henrike@webrtc.org | 0e118e7 | 2013-07-10 00:45:36 +0000 | [diff] [blame] | 1 | /* |
| 2 | * libjingle |
| 3 | * Copyright 2004--2009, Google Inc. |
| 4 | * |
| 5 | * Redistribution and use in source and binary forms, with or without |
| 6 | * modification, are permitted provided that the following conditions are met: |
| 7 | * |
| 8 | * 1. Redistributions of source code must retain the above copyright notice, |
| 9 | * this list of conditions and the following disclaimer. |
| 10 | * 2. Redistributions in binary form must reproduce the above copyright notice, |
| 11 | * this list of conditions and the following disclaimer in the documentation |
| 12 | * and/or other materials provided with the distribution. |
| 13 | * 3. The name of the author may not be used to endorse or promote products |
| 14 | * derived from this software without specific prior written permission. |
| 15 | * |
| 16 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED |
| 17 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF |
| 18 | * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO |
| 19 | * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| 20 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| 21 | * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; |
| 22 | * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, |
| 23 | * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR |
| 24 | * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF |
| 25 | * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 26 | */ |
| 27 | |
| 28 | #include <sys/types.h> |
| 29 | #include <dirent.h> |
| 30 | #include <errno.h> |
| 31 | #include <stdlib.h> |
| 32 | #include <string.h> |
| 33 | |
| 34 | #include "talk/base/linuxfdwalk.h" |
| 35 | |
| 36 | // Parses a file descriptor number in base 10, requiring the strict format used |
| 37 | // in /proc/*/fd. Returns the value, or -1 if not a valid string. |
| 38 | static int parse_fd(const char *s) { |
| 39 | if (!*s) { |
| 40 | // Empty string is invalid. |
| 41 | return -1; |
| 42 | } |
| 43 | int val = 0; |
| 44 | do { |
| 45 | if (*s < '0' || *s > '9') { |
| 46 | // Non-numeric characters anywhere are invalid. |
| 47 | return -1; |
| 48 | } |
| 49 | int digit = *s++ - '0'; |
| 50 | val = val * 10 + digit; |
| 51 | } while (*s); |
| 52 | return val; |
| 53 | } |
| 54 | |
| 55 | int fdwalk(void (*func)(void *, int), void *opaque) { |
| 56 | DIR *dir = opendir("/proc/self/fd"); |
| 57 | if (!dir) { |
| 58 | return -1; |
| 59 | } |
| 60 | int opendirfd = dirfd(dir); |
| 61 | int parse_errors = 0; |
| 62 | struct dirent *ent; |
| 63 | // Have to clear errno to distinguish readdir() completion from failure. |
| 64 | while (errno = 0, (ent = readdir(dir)) != NULL) { |
| 65 | if (strcmp(ent->d_name, ".") == 0 || |
| 66 | strcmp(ent->d_name, "..") == 0) { |
| 67 | continue; |
| 68 | } |
| 69 | // We avoid atoi or strtol because those are part of libc and they involve |
| 70 | // locale stuff, which is probably not safe from a post-fork context in a |
| 71 | // multi-threaded app. |
| 72 | int fd = parse_fd(ent->d_name); |
| 73 | if (fd < 0) { |
| 74 | parse_errors = 1; |
| 75 | continue; |
| 76 | } |
| 77 | if (fd != opendirfd) { |
| 78 | (*func)(opaque, fd); |
| 79 | } |
| 80 | } |
| 81 | int saved_errno = errno; |
| 82 | if (closedir(dir) < 0) { |
| 83 | if (!saved_errno) { |
| 84 | // Return the closedir error. |
| 85 | return -1; |
| 86 | } |
| 87 | // Else ignore it because we have a more relevant error to return. |
| 88 | } |
| 89 | if (saved_errno) { |
| 90 | errno = saved_errno; |
| 91 | return -1; |
| 92 | } else if (parse_errors) { |
| 93 | errno = EBADF; |
| 94 | return -1; |
| 95 | } else { |
| 96 | return 0; |
| 97 | } |
| 98 | } |