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#include <stdio.h>
#include <limits.h>
#include <dlfcn.h>
#include <sys/timerfd.h>
#include <unistd.h>
#include <string.h>
#include "nfcommander.h"
#include "reader.h"
#include "config.h"
#define MAX_PLUGIN_PATH NAME_MAX
#define DEFAULT_POLL_TIMEOUT 1000
#define MAX_TAGS 5
#define FLAG_PRESENT 8
#define FLAG_ACTIVE 16
static void* reader_module = NULL;
static reader_plugin_handle reader_backend_handle = NULL;
static reader_plugin_scan reader_backend_scan = NULL;
static int timer_fd = -1;
static struct {
uint8_t flags;
nfc_tag_info_t info;
} tags[MAX_TAGS] = { 0 };
static int reader_init_backend(){
char plugin[MAX_PLUGIN_PATH] = "";
char* reader = config_get("nfc", "reader");
if(!reader){
printf("No reader plugin configured\n");
return -1;
}
snprintf(plugin, sizeof(plugin), "./reader_%s.so", reader);
reader_module = dlopen(plugin, RTLD_NOW);
if(!reader_module){
printf("Failed to load reader plugin %s: %s\n", plugin, dlerror());
return -1;
}
reader_backend_handle = dlsym(reader_module, "handle");
reader_backend_scan = dlsym(reader_module, "scan");
//call initializer
reader_plugin_init init = dlsym(reader_module, "init");
if(!reader_backend_scan || !init || init()){
printf("Failed to initialize the reader\n");
return 1;
}
return 0;
}
int reader_init(){
//initialize poll timer
size_t poll_timeout = DEFAULT_POLL_TIMEOUT;
struct itimerspec timer_cfg = {
0
};
if(config_get("nfc", "interval")){
poll_timeout = strtoul(config_get("nfc", "interval"), NULL, 10);
}
timer_cfg.it_value.tv_sec = timer_cfg.it_interval.tv_sec = poll_timeout / 1000;
timer_cfg.it_value.tv_nsec = timer_cfg.it_interval.tv_nsec = (poll_timeout % 1000) * 1e6;
//create timerfd
timer_fd = timerfd_create(CLOCK_MONOTONIC, TFD_CLOEXEC);
if(timer_fd < 0){
printf("Failed to create timer fd\n");
return 1;
}
if(timerfd_settime(timer_fd, 0, &timer_cfg, NULL)){
printf("Failed to set timer\n");
return 1;
}
core_manage_fd(timer_fd, 1, system_reader);
return reader_init_backend();
}
static void reader_expire(){
size_t n = 0;
for(n = 0; n < MAX_TAGS; n++){
tags[n].flags &= ~(FLAG_PRESENT);
}
}
static int reader_process(){
size_t n = 0;
for(n = 0; n < MAX_TAGS; n++){
if(tags[n].flags & FLAG_PRESENT){
if(!(tags[n].flags & FLAG_ACTIVE)){
//new tag
tags[n].flags |= FLAG_ACTIVE;
if(tags[n].flags & FLAG_TAG_LOCKED){
printf("A tag was detected (slot %lu), but no key is known\n", n);
return 0;
}
if(tags[n].flags & FLAG_TAG_UNPROGRAMMED){
printf("Unprogrammed tag detected (slot %lu)\n", n);
//TODO
return 0;
}
if(tags[n].flags & FLAG_TAG_DATA_VALID){
printf("Command tag detected (slot %lu)\n", n);
//TODO
return 0;
}
printf("Tag detected (slot %lu), but no state flags set by reader\n", n);
}
}
else{
if(tags[n].flags & FLAG_ACTIVE){
//tag was removed
//TODO
printf("Tag in slot %lu removed\n", n);
}
//reset all flags
tags[n].flags = 0;
}
}
return 0;
}
int reader_tag_present(uint8_t flags, nfc_tag_info_t tag){
size_t n = 0;
//sanitize input flags
flags &= (FLAG_TAG_DATA_VALID | FLAG_TAG_UNPROGRAMMED | FLAG_TAG_LOCKED);
//check if tag already known
for(n = 0; n < MAX_TAGS; n++){
if((tags[n].flags & (FLAG_PRESENT | FLAG_ACTIVE))
&& tags[n].info.uid_length == tag.uid_length
&& !memcmp(tags[n].info.uid, tag.uid, tag.uid_length)){
//mark still present
tags[n].flags |= FLAG_PRESENT;
//if full data submitted, copy in and set flags
if(!(tags[n].flags & TAG_STATUS_FLAGS)){
if(flags & TAG_STATUS_FLAGS){
memcpy(&(tags[n].info), &tag, sizeof(tag));
tags[n].flags |= flags;
return 0;
}
//if data has not yet been fully read, request a full read
return TAG_READ_REQUESTED;
}
return 0;
}
}
//if not, add it
for(n = 0; n < MAX_TAGS; n++){
if(!tags[n].flags){
tags[n].flags |= FLAG_PRESENT | flags;
memcpy(&(tags[n].info), &tag, sizeof(tag));
return (tags[n].flags & TAG_STATUS_FLAGS) ? 0 : TAG_READ_REQUESTED;
}
}
//realistically, this will never happen as most readers barely
//provide enough energy to power two tags in the field
printf("Maximum of active tags reached, ignored\n");
return 0;
}
int reader_handle(int fd){
uint8_t buffer[1024];
if(fd == timer_fd){
//acknowledge timer
read(fd, buffer, sizeof(buffer));
//mark all tags expired
reader_expire();
//scan all tags
if(reader_backend_scan()){
return 1;
}
//handle changes in active set
return reader_process();
}
if(reader_backend_handle){
return reader_backend_handle(fd);
}
return 0;
}
void reader_free(){
if(reader_module){
dlclose(reader_module);
reader_backend_handle = NULL;
reader_backend_scan = NULL;
reader_module = NULL;
}
core_manage_fd(timer_fd, 0, system_reader);
close(timer_fd);
timer_fd = -1;
}
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