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f5ea0241 JG |
1 | /* |
2 | * Copyright (C) 2020 - Jérémie Galarneau <jeremie.galarneau@efficios.com> | |
3 | * | |
4 | * This library is free software; you can redistribute it and/or modify it | |
5 | * under the terms of the GNU Lesser General Public License as published by the | |
6 | * Free Software Foundation; version 2.1 of the License. | |
7 | * | |
8 | * This library is distributed in the hope that it will be useful, but WITHOUT | |
9 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
10 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License | |
11 | * for more details. | |
12 | * | |
13 | * You should have received a copy of the GNU Lesser General Public License | |
14 | * along with this library; if not, write to the Free Software Foundation, | |
15 | * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
16 | */ | |
17 | ||
18 | #ifndef FS_HANDLE_H | |
19 | #define FS_HANDLE_H | |
20 | ||
21 | #include <common/macros.h> | |
8bb66c3c | 22 | #include <stdio.h> |
f5ea0241 JG |
23 | |
24 | struct fs_handle; | |
25 | ||
26 | /* | |
27 | * Marks the handle as the most recently used and marks the 'fd' as | |
28 | * "in-use". This prevents the tracker from recycling the underlying | |
29 | * file descriptor while it is actively being used by a thread. | |
30 | * | |
31 | * Don't forget that the tracker may be initiating an fd 'suspension' | |
32 | * from another thread as the need to free an fd slot may arise from any | |
33 | * thread within the daemon. | |
34 | * | |
35 | * Note that a restorable fd should never be held for longer than | |
36 | * strictly necessary (e.g. the duration of a syscall()). | |
37 | * | |
38 | * Returns the fd on success, otherwise a negative value may be returned | |
39 | * if the restoration of the fd failed. | |
40 | */ | |
41 | LTTNG_HIDDEN | |
42 | int fs_handle_get_fd(struct fs_handle *handle); | |
43 | ||
44 | /* | |
45 | * Used by the caller to signal that it is no longer using the underlying fd and | |
46 | * that it may be safely suspended. | |
47 | */ | |
48 | LTTNG_HIDDEN | |
49 | void fs_handle_put_fd(struct fs_handle *handle); | |
50 | ||
51 | /* | |
52 | * Unlink the file associated to an fs_handle. Note that the unlink | |
53 | * operation will not be performed immediately. It will only be performed | |
54 | * once all references to the underlying file (through other fs_handle objects) | |
55 | * have been released. | |
56 | * | |
57 | * However, note that the file will be renamed so as to provide the observable | |
58 | * effect of an unlink(), that is removing a name from the filesystem. | |
59 | * | |
60 | * Returns 0 on success, otherwise a negative value will be returned | |
61 | * if the operation failed. | |
62 | */ | |
63 | LTTNG_HIDDEN | |
64 | int fs_handle_unlink(struct fs_handle *handle); | |
65 | ||
66 | /* | |
67 | * Frees the handle and discards the underlying fd. | |
68 | */ | |
69 | LTTNG_HIDDEN | |
70 | int fs_handle_close(struct fs_handle *handle); | |
71 | ||
8bb66c3c JG |
72 | LTTNG_HIDDEN |
73 | ssize_t fs_handle_read(struct fs_handle *handle, void *buf, size_t count); | |
74 | ||
75 | LTTNG_HIDDEN | |
76 | ssize_t fs_handle_write(struct fs_handle *handle, const void *buf, size_t count); | |
77 | ||
78 | LTTNG_HIDDEN | |
79 | int fs_handle_truncate(struct fs_handle *handle, off_t offset); | |
80 | ||
81 | LTTNG_HIDDEN | |
82 | int fs_handle_seek(struct fs_handle *handle, off_t offset, int whence); | |
83 | ||
f5ea0241 | 84 | #endif /* FS_HANDLE_H */ |