g_test_add_func("/xs_node/simple", test_xs_node_simple);
hw/xen: Implement XenStore transactions Given that the whole thing supported copy on write from the beginning, transactions end up being fairly simple. On starting a transaction, just take a ref of the existing root; swap it back in on a successful commit. The main tree has a transaction ID too, and we keep a record of the last transaction ID given out. if the main tree is ever modified when it isn't the latest, it gets a new transaction ID. A commit can only succeed if the main tree hasn't moved on since it was forked. Strictly speaking, the XenStore protocol allows a transaction to succeed as long as nothing *it* read or wrote has changed in the interim, but no implementations do that; *any* change is sufficient to abort a transaction. This does not yet fire watches on the changed nodes on a commit. That bit is more fun and will come in a follow-on commit. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-22 22:05:37 +00:00
g_test_add_func("/xs_node/tx_abort", test_xs_node_tx_abort);
g_test_add_func("/xs_node/tx_fail", test_xs_node_tx_fail);
g_test_add_func("/xs_node/tx_succeed", test_xs_node_tx_succeed);
hw/xen: Add basic XenStore tree walk and write/read/directory support This is a fairly simple implementation of a copy-on-write tree. The node walk function starts off at the root, with 'inplace == true'. If it ever encounters a node with a refcount greater than one (including the root node), then that node is shared with other trees, and cannot be modified in place, so the inplace flag is cleared and we copy on write from there on down. Xenstore write has 'mkdir -p' semantics and will create the intermediate nodes if they don't already exist, so in that case we flip the inplace flag back to true as we populate the newly-created nodes. We put a copy of the absolute path into the buffer in the struct walk_op, with *two* NUL terminators at the end. As xs_node_walk() goes down the tree, it replaces the next '/' separator with a NUL so that it can use the 'child name' in place. The next recursion down then puts the '/' back and repeats the exercise for the next path element... if it doesn't hit that *second* NUL termination which indicates the true end of the path. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-20 01:36:38 +00:00
return g_test_run();
}
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