# HG changeset patch
# User kfraser@xxxxxxxxxxxxxxxxxxxxx
# Node ID fed18f971f7203a663f4c8b3761f27e57ee65a78
# Parent 8e1ae72e905e0f052de3b61a883a935a08d121fc
[MINIOS] Implement XenBus transactions in MiniOS.
Signed-off-by: Steven Smith <sos22@xxxxxxxxx>
---
extras/mini-os/include/xenbus.h | 29 ++++++++---
extras/mini-os/xenbus/xenbus.c | 103 +++++++++++++++++++++++++++++++---------
2 files changed, 104 insertions(+), 28 deletions(-)
diff -r 8e1ae72e905e -r fed18f971f72 extras/mini-os/include/xenbus.h
--- a/extras/mini-os/include/xenbus.h Wed Jul 05 11:24:09 2006 +0100
+++ b/extras/mini-os/include/xenbus.h Wed Jul 05 11:26:57 2006 +0100
@@ -1,5 +1,8 @@
#ifndef XENBUS_H__
#define XENBUS_H__
+
+typedef unsigned long xenbus_transaction_t;
+#define XBT_NIL ((xenbus_transaction_t)0)
/* Initialize the XenBus system. */
void init_xenbus(void);
@@ -7,28 +10,42 @@ void init_xenbus(void);
/* Read the value associated with a path. Returns a malloc'd error
string on failure and sets *value to NULL. On success, *value is
set to a malloc'd copy of the value. */
-char *xenbus_read(const char *path, char **value);
+char *xenbus_read(xenbus_transaction_t xbt, const char *path, char **value);
/* Associates a value with a path. Returns a malloc'd error string on
failure. */
-char *xenbus_write(const char *path, const char *value);
+char *xenbus_write(xenbus_transaction_t xbt, const char *path, const char
*value);
/* Removes the value associated with a path. Returns a malloc'd error
string on failure. */
-char *xenbus_rm(const char *path);
+char *xenbus_rm(xenbus_transaction_t xbt, const char *path);
/* List the contents of a directory. Returns a malloc'd error string
on failure and sets *contents to NULL. On success, *contents is
set to a malloc'd array of pointers to malloc'd strings. The array
is NULL terminated. May block. */
-char *xenbus_ls(const char *prefix, char ***contents);
+char *xenbus_ls(xenbus_transaction_t xbt, const char *prefix, char
***contents);
/* Reads permissions associated with a path. Returns a malloc'd error
string on failure and sets *value to NULL. On success, *value is
set to a malloc'd copy of the value. */
-char *xenbus_get_perms(const char *path, char **value);
+char *xenbus_get_perms(xenbus_transaction_t xbt, const char *path, char
**value);
/* Sets the permissions associated with a path. Returns a malloc'd
error string on failure. */
-char *xenbus_set_perms(const char *path, domid_t dom, char perm);
+char *xenbus_set_perms(xenbus_transaction_t xbt, const char *path, domid_t
dom, char perm);
+
+/* Start a xenbus transaction. Returns the transaction in xbt on
+ success or a malloc'd error string otherwise. */
+char *xenbus_transaction_start(xenbus_transaction_t *xbt);
+
+/* End a xenbus transaction. Returns a malloc'd error string if it
+ fails. abort says whether the transaction should be aborted.
