| 1 | /* |
| 2 | * wrapper/random.c |
| 3 | * |
| 4 | * wrapper around bootid read. Using KALLSYMS to get its address when |
| 5 | * available, else we need to have a kernel that exports this function to GPL |
| 6 | * modules. |
| 7 | * |
| 8 | * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 9 | * |
| 10 | * This library is free software; you can redistribute it and/or |
| 11 | * modify it under the terms of the GNU Lesser General Public |
| 12 | * License as published by the Free Software Foundation; only |
| 13 | * version 2.1 of the License. |
| 14 | * |
| 15 | * This library is distributed in the hope that it will be useful, |
| 16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 18 | * Lesser General Public License for more details. |
| 19 | * |
| 20 | * You should have received a copy of the GNU Lesser General Public |
| 21 | * License along with this library; if not, write to the Free Software |
| 22 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 23 | */ |
| 24 | |
| 25 | /* boot_id depends on sysctl */ |
| 26 | #if defined(CONFIG_SYSCTL) |
| 27 | |
| 28 | #include <linux/fs.h> |
| 29 | #include <linux/file.h> |
| 30 | #include <linux/sched.h> |
| 31 | #include <linux/uaccess.h> |
| 32 | #include "random.h" |
| 33 | |
| 34 | /* |
| 35 | * Returns string boot id. |
| 36 | */ |
| 37 | int wrapper_get_bootid(char *bootid) |
| 38 | { |
| 39 | struct file *file; |
| 40 | int ret; |
| 41 | ssize_t len; |
| 42 | mm_segment_t old_fs; |
| 43 | |
| 44 | file = filp_open("/proc/sys/kernel/random/boot_id", O_RDONLY, 0); |
| 45 | if (IS_ERR(file)) |
| 46 | return PTR_ERR(file); |
| 47 | |
| 48 | old_fs = get_fs(); |
| 49 | set_fs(KERNEL_DS); |
| 50 | |
| 51 | if (!file->f_op || !file->f_op->read) { |
| 52 | ret = -EINVAL; |
| 53 | goto end; |
| 54 | } |
| 55 | |
| 56 | len = file->f_op->read(file, bootid, BOOT_ID_LEN - 1, &file->f_pos); |
| 57 | if (len != BOOT_ID_LEN - 1) { |
| 58 | ret = -EINVAL; |
| 59 | goto end; |
| 60 | } |
| 61 | |
| 62 | bootid[BOOT_ID_LEN - 1] = '\0'; |
| 63 | ret = 0; |
| 64 | end: |
| 65 | set_fs(old_fs); |
| 66 | filp_close(file, current->files); |
| 67 | return ret; |
| 68 | } |
| 69 | |
| 70 | #else |
| 71 | |
| 72 | int wrapper_get_bootid(char *bootid) |
| 73 | { |
| 74 | return -ENOSYS; |
| 75 | } |
| 76 | |
| 77 | #endif |