Mercurial > hg > octave-kai > gnulib-hg
annotate lib/openat-proc.c @ 17160:72f4bab621be
fts: introduce FTS_VERBATIM
This gives clients the option to disable stripping of trailing slashes
from input path names during fts_open initialization.
The recent change v0.0-7611-g3a9002d that made fts_open strip trailing
slashes from input path names had a negative impact on findutils that
relies on the old fts_open behavior to implement POSIX requirement that
each path operand of the find utility shall be evaluated unaltered as it
was provided, including all trailing slash characters.
* lib/fts_.h (FTS_VERBATIM): New bit flag.
(FTS_OPTIONMASK, FTS_NAMEONLY, FTS_STOP): Adjust.
* lib/fts.c (fts_open): Honor it.
| author | Dmitry V. Levin <ldv@altlinux.org> |
|---|---|
| date | Sun, 18 Nov 2012 04:40:18 +0400 |
| parents | 8250f2777afc |
| children | e542fd46ad6f |
| rev | line source |
|---|---|
| 7389 | 1 /* Create /proc/self/fd-related names for subfiles of open directories. |
| 2 | |
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3 Copyright (C) 2006, 2009-2012 Free Software Foundation, Inc. |
| 7389 | 4 |
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5 This program is free software: you can redistribute it and/or modify |
| 7389 | 6 it under the terms of the GNU General Public License as published by |
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7 the Free Software Foundation; either version 3 of the License, or |
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8 (at your option) any later version. |
| 7389 | 9 |
| 10 This program is distributed in the hope that it will be useful, | |
| 11 but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| 13 GNU General Public License for more details. | |
| 14 | |
| 15 You should have received a copy of the GNU General Public License | |
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16 along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 7389 | 17 |
| 18 /* Written by Paul Eggert. */ | |
| 19 | |
| 20 #include <config.h> | |
| 21 | |
| 22 #include "openat-priv.h" | |
| 23 | |
| 24 #include <sys/types.h> | |
| 25 #include <sys/stat.h> | |
| 26 #include <fcntl.h> | |
| 27 | |
| 28 #include <stdio.h> | |
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29 #include <stdlib.h> |
| 7389 | 30 #include <string.h> |
| 12501 | 31 #include <unistd.h> |
| 7389 | 32 |
| 33 #include "intprops.h" | |
| 34 | |
| 7863 | 35 /* The results of open() in this file are not used with fchdir, |
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36 and we do not leak fds to any single-threaded code that could use stdio, |
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37 therefore save some unnecessary work in fchdir.c. |
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38 FIXME - if the kernel ever adds support for multi-thread safety for |
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39 avoiding standard fds, then we should use open_safer. */ |
| 7863 | 40 #undef open |
| 41 #undef close | |
| 42 | |
| 7389 | 43 #define PROC_SELF_FD_FORMAT "/proc/self/fd/%d/%s" |
| 44 | |
| 45 #define PROC_SELF_FD_NAME_SIZE_BOUND(len) \ | |
| 46 (sizeof PROC_SELF_FD_FORMAT - sizeof "%d%s" \ | |
| 47 + INT_STRLEN_BOUND (int) + (len) + 1) | |
| 48 | |
| 49 | |
| 50 /* Set BUF to the expansion of PROC_SELF_FD_FORMAT, using FD and FILE | |
| 51 respectively for %d and %s. If successful, return BUF if the | |
| 52 result fits in BUF, dynamically allocated memory otherwise. But | |
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53 return NULL if /proc is not reliable, either because the operating |
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54 system support is lacking or because memory is low. */ |
| 7389 | 55 char * |
| 56 openat_proc_name (char buf[OPENAT_BUFFER_SIZE], int fd, char const *file) | |
| 57 { | |
| 58 static int proc_status = 0; | |
| 59 | |
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60 /* Make sure the caller gets ENOENT when appropriate. */ |
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61 if (!*file) |
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62 { |
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63 buf[0] = '\0'; |
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64 return buf; |
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65 } |
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66 |
| 7389 | 67 if (! proc_status) |
| 68 { | |
| 69 /* Set PROC_STATUS to a positive value if /proc/self/fd is | |
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70 reliable, and a negative value otherwise. Solaris 10 |
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71 /proc/self/fd mishandles "..", and any file name might expand |
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72 to ".." after symbolic link expansion, so avoid /proc/self/fd |
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73 if it mishandles "..". Solaris 10 has openat, but this |
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74 problem is exhibited on code that built on Solaris 8 and |
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75 running on Solaris 10. */ |
| 7389 | 76 |
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77 int proc_self_fd = open ("/proc/self/fd", |
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78 O_SEARCH | O_DIRECTORY | O_NOCTTY | O_NONBLOCK); |
| 7389 | 79 if (proc_self_fd < 0) |
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80 proc_status = -1; |
| 7389 | 81 else |
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82 { |
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83 /* Detect whether /proc/self/fd/%i/../fd exists, where %i is the |
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84 number of a file descriptor open on /proc/self/fd. On Linux, |
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85 that name resolves to /proc/self/fd, which was opened above. |
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86 However, on Solaris, it may resolve to /proc/self/fd/fd, which |
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87 cannot exist, since all names in /proc/self/fd are numeric. */ |
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88 char dotdot_buf[PROC_SELF_FD_NAME_SIZE_BOUND (sizeof "../fd" - 1)]; |
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89 sprintf (dotdot_buf, PROC_SELF_FD_FORMAT, proc_self_fd, "../fd"); |
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90 proc_status = access (dotdot_buf, F_OK) ? -1 : 1; |
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91 close (proc_self_fd); |
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92 } |
| 7389 | 93 } |
| 94 | |
| 95 if (proc_status < 0) | |
| 96 return NULL; | |
| 97 else | |
| 98 { | |
| 99 size_t bufsize = PROC_SELF_FD_NAME_SIZE_BOUND (strlen (file)); | |
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100 char *result = buf; |
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101 if (OPENAT_BUFFER_SIZE < bufsize) |
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102 { |
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103 result = malloc (bufsize); |
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104 if (! result) |
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105 return NULL; |
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106 } |
| 7389 | 107 sprintf (result, PROC_SELF_FD_FORMAT, fd, file); |
| 108 return result; | |
| 109 } | |
| 110 } |