Mercurial > hg > octave-nkf > gnulib-hg
annotate lib/openat-proc.c @ 17935:0ad1f4c9eed5 default tip
tests: support stderr verification with returns_()
* tests/init.sh (returns_): Disable tracing for this wrapper
function, so that stderr of the wrapped command is unchanged,
allowing for verification of the contents.
| author | Pádraig Brady <P@draigBrady.com> |
|---|---|
| date | Mon, 16 Feb 2015 17:20:39 +0000 |
| parents | ab58d4870664 |
| children |
| rev | line source |
|---|---|
| 7389 | 1 /* Create /proc/self/fd-related names for subfiles of open directories. |
| 2 | |
| 17848 | 3 Copyright (C) 2006, 2009-2015 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 | |
| 35 #define PROC_SELF_FD_FORMAT "/proc/self/fd/%d/%s" | |
| 36 | |
| 37 #define PROC_SELF_FD_NAME_SIZE_BOUND(len) \ | |
| 38 (sizeof PROC_SELF_FD_FORMAT - sizeof "%d%s" \ | |
| 39 + INT_STRLEN_BOUND (int) + (len) + 1) | |
| 40 | |
| 41 | |
| 42 /* Set BUF to the expansion of PROC_SELF_FD_FORMAT, using FD and FILE | |
| 43 respectively for %d and %s. If successful, return BUF if the | |
| 44 result fits in BUF, dynamically allocated memory otherwise. But | |
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45 return NULL if /proc is not reliable, either because the operating |
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46 system support is lacking or because memory is low. */ |
| 7389 | 47 char * |
| 48 openat_proc_name (char buf[OPENAT_BUFFER_SIZE], int fd, char const *file) | |
| 49 { | |
| 50 static int proc_status = 0; | |
| 51 | |
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52 /* Make sure the caller gets ENOENT when appropriate. */ |
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53 if (!*file) |
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54 { |
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55 buf[0] = '\0'; |
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56 return buf; |
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57 } |
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58 |
| 7389 | 59 if (! proc_status) |
| 60 { | |
| 61 /* Set PROC_STATUS to a positive value if /proc/self/fd is | |
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62 reliable, and a negative value otherwise. Solaris 10 |
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63 /proc/self/fd mishandles "..", and any file name might expand |
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64 to ".." after symbolic link expansion, so avoid /proc/self/fd |
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65 if it mishandles "..". Solaris 10 has openat, but this |
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66 problem is exhibited on code that built on Solaris 8 and |
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67 running on Solaris 10. */ |
| 7389 | 68 |
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69 int proc_self_fd = open ("/proc/self/fd", |
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70 O_SEARCH | O_DIRECTORY | O_NOCTTY | O_NONBLOCK); |
| 7389 | 71 if (proc_self_fd < 0) |
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72 proc_status = -1; |
| 7389 | 73 else |
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74 { |
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75 /* Detect whether /proc/self/fd/%i/../fd exists, where %i is the |
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76 number of a file descriptor open on /proc/self/fd. On Linux, |
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77 that name resolves to /proc/self/fd, which was opened above. |
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78 However, on Solaris, it may resolve to /proc/self/fd/fd, which |
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79 cannot exist, since all names in /proc/self/fd are numeric. */ |
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80 char dotdot_buf[PROC_SELF_FD_NAME_SIZE_BOUND (sizeof "../fd" - 1)]; |
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81 sprintf (dotdot_buf, PROC_SELF_FD_FORMAT, proc_self_fd, "../fd"); |
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82 proc_status = access (dotdot_buf, F_OK) ? -1 : 1; |
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83 close (proc_self_fd); |
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84 } |
| 7389 | 85 } |
| 86 | |
| 87 if (proc_status < 0) | |
| 88 return NULL; | |
| 89 else | |
| 90 { | |
| 91 size_t bufsize = PROC_SELF_FD_NAME_SIZE_BOUND (strlen (file)); | |
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92 char *result = buf; |
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93 if (OPENAT_BUFFER_SIZE < bufsize) |
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94 { |
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95 result = malloc (bufsize); |
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96 if (! result) |
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97 return NULL; |
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98 } |
| 7389 | 99 sprintf (result, PROC_SELF_FD_FORMAT, fd, file); |
| 100 return result; | |
| 101 } | |
| 102 } |