/*
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* Copyright (c) 2016 Facebook, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <ctype.h>
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#include <errno.h>
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#include <limits.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "bcc_perf_map.h"
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bool bcc_is_perf_map(const char *path) {
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char* pos = strstr(path, ".map");
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// Path ends with ".map"
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return (pos != NULL) && (*(pos + 4)== 0);
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}
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bool bcc_is_valid_perf_map(const char *path) {
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return bcc_is_perf_map(path) && (access(path, R_OK) == 0);
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}
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int bcc_perf_map_nstgid(int pid) {
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char status_path[64];
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FILE *status;
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snprintf(status_path, sizeof(status_path), "/proc/%d/status", pid);
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status = fopen(status_path, "r");
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if (!status)
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return -1;
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// return the original PID if we fail to work out the TGID
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int nstgid = pid;
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size_t size = 0;
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char *line = NULL;
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while (getline(&line, &size, status) != -1) {
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// check Tgid line first in case CONFIG_PID_NS is off
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if (strstr(line, "Tgid:") != NULL)
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nstgid = (int)strtol(strrchr(line, '\t'), NULL, 10);
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if (strstr(line, "NStgid:") != NULL)
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// PID namespaces can be nested -- last number is innermost PID
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nstgid = (int)strtol(strrchr(line, '\t'), NULL, 10);
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}
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free(line);
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fclose(status);
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return nstgid;
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}
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bool bcc_perf_map_path(char *map_path, size_t map_len, int pid) {
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char source[64];
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snprintf(source, sizeof(source), "/proc/%d/root", pid);
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char target[4096];
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ssize_t target_len = readlink(source, target, sizeof(target) - 1);
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if (target_len == -1)
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return false;
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target[target_len] = '\0';
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if (strcmp(target, "/") == 0)
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target[0] = '\0';
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int nstgid = bcc_perf_map_nstgid(pid);
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snprintf(map_path, map_len, "%s/tmp/perf-%d.map", target, nstgid);
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return true;
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}
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int bcc_perf_map_foreach_sym(const char *path, bcc_perf_map_symcb callback,
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void* payload) {
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FILE* file = fopen(path, "r");
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if (!file)
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return -1;
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char *line = NULL;
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size_t size = 0;
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long long begin, len;
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while (getline(&line, &size, file) != -1) {
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char *cursor = line;
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char *newline, *sep;
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begin = strtoull(cursor, &sep, 16);
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if (begin == 0 || *sep != ' ' || (begin == ULLONG_MAX && errno == ERANGE))
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continue;
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cursor = sep;
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while (*cursor && isspace(*cursor)) cursor++;
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len = strtoull(cursor, &sep, 16);
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if (*sep != ' ' ||
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(sep == cursor && len == 0) ||
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(len == ULLONG_MAX && errno == ERANGE))
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continue;
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cursor = sep;
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while (*cursor && isspace(*cursor)) cursor++;
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newline = strchr(cursor, '\n');
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if (newline)
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newline[0] = '\0';
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callback(cursor, begin, len, payload);
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}
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free(line);
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fclose(file);
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return 0;
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}
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