485 lines
11 KiB
C
485 lines
11 KiB
C
/*
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* probe-event.c : perf-probe definition to kprobe_events format converter
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*
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* Written by Masami Hiramatsu <mhiramat@redhat.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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*/
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#define _GNU_SOURCE
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#include <sys/utsname.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <string.h>
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#include <stdarg.h>
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#include <limits.h>
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#undef _GNU_SOURCE
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#include "event.h"
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#include "string.h"
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#include "strlist.h"
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#include "debug.h"
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#include "parse-events.h" /* For debugfs_path */
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#include "probe-event.h"
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#define MAX_CMDLEN 256
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#define MAX_PROBE_ARGS 128
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#define PERFPROBE_GROUP "probe"
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#define semantic_error(msg ...) die("Semantic error :" msg)
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/* If there is no space to write, returns -E2BIG. */
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static int e_snprintf(char *str, size_t size, const char *format, ...)
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{
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int ret;
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va_list ap;
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va_start(ap, format);
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ret = vsnprintf(str, size, format, ap);
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va_end(ap);
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if (ret >= (int)size)
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ret = -E2BIG;
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return ret;
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}
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/* Parse probepoint definition. */
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static void parse_perf_probe_probepoint(char *arg, struct probe_point *pp)
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{
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char *ptr, *tmp;
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char c, nc = 0;
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/*
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* <Syntax>
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* perf probe SRC:LN
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* perf probe FUNC[+OFFS|%return][@SRC]
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*/
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ptr = strpbrk(arg, ":+@%");
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if (ptr) {
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nc = *ptr;
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*ptr++ = '\0';
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}
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/* Check arg is function or file and copy it */
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if (strchr(arg, '.')) /* File */
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pp->file = strdup(arg);
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else /* Function */
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pp->function = strdup(arg);
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DIE_IF(pp->file == NULL && pp->function == NULL);
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/* Parse other options */
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while (ptr) {
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arg = ptr;
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c = nc;
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ptr = strpbrk(arg, ":+@%");
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if (ptr) {
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nc = *ptr;
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*ptr++ = '\0';
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}
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switch (c) {
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case ':': /* Line number */
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pp->line = strtoul(arg, &tmp, 0);
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if (*tmp != '\0')
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semantic_error("There is non-digit charactor"
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" in line number.");
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break;
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case '+': /* Byte offset from a symbol */
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pp->offset = strtoul(arg, &tmp, 0);
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if (*tmp != '\0')
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semantic_error("There is non-digit charactor"
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" in offset.");
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break;
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case '@': /* File name */
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if (pp->file)
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semantic_error("SRC@SRC is not allowed.");
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pp->file = strdup(arg);
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DIE_IF(pp->file == NULL);
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if (ptr)
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semantic_error("@SRC must be the last "
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"option.");
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break;
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case '%': /* Probe places */
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if (strcmp(arg, "return") == 0) {
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pp->retprobe = 1;
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} else /* Others not supported yet */
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semantic_error("%%%s is not supported.", arg);
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break;
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default:
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DIE_IF("Program has a bug.");
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break;
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}
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}
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/* Exclusion check */
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if (pp->line && pp->offset)
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semantic_error("Offset can't be used with line number.");
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if (!pp->line && pp->file && !pp->function)
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semantic_error("File always requires line number.");
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if (pp->offset && !pp->function)
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semantic_error("Offset requires an entry function.");
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if (pp->retprobe && !pp->function)
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semantic_error("Return probe requires an entry function.");
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if ((pp->offset || pp->line) && pp->retprobe)
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semantic_error("Offset/Line can't be used with return probe.");
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pr_debug("symbol:%s file:%s line:%d offset:%d, return:%d\n",
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pp->function, pp->file, pp->line, pp->offset, pp->retprobe);
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}
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/* Parse perf-probe event definition */
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int parse_perf_probe_event(const char *str, struct probe_point *pp)
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{
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char **argv;
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int argc, i, need_dwarf = 0;
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argv = argv_split(str, &argc);
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if (!argv)
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die("argv_split failed.");
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if (argc > MAX_PROBE_ARGS + 1)
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semantic_error("Too many arguments");
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/* Parse probe point */
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parse_perf_probe_probepoint(argv[0], pp);
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if (pp->file || pp->line)
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need_dwarf = 1;
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/* Copy arguments and ensure return probe has no C argument */
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pp->nr_args = argc - 1;
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pp->args = zalloc(sizeof(char *) * pp->nr_args);
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for (i = 0; i < pp->nr_args; i++) {
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pp->args[i] = strdup(argv[i + 1]);
