perf probe: Move probe event utility functions to probe-event.c

Split probe event (kprobe-events and perf probe events) utility
functions from builtin-probe.c to probe-event.c.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20091201001958.10235.90243.stgit@harusame>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 283 insertions, 0 deletions

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
new file mode 100644
index 00000000000..7335a3b5e49
--- /dev/null
+++ b/tools/perf/util/probe-event.c
@@ -0,0 +1,273 @@
+/*
+ * probe-event.c : perf-probe definition to kprobe_events format converter
+ *
+ * Written by Masami Hiramatsu <mhiramat@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ */
+
+#define _GNU_SOURCE
+#include <sys/utsname.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+
+#undef _GNU_SOURCE
+#include "event.h"
+#include "debug.h"
+#include "parse-events.h"  /* For debugfs_path */
+#include "probe-event.h"
+
+#define MAX_CMDLEN 256
+#define MAX_PROBE_ARGS 128
+#define PERFPROBE_GROUP "probe"
+
+#define semantic_error(msg ...) die("Semantic error :" msg)
+
+/* Parse probepoint definition. */
+static void parse_perf_probe_probepoint(char *arg, struct probe_point *pp)
+{
+	char *ptr, *tmp;
+	char c, nc = 0;
+	/*
+	 * <Syntax>
+	 * perf probe SRC:LN
+	 * perf probe FUNC[+OFFS|%return][@SRC]
+	 */
+
+	ptr = strpbrk(arg, ":+@%");
+	if (ptr) {
+		nc = *ptr;
+		*ptr++ = '\0';
+	}
+
+	/* Check arg is function or file and copy it */
+	if (strchr(arg, '.'))	/* File */
+		pp->file = strdup(arg);
+	else			/* Function */
+		pp->function = strdup(arg);
+	DIE_IF(pp->file == NULL && pp->function == NULL);
+
+	/* Parse other options */
+	while (ptr) {
+		arg = ptr;
+		c = nc;
+		ptr = strpbrk(arg, ":+@%");
+		if (ptr) {
+			nc = *ptr;
+			*ptr++ = '\0';
+		}
+		switch (c) {
+		case ':':	/* Line number */
+			pp->line = strtoul(arg, &tmp, 0);
+			if (*tmp != '\0')
+				semantic_error("There is non-digit charactor"
+						" in line number.");
+			break;
+		case '+':	/* Byte offset from a symbol */
+			pp->offset = strtoul(arg, &tmp, 0);
+			if (*tmp != '\0')
+				semantic_error("There is non-digit charactor"
+						" in offset.");
+			break;
+		case '@':	/* File name */
+			if (pp->file)
+				semantic_error("SRC@SRC is not allowed.");
+			pp->file = strdup(arg);
+			DIE_IF(pp->file == NULL);
+			if (ptr)
+				semantic_error("@SRC must be the last "
+					       "option.");
+			break;
+		case '%':	/* Probe places */
+			if (strcmp(arg, "return") == 0) {
+				pp->retprobe = 1;
+			} else	/* Others not supported yet */
+				semantic_error("%%%s is not supported.", arg);
+			break;
+		default:
+			DIE_IF("Program has a bug.");
+			break;
+		}
+	}
+
+	/* Exclusion check */
+	if (pp->line && pp->offset)
+		semantic_error("Offset can't be used with line number.");
+
+	if (!pp->line && pp->file && !pp->function)
+		semantic_error("File always requires line number.");
+
+	if (pp->offset && !pp->function)
+		semantic_error("Offset requires an entry function.");
+
+	if (pp->retprobe && !pp->function)
+		semantic_error("Return probe requires an entry function.");
+
+	if ((pp->offset || pp->line) && pp->retprobe)
