#define _GNU_SOURCE
#include "internal.h"
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <errno.h>

int msr_open(int cpu)
{
    char path[64];
    snprintf(path, sizeof(path), "/dev/cpu/%d/msr", cpu);
    int fd = open(path, O_RDWR);
    if (fd < 0) {
        if (errno == ENOENT)
            return ICEPICK_E_NO_CAT;
        if (errno == EACCES || errno == EPERM)
            return ICEPICK_E_PERMISSION;
        return ICEPICK_E_MSR;
    }
    return fd;
}

void msr_close(int fd)
{
    if (fd >= 0)
        close(fd);
}

int msr_read(int fd, uint32_t msr, uint64_t *value)
{
    if (pread(fd, value, sizeof(*value), msr) != sizeof(*value))
        return ICEPICK_E_MSR;
    return 0;
}

int msr_write(int fd, uint32_t msr, uint64_t value)
{
    if (pwrite(fd, &value, sizeof(value), msr) != sizeof(value))
        return ICEPICK_E_MSR;
    return 0;
}