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583 lines
14 KiB
583 lines
14 KiB
/* SPDX-License-Identifier: GPL-2.0 */ |
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#define _GNU_SOURCE |
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#include <stdio.h> |
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#include <sys/time.h> |
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#include <time.h> |
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#include <stdlib.h> |
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#include <sys/syscall.h> |
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#include <unistd.h> |
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#include <dlfcn.h> |
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#include <string.h> |
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#include <inttypes.h> |
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#include <signal.h> |
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#include <sys/ucontext.h> |
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#include <errno.h> |
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#include <err.h> |
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#include <sched.h> |
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#include <stdbool.h> |
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#include <setjmp.h> |
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#include <sys/uio.h> |
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#include "helpers.h" |
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#ifdef __x86_64__ |
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# define VSYS(x) (x) |
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#else |
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# define VSYS(x) 0 |
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#endif |
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#ifndef SYS_getcpu |
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# ifdef __x86_64__ |
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# define SYS_getcpu 309 |
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# else |
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# define SYS_getcpu 318 |
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# endif |
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#endif |
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/* max length of lines in /proc/self/maps - anything longer is skipped here */ |
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#define MAPS_LINE_LEN 128 |
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static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *), |
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int flags) |
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{ |
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struct sigaction sa; |
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memset(&sa, 0, sizeof(sa)); |
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sa.sa_sigaction = handler; |
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sa.sa_flags = SA_SIGINFO | flags; |
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sigemptyset(&sa.sa_mask); |
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if (sigaction(sig, &sa, 0)) |
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err(1, "sigaction"); |
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} |
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/* vsyscalls and vDSO */ |
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bool vsyscall_map_r = false, vsyscall_map_x = false; |
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typedef long (*gtod_t)(struct timeval *tv, struct timezone *tz); |
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const gtod_t vgtod = (gtod_t)VSYS(0xffffffffff600000); |
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gtod_t vdso_gtod; |
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typedef int (*vgettime_t)(clockid_t, struct timespec *); |
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vgettime_t vdso_gettime; |
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typedef long (*time_func_t)(time_t *t); |
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const time_func_t vtime = (time_func_t)VSYS(0xffffffffff600400); |
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time_func_t vdso_time; |
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typedef long (*getcpu_t)(unsigned *, unsigned *, void *); |
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const getcpu_t vgetcpu = (getcpu_t)VSYS(0xffffffffff600800); |
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getcpu_t vdso_getcpu; |
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static void init_vdso(void) |
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{ |
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void *vdso = dlopen("linux-vdso.so.1", RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD); |
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if (!vdso) |
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vdso = dlopen("linux-gate.so.1", RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD); |
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if (!vdso) { |
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printf("[WARN]\tfailed to find vDSO\n"); |
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return; |
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} |
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vdso_gtod = (gtod_t)dlsym(vdso, "__vdso_gettimeofday"); |
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if (!vdso_gtod) |
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printf("[WARN]\tfailed to find gettimeofday in vDSO\n"); |
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vdso_gettime = (vgettime_t)dlsym(vdso, "__vdso_clock_gettime"); |
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if (!vdso_gettime) |
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printf("[WARN]\tfailed to find clock_gettime in vDSO\n"); |
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vdso_time = (time_func_t)dlsym(vdso, "__vdso_time"); |
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if (!vdso_time) |
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printf("[WARN]\tfailed to find time in vDSO\n"); |
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vdso_getcpu = (getcpu_t)dlsym(vdso, "__vdso_getcpu"); |
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if (!vdso_getcpu) { |
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/* getcpu() was never wired up in the 32-bit vDSO. */ |
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printf("[%s]\tfailed to find getcpu in vDSO\n", |
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sizeof(long) == 8 ? "WARN" : "NOTE"); |
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} |
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} |
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static int init_vsys(void) |
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{ |
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#ifdef __x86_64__ |
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int nerrs = 0; |
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FILE *maps; |
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char line[MAPS_LINE_LEN]; |
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bool found = false; |
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maps = fopen("/proc/self/maps", "r"); |
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if (!maps) { |
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printf("[WARN]\tCould not open /proc/self/maps -- assuming vsyscall is r-x\n"); |
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vsyscall_map_r = true; |
