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0c76fc3c2b
Register rseq TLS for each thread (including main), and unregister for
each thread (excluding main). "rseq" stands for Restartable Sequences.
See the rseq(2) man page proposed here:
https://lkml.org/lkml/2018/9/19/647
Those are based on glibc master branch commit 3ee1e0ec5c.
The rseq system call was merged into Linux 4.18.
The TLS_STATIC_SURPLUS define is increased to leave additional room for
dlopen'd initial-exec TLS, which keeps elf/tst-auditmany working.
The increase (76 bytes) is larger than 32 bytes because it has not been
increased in quite a while. The cost in terms of additional TLS storage
is quite significant, but it will also obscure some initial-exec-related
dlopen failures.
74 lines
2.3 KiB
C
74 lines
2.3 KiB
C
/* Restartable Sequences internal API. Linux implementation.
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Copyright (C) 2020 Free Software Foundation, Inc.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#ifndef RSEQ_INTERNAL_H
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#define RSEQ_INTERNAL_H
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#include <sysdep.h>
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#include <errno.h>
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#include <kernel-features.h>
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#include <stdio.h>
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#include <sys/rseq.h>
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#ifdef RSEQ_SIG
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static inline void
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rseq_register_current_thread (void)
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{
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int ret;
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if (__rseq_abi.cpu_id != RSEQ_CPU_ID_UNINITIALIZED)
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__libc_fatal ("glibc fatal error: "
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"rseq already initialized for this thread\n");
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ret = INTERNAL_SYSCALL_CALL (rseq, &__rseq_abi, sizeof (struct rseq),
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0, RSEQ_SIG);
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if (INTERNAL_SYSCALL_ERROR_P (ret))
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{
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const char *msg = NULL;
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switch (INTERNAL_SYSCALL_ERRNO (ret))
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{
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case ENOSYS: /* rseq system call not implemented. */
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case EPERM: /* rseq system call filtered by seccomp. */
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case EACCES: /* rseq system call filtered by seccomp. */
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__rseq_abi.cpu_id = RSEQ_CPU_ID_REGISTRATION_FAILED;
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break;
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case EBUSY:
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msg = "glibc fatal error: rseq already registered for this thread\n";
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break;
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case EFAULT:
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msg = "glibc fatal error: rseq parameter is an invalid address\n";
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break;
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case EINVAL:
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msg = "glibc fatal error: rseq parameters are invalid\n";
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break;
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default:
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msg = "glibc fatal error: unexpected rseq errno\n";
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break;
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}
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if (msg != NULL)
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__libc_fatal (msg);
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}
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}
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#else /* RSEQ_SIG */
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static inline void
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rseq_register_current_thread (void)
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{
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}
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#endif /* RSEQ_SIG */
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#endif /* rseq-internal.h */
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