| 1 | /* f_setlk -- locking part of fcntl |
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| 2 | Copyright (C) 2014-2024 Free Software Foundation, Inc. |
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| 3 | This file is part of the GNU C Library. |
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| 4 | |
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| 5 | The GNU C Library is free software; you can redistribute it and/or |
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| 6 | modify it under the terms of the GNU Lesser General Public |
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| 7 | License as published by the Free Software Foundation; either |
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| 8 | version 2.1 of the License, or (at your option) any later version. |
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| 9 | |
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| 10 | The GNU C Library is distributed in the hope that it will be useful, |
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| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 13 | Lesser General Public License for more details. |
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| 14 | |
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| 15 | You should have received a copy of the GNU Lesser General Public |
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| 16 | License along with the GNU C Library; if not, see |
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| 17 | <https://www.gnu.org/licenses/>. */ |
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| 18 | |
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| 19 | #include <sys/types.h> |
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| 20 | #include <sys/file.h> |
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| 21 | #include <fcntl.h> |
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| 22 | #include <hurd.h> |
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| 23 | #include <unistd.h> |
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| 24 | #include <errno.h> |
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| 25 | |
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| 26 | /* XXX |
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| 27 | We need new RPCs to support POSIX.1 fcntl file locking!! |
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| 28 | For the time being we support the whole-file case only, |
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| 29 | with all kinds of WRONG WRONG WRONG semantics, |
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| 30 | by using flock. This is definitely the Wrong Thing, |
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| 31 | but it might be better than nothing (?). */ |
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| 32 | int |
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| 33 | __f_setlk (int fd, int type, int whence, __off64_t start, __off64_t len, int wait) |
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| 34 | { |
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| 35 | int cmd = 0; |
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| 36 | |
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| 37 | switch (type) |
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| 38 | { |
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| 39 | case F_RDLCK: cmd = LOCK_SH; break; |
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| 40 | case F_WRLCK: cmd = LOCK_EX; break; |
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| 41 | case F_UNLCK: cmd = LOCK_UN; break; |
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| 42 | default: |
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| 43 | return __hurd_fail (EINVAL); |
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| 44 | } |
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| 45 | |
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| 46 | if (cmd != LOCK_UN && wait == 0) |
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| 47 | cmd |= LOCK_NB; |
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| 48 | |
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| 49 | if (whence == SEEK_CUR) |
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| 50 | { |
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| 51 | /* In case the target position is 0, we can support it below. */ |
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| 52 | __off64_t cur = __lseek64 (fd: fd, offset: 0, SEEK_CUR); |
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| 53 | |
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| 54 | if (cur >= 0) |
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| 55 | { |
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| 56 | start = cur + start; |
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| 57 | whence = SEEK_SET; |
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| 58 | } |
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| 59 | } |
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| 60 | |
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| 61 | switch (whence) |
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| 62 | { |
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| 63 | case SEEK_SET: |
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| 64 | if (start == 0 && len == 0) /* Whole file request. */ |
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| 65 | break; |
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| 66 | /* It seems to be common for applications to lock the first |
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| 67 | byte of the file when they are really doing whole-file locking. |
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| 68 | So, since it's so wrong already, might as well do that too. */ |
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| 69 | if (start == 0 && len == 1) |
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| 70 | break; |
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| 71 | /* FALLTHROUGH */ |
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| 72 | case SEEK_CUR: |
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| 73 | case SEEK_END: |
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| 74 | return __hurd_fail (ENOTSUP); |
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| 75 | default: |
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| 76 | return __hurd_fail (EINVAL); |
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| 77 | } |
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| 78 | |
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| 79 | return __flock (fd: fd, operation: cmd); |
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| 80 | } |
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| 81 | |
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