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323592fd | 1 | /* futex helper functions for glibc-internal use. |
dff8da6b | 2 | Copyright (C) 2020-2024 Free Software Foundation, Inc. |
323592fd LM |
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 | |
17 | <https://www.gnu.org/licenses/>. */ | |
18 | ||
19 | #include <errno.h> | |
20 | #include <sysdep.h> | |
21 | #include <time.h> | |
22 | #include <futex-internal.h> | |
23 | #include <kernel-features.h> | |
24 | ||
25 | #ifndef __ASSUME_TIME64_SYSCALLS | |
26 | static int | |
a2b9e1ec AZ |
27 | __futex_abstimed_wait_common32 (unsigned int* futex_word, |
28 | unsigned int expected, int op, | |
29 | const struct __timespec64* abstime, | |
30 | int private, bool cancel) | |
323592fd | 31 | { |
50e19ddf AZ |
32 | struct timespec ts32, *pts32 = NULL; |
33 | if (abstime != NULL) | |
34 | { | |
50e19ddf AZ |
35 | ts32 = valid_timespec64_to_timespec (*abstime); |
36 | pts32 = &ts32; | |
37 | } | |
323592fd | 38 | |
a2b9e1ec AZ |
39 | if (cancel) |
40 | return INTERNAL_SYSCALL_CANCEL (futex, futex_word, op, expected, | |
41 | pts32, NULL /* Unused. */, | |
42 | FUTEX_BITSET_MATCH_ANY); | |
43 | else | |
44 | return INTERNAL_SYSCALL_CALL (futex, futex_word, op, expected, | |
50e19ddf | 45 | pts32, NULL /* Unused. */, |
323592fd LM |
46 | FUTEX_BITSET_MATCH_ANY); |
47 | } | |
9cb2c923 | 48 | #endif /* ! __ASSUME_TIME64_SYSCALLS */ |
323592fd | 49 | |
a2b9e1ec AZ |
50 | static int |
51 | __futex_abstimed_wait_common64 (unsigned int* futex_word, | |
b769b0a2 | 52 | unsigned int expected, int op, |
a2b9e1ec AZ |
53 | const struct __timespec64* abstime, |
54 | int private, bool cancel) | |
323592fd | 55 | { |
b769b0a2 AZ |
56 | if (cancel) |
57 | return INTERNAL_SYSCALL_CANCEL (futex_time64, futex_word, op, expected, | |
58 | abstime, NULL /* Unused. */, | |
59 | FUTEX_BITSET_MATCH_ANY); | |
60 | else | |
61 | return INTERNAL_SYSCALL_CALL (futex_time64, futex_word, op, expected, | |
7f0d9e61 | 62 | abstime, NULL /* Unused. */, |
b769b0a2 AZ |
63 | FUTEX_BITSET_MATCH_ANY); |
64 | } | |
65 | ||
66 | static int | |
67 | __futex_abstimed_wait_common (unsigned int* futex_word, | |
68 | unsigned int expected, clockid_t clockid, | |
69 | const struct __timespec64* abstime, | |
70 | int private, bool cancel) | |
71 | { | |
323592fd | 72 | int err; |
b769b0a2 | 73 | unsigned int clockbit; |
323592fd LM |
74 | |
75 | /* Work around the fact that the kernel rejects negative timeout values | |
76 | despite them being valid. */ | |
77 | if (__glibc_unlikely ((abstime != NULL) && (abstime->tv_sec < 0))) | |
78 | return ETIMEDOUT; | |
79 | ||
80 | if (! lll_futex_supported_clockid (clockid)) | |
81 | return EINVAL; | |
82 | ||
83 | clockbit = (clockid == CLOCK_REALTIME) ? FUTEX_CLOCK_REALTIME : 0; | |
84 | int op = __lll_private_flag (FUTEX_WAIT_BITSET | clockbit, private); | |
85 | ||
b769b0a2 AZ |
86 | #ifdef __ASSUME_TIME64_SYSCALLS |
87 | err = __futex_abstimed_wait_common64 (futex_word, expected, op, abstime, | |
88 | private, cancel); | |
89 | #else | |
a9acb7b3 | 90 | bool need_time64 = abstime != NULL && !in_int32_t_range (abstime->tv_sec); |
b769b0a2 AZ |
91 | if (need_time64) |
92 | { | |
93 | err = __futex_abstimed_wait_common64 (futex_word, expected, op, abstime, | |
94 | private, cancel); | |
95 | if (err == -ENOSYS) | |
96 | err = -EOVERFLOW; | |
97 | } | |
a2b9e1ec | 98 | else |
a2b9e1ec AZ |
99 | err = __futex_abstimed_wait_common32 (futex_word, expected, op, abstime, |
100 | private, cancel); | |
323592fd LM |
101 | #endif |
102 | ||
103 | switch (err) | |
104 | { | |
105 | case 0: | |
106 | case -EAGAIN: | |
107 | case -EINTR: | |
108 | case -ETIMEDOUT: | |
a3e7aead | 109 | case -EINVAL: |
323592fd LM |
110 | case -EOVERFLOW: /* Passed absolute timeout uses 64 bit time_t type, but |
111 | underlying kernel does not support 64 bit time_t futex | |
