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Don't try to open devices in the gettc() function which will always

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fail in the Capability mode. Instead silently fallback to the syscall
method, which is done for example in the gettimeofday(2) function.

Reviewed by:	kib
This commit is contained in:
Mariusz Zaborski 2017-02-26 22:07:26 +00:00
parent 43ad57d358
commit ba1b663656
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=314319
1 changed files with 28 additions and 11 deletions
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39
lib/libc/x86/sys/__vdso_gettc.c
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@ -33,6 +33,7 @@ __FBSDID("$FreeBSD$");
#include <sys/param.h>
#include "namespace.h"
#include <sys/capsicum.h>
#include <sys/elf.h>
#include <sys/fcntl.h>
#include <sys/mman.h>
@ -124,6 +125,7 @@ __vdso_init_hpet(uint32_t u)
static const char devprefix[] = "/dev/hpet";
char devname[64], *c, *c1, t;
volatile char *new_map, *old_map;
unsigned int mode;
uint32_t u1;
int fd;
@ -144,18 +146,26 @@ __vdso_init_hpet(uint32_t u)
if (old_map != NULL)
return;
mode = 0;
if (cap_getmode(&mode) == 0 && mode != 0)
goto fail;
fd = _open(devname, O_RDONLY);
if (fd == -1) {
atomic_cmpset_rel_ptr((volatile uintptr_t *)&hpet_dev_map[u],
(uintptr_t)old_map, (uintptr_t)MAP_FAILED);
return;
}
if (fd == -1)
goto fail;
new_map = mmap(NULL, PAGE_SIZE, PROT_READ, MAP_SHARED, fd, 0);
_close(fd);
if (atomic_cmpset_rel_ptr((volatile uintptr_t *)&hpet_dev_map[u],
(uintptr_t)old_map, (uintptr_t)new_map) == 0 &&
new_map != MAP_FAILED)
munmap((void *)new_map, PAGE_SIZE);
munmap((void *)new_map, PAGE_SIZE);
return;
fail:
/* Prevent the caller from re-entering. */
atomic_cmpset_rel_ptr((volatile uintptr_t *)&hpet_dev_map[u],
(uintptr_t)old_map, (uintptr_t)MAP_FAILED);
}
#ifdef WANT_HYPERV
@ -174,16 +184,23 @@ static void
__vdso_init_hyperv_tsc(void)
{
int fd;
unsigned int mode;
mode = 0;
if (cap_getmode(&mode) == 0 && mode != 0)
goto fail;
fd = _open(HYPERV_REFTSC_DEVPATH, O_RDONLY);
if (fd < 0) {
/* Prevent the caller from re-entering. */
hyperv_ref_tsc = MAP_FAILED;
return;
}
if (fd < 0)
goto fail;
hyperv_ref_tsc = mmap(NULL, sizeof(*hyperv_ref_tsc), PROT_READ,
MAP_SHARED, fd, 0);
_close(fd);
return;
fail:
/* Prevent the caller from re-entering. */
hyperv_ref_tsc = MAP_FAILED;
}
static int