s3-printing: use printcap IDL for IPC

Use printcap IDL for marshalling and unmarshalling messages between cups
child and parent smbd processes. This simplifies the IPC and ensures
the parent is notified of cups errors encountered by the child.

https://bugzilla.samba.org/show_bug.cgi?id=7994
Signed-off-by: Andreas Schneider <asn@samba.org>

1 files changed, 107 insertions, 131 deletions

diff --git a/source3/printing/print_cups.c b/source3/printing/print_cups.c
index 3031a88e5d..35e3b30dd8 100644
--- a/source3/printing/print_cups.c
+++ b/source3/printing/print_cups.c
@@ -25,6 +25,7 @@
 #include "includes.h"
 #include "printing.h"
 #include "printing/pcap.h"
+#include "librpc/gen_ndr/ndr_printcap.h"
 
 #ifdef HAVE_CUPS
 #include <cups/cups.h>
@@ -112,46 +113,54 @@ static http_t *cups_connect(TALLOC_CTX *frame)
 	return http;
 }
 
-static void send_pcap_info(const char *name, const char *info, void *pd)
+static bool send_pcap_blob(DATA_BLOB *pcap_blob, int fd)
 {
-	int fd = *(int *)pd;
-	size_t namelen = name ? strlen(name)+1 : 0;
-	size_t infolen = info ? strlen(info)+1 : 0;
-
-	DEBUG(11,("send_pcap_info: writing namelen %u\n", (unsigned int)namelen));
-	if (sys_write(fd, &namelen, sizeof(namelen)) != sizeof(namelen)) {
-		DEBUG(10,("send_pcap_info: namelen write failed %s\n",
-			strerror(errno)));
-		return;
-	}
-	DEBUG(11,("send_pcap_info: writing infolen %u\n", (unsigned int)infolen));
-	if (sys_write(fd, &infolen, sizeof(infolen)) != sizeof(infolen)) {
-		DEBUG(10,("send_pcap_info: infolen write failed %s\n",
-			strerror(errno)));
-		return;
-	}
-	if (namelen) {
-		DEBUG(11,("send_pcap_info: writing name %s\n", name));
-		if (sys_write(fd, name, namelen) != namelen) {
-			DEBUG(10,("send_pcap_info: name write failed %s\n",
-				strerror(errno)));
-			return;
-		}
+	size_t ret;
+
+	ret = sys_write(fd, &pcap_blob->length, sizeof(pcap_blob->length));
+	if (ret != sizeof(pcap_blob->length)) {
+		return false;
 	}
-	if (infolen) {
-		DEBUG(11,("send_pcap_info: writing info %s\n", info));
-		if (sys_write(fd, info, infolen) != infolen) {
-			DEBUG(10,("send_pcap_info: info write failed %s\n",
-				strerror(errno)));
-			return;
-		}
+
+	ret = sys_write(fd, pcap_blob->data, pcap_blob->length);
+	if (ret != pcap_blob->length) {
+		return false;
 	}
+
+	DEBUG(10, ("successfully sent blob of len %ld\n", (int64_t)ret));
+	return true;
+}
+
+static bool recv_pcap_blob(TALLOC_CTX *mem_ctx, int fd, DATA_BLOB *pcap_blob)
+{
+	size_t blob_len;
+	size_t ret;
+
+	ret = sys_read(fd, &blob_len, sizeof(blob_len));
+	if (ret != sizeof(blob_len)) {
+		return false;
+	}
+
+	*pcap_blob = data_blob_talloc_named(mem_ctx, NULL, blob_len,
+					   "cups pcap");
+	if (pcap_blob->length != blob_len) {
+		return false;
+	}
+	ret = sys_read(fd, pcap_blob->data, blob_len);
+	if (ret != blob_len) {
+		talloc_free(pcap_blob->data);
+		return false;
+	}
+
+	DEBUG(10, ("successfully recvd blob of len %ld\n", (int64_t)ret));
+	return true;
 }
 
 static bool cups_cache_reload_async(int fd)
 {
 	TALLOC_CTX *frame = talloc_stackframe();
-	struct pcap_cache *tmp_pcap_cache = NULL;
+	struct pcap_data pcap_data;
+	struct pcap_printer *printer;
 	http_t		*http = NULL;		/* HTTP connection to server */
 	ipp_t		*request = NULL,	/* IPP Request */
 			*response = NULL;	/* IPP Response */
@@ -166,6 +175,11 @@ static bool cups_cache_reload_async(int fd)
 			};
 	bool ret = False;
 	size_t size;
+	enum ndr_err_code ndr_ret;
+	DATA_BLOB pcap_blob;
+
+	ZERO_STRUCT(pcap_data);
+	pcap_data.status = NT_STATUS_UNSUCCESSFUL;
 
