From: David Goulet <dgoulet@efficios.com>
Date: Fri, 2 Nov 2012 16:38:33 +0000 (-0400)
Subject: Fix: Add output option to enable-channel command
X-Git-Tag: v2.1.0-rc7~28
X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=commitdiff_plain;h=a79d84dd6bf849361c34616ae9f60786c6a6bf20

Fix: Add output option to enable-channel command

Allow to specify an output mode for the channel (MMAP or SPLICE).

A new error code is introduced to notify the user that the operation is
not supported. Useful for user space tracing which does NOT support
splice mode.

Fixes #335

Signed-off-by: David Goulet <dgoulet@efficios.com>
---

diff --git a/include/lttng/lttng-error.h b/include/lttng/lttng-error.h
index c728913bc..26f05ab4a 100644
--- a/include/lttng/lttng-error.h
+++ b/include/lttng/lttng-error.h
@@ -35,7 +35,7 @@ enum lttng_error_code {
 	LTTNG_ERR_UND                    = 12,  /* Undefine command */
 	LTTNG_ERR_SESSION_STARTED        = 13,  /* Session is running */
 	LTTNG_ERR_UNKNOWN_DOMAIN         = 14,  /* Tracing domain not known */
-	/* 15 */
+	LTTNG_ERR_NOT_SUPPORTED          = 15,  /* Operation not supported */
 	LTTNG_ERR_NO_SESSION             = 16,  /* No session found */
 	LTTNG_ERR_CREATE_DIR_FAIL        = 17,  /* Create directory fail */
 	LTTNG_ERR_SESSION_FAIL           = 18,  /* Create session fail */
diff --git a/src/bin/lttng-sessiond/channel.c b/src/bin/lttng-sessiond/channel.c
index dfc789267..e2cdf563a 100644
--- a/src/bin/lttng-sessiond/channel.c
+++ b/src/bin/lttng-sessiond/channel.c
@@ -254,6 +254,11 @@ int channel_ust_create(struct ltt_ust_session *usess, int domain,
 		goto error;
 	}
 
+	if (attr->attr.output != LTTNG_EVENT_MMAP) {
+		ret = LTTNG_ERR_NOT_SUPPORTED;
+		goto error;
+	}
+
 	/* Create UST channel */
 	uchan = trace_ust_create_channel(attr, usess->pathname);
 	if (uchan == NULL) {
diff --git a/src/bin/lttng/commands/enable_channels.c b/src/bin/lttng/commands/enable_channels.c
index a5b15fae7..18574775b 100644
--- a/src/bin/lttng/commands/enable_channels.c
+++ b/src/bin/lttng/commands/enable_channels.c
@@ -34,6 +34,7 @@ static int opt_kernel;
 static char *opt_session_name;
 static int opt_userspace;
 static struct lttng_channel chan;
+static char *opt_output;
 #if 0
 /* Not implemented yet */
 static char *opt_cmd_name;
@@ -54,6 +55,9 @@ enum {
 
 static struct lttng_handle *handle;
 
+const char *output_mmap = "mmap";
+const char *output_splice = "splice";
+
 static struct poptOption long_options[] = {
 	/* longName, shortName, argInfo, argPtr, value, descrip, argDesc */
 	{"help",           'h', POPT_ARG_NONE, 0, OPT_HELP, 0, 0},
@@ -73,6 +77,7 @@ static struct poptOption long_options[] = {
 	{"switch-timer",   0,   POPT_ARG_INT, 0, OPT_SWITCH_TIMER, 0, 0},
 	{"read-timer",     0,   POPT_ARG_INT, 0, OPT_READ_TIMER, 0, 0},
 	{"list-options",   0, POPT_ARG_NONE, NULL, OPT_LIST_OPTIONS, NULL, NULL},
+	{"output",         0,   POPT_ARG_STRING, &opt_output, 0, 0, 0},
 	{0, 0, 0, 0, 0, 0, 0}
 };
 
@@ -110,6 +115,8 @@ static void usage(FILE *ofp)
 		DEFAULT_CHANNEL_SWITCH_TIMER);
 	fprintf(ofp, "      --read-timer USEC    Read timer interval in usec (default: %u)\n",
 		DEFAULT_CHANNEL_READ_TIMER);
+	fprintf(ofp, "      --output TYPE        Channel output type (Values: %s, %s)\n",
+			output_mmap, output_splice);
 	fprintf(ofp, "\n");
 }
 
@@ -168,6 +175,21 @@ static int enable_channel(char *session_name)
 
 	set_default_attr(&dom);
 
+	/* Setting channel output */
+	if (opt_output) {
+		if (!strncmp(output_mmap, opt_output, strlen(output_mmap))) {
+			chan.attr.output = LTTNG_EVENT_MMAP;
+		} else if (!strncmp(output_splice, opt_output, strlen(output_splice))) {
+			chan.attr.output = LTTNG_EVENT_SPLICE;
+		} else {
+			ERR("Unknown output type %s. Possible values are: %s, %s\n",
+					opt_output, output_mmap, output_splice);
+			usage(stderr);
+			ret = CMD_ERROR;
+			goto error;
+		}
+	}
+
 	handle = lttng_create_handle(session_name, &dom);
 	if (handle == NULL) {
 		ret = -1;
diff --git a/src/common/error.c b/src/common/error.c
index 4354cc3bb..0a3b5b3e1 100644
--- a/src/common/error.c
+++ b/src/common/error.c
@@ -100,6 +100,7 @@ static const char *error_string_array[] = {
 	[ ERROR_INDEX(LTTNG_ERR_NO_CONSUMER) ] = "Consumer not found for tracing session",
 	[ ERROR_INDEX(LTTNG_ERR_NO_SESSIOND) ] = "No session daemon is available",
 	[ ERROR_INDEX(LTTNG_ERR_SESSION_STARTED) ] = "Session is running",
+	[ ERROR_INDEX(LTTNG_ERR_NOT_SUPPORTED) ] = "Operation not supported",
 
 	/* Last element */
 	[ ERROR_INDEX(LTTNG_ERR_NR) ] = "Unknown error code"