Solaris doesn't like outputting a NULL to a %s in format strings.

Detect all platforms that don't like that, either, and ensure that when documentation is
missing, we pass a non-NULL pointer when outputting the corresponding documentation.

(closes issue #16689)
 Reported by: bklang
 Patches: 
       20100209__issue16689__with_tests.diff.txt uploaded by tilghman (license 14)
 
Review: https://reviewboard.asterisk.org/r/497/


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@246030 65c4cc65-6c06-0410-ace0-fbb531ad65f3

4 files changed, 139 insertions, 9 deletions

diff --git a/configure b/configure
index ec9ac0c55..004048620 100755
--- a/configure
+++ b/configure
@@ -1,5 +1,5 @@
 #! /bin/sh
-# From configure.ac Revision: 242857 .
+# From configure.ac Revision: 242967 .
 # Guess values for system-dependent variables and create Makefiles.
 # Generated by GNU Autoconf 2.61 for asterisk 1.6.
 #
@@ -18648,6 +18648,71 @@ fi
 rm -f core conftest.err conftest.$ac_objext conftest_ipa8_conftest.oo \
       conftest$ac_exeext conftest.$ac_ext
 
+# glibc, AFAIK, is the only C library that makes printing a NULL to a string safe.
+{ echo "$as_me:$LINENO: checking if your system printf is NULL-safe." >&5
+echo $ECHO_N "checking if your system printf is NULL-safe.... $ECHO_C" >&6; }
+if test "$cross_compiling" = yes; then
+  # It's unlikely an embedded system will have this.
+	{ echo "$as_me:$LINENO: result: unknown" >&5
+echo "${ECHO_T}unknown" >&6; }
+
+else
+  cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+#include <stdio.h>
+int
+main ()
+{
+printf("%s", NULL)
+  ;
+  return 0;
+}
+_ACEOF
+rm -f conftest$ac_exeext
+if { (ac_try="$ac_link"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_link") 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } && { ac_try='./conftest$ac_exeext'
+  { (case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_try") 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_NULLSAFE_PRINTF 1
+_ACEOF
+
+	{ echo "$as_me:$LINENO: result: yes" >&5
+echo "${ECHO_T}yes" >&6; }
+else
+  echo "$as_me: program exited with status $ac_status" >&5
+echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+( exit $ac_status )
+{ echo "$as_me:$LINENO: result: no" >&5
+echo "${ECHO_T}no" >&6; }
+fi
+rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext conftest.$ac_objext conftest.$ac_ext
+fi
+
+
+
 
 { echo "$as_me:$LINENO: checking for compiler 'attribute pure' support" >&5
 echo $ECHO_N "checking for compiler 'attribute pure' support... $ECHO_C" >&6; }
diff --git a/configure.ac b/configure.ac
index ea0e3eb18..b093d0af6 100644
--- a/configure.ac
+++ b/configure.ac
@@ -619,6 +619,18 @@ AC_DEFINE([HAVE_GCC_ATOMICS], 1, [Define to 1 if your GCC C compiler provides at
 AC_MSG_RESULT(no)
 )
 
+# glibc, AFAIK, is the only C library that makes printing a NULL to a string safe.
+AC_MSG_CHECKING([if your system printf is NULL-safe.])
+AC_RUN_IFELSE(
+	AC_LANG_PROGRAM([#include <stdio.h>],
+		[printf("%s", NULL)]),
+	AC_DEFINE([HAVE_NULLSAFE_PRINTF], 1, [Define to 1 if your C library can safely print NULL to string formats.])
+	AC_MSG_RESULT(yes),
+	AC_MSG_RESULT(no),
+	# It's unlikely an embedded system will have this.
+	AC_MSG_RESULT(unknown)
+)
+
 AST_GCC_ATTRIBUTE(pure)
 AST_GCC_ATTRIBUTE(malloc)
 AST_GCC_ATTRIBUTE(const)
diff --git a/include/asterisk/autoconfig.h.in b/include/asterisk/autoconfig.h.in
index 32f4d08d6..c2c33417e 100644
--- a/include/asterisk/autoconfig.h.in
+++ b/include/asterisk/autoconfig.h.in
@@ -591,6 +591,9 @@
 /* Define to 1 if you have the `ntohll' function. */
 #undef HAVE_NTOHLL
 
