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authorVolker Lendecke <vl@samba.org>2008-02-28 15:21:33 +0100
committerVolker Lendecke <vl@samba.org>2008-02-28 15:27:55 +0100
commit525aac775ecef275dbd0732830a9bac0fd023135 (patch)
treef94f42e0cff50c92d927f3b1c33d3d87305be997 /source3/libsmb
parent1d41b5bd2a58dcc6966a3a49ccb063ff05e46125 (diff)
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Add async cli_pull support
This is the big (and potentially controversial) one. It took a phone call to explain to metze what is going on inside cli_pull_read_done, but I would really like everybody to understand this function. It is a very good and reasonably complex example of async programming. If we want more asynchronism in s3, this is what we will have to deal with :-) Make use of it in the smbclient "get" command. Volker (This used to be commit 844a163458c7585e4306a21ffdae5d08e03d6e4d)
Diffstat (limited to 'source3/libsmb')
-rw-r--r--source3/libsmb/clireadwrite.c425
1 files changed, 425 insertions, 0 deletions
diff --git a/source3/libsmb/clireadwrite.c b/source3/libsmb/clireadwrite.c
index af13ed8f73..5aee8f18bd 100644
--- a/source3/libsmb/clireadwrite.c
+++ b/source3/libsmb/clireadwrite.c
@@ -20,6 +20,431 @@
#include "includes.h"
/****************************************************************************
+ Calculate the recommended read buffer size
+****************************************************************************/
+static size_t cli_read_max_bufsize(struct cli_state *cli)
+{
+ if (!client_is_signing_on(cli) && !cli_encryption_on(cli) == false
+ && (cli->posix_capabilities & CIFS_UNIX_LARGE_READ_CAP)) {
+ return CLI_SAMBA_MAX_POSIX_LARGE_READX_SIZE;
+ }
+ if (cli->capabilities & CAP_LARGE_READX) {
+ return cli->is_samba
+ ? CLI_SAMBA_MAX_LARGE_READX_SIZE
+ : CLI_WINDOWS_MAX_LARGE_READX_SIZE;
+ }
+ return (cli->max_xmit - (smb_size+32)) & ~1023;
+}
+
+/*
+ * Send a read&x request
+ */
+
+struct async_req *cli_read_andx_send(TALLOC_CTX *mem_ctx,
+ struct cli_state *cli, int fnum,
+ off_t offset, size_t size)
+{
+ struct async_req *result;
+ struct cli_request *req;
+ bool bigoffset = False;
+ char *enc_buf;
+
+ if (size > cli_read_max_bufsize(cli)) {
+ DEBUG(0, ("cli_read_andx_send got size=%d, can only handle "
+ "size=%d\n", (int)size,
+ (int)cli_read_max_bufsize(cli)));
+ return NULL;
+ }
+
+ result = cli_request_new(mem_ctx, cli->event_ctx, cli, 12, 0, &req);
+ if (result == NULL) {
+ DEBUG(0, ("cli_request_new failed\n"));
+ return NULL;
+ }
+
+ req = cli_request_get(result);
+
+ req->data.read.ofs = offset;
+ req->data.read.size = size;
+ req->data.read.received = 0;
+ req->data.read.rcvbuf = NULL;
+
+ if ((SMB_BIG_UINT)offset >> 32)
+ bigoffset = True;
+
+ cli_set_message(req->outbuf, bigoffset ? 12 : 10, 0, False);
+
+ SCVAL(req->outbuf,smb_com,SMBreadX);
+ SSVAL(req->outbuf,smb_tid,cli->cnum);
+ cli_setup_packet_buf(cli, req->outbuf);
+
+ SCVAL(req->outbuf,smb_vwv0,0xFF);
+ SCVAL(req->outbuf,smb_vwv0+1,0);
