1 files changed, 435 insertions, 0 deletions

diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
new file mode 100644
index 00000000000..d78a3d94549
--- /dev/null
+++ b/tools/perf/builtin-probe.c
@@ -0,0 +1,435 @@
+/*
+ * builtin-probe.c
+ *
+ * Builtin probe command: Set up probe events by C expression
+ *
+ * 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 "perf.h"
+#include "builtin.h"
+#include "util/util.h"
+#include "util/event.h"
+#include "util/debug.h"
+#include "util/parse-options.h"
+#include "util/parse-events.h"	/* For debugfs_path */
+#include "util/probe-finder.h"
+
+/* Default vmlinux search paths */
+#define NR_SEARCH_PATH 3
+const char *default_search_path[NR_SEARCH_PATH] = {
+"/lib/modules/%s/build/vmlinux",		/* Custom build kernel */
+"/usr/lib/debug/lib/modules/%s/vmlinux",	/* Red Hat debuginfo */
+"/boot/vmlinux-debug-%s",			/* Ubuntu */
+};
+
+#define MAX_PATH_LEN 256
+#define MAX_PROBES 128
+#define MAX_PROBE_ARGS 128
+#define PERFPROBE_GROUP "probe"
+
+/* Session management structure */
+static struct {
+	char *vmlinux;
+	char *release;
+	int need_dwarf;
+	int nr_probe;
+	struct probe_point probes[MAX_PROBES];
+} session;
+
+#define semantic_error(msg ...) die("Semantic error :" msg)
+
+/* Parse probe point. Return 1 if return probe */
+static void parse_probe_point(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 an event definition. Note that any error must die. */
+static void parse_probe_event(const char *str)
+{
+	char *argv[MAX_PROBE_ARGS + 2];	/* Event + probe + args */
+	int argc, i;
+	struct probe_point *pp = &session.probes[session.nr_probe];
+
+	pr_debug("probe-definition(%d): %s\n", session.nr_probe, str);
+	if (++session.nr_probe == MAX_PROBES)
+		semantic_error("Too many probes");
+
+	/* 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;
+
+			/* Skip the argument */
+			while (!isspace(*str) && *str != '\0')
+				str++;
+
+			/* Duplicate the argument */
+			argv[argc] = strndup(s, str - s);
+			if (argv[argc] == NULL)
+				die("strndup");
+			if (++argc == MAX_PROBE_ARGS)
+				semantic_error("Too many arguments");
+			pr_debug("argv[%d]=%s\n", argc, argv[argc - 1]);
+		}
+	} while (*str != '\0');
+	if (!argc)
+		semantic_error("An empty argument.");
+
+	/* Parse probe point */
+	parse_probe_point(argv[0], pp);
+	free(argv[0]);
+	if (pp->file || pp->line)
+		session.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");
+			session.need_dwarf = 1;
+		}
+
+	pr_debug("%d arguments\n", pp->nr_args);
+}
+
+static int opt_add_probe_event(const struct option *opt __used,
+			      const char *str, int unset __used)
+{
+	if (str)
+		parse_probe_event(str);
+	return 0;
+}
+
+#ifndef NO_LIBDWARF
+static int open_default_vmlinux(void)
+{
+	struct utsname uts;
+	char fname[MAX_PATH_LEN];
+	int fd, ret, i;
+
+	ret = uname(&uts);
+	if (ret) {
+		pr_debug("uname() failed.\n");
+		return -errno;
+	}
+	session.release = uts.release;
+	for (i = 0; i < NR_SEARCH_PATH; i++) {
+		ret = snprintf(fname, MAX_PATH_LEN,
+			       default_search_path[i], session.release);
+		if (ret >= MAX_PATH_LEN || ret < 0) {
+			pr_debug("Filename(%d,%s) is too long.\n", i,
+				uts.release);
+			errno = E2BIG;
+			return -E2BIG;
+		}
+		pr_debug("try to open %s\n", fname);
+		fd = open(fname, O_RDONLY);
+		if (fd >= 0)
+			break;
+	}
+	return fd;
+}
+#endif
+
+static const char * const probe_usage[] = {
+	"perf probe [<options>] 'PROBEDEF' ['PROBEDEF' ...]",
+	"perf probe [<options>] --add 'PROBEDEF' [--add 'PROBEDEF' ...]",
+	NULL