+/* Define to 1 if your C library can safely print NULL to string formats. */
+#undef HAVE_NULLSAFE_PRINTF
+
 /* Define to 1 if your ODBC library has wide (Unicode) types. */
 #undef HAVE_ODBC_WCHAR
 
diff --git a/res/res_agi.c b/res/res_agi.c
index b055a23e6..6113c7a3c 100644
--- a/res/res_agi.c
+++ b/res/res_agi.c
@@ -61,6 +61,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #include "asterisk/term.h"
 #include "asterisk/xmldoc.h"
 #include "asterisk/srv.h"
+#include "asterisk/test.h"
 
 #define AST_API_MODULE
 #include "asterisk/agi.h"
@@ -816,7 +817,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 			correspondingly receive a HANGUP in OOB data. Both of these signals may be disabled
 			by setting the <variable>AGISIGHUP</variable> channel variable to <literal>no</literal>
 			before executing the AGI application.</para>
-			<para>Use the CLI command <literal>agi show commnands</literal> to list available agi
+			<para>Use the CLI command <literal>agi show commands</literal> to list available agi
 			commands.</para>
 			<para>This application sets the following channel variable upon completion:</para>
 			<variablelist>
@@ -3000,7 +3001,7 @@ static char *help_workhorse(int fd, const char * const match[])
 		ast_join(fullcmd, sizeof(fullcmd), e->cmda);
 		if (match && strncasecmp(matchstr, fullcmd, strlen(matchstr)))
 			continue;
-		ast_cli(fd, "%5.5s %30.30s   %s\n", e->dead ? "Yes" : "No" , fullcmd, e->summary);
+		ast_cli(fd, "%5.5s %30.30s   %s\n", e->dead ? "Yes" : "No" , fullcmd, S_OR(e->summary, "Not available"));
 	}
 	AST_RWLIST_UNLOCK(&agi_commands);
 
@@ -3014,16 +3015,22 @@ int AST_OPTIONAL_API_NAME(ast_agi_register)(struct ast_module *mod, agi_command
 	ast_join(fullcmd, sizeof(fullcmd), cmd->cmda);
 