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return 0; |
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} |
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while (fgets(line, MAPS_LINE_LEN, maps)) { |
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char r, x; |
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void *start, *end; |
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char name[MAPS_LINE_LEN]; |
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/* sscanf() is safe here as strlen(name) >= strlen(line) */ |
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if (sscanf(line, "%p-%p %c-%cp %*x %*x:%*x %*u %s", |
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&start, &end, &r, &x, name) != 5) |
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continue; |
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if (strcmp(name, "[vsyscall]")) |
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continue; |
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printf("\tvsyscall map: %s", line); |
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if (start != (void *)0xffffffffff600000 || |
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end != (void *)0xffffffffff601000) { |
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printf("[FAIL]\taddress range is nonsense\n"); |
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nerrs++; |
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} |
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printf("\tvsyscall permissions are %c-%c\n", r, x); |
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vsyscall_map_r = (r == 'r'); |
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vsyscall_map_x = (x == 'x'); |
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found = true; |
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break; |
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} |
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fclose(maps); |
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if (!found) { |
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printf("\tno vsyscall map in /proc/self/maps\n"); |
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vsyscall_map_r = false; |
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vsyscall_map_x = false; |
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} |
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return nerrs; |
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#else |
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return 0; |
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#endif |
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} |
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/* syscalls */ |
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static inline long sys_gtod(struct timeval *tv, struct timezone *tz) |
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{ |
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return syscall(SYS_gettimeofday, tv, tz); |
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} |
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static inline int sys_clock_gettime(clockid_t id, struct timespec *ts) |
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{ |
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return syscall(SYS_clock_gettime, id, ts); |
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} |
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static inline long sys_time(time_t *t) |
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{ |
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return syscall(SYS_time, t); |
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} |
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static inline long sys_getcpu(unsigned * cpu, unsigned * node, |
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void* cache) |
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{ |
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return syscall(SYS_getcpu, cpu, node, cache); |
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} |
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static jmp_buf jmpbuf; |
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static volatile unsigned long segv_err; |
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static void sigsegv(int sig, siginfo_t *info, void *ctx_void) |
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{ |
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ucontext_t *ctx = (ucontext_t *)ctx_void; |
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segv_err = ctx->uc_mcontext.gregs[REG_ERR]; |
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siglongjmp(jmpbuf, 1); |
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} |
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static double tv_diff(const struct timeval *a, const struct timeval *b) |
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{ |
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return (double)(a->tv_sec - b->tv_sec) + |
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(double)((int)a->tv_usec - (int)b->tv_usec) * 1e-6; |
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} |
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static int check_gtod(const struct timeval *tv_sys1, |
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const struct timeval *tv_sys2, |
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const struct timezone *tz_sys, |
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const char *which, |
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const struct timeval *tv_other, |
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const struct timezone *tz_other) |
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{ |
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int nerrs = 0; |
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double d1, d2; |
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if (tz_other && (tz_sys->tz_minuteswest != tz_other->tz_minuteswest || tz_sys->tz_dsttime != tz_other->tz_dsttime)) { |
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printf("[FAIL] %s tz mismatch\n", which); |
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nerrs++; |
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} |
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d1 = tv_diff(tv_other, tv_sys1); |
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d2 = tv_diff(tv_sys2, tv_other); |
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printf("\t%s time offsets: %lf %lf\n", which, d1, d2); |
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if (d1 < 0 || d2 < 0) { |
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printf("[FAIL]\t%s time was inconsistent with the syscall\n", which); |
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nerrs++; |
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} else { |
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printf("[OK]\t%s gettimeofday()'s timeval was okay\n", which); |
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} |
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return nerrs; |
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} |
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static int test_gtod(void) |
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{ |
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struct timeval tv_sys1, tv_sys2, tv_vdso, tv_vsys; |
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struct timezone tz_sys, tz_vdso, tz_vsys; |
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long ret_vdso = -1; |
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long ret_vsys = -1; |
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int nerrs = 0; |