+};
+
+static const struct option options[] = {
+	OPT_BOOLEAN('v', "verbose", &verbose,
+		    "be more verbose (show parsed arguments, etc)"),
+#ifndef NO_LIBDWARF
+	OPT_STRING('k', "vmlinux", &session.vmlinux, "file",
+		"vmlinux/module pathname"),
+#endif
+	OPT_CALLBACK('a', "add", NULL,
+#ifdef NO_LIBDWARF
+		"FUNC[+OFFS|%return] [ARG ...]",
+#else
+		"FUNC[+OFFS|%return|:RLN][@SRC]|SRC:ALN [ARG ...]",
+#endif
+		"probe point definition, where\n"
+		"\t\tGRP:\tGroup name (optional)\n"
+		"\t\tNAME:\tEvent name\n"
+		"\t\tFUNC:\tFunction name\n"
+		"\t\tOFFS:\tOffset from function entry (in byte)\n"
+		"\t\t%return:\tPut the probe at function return\n"
+#ifdef NO_LIBDWARF
+		"\t\tARG:\tProbe argument (only \n"
+#else
+		"\t\tSRC:\tSource code path\n"
+		"\t\tRLN:\tRelative line number from function entry.\n"
+		"\t\tALN:\tAbsolute line number in file.\n"
+		"\t\tARG:\tProbe argument (local variable name or\n"
+#endif
+		"\t\t\tkprobe-tracer argument format is supported.)\n",
+		opt_add_probe_event),
+	OPT_END()
+};
+
+static int write_new_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;
+}
+
+#define MAX_CMDLEN 256
+
+static int synthesize_probe_event(struct probe_point *pp)
+{
+	char *buf;
+	int i, len, ret;
+	pp->probes[0] = buf = (char *)calloc(MAX_CMDLEN, sizeof(char));
+	if (!buf)
+		die("Failed to allocate memory by calloc.");
+	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;
+}
+
+int cmd_probe(int argc, const char **argv, const char *prefix __used)
+{
+	int i, j, fd, ret;
+	struct probe_point *pp;
+	char buf[MAX_CMDLEN];
+
+	argc = parse_options(argc, argv, options, probe_usage,
+			     PARSE_OPT_STOP_AT_NON_OPTION);
+	for (i = 0; i < argc; i++)
+		parse_probe_event(argv[i]);
+
+	if (session.nr_probe == 0)
+		usage_with_options(probe_usage, options);
+
+	if (session.need_dwarf)
+#ifdef NO_LIBDWARF
+		semantic_error("Debuginfo-analysis is not supported");
+#else	/* !NO_LIBDWARF */
+		pr_info("Some probes require debuginfo.\n");
+
+	if (session.vmlinux)
+		fd = open(session.vmlinux, O_RDONLY);
+	else
+		fd = open_default_vmlinux();
+	if (fd < 0) {
+		if (session.need_dwarf)
+			die("Could not open vmlinux/module file.");
+
+		pr_warning("Could not open vmlinux/module file."
+			   " Try to use symbols.\n");
+		goto end_dwarf;
+	}
+
+	/* Searching probe points */
+	for (j = 0; j < session.nr_probe; j++) {
+		pp = &session.probes[j];
+		if (pp->found)
+			continue;
+
+		lseek(fd, SEEK_SET, 0);
+		ret = find_probepoint(fd, pp);
+		if (ret < 0) {
+			if (session.need_dwarf)
+				die("Could not analyze debuginfo.");
+
+			pr_warning("An error occurred in debuginfo analysis. Try to use symbols.\n");
+			break;
+		}
+		if (ret == 0)	/* No error but failed to find probe point. */
+			die("No probe point found.");
+	}
+	close(fd);
+
+end_dwarf:
+#endif /* !NO_LIBDWARF */
+
+	/* Synthesize probes without dwarf */
+	for (j = 0; j < session.nr_probe; j++) {
+		pp = &session.probes[j];
+		if (pp->found)	/* This probe is already found. */
+			continue;
+
+		ret = synthesize_probe_event(pp);
+		if (ret == -E2BIG)
+			semantic_error("probe point is too long.");
+		else if (ret < 0)
+			die("Failed to synthesize a probe point.");
+	}
+
+	/* Settng up probe points */
+	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 < session.nr_probe; j++) {
+		pp = &session.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_new_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[0]);
+				write_new_event(fd, buf);
+			}
+	}
+	close(fd);
+	return 0;
+}
+