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/*
* File Name: pthread_dht11.c
* Workflow: periodically rw from coordinator, get TH data, push
* it to shared memory
* Return Value: NULL always
*/
/* Header files */
#include <errno.h>
#include <pthread.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <sys/types.h>
#include "debug.h"
#include "proto.h"
/* external variables */
extern pthread_mutex_t mutex_zigbee_coordinator;
extern volatile sig_atomic_t should_exit;
/* thread start routine function*/
void *pthread_dht11(void *args) {
ARG_STRUCT *p_resource_struct = malloc(sizeof(ARG_STRUCT));
SHM_STRUCT *p_shm_struct = malloc(sizeof(SHM_STRUCT));
char tmp[7];
ssize_t rwRetCount;
// get resources from main
p_resource_struct = args;
DebugLog("[DEBUG-INFO %s:%d]: Get read/write fd: %d.\n", __FUNCTION__,
__LINE__, p_resource_struct->rw_fd);
DebugLog("[DEBUG-INFO %s:%d]: Get shared memory ID: %d.\n", __FUNCTION__,
__LINE__, p_resource_struct->shm_id);
// attach shared memory to local
p_shm_struct = shmat(p_resource_struct->shm_id, NULL, 0);
// prepare buffer to get TH data
memset(tmp, '\0', 7);
// modify shared memory
while (!should_exit) {
pthread_mutex_lock(&mutex_zigbee_coordinator);
rwRetCount = write(p_resource_struct->rw_fd, "TH", sizeof("TH"));
// write failure retry
if (rwRetCount == -1) {
pthread_mutex_unlock(&mutex_zigbee_coordinator);
continue;
}
DebugLog("[DEBUG-INFO %s:%d]: write(\"TH\") to coordinator, %zd Byte(s) "
"written.\n",
__FUNCTION__, __LINE__, rwRetCount);
// zigbee end-device reaction time wait
sleep(3);
rwRetCount = read(p_resource_struct->rw_fd, tmp, 7);
DebugLog("[DEBUG-INFO %s:%d]: read() from coordinator, %zd Byte(s) read.\n",
__FUNCTION__, __LINE__, rwRetCount);
if (rwRetCount == -1) {
p_shm_struct->tempNow = 0;
DebugLog("[DEBUG-INFO %s:%d]: Nothing read, set temperature to 0.\n",
__FUNCTION__, __LINE__);
p_shm_struct->humiNow = 0;
DebugLog("[DEBUG-INFO %s:%d]: Nothing read, set humidity to 0.\n",
__FUNCTION__, __LINE__);
} else {
p_shm_struct->tempNow =
((int)(tmp[0] - '0')) * 10 + ((int)(tmp[1] - '0')) * 1;
DebugLog("[DEBUG-INFO %s:%d]: Current temperature: %d.\n", __FUNCTION__,
__LINE__, p_shm_struct->tempNow);
p_shm_struct->humiNow =
((int)(tmp[4] - '0')) * 10 + ((int)(tmp[5] - '0')) * 1;
DebugLog("[DEBUG-INFO %s:%d]: Current humidity: %d.\n", __FUNCTION__,
__LINE__, p_shm_struct->humiNow);
}
pthread_mutex_unlock(&mutex_zigbee_coordinator);
}
pthread_exit(NULL);
}
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