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if (!pp->args[i])
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die("Failed to copy argument.");
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if (is_c_varname(pp->args[i])) {
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if (pp->retprobe)
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semantic_error("You can't specify local"
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" variable for kretprobe");
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need_dwarf = 1;
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}
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}
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argv_free(argv);
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return need_dwarf;
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}
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/* Parse kprobe_events event into struct probe_point */
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void parse_trace_kprobe_event(const char *str, char **group, char **event,
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struct probe_point *pp)
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{
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char pr;
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char *p;
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int ret, i, argc;
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char **argv;
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pr_debug("Parsing kprobe_events: %s\n", str);
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argv = argv_split(str, &argc);
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if (!argv)
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die("argv_split failed.");
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if (argc < 2)
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semantic_error("Too less arguments.");
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/* Scan event and group name. */
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ret = sscanf(argv[0], "%c:%a[^/ \t]/%a[^ \t]",
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&pr, (float *)(void *)group, (float *)(void *)event);
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if (ret != 3)
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semantic_error("Failed to parse event name: %s", argv[0]);
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pr_debug("Group:%s Event:%s probe:%c\n", *group, *event, pr);
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if (!pp)
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goto end;
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pp->retprobe = (pr == 'r');
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/* Scan function name and offset */
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ret = sscanf(argv[1], "%a[^+]+%d", (float *)(void *)&pp->function, &pp->offset);
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if (ret == 1)
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pp->offset = 0;
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/* kprobe_events doesn't have this information */
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pp->line = 0;
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pp->file = NULL;
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pp->nr_args = argc - 2;
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pp->args = zalloc(sizeof(char *) * pp->nr_args);
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for (i = 0; i < pp->nr_args; i++) {
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p = strchr(argv[i + 2], '=');
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if (p) /* We don't need which register is assigned. */
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*p = '\0';
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pp->args[i] = strdup(argv[i + 2]);
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if (!pp->args[i])
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die("Failed to copy argument.");
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}
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end:
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argv_free(argv);
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}
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int synthesize_perf_probe_event(struct probe_point *pp)
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{
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char *buf;
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char offs[64] = "", line[64] = "";
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int i, len, ret;
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pp->probes[0] = buf = zalloc(MAX_CMDLEN);
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if (!buf)
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die("Failed to allocate memory by zalloc.");
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if (pp->offset) {
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ret = e_snprintf(offs, 64, "+%d", pp->offset);
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if (ret <= 0)
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goto error;
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}
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if (pp->line) {
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ret = e_snprintf(line, 64, ":%d", pp->line);
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if (ret <= 0)
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goto error;
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}
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if (pp->function)
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ret = e_snprintf(buf, MAX_CMDLEN, "%s%s%s%s", pp->function,
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offs, pp->retprobe ? "%return" : "", line);
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else
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ret = e_snprintf(buf, MAX_CMDLEN, "%s%s%s%s", pp->file, line);
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if (ret <= 0)
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goto error;
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len = ret;
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for (i = 0; i < pp->nr_args; i++) {
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ret = e_snprintf(&buf[len], MAX_CMDLEN - len, " %s",
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pp->args[i]);
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if (ret <= 0)
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goto error;
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len += ret;
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}
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pp->found = 1;
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return pp->found;
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error:
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free(pp->probes[0]);
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return ret;
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}
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int synthesize_trace_kprobe_event(struct probe_point *pp)
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{
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char *buf;
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int i, len, ret;
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pp->probes[0] = buf = zalloc(MAX_CMDLEN);
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if (!buf)
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die("Failed to allocate memory by zalloc.");
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ret = e_snprintf(buf, MAX_CMDLEN, "%s+%d", pp->function, pp->offset);
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if (ret <= 0)
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goto error;
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len = ret;
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for (i = 0; i < pp->nr_args; i++) {
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ret = e_snprintf(&buf[len], MAX_CMDLEN - len, " %s",
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pp->args[i]);
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if (ret <= 0)
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goto error;
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len += ret;
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}
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pp->found = 1;
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return pp->found;
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error:
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free(pp->probes[0]);
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return ret;
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}
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static int open_kprobe_events(int flags, int mode)
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{
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char buf[PATH_MAX];
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int ret;
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ret = e_snprintf(buf, PATH_MAX, "%s/../kprobe_events", debugfs_path);
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if (ret < 0)
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die("Failed to make kprobe_events path.");
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ret = open(buf, flags, mode);
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if (ret < 0) {
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if (errno == ENOENT)
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die("kprobe_events file does not exist -"
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" please rebuild with CONFIG_KPROBE_TRACER.");
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else
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die("Could not open kprobe_events file: %s",
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strerror(errno));
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}