+ SSVAL(req->outbuf,smb_vwv1,0);
+ SSVAL(req->outbuf,smb_vwv2,fnum);
+ SIVAL(req->outbuf,smb_vwv3,offset);
+ SSVAL(req->outbuf,smb_vwv5,size);
+ SSVAL(req->outbuf,smb_vwv6,size);
+ SSVAL(req->outbuf,smb_vwv7,(size >> 16));
+ SSVAL(req->outbuf,smb_vwv8,0);
+ SSVAL(req->outbuf,smb_vwv9,0);
+ SSVAL(req->outbuf,smb_mid,req->mid);
+
+ if (bigoffset) {
+ SIVAL(req->outbuf, smb_vwv10,
+ (((SMB_BIG_UINT)offset)>>32) & 0xffffffff);
+ }
+
+ cli_calculate_sign_mac(cli, req->outbuf);
+
+ event_fd_set_writeable(cli->fd_event);
+
+ if (cli_encryption_on(cli)) {
+ NTSTATUS status;
+ status = cli_encrypt_message(cli, req->outbuf, &enc_buf);
+ if (!NT_STATUS_IS_OK(status)) {
+ DEBUG(0, ("Error in encrypting client message. "
+ "Error %s\n", nt_errstr(status)));
+ TALLOC_FREE(req);
+ return NULL;
+ }
+ req->outbuf = enc_buf;
+ req->enc_state = cli->trans_enc_state;
+ }
+
+ return result;
+}
+
+/*
+ * Pull the data out of a finished async read_and_x request. rcvbuf is
+ * talloced from the request, so better make sure that you copy it away before
+ * you talloc_free(req). "rcvbuf" is NOT a talloc_ctx of its own, so do not
+ * talloc_move it!
+ */
+
+NTSTATUS cli_read_andx_recv(struct async_req *req, ssize_t *received,
+ uint8_t **rcvbuf)
+{
+ struct cli_request *cli_req = cli_request_get(req);
+ NTSTATUS status;
+ size_t size;
+
+ SMB_ASSERT(req->state >= ASYNC_REQ_DONE);
+ if (req->state == ASYNC_REQ_ERROR) {
+ return req->status;
+ }
+
+ status = cli_pull_error(cli_req->inbuf);
+
+ if (!NT_STATUS_IS_OK(status)) {
+ return status;
+ }
+
+ /* size is the number of bytes the server returned.
+ * Might be zero. */
+ size = SVAL(cli_req->inbuf, smb_vwv5);
+ size |= (((unsigned int)(SVAL(cli_req->inbuf, smb_vwv7))) << 16);
+
+ if (size > cli_req->data.read.size) {
+ DEBUG(5,("server returned more than we wanted!\n"));
+ return NT_STATUS_UNEXPECTED_IO_ERROR;
+ }
+
+ if (size < 0) {
+ DEBUG(5,("read return < 0!\n"));
+ return NT_STATUS_UNEXPECTED_IO_ERROR;
+ }
+
+ *rcvbuf = (uint8_t *)
+ (smb_base(cli_req->inbuf) + SVAL(cli_req->inbuf, smb_vwv6));
+ *received = size;
+ return NT_STATUS_OK;
+}
+
+/*
+ * Parallel read support.
+ *
+ * cli_pull sends as many read&x requests as the server would allow via
+ * max_mux at a time. When replies flow back in, the data is written into
+ * the callback function "sink" in the right order.
+ */
+
+struct cli_pull_state {
+ struct async_req *req;
+
+ struct cli_state *cli;
+ uint16_t fnum;
+ off_t start_offset;
+ size_t size;
+
+ NTSTATUS (*sink)(char *buf, size_t n, void *priv);
+ void *priv;
+
+ size_t chunk_size;
+
+ /*
+ * Outstanding requests
+ */
+ int num_reqs;
+ struct async_req **reqs;
+
+ /*
+ * For how many bytes did we send requests already?
+ */
+ off_t requested;
+
+ /*
+ * Next request index to push into "sink". This walks around the "req"
+ * array, taking care that the requests are pushed to "sink" in the
+ * right order. If necessary (i.e. replies don't come in in the right
+ * order), replies are held back in "reqs".
