简单的消息队列实现

**1. .h file**

#ifndef UPGRADE_H
#define UPGRADE_H
#define MSG_MAX_SIZE        (24)

enum 
{
    HTTP_TYPE_UPLOAD = 0x0,
    HTTP_TYPE_DOWNLOAD
};

typedef struct _DownloadInfo
{
    char download_url[128];
    char save_path[32];
    char save_name[32];
}DownloadInfo;

enum 
{
    MSG_START_UPGRADE = 0x01,
    MSG_STOP_UPGRADE
};

struct msgbuf
{
    long msg_type;
    char msg_text[MSG_MAX_SIZE];
};

enum
{
    MSG_TYPE_START_WIFIDOG_SETUP = 0x01,
    MSG_TYPE_START_UPGRADE = 0x02,
    MSG_TYPE_START_PING_SVR_IP = 0x03
};
#endif

**2.Makefile**
EXEC = smd
OBJS = main.o

#CFLAGS += -L$(ROOTDIR)/user/openssl-0.9.8e -L.
CFLAGS += -L$(ROOTDIR)/lib/libnvram -lnvram -I$(ROOTDIR)/lib/libnvram

all: $(EXEC)

.c.o:
    $(CC) -c $(CFLAGS) $<

$(EXEC): $(OBJS)
    $(CC) $(OBJS) $(CFLAGS) -o $@

romfs:
    $(ROMFSINST) /bin/smd

clean:
    -rm -f $(EXEC) *.elf *.o

**3.main.c**
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <linux/reboot.h>
#include <sys/stat.h>  
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#include "smd.h"
#include "nvram.h"

int main(int argc, char *argv[])
{
    int msg_id = 0;
    key_t key;
    struct msgbuf msg_buf;
    int nBytes = 0;
    key = ftok("/dev/null", ‘u‘);
    msg_id = msgget(key, IPC_CREAT|0666);
    if (msg_id < 0) {
    printf("msgget failed\n");
    return -1;
    } 

    while(1) {
    memset(&msg_buf, 0x0, sizeof(msg_buf));
    msgrcv(msg_id, &msg_buf, MSG_MAX_SIZE, 0, IPC_NOWAIT);
    if (nBytes >= 0) {
    switch (msg_buf.msg_type) {
    case MSG_TYPE_START_WIFIDOG_SETUP:
    nvram_commit(RT2860_NVRAM);
    nvram_commit(RT2860_BAK);
    system("vwanip.sh");
    system("wifimonitor.sh");
    break;
    case MSG_TYPE_START_PING_SVR_IP:
    {
    char command[64] = {0x0};
    snprintf(command, sizeof(command), "ping %s -c 5", msg_buf.msg_text);
    system(command);
    }
    break;
    case MSG_TYPE_START_UPGRADE:
    break;
    default:
    break;
    }
    }
    }

    return 0;
}

/****/
int msg_id = 0;
key_t key;
struct msgbuf msg_buf;

memset(&msg_buf, 0x0, sizeof(msg_buf));
msg_buf.msg_type = MSG_TYPE_START_WIFIDOG_SETUP;

if (msgsnd(msg_id, (void *)&msg_buf, 0, 0) < 0) {
    return -1;
}

/****/
if (!strcmp(svr_cmd, CMD_DO_PING)) {
    /* start do the ping action  */
    memset(&msg_buf, 0x0, sizeof(msg_buf));
    msg_buf.msg_type = MSG_TYPE_START_PING_SVR_IP;
    strncpy(msg_buf.msg_text, svr_ip, sizeof(msg_buf.msg_text));
    if (msgsnd(msg_id, (void *)&msg_buf, sizeof(msg_buf.msg_text), 0) < 0) 
    {
        ret = -1;
    }
}