source: mainline/uspace/srv/devman/devman.c@ 729fa2d6

/*
 * Copyright (c) 2010 Lenka Trochtova
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup devman
 * @{
 */

#include <errno.h>
#include <fcntl.h>
#include <sys/stat.h>

#include "devman.h"
#include "util.h"

/** Allocate and initialize a new driver structure.
 * 
 * @return driver structure.
 */
driver_t * create_driver() 
{
        printf(NAME ": create_driver\n");
        
        driver_t *res = malloc(sizeof(driver_t));
        if(res != NULL) {
                init_driver(res);
        }
        return res;
}

/** Add a driver to the list of drivers.
 * 
 * @param drivers_list the list of drivers.
 * @param drv the driver's structure.
 */
void add_driver(driver_list_t *drivers_list, driver_t *drv)
{
        fibril_mutex_lock(&drivers_list->drivers_mutex);
        list_prepend(&drv->drivers, &drivers_list->drivers);
        fibril_mutex_unlock(&drivers_list->drivers_mutex);
        
        printf(NAME": the '%s' driver was added to the list of available drivers.\n", drv->name);
}

/** Read match id at the specified position of a string and set 
 * the position in the string to the first character following the id.
 * 
 * @param buf the position in the input string.
 * 
 * @return the match id. 
 */
char * read_match_id(const char **buf) 
{
        char *res = NULL;
        size_t len = get_nonspace_len(*buf);
        if (len > 0) {
                res = malloc(len + 1);
                if (res != NULL) {
                        str_ncpy(res, len + 1, *buf, len);      
                        *buf += len;
                }
        }
        return res;
}

/**
 * Read match ids and associated match scores from a string.
 * 
 * Each match score in the string is followed by its match id. 
 * The match ids and match scores are separated by whitespaces. 
 * Neither match ids nor match scores can contain whitespaces. 
 * 
 * @param buf the string from which the match ids are read.
 * @param ids the list of match ids into which the match ids and scores are added.
 * 
 * @return true if at least one match id and associated match score was successfully read, false otherwise.
 */
bool parse_match_ids(const char *buf, match_id_list_t *ids)
{
        int score = 0;
        char *id = NULL;
        int ids_read = 0;
        
        while (true) {
                // skip spaces
                if (!skip_spaces(&buf)) {
                        break;
                }
                // read score
                score = strtoul(buf, &buf, 10);
                
                // skip spaces
                if (!skip_spaces(&buf)) {
                        break;
                }
                
                // read id
                if (NULL == (id = read_match_id(&buf))) {
                        break;                  
                }
                
                // create new match_id structure
                match_id_t *mid = create_match_id();
                mid->id = id;
                mid->score = score;
                
                /// add it to the list
                add_match_id(ids, mid);
                
                ids_read++;             
        }       
        
        return ids_read > 0;
}

/**
 * Read match ids and associated match scores from a file.
 * 
 * Each match score in the file is followed by its match id. 
 * The match ids and match scores are separated by whitespaces. 
 * Neither match ids nor match scores can contain whitespaces. 
 * 
 * @param buf the path to the file from which the match ids are read.
 * @param ids the list of match ids into which the match ids and scores are added.
 * 
 * @return true if at least one match id and associated match score was successfully read, false otherwise.
 */
bool read_match_ids(const char *conf_path, match_id_list_t *ids) 
{       
        printf(NAME ": read_match_ids conf_path = %s.\n", conf_path);
        
        bool suc = false;       
        char *buf = NULL;
        bool opened = false;
        int fd;         
        off_t len = 0;
        
        fd = open(conf_path, O_RDONLY);
        if (fd < 0) {
                printf(NAME ": unable to open %s\n", conf_path);
                goto cleanup;
        } 
        opened = true;  
        
        len = lseek(fd, 0, SEEK_END);
        lseek(fd, 0, SEEK_SET); 
        if (len == 0) {
                printf(NAME ": configuration file '%s' is empty.\n", conf_path);
                goto cleanup;           
        }
        
        buf = malloc(len + 1);
        if (buf == NULL) {
                printf(NAME ": memory allocation failed when parsing file '%s'.\n", conf_path);
                goto cleanup;
        }       
        
        if (0 >= read(fd, buf, len)) {
                printf(NAME ": unable to read file '%s'.\n", conf_path);
                goto cleanup;
        }
        buf[len] = 0;
        
        suc = parse_match_ids(buf, ids);
        
