root/lm-sensors/trunk/lib/sysfs.c

/*
    sysfs.c - Part of libsensors, a library for reading Linux sensor data
    Copyright (c) 2005 Mark M. Hoffman <mhoffman@lightlink.com>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

/* this define needed for strndup() */
#define _GNU_SOURCE

#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <limits.h>
#include <errno.h>
#include <sysfs/libsysfs.h>
#include "data.h"
#include "error.h"
#include "access.h"
#include "general.h"
#include "sysfs.h"

int sensors_found_sysfs = 0;

char sensors_sysfs_mount[NAME_MAX];

/* returns !0 if sysfs filesystem was found, 0 otherwise */
int sensors_init_sysfs(void)
{
        struct stat statbuf;

        /* libsysfs will return success even if sysfs is not mounted,
           so we have to double-check */
        if (sysfs_get_mnt_path(sensors_sysfs_mount, NAME_MAX) == 0
         && stat(sensors_sysfs_mount, &statbuf) == 0
         && statbuf.st_nlink > 2)
                sensors_found_sysfs = 1;

        return sensors_found_sysfs;
}

/* returns: 0 if successful, !0 otherwise */
static int sensors_read_one_sysfs_chip(struct sysfs_device *dev)
{
        int domain, bus, slot, fn;
        struct sysfs_attribute *attr, *bus_attr;
        char bus_path[SYSFS_PATH_MAX];
        sensors_proc_chips_entry entry;
        int err = -SENSORS_ERR_PARSE;

        /* ignore any device without name attribute */
        if (!(attr = sysfs_get_device_attr(dev, "name")))
                return 0;

        /* ignore subclients */
        if (attr->len >= 11 && !strcmp(attr->value + attr->len - 11,
                        " subclient\n"))
                return 0;

        /* also ignore eeproms */
        if (!strcmp(attr->value, "eeprom\n"))
                return 0;

        /* NB: attr->value[attr->len-1] == '\n'; chop that off */
        entry.name.prefix = strndup(attr->value, attr->len - 1);
        if (!entry.name.prefix)
                sensors_fatal_error(__FUNCTION__, "out of memory");

        entry.name.busname = strdup(dev->path);
        if (!entry.name.busname)
                sensors_fatal_error(__FUNCTION__, "out of memory");

        if (sscanf(dev->name, "%d-%x", &entry.name.bus, &entry.name.addr) == 2) {
                /* find out if legacy ISA or not */
                if (entry.name.bus == 9191)
                        entry.name.bus = SENSORS_CHIP_NAME_BUS_ISA;
                else {
                        snprintf(bus_path, sizeof(bus_path),
                                "%s/class/i2c-adapter/i2c-%d/device/name",
                                sensors_sysfs_mount, entry.name.bus);

                        if ((bus_attr = sysfs_open_attribute(bus_path))) {
                                if (sysfs_read_attribute(bus_attr)) {
                                        sysfs_close_attribute(bus_attr);
                                        goto exit_free;
                                }

                                if (bus_attr->value
                                 && !strncmp(bus_attr->value, "ISA ", 4))
                                        entry.name.bus = SENSORS_CHIP_NAME_BUS_ISA;

                                sysfs_close_attribute(bus_attr);
                        }
                }
        } else if (sscanf(dev->name, "%*[a-z0-9_].%d", &entry.name.addr) == 1) {
                /* must be new ISA (platform driver) */
                entry.name.bus = SENSORS_CHIP_NAME_BUS_ISA;
        } else if (sscanf(dev->name, "%x:%x:%x.%x", &domain, &bus, &slot, &fn) == 4) {
                /* PCI */
                entry.name.addr = (domain << 16) + (bus << 8) + (slot << 3) + fn;
                entry.name.bus = SENSORS_CHIP_NAME_BUS_PCI;
        } else {
                /* Ignore unknown devices */
                err = 0;
                goto exit_free;
        }

        sensors_add_proc_chips(&entry);

        return 0;

exit_free:
        free(entry.name.prefix);
        free(entry.name.busname);
        return err;
}