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return ret;
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}
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/* Get raw string list of current kprobe_events */
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static struct strlist *get_trace_kprobe_event_rawlist(int fd)
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{
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int ret, idx;
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FILE *fp;
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char buf[MAX_CMDLEN];
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char *p;
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struct strlist *sl;
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sl = strlist__new(true, NULL);
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fp = fdopen(dup(fd), "r");
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while (!feof(fp)) {
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p = fgets(buf, MAX_CMDLEN, fp);
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if (!p)
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break;
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idx = strlen(p) - 1;
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if (p[idx] == '\n')
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p[idx] = '\0';
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ret = strlist__add(sl, buf);
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if (ret < 0)
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die("strlist__add failed: %s", strerror(-ret));
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}
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fclose(fp);
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return sl;
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}
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/* Free and zero clear probe_point */
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static void clear_probe_point(struct probe_point *pp)
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{
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int i;
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if (pp->function)
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free(pp->function);
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if (pp->file)
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free(pp->file);
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for (i = 0; i < pp->nr_args; i++)
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free(pp->args[i]);
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if (pp->args)
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free(pp->args);
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for (i = 0; i < pp->found; i++)
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free(pp->probes[i]);
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memset(pp, 0, sizeof(pp));
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}
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/* List up current perf-probe events */
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void show_perf_probe_events(void)
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{
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unsigned int i;
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int fd;
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char *group, *event;
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struct probe_point pp;
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struct strlist *rawlist;
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struct str_node *ent;
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fd = open_kprobe_events(O_RDONLY, 0);
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rawlist = get_trace_kprobe_event_rawlist(fd);
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close(fd);
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for (i = 0; i < strlist__nr_entries(rawlist); i++) {
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ent = strlist__entry(rawlist, i);
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parse_trace_kprobe_event(ent->s, &group, &event, &pp);
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synthesize_perf_probe_event(&pp);
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printf("[%s:%s]\t%s\n", group, event, pp.probes[0]);
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free(group);
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free(event);
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clear_probe_point(&pp);
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}
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strlist__delete(rawlist);
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}
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/* Get current perf-probe event names */
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static struct strlist *get_perf_event_names(int fd)
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{
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unsigned int i;
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char *group, *event;
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struct strlist *sl, *rawlist;
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struct str_node *ent;
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rawlist = get_trace_kprobe_event_rawlist(fd);
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sl = strlist__new(false, NULL);
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for (i = 0; i < strlist__nr_entries(rawlist); i++) {
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ent = strlist__entry(rawlist, i);
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parse_trace_kprobe_event(ent->s, &group, &event, NULL);
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strlist__add(sl, event);
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free(group);
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}
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strlist__delete(rawlist);
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return sl;
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}
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static int write_trace_kprobe_event(int fd, const char *buf)
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{
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int ret;
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ret = write(fd, buf, strlen(buf));
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if (ret <= 0)
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die("Failed to create event.");
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else
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printf("Added new event: %s\n", buf);
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return ret;
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}
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static void get_new_event_name(char *buf, size_t len, const char *base,
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struct strlist *namelist)
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{
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int i, ret;
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for (i = 0; i < MAX_EVENT_INDEX; i++) {
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ret = e_snprintf(buf, len, "%s_%d", base, i);
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if (ret < 0)
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die("snprintf() failed: %s", strerror(-ret));
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if (!strlist__has_entry(namelist, buf))
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break;
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}
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if (i == MAX_EVENT_INDEX)
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die("Too many events are on the same function.");
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}
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void add_trace_kprobe_events(struct probe_point *probes, int nr_probes)
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{
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int i, j, fd;
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struct probe_point *pp;
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char buf[MAX_CMDLEN];
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char event[64];
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struct strlist *namelist;
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fd = open_kprobe_events(O_RDWR, O_APPEND);
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/* Get current event names */
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namelist = get_perf_event_names(fd);
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for (j = 0; j < nr_probes; j++) {
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pp = probes + j;
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for (i = 0; i < pp->found; i++) {
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/* Get an unused new event name */
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get_new_event_name(event, 64, pp->function, namelist);
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snprintf(buf, MAX_CMDLEN, "%c:%s/%s %s\n",
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pp->retprobe ? 'r' : 'p',
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PERFPROBE_GROUP, event,
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pp->probes[i]);
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write_trace_kprobe_event(fd, buf);
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/* Add added event name to namelist */
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strlist__add(namelist, event);
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}
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}
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close(fd);
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}
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