drv_admin.c

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#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include <stdio.h>
#include <dirent.h>
#include <dlfcn.h>

#include "lirc/driver.h"
#include "lirc/drv_admin.h"
#include "lirc/lirc_options.h"
#include "lirc_log.h"

#include "driver.h"

static const char* const PLUGIN_FILE_EXTENSION  = "so";


#define MAX_PLUGINS  256

extern struct driver drv;  
typedef struct {
        char*   array[MAX_PLUGINS];
        int     size;
} char_array;

static void* last_plugin = NULL;

const struct driver drv_null = {
        .name           = "null",
        .device         = "/dev/null",
        .features       = 0,
        .send_mode      = 0,
        .rec_mode       = 0,
        .code_length    = 0,
        .init_func      = NULL,
        .deinit_func    = NULL,
        .send_func      = NULL,
        .rec_func       = NULL,
        .decode_func    = NULL,
        .readdata       = NULL,
        .drvctl_func    = default_drvctl,
        .open_func      = default_open,
        .close_func     = default_close,
        .api_version    = 2,
        .driver_version = "0.9.2"
};


static int ends_with_so(const char* str)
{
        char* dot = strrchr(str, '.');

        return (NULL == dot) ? 0 : strcmp(dot + 1, PLUGIN_FILE_EXTENSION) == 0;
}


static int line_cmp(const void* arg1, const void* arg2)
{
        return strcmp(*(const char**)arg1, *(const char**)arg2);
}


static struct driver* add_hw_name(struct driver* hw, void* arg)
{
        char_array* a = (char_array*)arg;

        if (a->size >= MAX_PLUGINS) {
                logprintf(LIRC_ERROR, "Too many plugins(%d)", MAX_PLUGINS);
                return hw;
        }
        a->array[a->size] = strdup(hw->name);
        a->size += 1;
        return NULL;
}


static struct driver* match_hw_name(struct driver* drv, void* name)
{
// drv_guest_func. Returns hw if hw->name == name, else NULL.
        if (drv == (struct driver*)NULL || name == NULL)
                return (struct driver*)NULL;
        if (strcasecmp(drv->name, (char*)name) == 0)
                return drv;
        return (struct driver*)NULL;
}


static struct driver*
visit_plugin(const char* path, drv_guest_func func, void* arg)
{
// Apply func(hw, arg) for all drivers found in plugin on path.
        struct driver** drivers;
        struct driver* result = (struct driver*)NULL;

        (void)dlerror();
        if (last_plugin != NULL)
                dlclose(last_plugin);
        last_plugin = dlopen(path, RTLD_NOW);
        if (last_plugin == NULL) {
                logprintf(LIRC_ERROR, dlerror());
                return result;
        }
        drivers = (struct driver**)dlsym(last_plugin, "hardwares");
        if (drivers == (struct driver**)NULL) {
                logprintf(LIRC_WARNING,
                          "No hardwares entrypoint found in %s", path);
        } else {
                for (; *drivers; drivers++) {
                        if ((*drivers)->name == NULL) {
                                logprintf(LIRC_WARNING,
                                          "No driver name in %s", path);
                                continue;
                        }
                        result = (*func)(*drivers, arg);
                        if (result != (struct driver*)NULL)
                                break;
                }
        }
        return result;
}


/* Apply plugin_guest(path, drv_guest, arg) to all so-files in dir. */
static struct driver* for_each_plugin_in_dir(const char*        dirpath,
                                             plugin_guest_func  plugin_guest,
                                             drv_guest_func     drv_guest,
                                             void*              arg)
{
        DIR* dir;
        struct dirent* ent;
        struct driver* result = (struct driver*)NULL;
        char path[128];
        char buff[128];

        dir = opendir(dirpath);
        if (dir == NULL) {
                logprintf(LIRC_INFO, "Cannot open plugindir %s", dirpath);
                return (struct driver*)NULL;
        }
        while ((ent = readdir(dir)) != NULL) {
                if (!ends_with_so(ent->d_name))
                        continue;
                strncpy(buff, dirpath, sizeof(buff) - 1);
                if (buff[strlen(buff) - 1] == '/')
                        buff[strlen(buff) - 1] = '\0';
                snprintf(path, sizeof(path),
                         "%s/%s", buff, ent->d_name);
                result = plugin_guest(path, drv_guest, arg);
                if (result != (struct driver*)NULL)
                        break;
        }
        closedir(dir);
        return result;
}


static struct driver* for_each_path(plugin_guest_func   plg_guest,
                                    drv_guest_func      drv_guest,
                                    void*               arg)
{
        const char* pluginpath;
        char* tmp_path;
        char* s;
        struct driver* result = (struct driver*)NULL;

        pluginpath = ciniparser_getstring(lirc_options,
                                          "lircd:plugindir",
                                          getenv(PLUGINDIR_VAR));
        if (pluginpath == NULL)
                pluginpath = PLUGINDIR;
        if (strchr(pluginpath, ':') == (char*)NULL) {
                return for_each_plugin_in_dir(pluginpath,
                                              plg_guest,
                                              drv_guest,
                                              arg);
        }
        tmp_path = alloca(strlen(pluginpath) + 1);
        strncpy(tmp_path, pluginpath, strlen(pluginpath) + 1);
        for (s = strtok(tmp_path, ":"); s != NULL; s = strtok(NULL, ":")) {
                result = for_each_plugin_in_dir(s,
                                                plg_guest,
                                                drv_guest,
                                                arg);
                if (result != (struct driver*)NULL)
                        break;
        }
        return result;
}


struct driver* for_each_driver(drv_guest_func func, void* arg)
{
        return for_each_path(visit_plugin, func, arg);
}


void for_each_plugin(plugin_guest_func plugin_guest, void* arg)
{
        for_each_path(plugin_guest, NULL, arg);
}


void hw_print_drivers(FILE* file)
{
        char_array names;
        int i;

        names.size = 0;
        if (for_each_driver(add_hw_name, (void*)&names) != NULL) {
                fprintf(stderr, "Too many plugins (%d)\n", MAX_PLUGINS);
                return;
        }
        qsort(names.array, names.size, sizeof(char*), line_cmp);
        for (i = 0; i < names.size; i += 1) {
                fprintf(file, "%s\n", names.array[i]);
                free(names.array[i]);
        }
}


int hw_choose_driver(const char* name)
{
        struct driver* found;

        if (name == NULL) {
                memcpy(&drv, &drv_null, sizeof(struct driver));
                return 0;
        }
        if (strcasecmp(name, "dev/input") == 0)
                /* backwards compatibility */
                name = "devinput";
        found = for_each_driver(match_hw_name, (void*)name);
        if (found != (struct driver*)NULL) {
                memcpy(&drv, found, sizeof(struct driver));
                return 0;
        }
        return -1;
}