+		semantic_error("Offset/Line can't be used with return probe.");
+
+	pr_debug("symbol:%s file:%s line:%d offset:%d, return:%d\n",
+		 pp->function, pp->file, pp->line, pp->offset, pp->retprobe);
+}
+
+/* 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 */
+	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.");
+
+	/* Parse probe point */
+	parse_perf_probe_probepoint(argv[0], pp);
+	free(argv[0]);
+	if (pp->file || pp->line)
+		need_dwarf = 1;
+
+	/* Copy arguments */
+	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++)
+		if (is_c_varname(pp->args[i])) {
+			if (pp->retprobe)
+				semantic_error("You can't specify local"
+						" variable for kretprobe");
+			need_dwarf = 1;
+		}
+
+	return need_dwarf;
+}
+
+int synthesize_trace_kprobe_event(struct probe_point *pp)
+{
+	char *buf;
+	int i, len, ret;
+
+	pp->probes[0] = buf = zalloc(MAX_CMDLEN);
+	if (!buf)
+		die("Failed to allocate memory by zalloc.");
+	ret = snprintf(buf, MAX_CMDLEN, "%s+%d", pp->function, pp->offset);
+	if (ret <= 0 || ret >= MAX_CMDLEN)
+		goto error;
+	len = ret;
+
+	for (i = 0; i < pp->nr_args; i++) {
+		ret = snprintf(&buf[len], MAX_CMDLEN - len, " %s",
+			       pp->args[i]);
+		if (ret <= 0 || ret >= MAX_CMDLEN - len)
+			goto error;
+		len += ret;
+	}
+	pp->found = 1;
+
+	return pp->found;
+error:
+	free(pp->probes[0]);
+	if (ret > 0)
+		ret = -E2BIG;
+
+	return ret;
+}
+
+static int write_trace_kprobe_event(int fd, const char *buf)
+{
+	int ret;
+
+	ret = write(fd, buf, strlen(buf));
+	if (ret <= 0)
+		die("Failed to create event.");
+	else
+		printf("Added new event: %s\n", buf);
+
+	return ret;
+}
+
+void add_trace_kprobe_events(struct probe_point *probes, int nr_probes)
+{
+	int i, j, fd;
+	struct probe_point *pp;
+	char buf[MAX_CMDLEN];
+
+	snprintf(buf, MAX_CMDLEN, "%s/../kprobe_events", debugfs_path);
+	fd = open(buf, O_WRONLY, O_APPEND);
+	if (fd < 0) {
+		if (errno == ENOENT)
+			die("kprobe_events file does not exist -"
+			    " please rebuild with CONFIG_KPROBE_TRACER.");
+		else
+			die("Could not open kprobe_events file: %s",
+			    strerror(errno));
+	}
+
+	for (j = 0; j < nr_probes; j++) {
+		pp = probes + j;
+		if (pp->found == 1) {
+			snprintf(buf, MAX_CMDLEN, "%c:%s/%s_%x %s\n",
+				pp->retprobe ? 'r' : 'p', PERFPROBE_GROUP,
+				pp->function, pp->offset, pp->probes[0]);
+			write_trace_kprobe_event(fd, buf);
+		} else
+			for (i = 0; i < pp->found; i++) {
+				snprintf(buf, MAX_CMDLEN, "%c:%s/%s_%x_%d %s\n",
+					pp->retprobe ? 'r' : 'p',
+					PERFPROBE_GROUP,
+					pp->function, pp->offset, i,
+					pp->probes[i]);
+				write_trace_kprobe_event(fd, buf);
+			}
+	}
+	close(fd);
+}
diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h
new file mode 100644
index 00000000000..0089c455eca
--- /dev/null
+++ b/tools/perf/util/probe-event.h
@@ -0,0 +1,10 @@
+#ifndef _PROBE_EVENT_H
+#define _PROBE_EVENT_H
+
+#include "probe-finder.h"
+
+extern int parse_perf_probe_event(const char *str, struct probe_point *pp);
+extern int synthesize_trace_kprobe_event(struct probe_point *pp);
+extern void add_trace_kprobe_events(struct probe_point *probes, int nr_probes);
+
+#endif /*_PROBE_EVENT_H */