From: Michael Jeanson <mjeanson@efficios.com>
Date: Fri, 26 Mar 2021 19:34:21 +0000 (-0400)
Subject: fix: string constants (-Wwrite-strings)
X-Git-Tag: v2.13.0-rc1~160
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=74c3f8e27f5b750b71136ce1737972c28f288540;p=lttng-ust.git

fix: string constants (-Wwrite-strings)

Do not use an anonymous string literal with a non-const char pointer as
this will discard the implicit const, use static non-const string
instead when appropriate. Otherwise, we could end up trying to write to
a string constant.

Change-Id: Ie2bb0e5ab7978930f9edcdb379bd181caaacc15c
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/doc/examples/easy-ust/sample_component_provider.h b/doc/examples/easy-ust/sample_component_provider.h
index edfac8f5..d457664d 100644
--- a/doc/examples/easy-ust/sample_component_provider.h
+++ b/doc/examples/easy-ust/sample_component_provider.h
@@ -74,7 +74,7 @@ TRACEPOINT_EVENT(
 	 * 		TP_ARGS() is valid to mean no arguments
 	 * 		TP_ARGS( void ) is valid too
 	 */
-	TP_ARGS(char *, text),
+	TP_ARGS(const char *, text),
 	/*
 	 * TP_FIELDS describes how to write the fields of the trace event.
 	 * You can use the args here
diff --git a/doc/examples/gen-tp/sample_tracepoint.tp b/doc/examples/gen-tp/sample_tracepoint.tp
index fa7d18a5..22f7713f 100644
--- a/doc/examples/gen-tp/sample_tracepoint.tp
+++ b/doc/examples/gen-tp/sample_tracepoint.tp
@@ -1,7 +1,7 @@
 TRACEPOINT_EVENT(
 	sample_tracepoint,
 	message, // C++ Style comment
-	TP_ARGS(char *, text),
+	TP_ARGS(const char *, text),
 	TP_FIELDS(
 		ctf_string(message, text)
 		  )
diff --git a/liblttng-ust/lttng-context-procname.c b/liblttng-ust/lttng-context-procname.c
index a65585de..53c42d9e 100644
--- a/liblttng-ust/lttng-context-procname.c
+++ b/liblttng-ust/lttng-context-procname.c
@@ -37,7 +37,7 @@ static DEFINE_URCU_TLS(procname_array, cached_procname);
 static DEFINE_URCU_TLS(int, procname_nesting);
 
 static inline
-char *wrapper_getprocname(void)
+const char *wrapper_getprocname(void)
 {
 	int nesting = CMM_LOAD_SHARED(URCU_TLS(procname_nesting));
 
@@ -76,7 +76,7 @@ void procname_record(struct lttng_ust_ctx_field *field,
 		 struct lttng_ust_lib_ring_buffer_ctx *ctx,
 		 struct lttng_ust_channel_buffer *chan)
 {
-	char *procname;
+	const char *procname;
 
 	procname = wrapper_getprocname();
 	chan->ops->event_write(ctx, procname, LTTNG_UST_ABI_PROCNAME_LEN, 1);
diff --git a/liblttng-ust/ust-events-internal.h b/liblttng-ust/ust-events-internal.h
index daf72b9d..786b650d 100644
--- a/liblttng-ust/ust-events-internal.h
+++ b/liblttng-ust/ust-events-internal.h
@@ -250,14 +250,14 @@ struct lttng_event_notifier_group {
 };
 
 struct lttng_transport {
-	char *name;
+	const char *name;
 	struct cds_list_head node;
 	struct lttng_ust_channel_buffer_ops ops;
 	const struct lttng_ust_lib_ring_buffer_config *client_config;
 };
 
 struct lttng_counter_transport {
-	char *name;
+	const char *name;
 	struct cds_list_head node;
 	struct lttng_counter_ops ops;
 	const struct lib_counter_config *client_config;
diff --git a/snprintf/vfprintf.c b/snprintf/vfprintf.c
index 5cb356c2..c2b07eb0 100644
--- a/snprintf/vfprintf.c
+++ b/snprintf/vfprintf.c
@@ -35,6 +35,9 @@
 #include "fvwrite.h"
 #include "various.h"
 
+static char null_str[] = "(null)";
+static char bad_base_str[] = "bug in ust_safe_vfprintf: bad base";
+
 union arg {
 	int			intarg;
 	unsigned int		uintarg;
@@ -715,7 +718,7 @@ fp_common:
 			goto nosign;
 		case 's':
 			if ((cp = GETARG(char *)) == NULL)
-				cp = "(null)";
+				cp = null_str;
 			if (prec >= 0) {
 				/*
 				 * can't use strlen; can only look for the
@@ -802,7 +805,7 @@ number:			if ((dprec = prec) >= 0)
 					break;
 
 				default:
-					cp = "bug in ust_safe_vfprintf: bad base";
+					cp = bad_base_str;
 					size = strlen(cp);
 					goto skipsize;
 				}
diff --git a/tests/compile/test-app-ctx/hello.c b/tests/compile/test-app-ctx/hello.c
index c08fa8dd..da347714 100644
--- a/tests/compile/test-app-ctx/hello.c
+++ b/tests/compile/test-app-ctx/hello.c
@@ -243,9 +243,10 @@ void test_get_value(struct lttng_ust_ctx_field *field,
 	}
 }
 
+static char myprovider_name[] = "$app.myprovider";
 struct lttng_ust_context_provider myprovider = {
 	.struct_size = sizeof(struct lttng_ust_context_provider),
-	.name = "$app.myprovider",
+	.name = myprovider_name,
 	.get_size = test_get_size,
 	.record = test_record,
 	.get_value = test_get_value,