+ Returns 1 in *retry iff the transaction should be retried. */
+char *xenbus_transaction_end(xenbus_transaction_t, int abort,
+ int *retry);
+
+/* Read path and parse it as an integer. Returns -1 on error. */
+int xenbus_read_integer(char *path);
+
#endif /* XENBUS_H__ */
diff -r 8e1ae72e905e -r fed18f971f72 extras/mini-os/xenbus/xenbus.c
--- a/extras/mini-os/xenbus/xenbus.c Wed Jul 05 11:24:09 2006 +0100
+++ b/extras/mini-os/xenbus/xenbus.c Wed Jul 05 11:26:57 2006 +0100
@@ -174,7 +174,7 @@ void init_xenbus(void)
create_thread("xenstore", xenbus_thread_func, NULL);
DEBUG("buf at %p.\n", xenstore_buf);
err = bind_evtchn(start_info.store_evtchn,
- xenbus_evtchn_handler);
+ xenbus_evtchn_handler);
DEBUG("xenbus on irq %d\n", err);
}
@@ -187,8 +187,8 @@ struct write_req {
by xenbus as if sent atomically. The header is added
automatically, using type %type, req_id %req_id, and trans_id
%trans_id. */
-static void xb_write(int type, int req_id, int trans_id,
- const struct write_req *req, int nr_reqs)
+static void xb_write(int type, int req_id, xenbus_transaction_t trans_id,
+ const struct write_req *req, int nr_reqs)
{
XENSTORE_RING_IDX prod;
int r;
@@ -266,9 +266,9 @@ static void xb_write(int type, int req_i
freed by the caller. */
static struct xsd_sockmsg *
xenbus_msg_reply(int type,
- int trans,
- struct write_req *io,
- int nr_reqs)
+ xenbus_transaction_t trans,
+ struct write_req *io,
+ int nr_reqs)
{
int id;
DEFINE_WAIT(w);
@@ -322,14 +322,14 @@ static void xenbus_debug_msg(const char
/* List the contents of a directory. Returns a malloc()ed array of
pointers to malloc()ed strings. The array is NULL terminated. May
block. */
-char *xenbus_ls(const char *pre, char ***contents)
+char *xenbus_ls(xenbus_transaction_t xbt, const char *pre, char ***contents)
{
struct xsd_sockmsg *reply, *repmsg;
struct write_req req[] = { { pre, strlen(pre)+1 } };
int nr_elems, x, i;
char **res;
- repmsg = xenbus_msg_reply(XS_DIRECTORY, 0, req, ARRAY_SIZE(req));
+ repmsg = xenbus_msg_reply(XS_DIRECTORY, xbt, req, ARRAY_SIZE(req));
char *msg = errmsg(repmsg);
if (msg) {
*contents = NULL;
@@ -351,12 +351,12 @@ char *xenbus_ls(const char *pre, char **
return NULL;
}
-char *xenbus_read(const char *path, char **value)
+char *xenbus_read(xenbus_transaction_t xbt, const char *path, char **value)
{
struct write_req req[] = { {path, strlen(path) + 1} };
struct xsd_sockmsg *rep;
char *res;
- rep = xenbus_msg_reply(XS_READ, 0, req, ARRAY_SIZE(req));
+ rep = xenbus_msg_reply(XS_READ, xbt, req, ARRAY_SIZE(req));
char *msg = errmsg(rep);
if (msg) {
*value = NULL;
@@ -370,14 +370,14 @@ char *xenbus_read(const char *path, char
return NULL;
}
-char *xenbus_write(const char *path, const char *value)
+char *xenbus_write(xenbus_transaction_t xbt, const char *path, const char
*value)
{
struct write_req req[] = {
{path, strlen(path) + 1},
{value, strlen(value) + 1},
};
struct xsd_sockmsg *rep;
- rep = xenbus_msg_reply(XS_WRITE, 0, req, ARRAY_SIZE(req));
+ rep = xenbus_msg_reply(XS_WRITE, xbt, req, ARRAY_SIZE(req));
char *msg = errmsg(rep);
if (msg)
return msg;
@@ -385,11 +385,11 @@ char *xenbus_write(const char *path, con
return NULL;
}
-char *xenbus_rm(const char *path)
+char *xenbus_rm(xenbus_transaction_t xbt, const char *path)
{
struct write_req req[] = { {path, strlen(path) + 1} };
struct xsd_sockmsg *rep;
- rep = xenbus_msg_reply(XS_RM, 0, req, ARRAY_SIZE(req));
+ rep = xenbus_msg_reply(XS_RM, xbt, req, ARRAY_SIZE(req));
