108 lines
2.5 KiB
C
108 lines
2.5 KiB
C
#include <time.h>
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#include <errno.h>
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#include <stdint.h>
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#include "syscall.h"
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#include "atomic.h"
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#ifdef VDSO_CGT_SYM
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static void *volatile vdso_func;
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#ifdef VDSO_CGT32_SYM
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static void *volatile vdso_func_32;
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static int cgt_time32_wrap(clockid_t clk, struct timespec *ts)
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{
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long ts32[2];
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int (*f)(clockid_t, long[2]) =
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(int (*)(clockid_t, long[2]))vdso_func_32;
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int r = f(clk, ts32);
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if (!r) {
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/* Fallback to syscalls if time32 overflowed. Maybe
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* we lucked out and somehow migrated to a kernel with
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* time64 syscalls available. */
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if (ts32[0] < 0) {
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a_cas_p(&vdso_func, (void *)cgt_time32_wrap, 0);
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return -ENOSYS;
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}
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ts->tv_sec = ts32[0];
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ts->tv_nsec = ts32[1];
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}
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return r;
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}
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#endif
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static int cgt_init(clockid_t clk, struct timespec *ts)
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{
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void *p = __vdsosym(VDSO_CGT_VER, VDSO_CGT_SYM);
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#ifdef VDSO_CGT32_SYM
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if (!p) {
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void *q = __vdsosym(VDSO_CGT32_VER, VDSO_CGT32_SYM);
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if (q) {
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a_cas_p(&vdso_func_32, 0, q);
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p = cgt_time32_wrap;
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}
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}
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#endif
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int (*f)(clockid_t, struct timespec *) =
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(int (*)(clockid_t, struct timespec *))p;
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a_cas_p(&vdso_func, (void *)cgt_init, p);
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return f ? f(clk, ts) : -ENOSYS;
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}
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static void *volatile vdso_func = (void *)cgt_init;
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#endif
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int __clock_gettime(clockid_t clk, struct timespec *ts)
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{
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int r;
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#ifdef VDSO_CGT_SYM
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int (*f)(clockid_t, struct timespec *) =
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(int (*)(clockid_t, struct timespec *))vdso_func;
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if (f) {
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r = f(clk, ts);
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if (!r) return r;
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if (r == -EINVAL) return __syscall_ret(r);
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/* Fall through on errors other than EINVAL. Some buggy
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* vdso implementations return ENOSYS for clocks they
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* can't handle, rather than making the syscall. This
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* also handles the case where cgt_init fails to find
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* a vdso function to use. */
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}
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#endif
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#ifdef SYS_clock_gettime64
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r = -ENOSYS;
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if (sizeof(time_t) > 4)
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r = __syscall(SYS_clock_gettime64, clk, ts);
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if (SYS_clock_gettime == SYS_clock_gettime64 || r!=-ENOSYS)
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return __syscall_ret(r);
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long ts32[2];
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r = __syscall(SYS_clock_gettime, clk, ts32);
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if (r==-ENOSYS && clk==CLOCK_REALTIME) {
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r = __syscall(SYS_gettimeofday, ts32, 0);
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ts32[1] *= 1000;
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}
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if (!r) {
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ts->tv_sec = ts32[0];
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ts->tv_nsec = ts32[1];
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return r;
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}
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return __syscall_ret(r);
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#else
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r = __syscall(SYS_clock_gettime, clk, ts);
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if (r == -ENOSYS) {
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if (clk == CLOCK_REALTIME) {
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__syscall(SYS_gettimeofday, ts, 0);
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ts->tv_nsec = (int)ts->tv_nsec * 1000;
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return 0;
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}
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r = -EINVAL;
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}
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return __syscall_ret(r);
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#endif
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}
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weak_alias(__clock_gettime, clock_gettime);
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