 	if (!find_command(cmd->cmda, 1)) {
-#ifdef AST_XML_DOCS
 		*((enum ast_doc_src *) &cmd->docsrc) = AST_STATIC_DOC;
 		if (ast_strlen_zero(cmd->summary) && ast_strlen_zero(cmd->usage)) {
+#ifdef AST_XML_DOCS
 			*((char **) &cmd->summary) = ast_xmldoc_build_synopsis("agi", fullcmd);
 			*((char **) &cmd->usage) = ast_xmldoc_build_description("agi", fullcmd);
 			*((char **) &cmd->syntax) = ast_xmldoc_build_syntax("agi", fullcmd);
 			*((char **) &cmd->seealso) = ast_xmldoc_build_seealso("agi", fullcmd);
 			*((enum ast_doc_src *) &cmd->docsrc) = AST_XML_DOC;
-		}
+#elif (!defined(HAVE_NULLSAFE_PRINTF))
+			*((char **) &cmd->summary) = ast_strdup("");
+			*((char **) &cmd->usage) = ast_strdup("");
+			*((char **) &cmd->syntax) = ast_strdup("");
+			*((char **) &cmd->seealso) = ast_strdup("");
 #endif
+		}
+
 		cmd->mod = mod;
 		AST_RWLIST_WRLOCK(&agi_commands);
 		AST_LIST_INSERT_TAIL(&agi_commands, cmd, list);
@@ -3266,9 +3273,13 @@ static int agi_handle_command(struct ast_channel *chan, AGI *agi, char *buf, int
 				"Result: %s\r\n", chan->name, command_id, ami_cmd, resultcode, ami_res);
 		switch(res) {
 		case RESULT_SHOWUSAGE:
-			ast_agi_send(agi->fd, chan, "520-Invalid command syntax.  Proper usage follows:\n");
-			ast_agi_send(agi->fd, chan, "%s", c->usage);
-			ast_agi_send(agi->fd, chan, "520 End of proper usage.\n");
+			if (ast_strlen_zero(c->usage)) {
+				ast_agi_send(agi->fd, chan, "520 Invalid command syntax.  Proper usage not available.\n");
+			} else {
+				ast_agi_send(agi->fd, chan, "520-Invalid command syntax.  Proper usage follows:\n");
+				ast_agi_send(agi->fd, chan, "%s", c->usage);
+				ast_agi_send(agi->fd, chan, "520 End of proper usage.\n");
+			}
 			break;
 		case RESULT_FAILURE:
 			/* They've already given the failure.  We've been hung up on so handle this
@@ -3449,7 +3460,7 @@ static char *handle_cli_agi_show(struct ast_cli_entry *e, int cmd, struct ast_cl
 	case CLI_INIT:
 		e->command = "agi show commands [topic]";
 		e->usage =
-			"Usage: agi show commands [topic]\n"
+			"Usage: agi show commands [topic] <topic>\n"
 			"       When called with a topic as an argument, displays usage\n"
 			"       information on the given command.  If called without a\n"
 			"       topic, it provides a list of AGI commands.\n";
@@ -3766,6 +3777,43 @@ static struct ast_cli_entry cli_agi[] = {
 	AST_CLI_DEFINE(handle_cli_agi_dump_html, "Dumps a list of AGI commands in HTML format")
 };
 
+#ifdef TEST_FRAMEWORK
+AST_TEST_DEFINE(test_agi_null_docs)
+{
+	int res = AST_TEST_PASS;
+	struct agi_command noop_command =
+		{ { "testnoop", NULL }, handle_noop, NULL, NULL, 0 };
+
+	switch (cmd) {
+	case TEST_INIT:
+		info->name = "null_agi_docs";
+		info->category = "res/agi/";
+		info->summary = "AGI command with no documentation";
+		info->description = "Test whether an AGI command with no documentation will crash Asterisk";
+		return AST_TEST_NOT_RUN;
+	case TEST_EXECUTE:
+		break;
+	}
+
+	if (ast_agi_register(ast_module_info->self, &noop_command) == 0) {
+		return AST_TEST_NOT_RUN;
+	}
+
+#ifndef HAVE_NULLSAFE_PRINTF
+	/* Test for condition without actually crashing Asterisk */
+	if (noop_command.usage == NULL) {
+		res = AST_TEST_FAIL;
+	}
+	if (noop_command.description == NULL) {
+		res = AST_TEST_FAIL;
+	}
+#endif
+
+	ast_agi_unregister(ast_module_info->self, &noop_command);
+	return res;
+}
+#endif
+
 static int unload_module(void)
 {
 	ast_cli_unregister_multiple(cli_agi, ARRAY_LEN(cli_agi));
@@ -3776,6 +3824,7 @@ static int unload_module(void)
 	ast_unregister_application(eapp);
 	ast_unregister_application(deadapp);
 	ast_manager_unregister("AGI");
+	AST_TEST_UNREGISTER(test_agi_null_docs);
 	return ast_unregister_application(app);
 }
 
@@ -3789,6 +3838,7 @@ static int load_module(void)
 	ast_register_application_xml(deadapp, deadagi_exec);
 	ast_register_application_xml(eapp, eagi_exec);
 	ast_manager_register_xml("AGI", EVENT_FLAG_AGI, action_add_agi_cmd);
+	AST_TEST_REGISTER(test_agi_null_docs);
 	return ast_register_application_xml(app, agi_exec);
 }