char *msg = errmsg(rep);
if (msg)
return msg;
@@ -397,12 +397,12 @@ char *xenbus_rm(const char *path)
return NULL;
}
-char *xenbus_get_perms(const char *path, char **value)
+char *xenbus_get_perms(xenbus_transaction_t xbt, const char *path, char
**value)
{
struct write_req req[] = { {path, strlen(path) + 1} };
struct xsd_sockmsg *rep;
char *res;
- rep = xenbus_msg_reply(XS_GET_PERMS, 0, req, ARRAY_SIZE(req));
+ rep = xenbus_msg_reply(XS_GET_PERMS, xbt, req, ARRAY_SIZE(req));
char *msg = errmsg(rep);
if (msg) {
*value = NULL;
@@ -417,7 +417,7 @@ char *xenbus_get_perms(const char *path,
}
#define PERM_MAX_SIZE 32
-char *xenbus_set_perms(const char *path, domid_t dom, char perm)
+char *xenbus_set_perms(xenbus_transaction_t xbt, const char *path, domid_t
dom, char perm)
{
char value[PERM_MAX_SIZE];
snprintf(value, PERM_MAX_SIZE, "%c%hu", perm, dom);
@@ -426,7 +426,7 @@ char *xenbus_set_perms(const char *path,
{value, strlen(value) + 1},
};
struct xsd_sockmsg *rep;
- rep = xenbus_msg_reply(XS_SET_PERMS, 0, req, ARRAY_SIZE(req));
+ rep = xenbus_msg_reply(XS_SET_PERMS, xbt, req, ARRAY_SIZE(req));
char *msg = errmsg(rep);
if (msg)
return msg;
@@ -434,13 +434,72 @@ char *xenbus_set_perms(const char *path,
return NULL;
}
+char *xenbus_transaction_start(xenbus_transaction_t *xbt)
+{
+ /* xenstored becomes angry if you send a length 0 message, so just
+ shove a nul terminator on the end */
+ struct write_req req = { "", 1};
+ struct xsd_sockmsg *rep;
+ char *err;
+
+ rep = xenbus_msg_reply(XS_TRANSACTION_START, 0, &req, 1);
+ err = errmsg(rep);
+ if (err)
+ return err;
+ sscanf((char *)(rep + 1), "%u", xbt);
+ free(rep);
+ return NULL;
+}
+
+char *
+xenbus_transaction_end(xenbus_transaction_t t, int abort, int *retry)
+{
+ struct xsd_sockmsg *rep;
+ struct write_req req;
+ char *err;
+
+ *retry = 0;
+
+ req.data = abort ? "F" : "T";
+ req.len = 2;
+ rep = xenbus_msg_reply(XS_TRANSACTION_END, t, &req, 1);
+ err = errmsg(rep);
+ if (err) {
+ if (!strcmp(err, "EAGAIN")) {
+ *retry = 1;
+ free(err);
+ return NULL;
+ } else {
+ return err;
+ }
+ }
+ free(rep);
+ return NULL;
+}
+
+int xenbus_read_integer(char *path)
+{
+ char *res, *buf;
+ int t;
+
+ res = xenbus_read(XBT_NIL, path, &buf);
+ if (res) {
+ printk("Failed to read %s.\n", path);
+ free(res);
+ return -1;
+ }
+ sscanf(buf, "%d", &t);
+ free(buf);
+ return t;
+}
+
static void do_ls_test(const char *pre)
{
char **dirs;
int x;
DEBUG("ls %s...\n", pre);
- char *msg = xenbus_ls(pre, &dirs);
+ char *msg = xenbus_ls(XBT_NIL, pre, &dirs);
if (msg) {
DEBUG("Error in xenbus ls: %s\n", msg);
free(msg);
@@ -458,7 +517,7 @@ static void do_read_test(const char *pat
{
char *res;
DEBUG("Read %s...\n", path);
- char *msg = xenbus_read(path, &res);
+ char *msg = xenbus_read(XBT_NIL, path, &res);
if (msg) {
DEBUG("Error in xenbus read: %s\n", msg);
free(msg);
@@ -471,7 +530,7 @@ static void do_write_test(const char *pa
static void do_write_test(const char *path, const char *val)
{
DEBUG("Write %s to %s...\n", val, path);
- char *msg = xenbus_write(path, val);
+ char *msg = xenbus_write(XBT_NIL, path, val);
if (msg) {
DEBUG("Result %s\n", msg);
free(msg);
@@ -483,7 +542,7 @@ static void do_rm_test(const char *path)
static void do_rm_test(const char *path)
{
DEBUG("rm %s...\n", path);
- char *msg = xenbus_rm(path);
+ char *msg = xenbus_rm(XBT_NIL, path);
if (msg) {
DEBUG("Result %s\n", msg);
free(msg);
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