cleanup:
        
        free(buf);
        
        if(opened) {
                close(fd);      
        }
        
        return suc;
}

/**
 * Get information about a driver.
 * 
 * Each driver has its own directory in the base directory. 
 * The name of the driver's directory is the same as the name of the driver.
 * The driver's directory contains driver's binary (named as the driver without extension)
 * and the configuration file with match ids for device-to-driver matching 
 * (named as the driver with a special extension).
 * 
 * This function searches for the driver's directory and containing configuration files.
 * If all the files needed are found, they are parsed and 
 * the information about the driver is stored to the driver's structure.
 * 
 * @param base_path the base directory, in which we look for driver's subdirectory.
 * @param name the name of the driver.
 * @param drv the driver structure to fill information in.
 * 
 * @return true on success, false otherwise.
 */
bool get_driver_info(const char *base_path, const char *name, driver_t *drv)
{
        printf(NAME ": get_driver_info base_path = %s, name = %s.\n", base_path, name);
        
        assert(base_path != NULL && name != NULL && drv != NULL);
        
        bool suc = false;
        char *match_path = NULL;        
        size_t name_size = 0;
        
        // read the list of match ids from the driver's configuration file
        if (NULL == (match_path = get_abs_path(base_path, name, MATCH_EXT))) {
                goto cleanup;
        }       
        
        printf(NAME ": get_driver_info - path to match id list = %s.\n", match_path);
        
        if (!read_match_ids(match_path, &drv->match_ids)) {
                goto cleanup;
        }       
        
        // allocate and fill driver's name
        name_size = str_size(name)+1;
        drv->name = malloc(name_size);
        if (!drv->name) {
                goto cleanup;
        }       
        str_cpy(drv->name, name_size, name);
        
        // initialize path with driver's binary
        if (NULL == (drv->binary_path = get_abs_path(base_path, name, ""))) {
                goto cleanup;
        }
        
        // check whether the driver's binary exists
        struct stat s;
        if (stat(drv->binary_path, &s) == ENOENT) {
                printf(NAME ": driver not found at path %s.", drv->binary_path);
                goto cleanup;
        }
        
        suc = true;
        
cleanup:
        
        if (!suc) {
                free(drv->binary_path);
                free(drv->name);
                // set the driver structure to the default state
                init_driver(drv); 
        }
        
        free(match_path);
        
        return suc;
}

/** Lookup drivers in the directory.
 * 
 * @param drivers_list the list of available drivers.
 * @param dir_path the path to the directory where we search for drivers. 
 * 
 * @return number of drivers which were found.
 */ 
int lookup_available_drivers(driver_list_t *drivers_list, const char *dir_path)
{
        printf(NAME ": lookup_available_drivers \n");
        
        int drv_cnt = 0;
        DIR *dir = NULL;
        struct dirent *diren;

        dir = opendir(dir_path);
        printf(NAME ": lookup_available_drivers has opened directory %s for driver search.\n", dir_path);
        
        if (dir != NULL) {
                driver_t *drv = create_driver();
                printf(NAME ": lookup_available_drivers has created driver structure.\n");
                while ((diren = readdir(dir))) {                        
                        if (get_driver_info(dir_path, diren->d_name, drv)) {
                                add_driver(drivers_list, drv);
                                drv_cnt++;
                                drv = create_driver();
                        }       
                }
                delete_driver(drv);
                closedir(dir);
        }
        
        return drv_cnt;
}

/** Create root device node of the device tree.
 * 
 * @return root device node.
 */
node_t * create_root_node()
{
        printf(NAME ": create_root_node\n");
        node_t *node = create_dev_node();
        if (node) {
                init_dev_node(node, NULL);
                match_id_t *id = create_match_id();
                id->id = "root";
                id->score = 100;
                add_match_id(&node->match_ids, id);
        }
        return node;    
}

