diff options
Diffstat (limited to 'tools/perf/builtin-probe.c')
| -rw-r--r-- | tools/perf/builtin-probe.c | 358 |
1 files changed, 358 insertions, 0 deletions
diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c new file mode 100644 index 000000000000..24b64b5cefce --- /dev/null +++ b/tools/perf/builtin-probe.c @@ -0,0 +1,358 @@ +/* + * 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/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 + +/* Session management structure */ +static struct { + char *vmlinux; + char *release; + int nr_probe; + struct probe_point probes[MAX_PROBES]; + char *events[MAX_PROBES]; +} session; + +static void semantic_error(const char *msg) +{ + fprintf(stderr, "Semantic error: %s\n", msg); + exit(1); +} + +static void perror_exit(const char *msg) +{ + perror(msg); + exit(1); +} + +#define MAX_PROBE_ARGS 128 + +static int parse_probepoint(const struct option *opt __used, + const char *str, int unset __used) +{ + char *argv[MAX_PROBE_ARGS + 2]; /* Event + probe + args */ + int argc, i; + char *arg, *ptr; + struct probe_point *pp = &session.probes[session.nr_probe]; + char **event = &session.events[session.nr_probe]; + int retp = 0; + + if (!str) /* The end of probe points */ + return 0; + + debug("Probe-define(%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) + perror_exit("strndup"); + if (++argc == MAX_PROBE_ARGS) + semantic_error("Too many arguments"); + debug("argv[%d]=%s\n", argc, argv[argc - 1]); + } + } while (*str != '\0'); + if (argc < 2) + semantic_error("Need event-name and probe-point at least."); + + /* Parse the event name */ + if (argv[0][0] == 'r') + retp = 1; + else if (argv[0][0] != 'p') + semantic_error("You must specify 'p'(kprobe) or" + " 'r'(kretprobe) first."); + /* TODO: check event name */ + *event = argv[0]; + + /* Parse probe point */ + arg = argv[1]; + if (arg[0] == '@') { + /* Source Line */ + arg++; + ptr = strchr(arg, ':'); + if (!ptr || !isdigit(ptr[1])) + semantic_error("Line number is required."); + *ptr++ = '\0'; + if (strlen(arg) == 0) + semantic_error("No file name."); + pp->file = strdup(arg); + pp->line = atoi(ptr); + if (!pp->file || !pp->line) + semantic_error("Failed to parse line."); + debug("file:%s line:%d\n", pp->file, pp->line); + } else { + /* Function name */ + ptr = strchr(arg, '+'); + if (ptr) { + if (!isdigit(ptr[1])) + semantic_error("Offset is required."); + *ptr++ = '\0'; + pp->offset = atoi(ptr); + } else + ptr = arg; + ptr = strchr(ptr, '@'); + if (ptr) { + *ptr++ = '\0'; + pp->file = strdup(ptr); + } + pp->function = strdup(arg); + debug("symbol:%s file:%s offset:%d\n", + pp->function, pp->file, pp->offset); + } + free(argv[1]); + + /* Copy arguments */ + pp->nr_args = argc - 2; + if (pp->nr_args > 0) { + pp->args = (char **)malloc(sizeof(char *) * pp->nr_args); + if (!pp->args) + perror_exit("malloc"); + memcpy(pp->args, &argv[2], sizeof(char *) * pp->nr_args); + } + + /* Ensure return probe has no C argument */ + if (retp) + for (i = 0; i < pp->nr_args; i++) + if (is_c_varname(pp->args[i])) + semantic_error("You can't specify local" + " variable for kretprobe"); + debug("%d arguments\n", pp->nr_args); + return 0; +} + +static int open_default_vmlinux(void) +{ + struct utsname uts; + char fname[MAX_PATH_LEN]; + int fd, ret, i; + + ret = uname(&uts); + if (ret) { + 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) { + debug("Filename(%d,%s) is too long.\n", i, uts.release); + errno = E2BIG; + return -E2BIG; + } + debug("try to open %s\n", fname); + fd = open(fname, O_RDONLY); + if (fd >= 0) + break; + } + return fd; +} + +static const char * const probe_usage[] = { + "perf probe [<options>] -P 'PROBEDEF' [-P 'PROBEDEF' ...]", + NULL +}; + +static const struct option options[] = { + OPT_STRING('k', "vmlinux", &session.vmlinux, "file", + "vmlinux/module pathname"), + OPT_CALLBACK('P', "probe", NULL, + "p|r:[GRP/]NAME FUNC[+OFFS][@SRC]|@SRC:LINE [ARG ...]", + "probe point definition, where\n" + "\t\tp:\tkprobe probe\n" + "\t\tr:\tkretprobe probe\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\tSRC:\tSource code path\n" + "\t\tLINE:\tLine number\n" + "\t\tARG:\tProbe argument (local variable name or\n" + "\t\t\tkprobe-tracer argument format is supported.)\n", + parse_probepoint), + OPT_END() +}; + +static int write_new_event(int fd, const char *buf) +{ + int ret; + + printf("Adding new event: %s\n", buf); + ret = write(fd, buf, strlen(buf)); + if (ret <= 0) + perror("Error: Failed to create event"); + + return ret; +} + +#define MAX_CMDLEN 256 + +static int synthesize_probepoint(struct probe_point *pp) +{ + char *buf; + int i, len, ret; + pp->probes[0] = buf = (char *)calloc(MAX_CMDLEN, sizeof(char)); + if (!buf) + perror_exit("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, need_dwarf = 0; + struct probe_point *pp; + char buf[MAX_CMDLEN]; + + argc = parse_options(argc, argv, options, probe_usage, + PARSE_OPT_STOP_AT_NON_OPTION); + if (argc || session.nr_probe == 0) + usage_with_options(probe_usage, options); + + /* Synthesize return probes */ + for (j = 0; j < session.nr_probe; j++) { + if (session.events[j][0] != 'r') { + need_dwarf = 1; + continue; + } + ret = synthesize_probepoint(&session.probes[j]); + if (ret == -E2BIG) + semantic_error("probe point is too long."); + else if (ret < 0) { + perror("snprintf"); + return -1; + } + } + + if (!need_dwarf) + goto setup_probes; + + if (session.vmlinux) + fd = open(session.vmlinux, O_RDONLY); + else + fd = open_default_vmlinux(); + if (fd < 0) { + perror("vmlinux/module file open"); + return -1; + } + + /* 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) { + fprintf(stderr, "Error: No probe point found.\n"); + return -1; + } + debug("probe event %s found\n", session.events[j]); + } + close(fd); + +setup_probes: + /* Settng up probe points */ + snprintf(buf, MAX_CMDLEN, "%s/../kprobe_events", debugfs_path); + fd = open(buf, O_WRONLY, O_APPEND); + if (fd < 0) { + perror("kprobe_events open"); + return -1; + } + for (j = 0; j < session.nr_probe; j++) { + pp = &session.probes[j]; + if (pp->found == 1) { + snprintf(buf, MAX_CMDLEN, "%s %s\n", + session.events[j], pp->probes[0]); + write_new_event(fd, buf); + } else + for (i = 0; i < pp->found; i++) { + snprintf(buf, MAX_CMDLEN, "%s%d %s\n", + session.events[j], i, pp->probes[i]); + write_new_event(fd, buf); + } + } + close(fd); + return 0; +} + |