perf probe: Add argv_split() from lib/argv_split.c

Add argv_split() ported from lib/argv_split.c to string.c and
use it in util/probe-event.c.

Signed-off-by: Masami Hiramatsu <[email protected]>
Cc: systemtap <[email protected]>
Cc: DLE <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Jim Keniston <[email protected]>
Cc: Ananth N Mavinakayanahalli <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Frank Ch. Eigler <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Jason Baron <[email protected]>
Cc: K.Prasad <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Srikar Dronamraju <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
LKML-Reference: <20091201002005.10235.55602.stgit@harusame>
Signed-off-by: Ingo Molnar <[email protected]>

tools/perf/util/probe-event.c

@@ -32,6 +32,7 @@
 
 #undef _GNU_SOURCE
 #include "event.h"
+#include "string.h"
 #include "debug.h"
 #include "parse-events.h"  /* For debugfs_path */
 #include "probe-event.h"
@@ -132,62 +133,36 @@ static void parse_perf_probe_probepoint(char *arg, struct probe_point *pp)
 /* Parse perf-probe event definition */
 int parse_perf_probe_event(const char *str, struct probe_point *pp)
 {
-	char *argv[MAX_PROBE_ARGS + 1];	/* probe + args */
+	char **argv;
 	int argc, i, need_dwarf = 0;
 
-	/* Separate arguments, similar to argv_split */
-	argc = 0;
-	do {
-		/* Skip separators */
-		while (isspace(*str))
-			str++;
-
-		/* Add an argument */
-		if (*str != '\0') {
-			const char *s = str;
-			/* Check the limit number of arguments */
-			if (argc == MAX_PROBE_ARGS + 1)
-				semantic_error("Too many arguments");
-
-			/* Skip the argument */
-			while (!isspace(*str) && *str != '\0')
-				str++;
-
-			/* Duplicate the argument */
-			argv[argc] = strndup(s, str - s);
-			if (argv[argc] == NULL)
-				die("strndup");
-			pr_debug("argv[%d]=%s\n", argc, argv[argc]);
-			argc++;
-		}
-	} while (*str != '\0');
-	if (!argc)
-		semantic_error("An empty argument.");
+	argv = argv_split(str, &argc);
+	if (!argv)
+		die("argv_split failed.");
+	if (argc > MAX_PROBE_ARGS + 1)
+		semantic_error("Too many arguments");
 
 	/* Parse probe point */
 	parse_perf_probe_probepoint(argv[0], pp);
-	free(argv[0]);
 	if (pp->file || pp->line)
 		need_dwarf = 1;
 
-	/* Copy arguments */
+	/* Copy arguments and ensure return probe has no C argument */
 	pp->nr_args = argc - 1;
-	if (pp->nr_args > 0) {
-		pp->args = (char **)malloc(sizeof(char *) * pp->nr_args);
-		if (!pp->args)
-			die("malloc");
-		memcpy(pp->args, &argv[1], sizeof(char *) * pp->nr_args);
-	}
-
-	/* Ensure return probe has no C argument */
-	for (i = 0; i < pp->nr_args; i++)
+	pp->args = zalloc(sizeof(char *) * pp->nr_args);
+	for (i = 0; i < pp->nr_args; i++) {
+		pp->args[i] = strdup(argv[i + 1]);
+		if (!pp->args[i])
+			die("Failed to copy argument.");
 		if (is_c_varname(pp->args[i])) {
 			if (pp->retprobe)
 				semantic_error("You can't specify local"
 						" variable for kretprobe");
 			need_dwarf = 1;
 		}
+	}
 
+	argv_free(argv);
 	return need_dwarf;
 }
 

tools/perf/util/string.c

@@ -127,3 +127,104 @@ s64 perf_atoll(const char *str)
 out:
 	return length;
 }
+
+/*
+ * Helper function for splitting a string into an argv-like array.
+ * originaly copied from lib/argv_split.c
+ */
+static const char *skip_sep(const char *cp)
+{
+	while (*cp && isspace(*cp))
+		cp++;
+
+	return cp;
+}
+
+static const char *skip_arg(const char *cp)
+{
+	while (*cp && !isspace(*cp))
+		cp++;
+
+	return cp;
+}
+
+static int count_argc(const char *str)
+{
+	int count = 0;
+
+	while (*str) {
+		str = skip_sep(str);
+		if (*str) {
+			count++;
+			str = skip_arg(str);
+		}
+	}
+
+	return count;
+}
+
+/**
+ * argv_free - free an argv
+ * @argv - the argument vector to be freed
+ *
+ * Frees an argv and the strings it points to.
+ */
+void argv_free(char **argv)
+{
+	char **p;
+	for (p = argv; *p; p++)
+		free(*p);
+
+	free(argv);
+}
+
+/**
+ * argv_split - split a string at whitespace, returning an argv
+ * @str: the string to be split
+ * @argcp: returned argument count
+ *
+ * Returns an array of pointers to strings which are split out from
+ * @str.  This is performed by strictly splitting on white-space; no
+ * quote processing is performed.  Multiple whitespace characters are
+ * considered to be a single argument separator.  The returned array
+ * is always NULL-terminated.  Returns NULL on memory allocation
+ * failure.
+ */
+char **argv_split(const char *str, int *argcp)
+{
+	int argc = count_argc(str);
+	char **argv = zalloc(sizeof(*argv) * (argc+1));
+	char **argvp;
+
+	if (argv == NULL)
+		goto out;
+
+	if (argcp)
+		*argcp = argc;
+
+	argvp = argv;
+
+	while (*str) {
+		str = skip_sep(str);
+
+		if (*str) {
+			const char *p = str;
+			char *t;
+
+			str = skip_arg(str);
+
+			t = strndup(p, str-p);
+			if (t == NULL)
+				goto fail;
+			*argvp++ = t;
+		}
+	}
+	*argvp = NULL;
+
+out:
+	return argv;
+
+fail:
+	argv_free(argv);
+	return NULL;
+}

tools/perf/util/string.h

@@ -6,6 +6,8 @@
 int hex2u64(const char *ptr, u64 *val);
 char *strxfrchar(char *s, char from, char to);
 s64 perf_atoll(const char *str);
+char **argv_split(const char *str, int *argcp);
+void argv_free(char **argv);
 
 #define _STR(x) #x
 #define STR(x) _STR(x)