+ */
+ int top_req;
+
+ /*
+ * How many bytes did we push into "sink"?
+ */
+
+ off_t pushed;
+};
+
+static char *cli_pull_print(TALLOC_CTX *mem_ctx, struct async_req *req)
+{
+ struct cli_pull_state *state = talloc_get_type_abort(
+ req->private_data, struct cli_pull_state);
+ char *result;
+
+ result = async_req_print(mem_ctx, req);
+ if (result == NULL) {
+ return NULL;
+ }
+
+ return talloc_asprintf_append_buffer(
+ result, "num_reqs=%d, top_req=%d",
+ state->num_reqs, state->top_req);
+}
+
+static void cli_pull_read_done(struct async_req *read_req);
+
+/*
+ * Prepare an async pull request
+ */
+
+struct async_req *cli_pull_send(TALLOC_CTX *mem_ctx, struct cli_state *cli,
+ uint16_t fnum, off_t start_offset,
+ size_t size, size_t window_size,
+ NTSTATUS (*sink)(char *buf, size_t n,
+ void *priv),
+ void *priv)
+{
+ struct async_req *result;
+ struct cli_pull_state *state;
+ int i;
+
+ result = async_req_new(mem_ctx, cli->event_ctx);
+ if (result == NULL) {
+ goto failed;
+ }
+ state = talloc(result, struct cli_pull_state);
+ if (state == NULL) {
+ goto failed;
+ }
+ result->private_data = state;
+ result->print = cli_pull_print;
+ state->req = result;
+
+ state->cli = cli;
+ state->fnum = fnum;
+ state->start_offset = start_offset;
+ state->size = size;
+ state->sink = sink;
+ state->priv = priv;
+
+ state->pushed = 0;
+ state->top_req = 0;
+ state->chunk_size = cli_read_max_bufsize(cli);
+
+ state->num_reqs = MAX(window_size/state->chunk_size, 1);
+ state->num_reqs = MIN(state->num_reqs, cli->max_mux);
+
+ state->reqs = TALLOC_ZERO_ARRAY(state, struct async_req *,
+ state->num_reqs);
+ if (state->reqs == NULL) {
+ goto failed;
+ }
+
+ state->requested = 0;
+
+ for (i=0; i<state->num_reqs; i++) {
+ size_t size_left, request_thistime;
+
+ if (state->requested >= size) {
+ state->num_reqs = i;
+ break;
+ }
+
+ size_left = size - state->requested;
+ request_thistime = MIN(size_left, state->chunk_size);
+
+ state->reqs[i] = cli_read_andx_send(
+ state->reqs, cli, fnum,
+ state->start_offset + state->requested,
+ request_thistime);
+
+ if (state->reqs[i] == NULL) {
+ goto failed;
+ }
+
+ state->reqs[i]->async.fn = cli_pull_read_done;
+ state->reqs[i]->async.priv = result;
+
+ state->requested += request_thistime;
+ }
+ return result;
+
+failed:
+ TALLOC_FREE(result);
+ return NULL;
+}
+
+/*
+ * Handle incoming read replies, push the data into sink and send out new
+ * requests if necessary.
+ */
+
+static void cli_pull_read_done(struct async_req *read_req)
+{
+ struct async_req *pull_req = talloc_get_type_abort(
+ read_req->async.priv, struct async_req);
+ struct cli_pull_state *state = talloc_get_type_abort(
+ pull_req->private_data, struct cli_pull_state);
+ struct cli_request *read_state = cli_request_get(read_req);
+ NTSTATUS status;
+
+ status = cli_read_andx_recv(read_req, &read_state->data.read.received,
+ &read_state->data.read.rcvbuf);
+ if (!NT_STATUS_IS_OK(status)) {
+ async_req_error(state->req, status);
+ return;
+ }
+
+ /*
+ * This loop is the one to take care of out-of-order replies. All
+ * pending requests are in state->reqs, state->reqs[top_req] is the
+ * one that is to be pushed next. If however a request later than
+ * top_req is replied to, then we can't push yet. If top_req is
+ * replied to at a later point then, we need to push all the finished
+ * requests.
