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d5e82754 | 1 | /* Message-writing for the dynamic linker. Generic version. |
581c785b | 2 | Copyright (C) 2013-2022 Free Software Foundation, Inc. |
d5e82754 RM |
3 | This file is part of the GNU C Library. |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
6 | modify it under the terms of the GNU Lesser General Public | |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 of the License, or (at your option) any later version. | |
9 | ||
10 | The GNU C Library 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 GNU | |
13 | Lesser General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Lesser General Public | |
16 | License along with the GNU C Library; if not, see | |
5a82c748 | 17 | <https://www.gnu.org/licenses/>. */ |
d5e82754 RM |
18 | |
19 | #include <sys/uio.h> | |
20 | #include <ldsodefs.h> | |
ec999b8e | 21 | #include <libc-lock.h> |
d5e82754 RM |
22 | |
23 | /* This is used from only one place: dl-misc.c:_dl_debug_vdprintf. | |
24 | Hence it's in a header with the expectation it will be inlined. | |
25 | ||
26 | This is writev, but with a constraint added and others loosened: | |
27 | ||
28 | 1. Under RTLD_PRIVATE_ERRNO, it must not clobber the private errno | |
29 | when another thread holds the dl_load_lock. | |
30 | 2. It is not obliged to detect and report errors at all. | |
31 | 3. It's not really obliged to deliver a single atomic write | |
32 | (though it may be preferable). */ | |
33 | ||
34 | static inline void | |
35 | _dl_writev (int fd, const struct iovec *iov, size_t niov) | |
36 | { | |
37 | /* Note that if __writev is an implementation that calls malloc, | |
38 | this will cause linking problems building the dynamic linker. */ | |
39 | ||
40 | #if RTLD_PRIVATE_ERRNO | |
41 | /* We have to take this lock just to be sure we don't clobber the private | |
42 | errno when it's being used by another thread that cares about it. | |
43 | Yet we must be sure not to try calling the lock functions before | |
44 | the thread library is fully initialized. */ | |
9cf27b8d | 45 | if (__glibc_unlikely (_dl_starting_up)) |
d5e82754 RM |
46 | __writev (fd, iov, niov); |
47 | else | |
48 | { | |
49 | __rtld_lock_lock_recursive (GL(dl_load_lock)); | |
50 | __writev (fd, iov, niov); | |
51 | __rtld_lock_unlock_recursive (GL(dl_load_lock)); | |
52 | } | |
53 | #else | |
54 | __writev (fd, iov, niov); | |
55 | #endif | |
56 | } |