/* returns 0 if successful, !0 otherwise */
static int sensors_read_sysfs_chips_compat(void)
{
        struct sysfs_bus *bus;
        struct dlist *devs;
        struct sysfs_device *dev;
        int ret = 0;

        if (!(bus = sysfs_open_bus("i2c"))) {
                if (errno && errno != ENOENT)
                        ret = -SENSORS_ERR_PROC;
                goto exit0;
        }

        if (!(devs = sysfs_get_bus_devices(bus))) {
                if (errno && errno != ENOENT)
                        ret = -SENSORS_ERR_PROC;
                goto exit1;
        }

        dlist_for_each_data(devs, dev, struct sysfs_device)
                if ((ret = sensors_read_one_sysfs_chip(dev)))
                        goto exit1;

exit1:
        /* this frees bus and devs */
        sysfs_close_bus(bus);

exit0:
        return ret;
}

/* returns 0 if successful, !0 otherwise */
int sensors_read_sysfs_chips(void)
{
        struct sysfs_class *cls;
        struct dlist *clsdevs;
        struct sysfs_class_device *clsdev;
        int ret = 0;

        if (!(cls = sysfs_open_class("hwmon"))) {
                /* compatibility function for kernel 2.6.n where n <= 13 */
                return sensors_read_sysfs_chips_compat();
        }

        if (!(clsdevs = sysfs_get_class_devices(cls))) {
                if (errno && errno != ENOENT)
                        ret = -SENSORS_ERR_PROC;
                goto exit;
        }

        dlist_for_each_data(clsdevs, clsdev, struct sysfs_class_device) {
                struct sysfs_device *dev;
                if (!(dev = sysfs_get_classdev_device(clsdev)))
                        continue;
                if ((ret = sensors_read_one_sysfs_chip(dev)))
                        goto exit;
        }

exit:
        /* this frees cls and clsdevs */
        sysfs_close_class(cls);
        return ret;
}

/* returns 0 if successful, !0 otherwise */
int sensors_read_sysfs_bus(void)
{
        struct sysfs_class *cls;
        struct dlist *clsdevs;
        struct sysfs_class_device *clsdev;
        sensors_bus entry;
        int ret = 0;

        if (!(cls = sysfs_open_class("i2c-adapter"))) {
                if (errno && errno != ENOENT)
                        ret = -SENSORS_ERR_PROC;
                goto exit0;
        }

        if (!(clsdevs = sysfs_get_class_devices(cls))) {
                if (errno && errno != ENOENT)
                        ret = -SENSORS_ERR_PROC;
                goto exit1;
        }

        dlist_for_each_data(clsdevs, clsdev, struct sysfs_class_device) {
                struct sysfs_device *dev;
                struct sysfs_attribute *attr;

                /* Get the adapter name from the classdev "name" attribute
                 * (Linux 2.6.20 and later). If it fails, fall back to
                 * the device "name" attribute (for older kernels). */
                if (!(attr = sysfs_get_classdev_attr(clsdev, "name"))
                 && !((dev = sysfs_get_classdev_device(clsdev)) &&
                      (attr = sysfs_get_device_attr(dev, "name"))))
                        continue;

                /* NB: attr->value[attr->len-1] == '\n'; chop that off */
                entry.adapter = strndup(attr->value, attr->len - 1);
                if (!entry.adapter)
                        sensors_fatal_error(__FUNCTION__, "out of memory");

                if (!strncmp(entry.adapter, "ISA ", 4)) {
                        entry.number = SENSORS_CHIP_NAME_BUS_ISA;
                } else if (sscanf(clsdev->name, "i2c-%d", &entry.number) != 1) {
                        entry.number = SENSORS_CHIP_NAME_BUS_DUMMY;
                }

                sensors_add_proc_bus(&entry);
        }

exit1:
        /* this frees *cls _and_ *clsdevs */
        sysfs_close_class(cls);

exit0:
        return ret;
}