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printf("[RUN]\ttest gettimeofday()\n"); |
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if (sys_gtod(&tv_sys1, &tz_sys) != 0) |
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err(1, "syscall gettimeofday"); |
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if (vdso_gtod) |
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ret_vdso = vdso_gtod(&tv_vdso, &tz_vdso); |
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if (vsyscall_map_x) |
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ret_vsys = vgtod(&tv_vsys, &tz_vsys); |
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if (sys_gtod(&tv_sys2, &tz_sys) != 0) |
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err(1, "syscall gettimeofday"); |
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if (vdso_gtod) { |
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if (ret_vdso == 0) { |
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nerrs += check_gtod(&tv_sys1, &tv_sys2, &tz_sys, "vDSO", &tv_vdso, &tz_vdso); |
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} else { |
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printf("[FAIL]\tvDSO gettimeofday() failed: %ld\n", ret_vdso); |
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nerrs++; |
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} |
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} |
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if (vsyscall_map_x) { |
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if (ret_vsys == 0) { |
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nerrs += check_gtod(&tv_sys1, &tv_sys2, &tz_sys, "vsyscall", &tv_vsys, &tz_vsys); |
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} else { |
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printf("[FAIL]\tvsys gettimeofday() failed: %ld\n", ret_vsys); |
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nerrs++; |
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} |
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} |
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return nerrs; |
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} |
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static int test_time(void) { |
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int nerrs = 0; |
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printf("[RUN]\ttest time()\n"); |
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long t_sys1, t_sys2, t_vdso = 0, t_vsys = 0; |
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long t2_sys1 = -1, t2_sys2 = -1, t2_vdso = -1, t2_vsys = -1; |
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t_sys1 = sys_time(&t2_sys1); |
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if (vdso_time) |
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t_vdso = vdso_time(&t2_vdso); |
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if (vsyscall_map_x) |
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t_vsys = vtime(&t2_vsys); |
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t_sys2 = sys_time(&t2_sys2); |
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if (t_sys1 < 0 || t_sys1 != t2_sys1 || t_sys2 < 0 || t_sys2 != t2_sys2) { |
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printf("[FAIL]\tsyscall failed (ret1:%ld output1:%ld ret2:%ld output2:%ld)\n", t_sys1, t2_sys1, t_sys2, t2_sys2); |
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nerrs++; |
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return nerrs; |
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} |
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if (vdso_time) { |
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if (t_vdso < 0 || t_vdso != t2_vdso) { |
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printf("[FAIL]\tvDSO failed (ret:%ld output:%ld)\n", t_vdso, t2_vdso); |
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nerrs++; |
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} else if (t_vdso < t_sys1 || t_vdso > t_sys2) { |
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printf("[FAIL]\tvDSO returned the wrong time (%ld %ld %ld)\n", t_sys1, t_vdso, t_sys2); |
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nerrs++; |
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} else { |
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printf("[OK]\tvDSO time() is okay\n"); |
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} |
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} |
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if (vsyscall_map_x) { |
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if (t_vsys < 0 || t_vsys != t2_vsys) { |
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printf("[FAIL]\tvsyscall failed (ret:%ld output:%ld)\n", t_vsys, t2_vsys); |
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nerrs++; |
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} else if (t_vsys < t_sys1 || t_vsys > t_sys2) { |
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printf("[FAIL]\tvsyscall returned the wrong time (%ld %ld %ld)\n", t_sys1, t_vsys, t_sys2); |
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nerrs++; |
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} else { |
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printf("[OK]\tvsyscall time() is okay\n"); |
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} |
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} |
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return nerrs; |
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} |
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static int test_getcpu(int cpu) |
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{ |
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int nerrs = 0; |
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long ret_sys, ret_vdso = -1, ret_vsys = -1; |
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printf("[RUN]\tgetcpu() on CPU %d\n", cpu); |
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cpu_set_t cpuset; |
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CPU_ZERO(&cpuset); |
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CPU_SET(cpu, &cpuset); |
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if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0) { |
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printf("[SKIP]\tfailed to force CPU %d\n", cpu); |
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return nerrs; |
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} |
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unsigned cpu_sys, cpu_vdso, cpu_vsys, node_sys, node_vdso, node_vsys; |
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unsigned node = 0; |
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bool have_node = false; |
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ret_sys = sys_getcpu(&cpu_sys, &node_sys, 0); |
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if (vdso_getcpu) |
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ret_vdso = vdso_getcpu(&cpu_vdso, &node_vdso, 0); |
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if (vsyscall_map_x) |
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ret_vsys = vgetcpu(&cpu_vsys, &node_vsys, 0); |
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if (ret_sys == 0) { |
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if (cpu_sys != cpu) { |
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printf("[FAIL]\tsyscall reported CPU %hu but should be %d\n", cpu_sys, cpu); |
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nerrs++; |
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} |
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have_node = true; |
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node = node_sys; |
