henrike@webrtc.org | f7795df | 2014-05-13 18:00:26 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2004 The WebRTC Project Authors. All rights reserved. |
| 3 | * |
| 4 | * Use of this source code is governed by a BSD-style license |
| 5 | * that can be found in the LICENSE file in the root of the source |
| 6 | * tree. An additional intellectual property rights grant can be found |
| 7 | * in the file PATENTS. All contributing project authors may |
| 8 | * be found in the AUTHORS file in the root of the source tree. |
| 9 | */ |
| 10 | |
| 11 | #include <sys/types.h> |
| 12 | #include <dirent.h> |
| 13 | #include <errno.h> |
| 14 | #include <stdlib.h> |
| 15 | #include <string.h> |
| 16 | |
| 17 | #include "webrtc/base/linuxfdwalk.h" |
| 18 | |
| 19 | // Parses a file descriptor number in base 10, requiring the strict format used |
| 20 | // in /proc/*/fd. Returns the value, or -1 if not a valid string. |
| 21 | static int parse_fd(const char *s) { |
| 22 | if (!*s) { |
| 23 | // Empty string is invalid. |
| 24 | return -1; |
| 25 | } |
| 26 | int val = 0; |
| 27 | do { |
| 28 | if (*s < '0' || *s > '9') { |
| 29 | // Non-numeric characters anywhere are invalid. |
| 30 | return -1; |
| 31 | } |
| 32 | int digit = *s++ - '0'; |
| 33 | val = val * 10 + digit; |
| 34 | } while (*s); |
| 35 | return val; |
| 36 | } |
| 37 | |
| 38 | int fdwalk(void (*func)(void *, int), void *opaque) { |
| 39 | DIR *dir = opendir("/proc/self/fd"); |
| 40 | if (!dir) { |
| 41 | return -1; |
| 42 | } |
| 43 | int opendirfd = dirfd(dir); |
| 44 | int parse_errors = 0; |
| 45 | struct dirent *ent; |
| 46 | // Have to clear errno to distinguish readdir() completion from failure. |
| 47 | while (errno = 0, (ent = readdir(dir)) != NULL) { |
| 48 | if (strcmp(ent->d_name, ".") == 0 || |
| 49 | strcmp(ent->d_name, "..") == 0) { |
| 50 | continue; |
| 51 | } |
| 52 | // We avoid atoi or strtol because those are part of libc and they involve |
| 53 | // locale stuff, which is probably not safe from a post-fork context in a |
| 54 | // multi-threaded app. |
| 55 | int fd = parse_fd(ent->d_name); |
| 56 | if (fd < 0) { |
| 57 | parse_errors = 1; |
| 58 | continue; |
| 59 | } |
| 60 | if (fd != opendirfd) { |
| 61 | (*func)(opaque, fd); |
| 62 | } |
| 63 | } |
| 64 | int saved_errno = errno; |
| 65 | if (closedir(dir) < 0) { |
| 66 | if (!saved_errno) { |
| 67 | // Return the closedir error. |
| 68 | return -1; |
| 69 | } |
| 70 | // Else ignore it because we have a more relevant error to return. |
| 71 | } |
| 72 | if (saved_errno) { |
| 73 | errno = saved_errno; |
| 74 | return -1; |
| 75 | } else if (parse_errors) { |
| 76 | errno = EBADF; |
| 77 | return -1; |
| 78 | } else { |
| 79 | return 0; |
| 80 | } |
| 81 | } |