112 | syscalls. */ | |
113 | return -err; | |
114 | ||
115 | case -EFAULT: /* Must have been caused by a glibc or application bug. */ | |
323592fd LM |
116 | case -ENOSYS: /* Must have been caused by a glibc bug. */ |
117 | /* No other errors are documented at this time. */ | |
118 | default: | |
119 | futex_fatal_error (); | |
120 | } | |
121 | } | |
b2cdadde LM |
122 | |
123 | int | |
124 | __futex_abstimed_wait64 (unsigned int* futex_word, unsigned int expected, | |
125 | clockid_t clockid, | |
126 | const struct __timespec64* abstime, int private) | |
127 | { | |
b769b0a2 AZ |
128 | return __futex_abstimed_wait_common (futex_word, expected, clockid, |
129 | abstime, private, false); | |
a2b9e1ec | 130 | } |
b5be9ae7 | 131 | libc_hidden_def (__futex_abstimed_wait64) |
b2cdadde | 132 | |
a2b9e1ec AZ |
133 | int |
134 | __futex_abstimed_wait_cancelable64 (unsigned int* futex_word, | |
135 | unsigned int expected, clockid_t clockid, | |
136 | const struct __timespec64* abstime, | |
137 | int private) | |
138 | { | |
b769b0a2 AZ |
139 | return __futex_abstimed_wait_common (futex_word, expected, clockid, |
140 | abstime, private, true); | |
b2cdadde | 141 | } |
b5be9ae7 | 142 | libc_hidden_def (__futex_abstimed_wait_cancelable64) |
8352b6df AZ |
143 | |
144 | int | |
145 | __futex_lock_pi64 (int *futex_word, clockid_t clockid, | |
146 | const struct __timespec64 *abstime, int private) | |
147 | { | |
148 | int err; | |
149 | ||
150 | unsigned int clockbit = clockid == CLOCK_REALTIME | |
151 | ? FUTEX_CLOCK_REALTIME : 0; | |
152 | int op_pi2 = __lll_private_flag (FUTEX_LOCK_PI2 | clockbit, private); | |
153 | #if __ASSUME_FUTEX_LOCK_PI2 | |
154 | /* Assume __ASSUME_TIME64_SYSCALLS since FUTEX_LOCK_PI2 was added later. */ | |
155 | err = INTERNAL_SYSCALL_CALL (futex_time64, futex_word, op_pi2, 0, abstime); | |
156 | #else | |
157 | /* FUTEX_LOCK_PI does not support clock selection, so for CLOCK_MONOTONIC | |
158 | the only option is to use FUTEX_LOCK_PI2. */ | |
159 | int op_pi1 = __lll_private_flag (FUTEX_LOCK_PI, private); | |
160 | int op_pi = abstime != NULL && clockid != CLOCK_REALTIME ? op_pi2 : op_pi1; | |
161 | ||
162 | # ifdef __ASSUME_TIME64_SYSCALLS | |
163 | err = INTERNAL_SYSCALL_CALL (futex_time64, futex_word, op_pi, 0, abstime); | |
164 | # else | |
a9acb7b3 | 165 | bool need_time64 = abstime != NULL && !in_int32_t_range (abstime->tv_sec); |
8352b6df AZ |
166 | if (need_time64) |
167 | err = INTERNAL_SYSCALL_CALL (futex_time64, futex_word, op_pi, 0, abstime); | |
168 | else | |
169 | { | |
170 | struct timespec ts32, *pts32 = NULL; | |
171 | if (abstime != NULL) | |
172 | { | |
173 | ts32 = valid_timespec64_to_timespec (*abstime); | |
174 | pts32 = &ts32; | |
175 | } | |
176 | err = INTERNAL_SYSCALL_CALL (futex, futex_word, op_pi, 0, pts32); | |
177 | } | |
178 | # endif /* __ASSUME_TIME64_SYSCALLS */ | |
179 | /* FUTEX_LOCK_PI2 is not available on this kernel. */ | |
180 | if (err == -ENOSYS) | |
181 | err = -EINVAL; | |
182 | #endif /* __ASSUME_FUTEX_LOCK_PI2 */ | |
183 | ||
184 | switch (err) | |
185 | { | |
186 | case 0: | |
187 | case -EAGAIN: | |
188 | case -EINTR: | |
189 | case -ETIMEDOUT: | |
190 | case -ESRCH: | |
191 | case -EDEADLK: | |
192 | case -EINVAL: /* This indicates either state corruption or that the kernel | |
193 | found a waiter on futex address which is waiting via | |
194 | FUTEX_WAIT or FUTEX_WAIT_BITSET. This is reported on | |
195 | some futex_lock_pi usage (pthread_mutex_timedlock for | |
196 | instance). */ | |
197 | return -err; | |
198 | ||
199 | case -EFAULT: /* Must have been caused by a glibc or application bug. */ | |
200 | case -ENOSYS: /* Must have been caused by a glibc bug. */ | |
201 | /* No other errors are documented at this time. */ | |
202 | default: | |
203 | futex_fatal_error (); | |
204 | } | |
205 | } |