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} |
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if (vdso_getcpu) { |
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if (ret_vdso) { |
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printf("[FAIL]\tvDSO getcpu() failed\n"); |
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nerrs++; |
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} else { |
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if (!have_node) { |
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have_node = true; |
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node = node_vdso; |
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} |
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if (cpu_vdso != cpu) { |
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printf("[FAIL]\tvDSO reported CPU %hu but should be %d\n", cpu_vdso, cpu); |
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nerrs++; |
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} else { |
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printf("[OK]\tvDSO reported correct CPU\n"); |
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} |
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if (node_vdso != node) { |
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printf("[FAIL]\tvDSO reported node %hu but should be %hu\n", node_vdso, node); |
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nerrs++; |
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} else { |
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printf("[OK]\tvDSO reported correct node\n"); |
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} |
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} |
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} |
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if (vsyscall_map_x) { |
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if (ret_vsys) { |
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printf("[FAIL]\tvsyscall getcpu() failed\n"); |
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nerrs++; |
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} else { |
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if (!have_node) { |
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have_node = true; |
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node = node_vsys; |
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} |
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if (cpu_vsys != cpu) { |
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printf("[FAIL]\tvsyscall reported CPU %hu but should be %d\n", cpu_vsys, cpu); |
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nerrs++; |
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} else { |
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printf("[OK]\tvsyscall reported correct CPU\n"); |
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} |
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if (node_vsys != node) { |
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printf("[FAIL]\tvsyscall reported node %hu but should be %hu\n", node_vsys, node); |
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nerrs++; |
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} else { |
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printf("[OK]\tvsyscall reported correct node\n"); |
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} |
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} |
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} |
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return nerrs; |
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} |
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static int test_vsys_r(void) |
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{ |
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#ifdef __x86_64__ |
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printf("[RUN]\tChecking read access to the vsyscall page\n"); |
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bool can_read; |
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if (sigsetjmp(jmpbuf, 1) == 0) { |
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*(volatile int *)0xffffffffff600000; |
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can_read = true; |
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} else { |
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can_read = false; |
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} |
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if (can_read && !vsyscall_map_r) { |
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printf("[FAIL]\tWe have read access, but we shouldn't\n"); |
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return 1; |
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} else if (!can_read && vsyscall_map_r) { |
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printf("[FAIL]\tWe don't have read access, but we should\n"); |
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return 1; |
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} else if (can_read) { |
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printf("[OK]\tWe have read access\n"); |
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} else { |
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printf("[OK]\tWe do not have read access: #PF(0x%lx)\n", |
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segv_err); |
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} |
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#endif |
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return 0; |
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} |
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static int test_vsys_x(void) |
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{ |
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#ifdef __x86_64__ |
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if (vsyscall_map_x) { |
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/* We already tested this adequately. */ |
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return 0; |
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} |
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printf("[RUN]\tMake sure that vsyscalls really page fault\n"); |
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bool can_exec; |
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if (sigsetjmp(jmpbuf, 1) == 0) { |
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vgtod(NULL, NULL); |
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can_exec = true; |
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} else { |
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can_exec = false; |
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} |
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if (can_exec) { |
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printf("[FAIL]\tExecuting the vsyscall did not page fault\n"); |
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return 1; |
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} else if (segv_err & (1 << 4)) { /* INSTR */ |
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printf("[OK]\tExecuting the vsyscall page failed: #PF(0x%lx)\n", |
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segv_err); |
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} else { |
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printf("[FAIL]\tExecution failed with the wrong error: #PF(0x%lx)\n", |
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segv_err); |
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return 1; |
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} |
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#endif |
