Program for reading temperature of Broadcom wireless adapters.

wltemp.c

#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <net/if.h>

#define	WLC_IOCTL_SMLEN 256	/* "small" length ioctl buffer required */
#define WLC_GET_VAR     262	/* get value of named variable */
#define WLC_SET_VAR     263	/* set named variable to value */

typedef unsigned char uint8;

/* Linux network driver ioctl encoding */
typedef struct wl_ioctl {
        uint cmd;       /* common ioctl definition */
        void *buf;      /* pointer to user buffer */
        uint len;       /* length of user buffer */
        uint8 set;      /* 1=set IOCTL; 0=query IOCTL */
        uint used;      /* bytes read or written (optional) */
        uint needed;    /* bytes needed (optional) */
} wl_ioctl_t;

static int wl_ioctl(char *name, int cmd, void *buf, int len)
{
	struct ifreq ifr;
	wl_ioctl_t ioc;
	int ret = 0;
	int s;

	/* open socket to kernel */
	if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
		perror("socket");
		return errno;
	}

	/* do it */
	ioc.cmd = cmd;
	ioc.buf = buf;
	ioc.len = len;

	/* initializing the remaining fields */
	ioc.set = 0;
	ioc.used = 0;
	ioc.needed = 0;

	strncpy(ifr.ifr_name, name, sizeof(ifr.ifr_name) - 1);
	ifr.ifr_name[sizeof(ifr.ifr_name) - 1] = '\0';
	ifr.ifr_data = (caddr_t) &ioc;
	if ((ret = ioctl(s, SIOCDEVPRIVATE, &ifr)) < 0)
                perror("ioctl failed");
	/* cleanup */
	close(s);
	return ret;
}

static unsigned int get_phy_temperature(char* interface)
{
	int ret = 0;
	unsigned int *temp;
	char buf[WLC_IOCTL_SMLEN];

	strcpy(buf, "phy_tempsense");

	if ((ret = wl_ioctl(interface, WLC_GET_VAR, buf, sizeof(buf)))) {
		return 0;
	} else {
		temp = (unsigned int *)buf;
		return *temp / 2 + 20;
	}
}

static void usage(char* self)
{
        printf("USAGE: %s IFNAME\nMust be a wireless adapter.\n", self);
}

int main(int argc, char* argv[])
{
        if (argc < 2) {
                usage(argv[0]);
                return EINVAL;
        }
        
        printf("%d\n", get_phy_temperature(argv[1]));
        
        return 0;
}