projects / lttng-tools.git / blame
| Commit | Line | Data |
|---|---|---|
| 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> | |
| 22 | ||
| 23 | struct fs_handle; | |
| 24 | ||
| 25 | /* | |
| 26 | * Marks the handle as the most recently used and marks the 'fd' as | |
| 27 | * "in-use". This prevents the tracker from recycling the underlying | |
| 28 | * file descriptor while it is actively being used by a thread. | |
| 29 | * | |
| 30 | * Don't forget that the tracker may be initiating an fd 'suspension' | |
| 31 | * from another thread as the need to free an fd slot may arise from any | |
| 32 | * thread within the daemon. | |
| 33 | * | |
| 34 | * Note that a restorable fd should never be held for longer than | |
| 35 | * strictly necessary (e.g. the duration of a syscall()). | |
| 36 | * | |
| 37 | * Returns the fd on success, otherwise a negative value may be returned | |
| 38 | * if the restoration of the fd failed. | |
| 39 | */ | |
| 40 | LTTNG_HIDDEN | |
| 41 | int fs_handle_get_fd(struct fs_handle *handle); | |
| 42 | ||
| 43 | /* | |
| 44 | * Used by the caller to signal that it is no longer using the underlying fd and | |
| 45 | * that it may be safely suspended. | |
| 46 | */ | |
| 47 | LTTNG_HIDDEN | |
| 48 | void fs_handle_put_fd(struct fs_handle *handle); | |
| 49 | ||
| 50 | /* | |
| 51 | * Unlink the file associated to an fs_handle. Note that the unlink | |
| 52 | * operation will not be performed immediately. It will only be performed | |
| 53 | * once all references to the underlying file (through other fs_handle objects) | |
| 54 | * have been released. | |
| 55 | * | |
| 56 | * However, note that the file will be renamed so as to provide the observable | |
| 57 | * effect of an unlink(), that is removing a name from the filesystem. | |
| 58 | * | |
| 59 | * Returns 0 on success, otherwise a negative value will be returned | |
| 60 | * if the operation failed. | |
| 61 | */ | |
| 62 | LTTNG_HIDDEN | |
| 63 | int fs_handle_unlink(struct fs_handle *handle); | |
| 64 | ||
| 65 | /* | |
| 66 | * Frees the handle and discards the underlying fd. | |
| 67 | */ | |
| 68 | LTTNG_HIDDEN | |
| 69 | int fs_handle_close(struct fs_handle *handle); | |
| 70 | ||
| 71 | #endif /* FS_HANDLE_H */ |