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#include <errno.h>
#include <stdio.h>
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <unistd.h>
#include <fcntl.h>
#include "kcov.h"
static int kcovfd;
static unsigned long *cover;
//TODO: Make sure get_random_fd can't touch the kcovfd
void init_kcov(void)
{
/* A single fd descriptor allows coverage collection on a single
* thread.
*/
kcovfd = open("/sys/kernel/debug/kcov", O_RDWR);
if (kcovfd == -1)
return;
/* Setup trace mode and trace size. */
if (ioctl(kcovfd, KCOV_INIT_TRACE, COVER_SIZE)) {
printf("Failed to init kcov: %s\n", strerror(errno));
goto fail;
}
/* Mmap buffer shared between kernel- and user-space. */
cover = (unsigned long*)mmap(NULL, COVER_SIZE * sizeof(unsigned long),
PROT_READ | PROT_WRITE, MAP_SHARED, kcovfd, 0);
if ((void*)cover == MAP_FAILED) {
printf("Failed to mmap kcov buffer: %s\n", strerror(errno));
goto fail;
}
return;
fail:
close(kcovfd);
kcovfd = -1;
return;
}
void enable_kcov(void)
{
/* Enable coverage collection on the current thread. */
if (ioctl(kcovfd, KCOV_ENABLE, 0))
printf("Error enabling kcov: %s\n", strerror(errno));
/* Reset coverage from the tail of the ioctl() call. */
__atomic_store_n(&cover[0], 0, __ATOMIC_RELAXED);
}
void dump_kcov_buffer(void)
{
unsigned long n, i;
/* Read number of PCs collected. */
n = __atomic_load_n(&cover[0], __ATOMIC_RELAXED);
for (i = 0; i < n; i++)
printf("0x%lx\n", cover[i + 1]);
}
void disable_kcov(void)
{
/* Disable coverage collection for the current thread. After this call
* coverage can be enabled for a different thread.
*/
if (ioctl(kcovfd, KCOV_DISABLE, 0))
printf("Failed to disable kcov: %s\n", strerror(errno));
}
void shutdown_kcov(void)
{
if (kcovfd == -1)
return;
if (munmap(cover, COVER_SIZE * sizeof(unsigned long)))
printf("Couldn't munmap kcov buffer : %s\n", strerror(errno));
if (close(kcovfd))
printf("Couldn't close kcov fd (%d) : %s\n", kcovfd, strerror(errno));
}
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