Related
I attach here my kernel module I developed and the test I am using at application level
memalloc.c
/*
* DMA memory allocation
* This kernel module allocates coherent, non-cached memory
* and returns the physical and virtual address of the allocated buffer
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/dma-mapping.h>
#include <linux/device.h>
#include <linux/cdev.h>
#include "memalloc.h"
#define DEVICE_NAME "memalloc"
// Max number of buffers
#define BUFFER_MAX_NUMBER 16
// Structure for buffer information
struct bufferInfo {
int active;
int size;
dma_addr_t handle;
int virtualAddress;
int *kernelAddress;
};
static struct bufferInfo bufferInfoTable[BUFFER_MAX_NUMBER];
// Defines which buffer is currently active - for mmap
static int activeBufferID;
struct memAllocIF {
struct device *device_p;
dev_t dev_node;
struct cdev cdev;
struct class *class_p;
};
static struct memAllocIF interface;
// Methods
static int releaseBuffer(int i)
{
if (i > BUFFER_MAX_NUMBER)
{
printk("Wrong bufferID %d\n", i);
return -1;
}
printk("Releasing buffer %d\n", i);
bufferInfoTable[i].active = 0;
dma_free_coherent(NULL, bufferInfoTable[i].size, bufferInfoTable[i].kernelAddress, bufferInfoTable[i].handle);
return 0;
}
static int reserveBuffer(size_t size)
{
int i;
for (i = 0; i < BUFFER_MAX_NUMBER; i++)
{
if (bufferInfoTable[i].active == 0)
{
printk("Reserving buffer %d\n", i);
bufferInfoTable[i].active = 1;
break;
}
}
if (i < BUFFER_MAX_NUMBER)
{
bufferInfoTable[i].kernelAddress = dma_alloc_coherent(NULL, size, &bufferInfoTable[i].handle, GFP_KERNEL);
if (bufferInfoTable[i].kernelAddress == NULL)
{
printk("Allocation failure\n");
return -1;
}
bufferInfoTable[i].size = (int)size;
return i;
}
else
{
printk("No buffer available\n");
return -1;
}
}
static void cleanup(void)
{
int i;
for (i = 0; i < BUFFER_MAX_NUMBER; i++)
{
if (bufferInfoTable[i].active != 0)
{
dma_free_coherent(NULL, bufferInfoTable[i].size, bufferInfoTable[i].kernelAddress, bufferInfoTable[i].handle);
bufferInfoTable[i].active = 0;
}
}
}
static unsigned int memAllocGetVirtual (int i)
{
if (i > BUFFER_MAX_NUMBER)
{
printk("Wrong bufferID %d\n", i);
return -1;
}
if (bufferInfoTable[i].active == 0)
{
printk("Inactive buffer - ID %d\n", i);
return -1;
}
printk("request for buffer %d: vaddr = %X\n", i, (unsigned int)bufferInfoTable[i].virtualAddress);
return bufferInfoTable[i].virtualAddress;
}
static unsigned int memAllocGetPhysical (int i)
{
if (i > BUFFER_MAX_NUMBER)
{
printk("Wrong bufferID %d\n", i);
return -1;
}
return (unsigned int)bufferInfoTable[i].handle;
}
static long memAllocIoctl (struct file *fd, unsigned int cmd, unsigned long arg)
{
printk("received command %u arg %lu\n", cmd, arg);
switch(cmd)
{
case MEMALLOC_RESERVE:
return reserveBuffer(arg);
break;
case MEMALLOC_RELEASE:
return releaseBuffer(arg);
break;
case MEMALLOC_GET_VIRTUAL:
return memAllocGetVirtual(arg);
break;
case MEMALLOC_GET_PHYSICAL:
return memAllocGetPhysical(arg);
break;
case MEMALLOC_ACTIVATE_BUFFER:
if (arg > BUFFER_MAX_NUMBER || bufferInfoTable[arg].active == 0)
{
printk("Wrong bufferID %lu\n", arg);
return -1;
}
activeBufferID = arg;
return arg;
break;
default:
printk("Wrong command: %d\n", cmd);
return -1;
break;
}
}
static int memAllocMmap (struct file *fd, struct vm_area_struct *vma)
{
bufferInfoTable[activeBufferID].virtualAddress = dma_common_mmap(interface.device_p, vma, bufferInfoTable[activeBufferID].kernelAddress, bufferInfoTable[activeBufferID].handle, vma->vm_end-vma->vm_start);
printk("mmap for idx %d: vaddr = %X\n", activeBufferID, (int)bufferInfoTable[activeBufferID].virtualAddress);
return bufferInfoTable[activeBufferID].virtualAddress;
}
static int memAllocRelease(struct inode *in, struct file *fd)
{
cleanup();
return 0;
}
static int memAllocOpen(struct inode *ino, struct file *file)
{
file->private_data = container_of(ino->i_cdev, struct memAllocIF, cdev);
return 0;
}
static struct file_operations fops = {
.unlocked_ioctl = memAllocIoctl,
.mmap = memAllocMmap,
.release = memAllocRelease,
.open = memAllocOpen
};
static int __init memAllocInit(void)
{
int rc;
int i;
static struct class *local_class_p = NULL;
printk("Loading DMA allocation module\n");
// Allocate a character device from the kernel for this driver