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return 0; |
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} |
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|
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/* |
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* Debuggers expect ptrace() to be able to peek at the vsyscall page. |
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* Use process_vm_readv() as a proxy for ptrace() to test this. We |
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* want it to work in the vsyscall=emulate case and to fail in the |
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* vsyscall=xonly case. |
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* |
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* It's worth noting that this ABI is a bit nutty. write(2) can't |
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* read from the vsyscall page on any kernel version or mode. The |
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* fact that ptrace() ever worked was a nice courtesy of old kernels, |
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* but the code to support it is fairly gross. |
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*/ |
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static int test_process_vm_readv(void) |
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{ |
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#ifdef __x86_64__ |
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char buf[4096]; |
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struct iovec local, remote; |
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int ret; |
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printf("[RUN]\tprocess_vm_readv() from vsyscall page\n"); |
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local.iov_base = buf; |
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local.iov_len = 4096; |
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remote.iov_base = (void *)0xffffffffff600000; |
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remote.iov_len = 4096; |
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ret = process_vm_readv(getpid(), &local, 1, &remote, 1, 0); |
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if (ret != 4096) { |
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/* |
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* We expect process_vm_readv() to work if and only if the |
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* vsyscall page is readable. |
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*/ |
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printf("[%s]\tprocess_vm_readv() failed (ret = %d, errno = %d)\n", vsyscall_map_r ? "FAIL" : "OK", ret, errno); |
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return vsyscall_map_r ? 1 : 0; |
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} |
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|
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if (vsyscall_map_r) { |
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if (!memcmp(buf, (const void *)0xffffffffff600000, 4096)) { |
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printf("[OK]\tIt worked and read correct data\n"); |
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} else { |
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printf("[FAIL]\tIt worked but returned incorrect data\n"); |
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return 1; |
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} |
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} else { |
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printf("[FAIL]\tprocess_rm_readv() succeeded, but it should have failed in this configuration\n"); |
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return 1; |
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} |
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#endif |
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return 0; |
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} |
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|
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#ifdef __x86_64__ |
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static volatile sig_atomic_t num_vsyscall_traps; |
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|
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static void sigtrap(int sig, siginfo_t *info, void *ctx_void) |
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{ |
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ucontext_t *ctx = (ucontext_t *)ctx_void; |
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unsigned long ip = ctx->uc_mcontext.gregs[REG_RIP]; |
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|
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if (((ip ^ 0xffffffffff600000UL) & ~0xfffUL) == 0) |
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num_vsyscall_traps++; |
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} |
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|
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static int test_emulation(void) |
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{ |
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time_t tmp; |
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bool is_native; |
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|
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if (!vsyscall_map_x) |
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return 0; |
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|
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printf("[RUN]\tchecking that vsyscalls are emulated\n"); |
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sethandler(SIGTRAP, sigtrap, 0); |
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set_eflags(get_eflags() | X86_EFLAGS_TF); |
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vtime(&tmp); |
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set_eflags(get_eflags() & ~X86_EFLAGS_TF); |
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|
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/* |
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* If vsyscalls are emulated, we expect a single trap in the |
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* vsyscall page -- the call instruction will trap with RIP |
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* pointing to the entry point before emulation takes over. |
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* In native mode, we expect two traps, since whatever code |
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* the vsyscall page contains will be more than just a ret |
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* instruction. |
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*/ |
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is_native = (num_vsyscall_traps > 1); |
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|
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printf("[%s]\tvsyscalls are %s (%d instructions in vsyscall page)\n", |
|
(is_native ? "FAIL" : "OK"), |
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(is_native ? "native" : "emulated"), |
|
(int)num_vsyscall_traps); |
|
|
|
return is_native; |
|
} |
|
#endif |
|
|
|
int main(int argc, char **argv) |
|
{ |
|
int nerrs = 0; |
|
|
|
init_vdso(); |
|
nerrs += init_vsys(); |
|
|
|
nerrs += test_gtod(); |
|
nerrs += test_time(); |
|
nerrs += test_getcpu(0); |
|
nerrs += test_getcpu(1); |
|
|
|
sethandler(SIGSEGV, sigsegv, 0); |
|
nerrs += test_vsys_r(); |
|
nerrs += test_vsys_x(); |
|
|
|
nerrs += test_process_vm_readv(); |
|
|
|
#ifdef __x86_64__ |
|
nerrs += test_emulation(); |
|
#endif |
|
|
|
return nerrs ? 1 : 0; |
|
}
|
|
|