ktrace: Add code to create a kprobe

Add the code to create a kprobe. It only prints the command for now, but
will later actually create it.

Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

1 files changed, 131 insertions, 50 deletions

diff --git a/src/create.c b/src/create.c
index d66cc34..d1ba688 100644
--- a/src/create.c
+++ b/src/create.c
@@ -11,55 +11,16 @@ static void create_usage(struct ccli *ccli)
 		    "  <type> : kprobe, eprobe, synthetic_event\n");
 }
 
-static int create_kprobe(struct ccli *ccli, void *data,
-			 int argc, char **argv)
-{
-	return 0;
-}
-
-static int add_event_var(struct ccli *ccli, struct tep_handle *tep,
-			 char **command, struct tep_event *event,
-			 char *line)
+static int add_type_offset(struct ccli *ccli, char *p, char **pvar, char *line)
 {
-	struct tep_format_field *field;
 	long long offset;
-	bool neg;
-	char *fname;
+	char *var = *pvar;
 	char *type;
-	char *var;
 	char *tmp;
 	char *end;
-	char *p;
-	char ch;
-	int ret;
-
-	p = strchr(line, '=');
-	if (!p) {
-		ccli_printf(ccli, "Invalid variable '%s'\n", line);
-		return -1;
-	}
-
-	*p = '\0';
-	fname = p + 1;
-	for (p++; *p; p++) {
-		if (*p == '.' || *p == '-')
-			break;
-	}
-	ch = *p;
-	*p = '\0';
-
-	field = tep_find_any_field(event, fname);
-	if (!field) {
-		ccli_printf(ccli, "# Cannot find field '%s' for event '%s'\n",
-			    fname, event->name);
-		return -1;
-	}
-
-	ret = asprintf(&var, "$%s", fname);
-	if (ret < 0)
-		return -1;
+	bool neg;
+	int ret = 0;
 
-	*p = ch;
 	for (; *p; p++) {
 		switch(*p) {
 		case '.':
@@ -72,14 +33,14 @@ static int add_event_var(struct ccli *ccli, struct tep_handle *tep,
 			if (*p == '.') {
 				ccli_printf(ccli, "# Two types can not be togethe '%s'\n",
 					    line);
-				goto out;
+				return -1;
 			}
 			if (strncmp(type, "string", 6) == 0 ||
 			    strncmp(type, "ustring", 7) == 0) {
 				if (*p) {
 					ccli_printf(ccli, "# Strings can not be deferenced '%s'\n",
 						type);
-					goto out;
+					return -1;
 				}
 				ret = asprintf(&tmp, "+0(%s):%.*s",
 					       var, (int)(p - type),
@@ -90,7 +51,7 @@ static int add_event_var(struct ccli *ccli, struct tep_handle *tep,
 					       type);
 			}
 			if (ret < 0)
-				goto out;
+				return -1;
 			free(var);
 			var = tmp;
 			/* We need to compare current p again */
@@ -101,7 +62,7 @@ static int add_event_var(struct ccli *ccli, struct tep_handle *tep,
 			if (*p != '>') {
 				ccli_printf(ccli, "# Invalid variable '%s'\n",
 					    type);
-				goto out;
+				return -1;
 			}
 			p++;
 			if (*p == '-') {
@@ -112,15 +73,135 @@ static int add_event_var(struct ccli *ccli, struct tep_handle *tep,
 			ret = asprintf(&tmp, "%s%llu(%s)",
 				       neg ? "-" : "+", offset, var);
 			if (ret < 0)
-				goto out;
+				return -1;
 			free(var);
 			var = tmp;
 			break;
 		}
 	}
-	/* Finished */
-	ret = asprintf(&tmp, "%s %s=%s", *command, line, var);
+	*pvar = var;
+	return ret;
+}
+
+static int add_var(struct ccli *ccli, char **command, char *line)
+{
+	char *sym;
+	char *var;
+	char *tmp;
+	char *p;
+	char ch;
+	int ret;
+
+	p = strchr(line, '=');
+	if (!p) {
+		ccli_printf(ccli, "Invalid variable '%s'\n", line);
+		return -1;
+	}
+
+	*p = '\0';
+	sym = p + 1;
+	for (p++; *p; p++) {
+		if (*p == '.' || *p == '-')
+			break;
+	}
+	ch = *p;
+	*p = '\0';
+
+	var = strdup(sym);
+	if (!var)
+		return -1;
+
+	*p = ch;
+	ret = add_type_offset(ccli, p, &var, line);
+
+	if (ret >= 0)
+		ret = asprintf(&tmp, "%s %s=%s", *command, line, var);
+
+	free(var);
+	if (ret < 0)
+		return -1;
+	free(*command);
+	*command = tmp;
+	return 0;
+}
+
+static int create_kprobe(struct ccli *ccli, void *data,
+			 int argc, char **argv)
+{
+	char *command;
+	char *sym;
+	char *name;
+	int ret;
+	int i;
+
+	if (argc < 3) {
+		ccli_printf(ccli, "# usage: create kprobe name function/address fields\n");
+		return 0;
+	}
+
+	name = argv[0];
+	sym = argv[1];
+
+	ret = asprintf(&command, "k:%s %s", name, sym);
+	if (ret < 0)
+		return 0;
+
+	for (i = 2 ; i < argc; i++ ) {
+		ret = add_var(ccli, &command, argv[i]);
+		if (ret < 0)
+			goto out;
+	}
+	ccli_printf(ccli, "# echo '%s' >> %s/dynamic_events\n",
+		    command, tracefs_tracing_dir());
  out:
+	free(command);
+	return 0;
+}
+
+static int add_event_var(struct ccli *ccli, struct tep_handle *tep,
+			 char **command, struct tep_event *event,
+			 char *line)
+{
+	struct tep_format_field *field;
+	char *fname;
+	char *var;
+	char *tmp;
+	char *p;
+	char ch;
+	int ret;
+
+	p = strchr(line, '=');
+	if (!p) {
+		ccli_printf(ccli, "Invalid variable '%s'\n", line);
+		return -1;
+	}
+
+	*p = '\0';
+	fname = p + 1;
+	for (p++; *p; p++) {
+		if (*p == '.' || *p == '-')
+			break;
+	}
+	ch = *p;
+	*p = '\0';
+
+	field = tep_find_any_field(event, fname);
+	if (!field) {
+		ccli_printf(ccli, "# Cannot find field '%s' for event '%s'\n",
+			    fname, event->name);
+		return -1;
+	}
+
+	ret = asprintf(&var, "$%s", fname);
+	if (ret < 0)
+		return -1;
+
+	*p = ch;
+	ret = add_type_offset(ccli, p, &var, line);
+
+	if (ret >= 0)
+		ret = asprintf(&tmp, "%s %s=%s", *command, line, var);
+
 	free(var);
 	if (ret < 0)
 		return -1;