+ */
+
+ while (state->reqs[state->top_req] != NULL) {
+ struct cli_request *top_read;
+
+ DEBUG(11, ("cli_pull_read_done: top_req = %d\n",
+ state->top_req));
+
+ if (state->reqs[state->top_req]->state < ASYNC_REQ_DONE) {
+ DEBUG(11, ("cli_pull_read_done: top request not yet "
+ "done\n"));
+ return;
+ }
+
+ top_read = cli_request_get(state->reqs[state->top_req]);
+
+ DEBUG(10, ("cli_pull_read_done: Pushing %d bytes, %d already "
+ "pushed\n", (int)top_read->data.read.received,
+ (int)state->pushed));
+
+ status = state->sink((char *)top_read->data.read.rcvbuf,
+ top_read->data.read.received,
+ state->priv);
+ if (!NT_STATUS_IS_OK(status)) {
+ async_req_error(state->req, status);
+ return;
+ }
+ state->pushed += top_read->data.read.received;
+
+ TALLOC_FREE(state->reqs[state->top_req]);
+
+ if (state->requested < state->size) {
+ struct async_req *new_req;
+ size_t size_left, request_thistime;
+
+ size_left = state->size - state->requested;
+ request_thistime = MIN(size_left, state->chunk_size);
+
+ DEBUG(10, ("cli_pull_read_done: Requesting %d bytes "
+ "at %d, position %d\n",
+ (int)request_thistime,
+ (int)(state->start_offset
+ + state->requested),
+ state->top_req));
+
+ new_req = cli_read_andx_send(
+ state->reqs, state->cli, state->fnum,
+ state->start_offset + state->requested,
+ request_thistime);
+
+ if (async_req_nomem(new_req, state->req)) {
+ return;
+ }
+
+ new_req->async.fn = cli_pull_read_done;
+ new_req->async.priv = pull_req;
+
+ state->reqs[state->top_req] = new_req;
+ state->requested += request_thistime;
+ }
+
+ state->top_req = (state->top_req+1) % state->num_reqs;
+ }
+
+ async_req_done(pull_req);
+}
+
+NTSTATUS cli_pull_recv(struct async_req *req, ssize_t *received)
+{
+ struct cli_pull_state *state = talloc_get_type_abort(
+ req->private_data, struct cli_pull_state);
+
+ SMB_ASSERT(req->state >= ASYNC_REQ_DONE);
+ if (req->state == ASYNC_REQ_ERROR) {
+ return req->status;
+ }
+ *received = state->pushed;
+ return NT_STATUS_OK;
+}
+
+NTSTATUS cli_pull(struct cli_state *cli, uint16_t fnum,
+ off_t start_offset, size_t size, size_t window_size,
+ NTSTATUS (*sink)(char *buf, size_t n, void *priv),
+ void *priv, ssize_t *received)
+{
+ TALLOC_CTX *frame = talloc_stackframe();
+ struct async_req *req;
+ NTSTATUS result = NT_STATUS_NO_MEMORY;
+
+ if (cli_tmp_event_ctx(frame, cli) == NULL) {
+ goto nomem;
+ }
+
+ req = cli_pull_send(frame, cli, fnum, start_offset, size, window_size,
+ sink, priv);
+ if (req == NULL) {
+ goto nomem;
+ }
+
+ while (req->state < ASYNC_REQ_DONE) {
+ event_loop_once(cli->event_ctx);
+ }
+
+ result = cli_pull_recv(req, received);
+ nomem:
+ TALLOC_FREE(frame);
+ return result;
+}
+
+/****************************************************************************
Issue a single SMBread and don't wait for a reply.
****************************************************************************/