 	DEBUG(5, ("reloading cups printcap cache\n"));
 
@@ -269,9 +283,20 @@ static bool cups_cache_reload_async(int fd)
 		if (name == NULL)
 			break;
 
-		if (!pcap_cache_add_specific(&tmp_pcap_cache, name, info)) {
+		if (pcap_data.count == 0) {
+			printer = talloc_array(frame, struct pcap_printer, 1);
+		} else {
+			printer = talloc_realloc(frame, pcap_data.printers,
+						 struct pcap_printer,
+						 pcap_data.count + 1);
+		}
+		if (printer == NULL) {
 			goto out;
 		}
+		pcap_data.printers = printer;
+		pcap_data.printers[pcap_data.count].name = name;
+		pcap_data.printers[pcap_data.count].info = info;
+		pcap_data.count++;
 	}
 
 	ippDelete(response);
@@ -361,13 +386,24 @@ static bool cups_cache_reload_async(int fd)
 		if (name == NULL)
 			break;
 
-		if (!pcap_cache_add_specific(&tmp_pcap_cache, name, info)) {
+		if (pcap_data.count == 0) {
+			printer = talloc_array(frame, struct pcap_printer, 1);
+		} else {
+			printer = talloc_realloc(frame, pcap_data.printers,
+						 struct pcap_printer,
+						 pcap_data.count + 1);
+		}
+		if (printer == NULL) {
 			goto out;
 		}
+		pcap_data.printers = printer;
+		pcap_data.printers[pcap_data.count].name = name;
+		pcap_data.printers[pcap_data.count].info = info;
+		pcap_data.count++;
 	}
 
-	ret = True;
-
+	ret = true;
+	pcap_data.status = NT_STATUS_OK;
  out:
 	if (response)
 		ippDelete(response);
@@ -379,13 +415,14 @@ static bool cups_cache_reload_async(int fd)
 		httpClose(http);
 
 	/* Send all the entries up the pipe. */
-	if (tmp_pcap_cache) {
-		pcap_printer_fn_specific(tmp_pcap_cache,
-				send_pcap_info,
-				(void *)&fd);
-
-		pcap_cache_destroy_specific(&tmp_pcap_cache);
+	ndr_ret = ndr_push_struct_blob(&pcap_blob, frame, &pcap_data,
+				       (ndr_push_flags_fn_t)ndr_push_pcap_data);
+	if (ndr_ret == NDR_ERR_SUCCESS) {
+		ret = send_pcap_blob(&pcap_blob, fd);
+	} else {
+		ret = false;
 	}
+
 	TALLOC_FREE(frame);
 	return ret;
 }
@@ -463,104 +500,44 @@ static void cups_async_callback(struct event_context *event_ctx,
 {
 	TALLOC_CTX *frame = talloc_stackframe();
 	struct cups_async_cb_args *cb_args = (struct cups_async_cb_args *)p;
-	int fd = cb_args->pipe_fd;
 	struct pcap_cache *tmp_pcap_cache = NULL;
-	bool ret_ok = true;
+	bool ret_ok;
+	struct pcap_data pcap_data;
+	DATA_BLOB pcap_blob;
+	enum ndr_err_code ndr_ret;
+	int i;
 
 	DEBUG(5,("cups_async_callback: callback received for printer data. "
-		"fd = %d\n", fd));
+		"fd = %d\n", cb_args->pipe_fd));
 