rc = alloc_chrdev_region(&interface.dev_node, 0, 1, DEVICE_NAME);
if (rc)
{
printk("Unable to get a char device number\n");
return rc;
}
// Initialize the ter device data structure before registering the character device with the kernel
cdev_init(&interface.cdev, &fops);
rc = cdev_add(&interface.cdev, interface.dev_node, 1);
if (rc)
{
printk("Unable to add char device\n");
cdev_del(&interface.cdev);
return rc;
}
// Create the device in sysfs which will allow the device node in /dev to be created
local_class_p = class_create(THIS_MODULE, DEVICE_NAME);
interface.class_p = local_class_p;
// Create the device node in /dev so the device is accessible as a character device
interface.device_p = device_create(interface.class_p, NULL, interface.dev_node, NULL, DEVICE_NAME);
if (IS_ERR(interface.device_p))
{
printk("Unable to create the device\n");
class_destroy(interface.class_p);
cdev_del(&interface.cdev);
return rc;
}
for (i = 0; i < BUFFER_MAX_NUMBER; i++)
{
bufferInfoTable[activeBufferID].active = 0;
}
return 0;
}
static void __exit my_memAllocExit(void)
{
printk("Module unloading\n");
cleanup();
cdev_del(&interface.cdev);
device_destroy(interface.class_p, interface.dev_node);
class_destroy(interface.class_p);
unregister_chrdev_region(interface.dev_node, 1);
}
module_init(memAllocInit);
module_exit(my_memAllocExit);
MODULE_AUTHOR("me");
MODULE_DESCRIPTION("Create a buffer and return physical and virtual address, for DMA userspace driver");
MODULE_LICENSE("GPL");
memalloc.h
#ifndef MEMALLOC_H
#define MEMALLOC_H
#ifdef __cplusplus
extern "C" {
#endif
#include <linux/types.h>
#include <asm/ioctl.h>
static long memAllocIoctl (struct file *, unsigned int, unsigned long);
static int memAllocMmap (struct file *, struct vm_area_struct *);
static int memAllocRelease (struct inode *, struct file *);
static int memAllocOpen(struct inode *, struct file *);
enum memAllocCmd
{
MEMALLOC_RESERVE = 0,
MEMALLOC_RELEASE = 1,
MEMALLOC_GET_VIRTUAL = 2,
MEMALLOC_GET_PHYSICAL = 3,
MEMALLOC_ACTIVATE_BUFFER = 4,
};
#ifdef __cplusplus
}
#endif
#endif /* MEMALLOC_H */
test.c
#include <stdlib.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <stdio.h>
// derive this from memalloc.h
enum memAllocCmd
{
MEMALLOC_RESERVE = 0,
MEMALLOC_RELEASE = 1,
MEMALLOC_GET_VIRTUAL = 2,
MEMALLOC_GET_PHYSICAL = 3,
MEMALLOC_ACTIVATE_BUFFER = 4,
};
int main ()
{
int memAllocFd;
volatile int iVaddr;
volatile int oVaddr;
volatile int iVaddr_2;
volatile int oVaddr_2;
volatile void * iPaddr;
volatile void * oPaddr;
int iBufID;
int oBufID;
int size = 2048;
memAllocFd = open("/dev/memalloc", O_RDWR);
// create iBuffer
iBufID = ioctl(memAllocFd, MEMALLOC_RESERVE, size);
iPaddr = (void *)ioctl(memAllocFd, MEMALLOC_GET_PHYSICAL, iBufID);
ioctl(memAllocFd, MEMALLOC_ACTIVATE_BUFFER, iBufID);
iVaddr = (int)mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, memAllocFd, 0);
ioctl(memAllocFd, MEMALLOC_GET_VIRTUAL, iBufID);
/*
if (iVaddr != iVaddr_2)
{
printf("Error: virtual addresses for buffer %d don't match: %X %X\n", iBufID, iVaddr, iVaddr_2);
}
*/
// create oBuffer
oBufID = ioctl(memAllocFd, MEMALLOC_RESERVE, size);
oPaddr = (void *)ioctl(memAllocFd, MEMALLOC_GET_PHYSICAL, oBufID);
ioctl(memAllocFd, MEMALLOC_ACTIVATE_BUFFER, oBufID);
oVaddr = (int)mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, memAllocFd, 0);
ioctl(memAllocFd, MEMALLOC_GET_VIRTUAL, oBufID);
/*
if (oVaddr != oVaddr_2)
{
printf("Error: virtual addresses for buffer %d don't match: %X %X\n", oBufID, oVaddr, oVaddr_2);
}
*/
ioctl(memAllocFd, MEMALLOC_RELEASE, iBufID);
ioctl(memAllocFd, MEMALLOC_RELEASE, oBufID);
return 0;
}
Result of the test is
received command 0 arg 2048
Reserving buffer 0
received command 3 arg 0
received command 4 arg 0
mmap for idx 0: vaddr = 0
received command 0 arg 2048
Reserving buffer 1
received command 3 arg 1
received command 4 arg 1
mmap for idx 1: vaddr = 0
received command 1 arg 0
Releasing buffer 0
received command 1 arg 1
Releasing buffer 1
Which means that all ioctl calls with arg=MEMALLOC_GET_VIRTUAL are not executed, while all the others are.
What can be the reason for that?
Thanks,
Max
I've writen this code but it doesn't work correctly.
This is menu interface:
*************ENCODE_DECODE_BASE64**************
******* 1. Encode ********
******* 2. Decode ********
******* 3. