Make CLI "core show channel" not hold the channel lock during console output.

Holding the channel lock while the CLI "core show channel" command is
executing can slow down the system.  It could block the system if the
console output is halted or paused.

* Made capture the CLI "core show channel" output into a buffer to be
output after the channel is unlocked.

* Removed use of C++ keyword as a variable name.  out renamed to obuf.

* Checked allocation of obuf for failure so will not crash.

(closes issue ASTERISK-18571)
Reported by: Pavel Troller
Tested by: rmudgett
........

Merged revisions 344661 from http://svn.asterisk.org/svn/asterisk/branches/1.8
........

Merged revisions 344662 from http://svn.asterisk.org/svn/asterisk/branches/10


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@344663 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 23 insertions, 9 deletions

diff --git a/main/cli.c b/main/cli.c
index 85f4473ee..c35b941d1 100644
--- a/main/cli.c
+++ b/main/cli.c
@@ -1385,11 +1385,12 @@ static char *handle_showchan(struct ast_cli_entry *e, int cmd, struct ast_cli_ar
 {
 	struct ast_channel *c=NULL;
 	struct timeval now;
-	struct ast_str *out = ast_str_thread_get(&ast_str_thread_global_buf, 16);
 	char cdrtime[256];
 	char nf[256];
 	struct ast_str *write_transpath = ast_str_alloca(256);
 	struct ast_str *read_transpath = ast_str_alloca(256);
+	struct ast_str *obuf;/*!< Buffer for variable, CDR variable, and trace output. */
+	struct ast_str *output;/*!< Accumulation buffer for all output. */
 	long elapsed_seconds=0;
 	int hour=0, min=0, sec=0;
 #ifdef CHANNEL_TRACE
@@ -1418,6 +1419,15 @@ static char *handle_showchan(struct ast_cli_entry *e, int cmd, struct ast_cli_ar
 		return CLI_SUCCESS;
 	}
 
+	obuf = ast_str_thread_get(&ast_str_thread_global_buf, 16);
+	if (!obuf) {
+		return CLI_FAILURE;
+	}
+	output = ast_str_create(8192);
+	if (!output) {
+		return CLI_FAILURE;
+	}
+
 	ast_channel_lock(c);
 
 	if (c->cdr) {
@@ -1430,7 +1440,7 @@ static char *handle_showchan(struct ast_cli_entry *e, int cmd, struct ast_cli_ar
 		strcpy(cdrtime, "N/A");
 	}
 
-	ast_cli(a->fd, 
+	ast_str_append(&output, 0,
 		" -- General --\n"
 		"           Name: %s\n"
 		"           Type: %s\n"
@@ -1489,24 +1499,28 @@ static char *handle_showchan(struct ast_cli_entry *e, int cmd, struct ast_cli_ar
 		( c-> data ? S_OR(c->data, "(Empty)") : "(None)"),
 		(ast_test_flag(c, AST_FLAG_BLOCKING) ? c->blockproc : "(Not Blocking)"));
 	
-	if (pbx_builtin_serialize_variables(c, &out)) {
-		ast_cli(a->fd,"      Variables:\n%s\n", ast_str_buffer(out));
+	if (pbx_builtin_serialize_variables(c, &obuf)) {
+		ast_str_append(&output, 0, "      Variables:\n%s\n", ast_str_buffer(obuf));
 	}
 
-	if (c->cdr && ast_cdr_serialize_variables(c->cdr, &out, '=', '\n', 1)) {
-		ast_cli(a->fd,"  CDR Variables:\n%s\n", ast_str_buffer(out));
+	if (c->cdr && ast_cdr_serialize_variables(c->cdr, &obuf, '=', '\n', 1)) {
+		ast_str_append(&output, 0, "  CDR Variables:\n%s\n", ast_str_buffer(obuf));
 	}
 
 #ifdef CHANNEL_TRACE
 	trace_enabled = ast_channel_trace_is_enabled(c);
-	ast_cli(a->fd, "  Context Trace: %s\n", trace_enabled ? "Enabled" : "Disabled");
-	if (trace_enabled && ast_channel_trace_serialize(c, &out))
-		ast_cli(a->fd, "          Trace:\n%s\n", ast_str_buffer(out));
+	ast_str_append(&output, 0, "  Context Trace: %s\n",
+		trace_enabled ? "Enabled" : "Disabled");
+	if (trace_enabled && ast_channel_trace_serialize(c, &obuf)) {
+		ast_str_append(&output, 0, "          Trace:\n%s\n", ast_str_buffer(obuf));
+	}
 #endif
 
 	ast_channel_unlock(c);
 	c = ast_channel_unref(c);
 
+	ast_cli(a->fd, "%s", ast_str_buffer(output));
+	ast_free(output);
 	return CLI_SUCCESS;
 }