-	while (1) {
-		char *name = NULL, *info = NULL;
-		size_t namelen = 0, infolen = 0;
-		ssize_t ret = -1;
-
-		ret = sys_read(fd, &namelen, sizeof(namelen));
-		if (ret == 0) {
-			/* EOF */
-			break;
-		}
-		if (ret != sizeof(namelen)) {
-			DEBUG(10,("cups_async_callback: namelen read failed %d %s\n",
-				errno, strerror(errno)));
-			ret_ok = false;
-			break;
-		}
-
-		DEBUG(11,("cups_async_callback: read namelen %u\n",
-			(unsigned int)namelen));
-
-		ret = sys_read(fd, &infolen, sizeof(infolen));
-		if (ret == 0) {
-			/* EOF */
-			break;
-		}
-		if (ret != sizeof(infolen)) {
-			DEBUG(10,("cups_async_callback: infolen read failed %s\n",
-				strerror(errno)));
-			ret_ok = false;
-			break;
-		}
+	ret_ok = recv_pcap_blob(frame, cb_args->pipe_fd, &pcap_blob);
+	if (!ret_ok) {
+		DEBUG(0,("failed to recv pcap blob\n"));
+		goto err_out;
+	}
 
-		DEBUG(11,("cups_async_callback: read infolen %u\n",
-			(unsigned int)infolen));
+	ndr_ret = ndr_pull_struct_blob(&pcap_blob, frame, &pcap_data,
+				       (ndr_pull_flags_fn_t)ndr_pull_pcap_data);
+	if (ndr_ret != NDR_ERR_SUCCESS) {
+		goto err_out;
+	}
 
-		if (namelen) {
-			name = TALLOC_ARRAY(frame, char, namelen);
-			if (!name) {
-				ret_ok = false;
-				break;
-			}
-			ret = sys_read(fd, name, namelen);
-			if (ret == 0) {
-				/* EOF */
-				break;
-			}
-			if (ret != namelen) {
-				DEBUG(10,("cups_async_callback: name read failed %s\n",
-					strerror(errno)));
-				ret_ok = false;
-				break;
-			}
-			DEBUG(11,("cups_async_callback: read name %s\n",
-				name));
-		} else {
-			name = NULL;
-		}
-		if (infolen) {
-			info = TALLOC_ARRAY(frame, char, infolen);
-			if (!info) {
-				ret_ok = false;
-				break;
-			}
-			ret = sys_read(fd, info, infolen);
-			if (ret == 0) {
-				/* EOF */
-				break;
-			}
-			if (ret != infolen) {
-				DEBUG(10,("cups_async_callback: info read failed %s\n",
-					strerror(errno)));
-				ret_ok = false;
-				break;
-			}
-			DEBUG(11,("cups_async_callback: read info %s\n",
-				info));
-		} else {
-			info = NULL;
-		}
+	if (!NT_STATUS_IS_OK(pcap_data.status)) {
+		DEBUG(0,("failed to retrieve printer list: %s\n",
+			 nt_errstr(pcap_data.status)));
+		goto err_out;
+	}
 
-		/* Add to our local pcap cache. */
-		ret_ok = pcap_cache_add_specific(&tmp_pcap_cache, name, info);
-		TALLOC_FREE(name);
-		TALLOC_FREE(info);
+	for (i = 0; i < pcap_data.count; i++) {
+		ret_ok = pcap_cache_add_specific(&tmp_pcap_cache,
+						 pcap_data.printers[i].name,
+						 pcap_data.printers[i].info);
 		if (!ret_ok) {
 			DEBUG(0, ("failed to add to tmp pcap cache\n"));
 			break;
 		}
 	}
 
-	TALLOC_FREE(frame);
 	if (!ret_ok) {
 		DEBUG(0, ("failed to read a new printer list\n"));
 		pcap_cache_destroy_specific(&tmp_pcap_cache);
@@ -568,9 +545,6 @@ static void cups_async_callback(struct event_context *event_ctx,
 		/*
 		 * replace the system-wide pcap cache with a (possibly empty)
 		 * new one.
-		 * FIXME The child process does not currently propagate cups
-		 * errors back up to the parent, therefore we cannot
-		 * differentiate between an empty printer list and a failure.
 		 */
 		ret_ok = pcap_cache_replace(tmp_pcap_cache);
 		if (!ret_ok) {
@@ -581,7 +555,9 @@ static void cups_async_callback(struct event_context *event_ctx,
 						    cb_args->msg_ctx);
 		}
 	}
-	close(fd);
+err_out:
+	TALLOC_FREE(frame);
+	close(cb_args->pipe_fd);
 	TALLOC_FREE(cb_args);
 	TALLOC_FREE(cache_fd_event);
 }