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[Qemu-devel] [RFC][PATCH v5 04/21] virtagent: transport definitions and
From: |
Michael Roth |
Subject: |
[Qemu-devel] [RFC][PATCH v5 04/21] virtagent: transport definitions and job callbacks |
Date: |
Fri, 3 Dec 2010 12:03:05 -0600 |
Async read/send handlers for managing RPC/HTTP request/responses. The
read handler runs continuously and calls into client or server RPC
callbacks based on the HTTP header. The send handlers are started up to
send RPC client requests/server responses.
Signed-off-by: Michael Roth <address@hidden>
---
virtagent-common.c | 332 ++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 332 insertions(+), 0 deletions(-)
diff --git a/virtagent-common.c b/virtagent-common.c
index 45f9d9f..1ed2b55 100644
--- a/virtagent-common.c
+++ b/virtagent-common.c
@@ -89,6 +89,12 @@ typedef struct VAState {
static VAState *va_state;
+static bool va_set_client_state(enum va_client_state client_state);
+static VAServerJob *va_pop_server_job(void);
+static VAClientJob *va_pop_client_job(void);
+static int va_server_job_add(xmlrpc_mem_block *resp_xml);
+static int va_kick(void);
+
static VAClientJob *va_current_client_job(void)
{
TRACE("called");
@@ -96,6 +102,332 @@ static VAClientJob *va_current_client_job(void)
}
/***********************************************************/
+/* callbacks for read/send handlers */
+
+static void va_client_send_cb(enum va_http_status http_status,
+ const char *content, size_t content_len)
+{
+ VAClientJob *client_job = va_current_client_job();
+
+ TRACE("called");
+ assert(client_job != NULL);
+
+ if (http_status != VA_HTTP_STATUS_OK) {
+ /* TODO: we should reset everything at this point...guest/host will
+ * be out of whack with each other since there's no way to let the
+ * other know job failed (server or client job) if the send channel
+ * is down. But how do we induce the other side to do the same?
+ */
+ LOG("error sending http request");
+ }
+
+ /* request sent ok. free up request xml, then move to
+ * wait (for response) state
+ */
+ XMLRPC_MEMBLOCK_FREE(char, client_job->req_data);
+ assert(va_set_client_state(VA_CLIENT_WAIT));
+}
+
+static void va_server_send_cb(enum va_http_status http_status,
+ const char *content, size_t content_len)
+{
+ VAServerJob *server_job = va_pop_server_job();
+
+ TRACE("called");
+ assert(server_job != NULL);
+
+ if (http_status != VA_HTTP_STATUS_OK) {
+ /* TODO: we should reset everything at this point...guest/host will
+ * be out of whack with each other since there's no way to let the
+ * other know job failed (server or client job) if the send channel
+ * is down
+ */
+ LOG("error sending http response");
+ return;
+ }
+
+ /* response sent ok, cleanup server job and kick off the next one */
+ XMLRPC_MEMBLOCK_FREE(char, server_job->resp_data);
+ qemu_free(server_job);
+ va_kick();
+}
+
+static void va_client_read_cb(const char *content, size_t content_len)
+{
+ VAClientJob *client_job;
+
+ client_job = va_pop_client_job();
+ assert(client_job != NULL);
+TRACE("marker");
+ client_job->cb(content, content_len, client_job->mon_cb,
+ client_job->mon_data);
+ va_kick();
+}
+
+static void va_server_read_cb(const char *content, size_t content_len)
+{
+ xmlrpc_mem_block *resp_xml;
+ VAServerData *server_data = &va_state->server_data;
+ int ret;
+
+ TRACE("called");
+ resp_xml = xmlrpc_registry_process_call(&server_data->env,
+ server_data->registry,
+ NULL, content, content_len);
+ if (resp_xml == NULL) {
+ LOG("error processing RPC request");
+ goto out_bad;
+ }
+
+ ret = va_server_job_add(resp_xml);
+ if (ret != 0) {
+ LOG("error adding server job: %s", strerror(ret));
+ }
+
+ return;
+out_bad:
+ /* TODO: should reset state here */