/** Lookup the best matching driver for the specified device in the list of drivers.
 * 
 * A match between a device and a driver is found 
 * if one of the driver's match ids match one of the device's match ids.
 * The score of the match is the product of the driver's and device's score associated with the matching id.
 * The best matching driver for a device is the driver
 * with the highest score of the match between the device and the driver.
 * 
 * @param drivers_list the list of drivers, where we look for the driver suitable for handling the device.
 * @param node the device node structure of the device.
 *
 * @return the best matching driver or NULL if no matching driver is found.
 */
driver_t * find_best_match_driver(driver_list_t *drivers_list, node_t *node)
{
        printf(NAME ": find_best_match_driver\n");
        driver_t *best_drv = NULL, *drv = NULL;
        int best_score = 0, score = 0;
        
        fibril_mutex_lock(&drivers_list->drivers_mutex);
        
        link_t *link = drivers_list->drivers.next;              
        while (link != &drivers_list->drivers) {
                drv = list_get_instance(link, driver_t, drivers);
                score = get_match_score(drv, node);
                if (score > best_score) {
                        best_score = score;
                        best_drv = drv;
                }       
                link = link->next;
        }
        
        fibril_mutex_unlock(&drivers_list->drivers_mutex);
        
        return best_drv;        
}

/**
 * Assign a driver to a device.
 * 
 * @param node the device's node in the device tree.
 * @param drv the driver.
 */
void attach_driver(node_t *node, driver_t *drv) 
{
        fibril_mutex_lock(&drv->driver_mutex);
        
        node->drv = drv;
        list_append(&node->driver_devices, &drv->devices);
        
        fibril_mutex_unlock(&drv->driver_mutex);
}

/** Start a driver.
 * 
 * The driver's mutex is assumed to be locked.
 * 
 * @param drv the driver's structure.
 * @return true if the driver's task is successfully spawned, false otherwise.
 */
bool start_driver(driver_t *drv)
{
        printf(NAME ": start_driver\n");
        
        char *argv[2];
        
        printf(NAME ": spawning driver %s\n", drv->name);
        
        argv[0] = drv->name;
        argv[1] = NULL;
        
        if (!task_spawn(drv->binary_path, argv)) {
                printf(NAME ": error spawning %s\n", drv->name);
                return false;
        }
        
        drv->state = DRIVER_STARTING;
        return true;
}

driver_t * find_driver(driver_list_t *drv_list, const char *drv_name) 
{       
        driver_t *res = NULL;
        
        fibril_mutex_lock(&drv_list->drivers_mutex);    
        
        driver_t *drv = NULL;
        link_t *link = drv_list->drivers.next;  
        while (link !=  &drv_list->drivers) {
                drv = list_get_instance(link, driver_t, drivers);
                if (0 == str_cmp(drv->name, drv_name)) {
                        res = drv;
                        break;
                }               
                link = link->next;
        }       
        
        fibril_mutex_unlock(&drv_list->drivers_mutex);
        
        return res;
}

/** Pass a device to running driver.
 * 
 * @param drv the driver's structure.
 * @param node the device's node in the device tree.
 * 
 * @return true on success, false otherwise.
 */
bool add_device(driver_t *drv, node_t *node)
{
        printf(NAME ": add_device\n");
        
        // TODO
        
        // pass a new device to the running driver, which was previously assigned to it
                // send the phone of the parent's driver and device's handle within the parent's driver to the driver 
                // let the driver to probe the device and specify whether the device is actually present
                // if the device is present, remember its handle within the driver
        
        return true;
}

/**
 * Find suitable driver for a device and assign the driver to it.
 * 
 * @param node the device node of the device in the device tree.
 * @param drivers_list the list of available drivers.
 * 
 * @return true if the suitable driver is found and successfully assigned to the device, false otherwise. 
 */
bool assign_driver(node_t *node, driver_list_t *drivers_list) 
{
        printf(NAME ": assign_driver\n");
        
        // find the driver which is the most suitable for handling this device
        driver_t *drv = find_best_match_driver(drivers_list, node);
        if (NULL == drv) {
                printf(NAME ": no driver found for device.\n"); 
                return false;           
        }
        
        // attach the driver to the device
        attach_driver(node, drv);
        
        if (DRIVER_NOT_STARTED == drv->state) {
                // start driver
                start_driver(drv);
        } 
        
        if (DRIVER_RUNNING == drv->state) {
                // notify driver about new device
                add_device(drv, node);          
        }
        
        return true;
}

/**
 * Initialize the device tree.
 * 
 * Create root device node of the tree and assign driver to it.
 * 
 * @param tree the device tree.
 * @param the list of available drivers.
 * @return true on success, false otherwise.
 */
bool init_device_tree(dev_tree_t *tree, driver_list_t *drivers_list)
{
        printf(NAME ": init_device_tree.\n");
        
        // create root node and add it to the device tree
        if (NULL == (tree->root_node = create_root_node())) {
                return false;
        }

        // find suitable driver and start it
        return assign_driver(tree->root_node, drivers_list);
}