69 lines
1.4 KiB
C
69 lines
1.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <errno.h>
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#include <linux/unistd.h>
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#include <sys/ptrace.h>
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#include <sys/syscall.h>
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#include <unistd.h>
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#include <sysdep/tls.h>
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#ifndef PTRACE_GET_THREAD_AREA
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#define PTRACE_GET_THREAD_AREA 25
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#endif
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#ifndef PTRACE_SET_THREAD_AREA
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#define PTRACE_SET_THREAD_AREA 26
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#endif
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/* Checks whether host supports TLS, and sets *tls_min according to the value
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* valid on the host.
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* i386 host have it == 6; x86_64 host have it == 12, for i386 emulation. */
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void check_host_supports_tls(int *supports_tls, int *tls_min)
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{
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/* Values for x86 and x86_64.*/
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int val[] = {GDT_ENTRY_TLS_MIN_I386, GDT_ENTRY_TLS_MIN_X86_64};
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int i;
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for (i = 0; i < ARRAY_SIZE(val); i++) {
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user_desc_t info;
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info.entry_number = val[i];
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if (syscall(__NR_get_thread_area, &info) == 0) {
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*tls_min = val[i];
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*supports_tls = 1;
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return;
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} else {
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if (errno == EINVAL)
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continue;
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else if (errno == ENOSYS)
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*supports_tls = 0;
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return;
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}
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}
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*supports_tls = 0;
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}
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int os_set_thread_area(user_desc_t *info, int pid)
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{
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int ret;
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ret = ptrace(PTRACE_SET_THREAD_AREA, pid, info->entry_number,
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(unsigned long) info);
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if (ret < 0)
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ret = -errno;
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return ret;
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}
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int os_get_thread_area(user_desc_t *info, int pid)
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{
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int ret;
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ret = ptrace(PTRACE_GET_THREAD_AREA, pid, info->entry_number,
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(unsigned long) info);
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if (ret < 0)
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ret = -errno;
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return ret;
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}
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