+ return;
+}
+
+static void va_http_read_cb(enum va_http_status http_status,
+ const char *content, size_t content_len, bool
is_request)
+{
+ TRACE("called");
+ if (http_status != VA_HTTP_STATUS_OK) {
+ LOG("error reading http %s", is_request ? "request" : "response");
+ content = NULL;
+ }
+
+ if (is_request) {
+ va_server_read_cb(content, content_len);
+ } else {
+ va_client_read_cb(content, content_len);
+ }
+
+ return;
+}
+
+/***********************************************************/
+/* utility functions for handling http calls */
+
+#define VA_HTTP_REQUEST 1
+#define VA_HTTP_RESPONSE 2
+
+static void va_http_hdr_init(VAHTState *s, int request_type) {
+ const char *preamble;
+
+ TRACE("called");
+ /* essentially ignored in the context of virtagent, but might as well */
+ if (request_type == VA_HTTP_REQUEST) {
+ preamble = "POST /RPC2 HTTP/1.1";
+ } else if (request_type == VA_HTTP_RESPONSE) {
+ preamble = "HTTP/1.1 200 OK";
+ } else {
+ s->hdr_len = 0;
+ return;
+ }
+ s->hdr_len = sprintf(s->hdr,
+ "%s" EOL
+ "Content-Type: text/xml" EOL
+ "Content-Length: %u" EOL EOL,
+ preamble,
+ (uint32_t)s->content_len);
+}
+
+static void va_rpc_parse_hdr(VAHTState *s)
+{
+ int i, line_pos = 0;
+ bool first_line = true;
+ char line_buf[4096];
+
+ TRACE("called");
+
+ for (i = 0; i < VA_HDR_LEN_MAX; ++i) {
+ if (s->hdr[i] != '\n') {
+ /* read line */
+ line_buf[line_pos++] = s->hdr[i];
+ } else {
+ /* process line */
+ if (first_line) {
+ s->is_request = (strncmp(line_buf, "POST", 4) == 0) ?
+ true : false;
+ first_line = false;
+ }
+ if (strncmp(line_buf, "Content-Length: ", 16) == 0) {
+ s->content_len = atoi(&line_buf[16]);
+ return;
+ }
+ line_pos = 0;
+ }
+ }
+}
+
+static int va_end_of_header(char *buf, int end_pos)
+{
+ return !strncmp(buf+(end_pos-2), "\n\r\n", 3);
+}
+
+/***********************************************************/
+/* read/send handlers */
+
+static void va_http_read_handler(void *opaque)
+{
+ VAHTState *s = &va_state->read_state;
+ enum va_http_status http_status;
+ int fd = va_state->fd;
+ int ret;
+
+ TRACE("called with opaque: %p", opaque);
+
+ switch (s->state) {
+ case VA_READ_START:
+ s->state = VA_READ_HDR;
+ case VA_READ_HDR:
+ while((ret = read(fd, s->hdr + s->hdr_pos, 1)) > 0
+ && s->hdr_pos < VA_HDR_LEN_MAX) {
+ s->hdr_pos += ret;
+ if (va_end_of_header(s->hdr, s->hdr_pos - 1)) {
+ break;
+ }
+ }
+ if (ret == -1) {
+ if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR) {
+ return;
+ } else {
+ LOG("error reading connection: %s", strerror(errno));
+ goto out_bad;
+ }
+ } else if (ret == 0) {
+ LOG("connected closed unexpectedly");
+ goto out_bad;
+ } else if (s->hdr_pos >= VA_HDR_LEN_MAX) {
+ LOG("http header too long");
+ goto out_bad;
+ } else {
+ s->content_len = -1;
+ va_rpc_parse_hdr(s);
+ if (s->content_len == -1) {
+ LOG("malformed http header");
+ goto out_bad;
+ } else if (s->content_len > VA_CONTENT_LEN_MAX) {
+ LOG("http content length too long");
+ goto out_bad;
+ }
+ s->content = qemu_mallocz(s->content_len);
+ s->state = VA_READ_BODY;
+ }
+ case VA_READ_BODY:
+ while(s->content_pos < s->content_len) {
+ ret = read(fd, s->content + s->content_pos,
+ s->content_len - s->content_pos);
+ if (ret == -1) {
+ if (errno == EAGAIN || errno == EWOULDBLOCK
+ || errno == EINTR) {
+ return;
+ } else {
+ LOG("error reading connection: %s", strerror(errno));
+ goto out_bad;
+ }
+ } else if (ret == 0) {
+ LOG("connection closed unexpectedly:"
+ " read %u bytes, expected %u bytes",
+ (unsigned int)s->content_pos, (unsigned
int)s->content_len);
+ goto out_bad;
+ }
+ s->content_pos += ret;
+ }
+
+ http_status = VA_HTTP_STATUS_OK;
+ goto out;
+ default:
+ LOG("unknown state");
+ goto out_bad;
+ }
+
+out_bad:
+ http_status = VA_HTTP_STATUS_ERROR;
+out:
+ /* handle the response or request we just read */
+ s->read_cb(http_status, s->content, s->content_len, s->is_request);
+ /* restart read handler */
+ s->state = VA_READ_START;
+ s->hdr_pos = 0;
+ s->content_len = 0;
+ s->content_pos = 0;
+ qemu_free(s->content);
+ http_status = VA_HTTP_STATUS_NEW;
+}
+
+static void va_http_send_handler(void *opaque)
+{
+ VAHTState *s = &va_state->send_state;
+ enum va_http_status http_status;
+ int fd = va_state->fd;
+ int ret;
+
+ TRACE("called, fd: %d", fd);
+
+ switch (s->state) {
+ case VA_SEND_START:
+ s->state = VA_SEND_HDR;
+ case VA_SEND_HDR:
+ do {
+ ret = write(fd, s->hdr + s->hdr_pos, s->hdr_len - s->hdr_pos);
+ if (ret <= 0) {
+ break;
+ }
+ s->hdr_pos += ret;
+ } while (s->hdr_pos < s->hdr_len);
+ if (ret == -1) {
+ if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR) {
+ return;
+ } else {
+ LOG("error writing header: %s", strerror(errno));
+ goto out_bad;
+ }
+ } else if (ret == 0) {
+ LOG("connected closed unexpectedly");
+ goto out_bad;
+ } else {
+ s->state = VA_SEND_BODY;
+ }
+ case VA_SEND_BODY:
+ do {
+ ret = write(fd, s->content + s->content_pos,
+ s->content_len - s->content_pos);
+ if (ret <= 0) {
+ break;
+ }
+ s->content_pos += ret;
+ } while (s->content_pos < s->content_len);
+ if (ret == -1) {
+ if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR) {
+ return;
+ } else {
+ LOG("error writing content: %s", strerror(errno));
+ goto out_bad;
+ }
+ } else if (ret == 0) {
+ LOG("connected closed unexpectedly");
+ goto out_bad;
+ } else {
+ http_status = VA_HTTP_STATUS_OK;
+ goto out;
+ }
+ default:
+ LOG("unknown state");
+ goto out_bad;
+ }
+
+out_bad:
+ http_status = VA_HTTP_STATUS_ERROR;
+out:
+ s->send_cb(http_status, s->content, s->content_len);
+ qemu_set_fd_handler(fd, va_http_read_handler, NULL, NULL);
+}
+
+/***********************************************************/
/* functions for starting/managing client/server rpc jobs */
static int va_send_server_response(VAServerJob *server_job)
--
1.7.0.4
- [Qemu-devel] [RFC][PATCH v5 00/21] virtagent: host/guest RPC communication agent, Michael Roth, 2010/12/03
- [Qemu-devel] [RFC][PATCH v5 01/21] Move code related to fd handlers into utility functions, Michael Roth, 2010/12/03
- [Qemu-devel] Re: [RFC][PATCH v5 01/21] Move code related to fd handlers into utility functions, Jes Sorensen, 2010/12/07
- Re: [Qemu-devel] Re: [RFC][PATCH v5 01/21] Move code related to fd handlers into utility functions, Michael Roth, 2010/12/07
- Re: [Qemu-devel] Re: [RFC][PATCH v5 01/21] Move code related to fd handlers into utility functions, Jes Sorensen, 2010/12/07
- Re: [Qemu-devel] Re: [RFC][PATCH v5 01/21] Move code related to fd handlers into utility functions, Stefan Hajnoczi, 2010/12/08
- Re: [Qemu-devel] Re: [RFC][PATCH v5 01/21] Move code related to fd handlers into utility functions, Jes Sorensen, 2010/12/08
- Re: [Qemu-devel] Re: [RFC][PATCH v5 01/21] Move code related to fd handlers into utility functions, Stefan Hajnoczi, 2010/12/08
- Re: [Qemu-devel] Re: [RFC][PATCH v5 01/21] Move code related to fd handlers into utility functions, Jes Sorensen, 2010/12/08
- Re: [Qemu-devel] Re: [RFC][PATCH v5 01/21] Move code related to fd handlers into utility functions, Anthony Liguori, 2010/12/08
[Qemu-devel] [RFC][PATCH v5 04/21] virtagent: transport definitions and job callbacks,
Michael Roth <=
[Qemu-devel] [RFC][PATCH v5 02/21] Add qemu_set_fd_handler() wrappers to qemu-tools.c, Michael Roth, 2010/12/03
[Qemu-devel] [RFC][PATCH v5 05/21] virtagent: base client definitions, Michael Roth, 2010/12/03
[Qemu-devel] [RFC][PATCH v5 03/21] virtagent: common code for managing client/server rpc jobs, Michael Roth, 2010/12/03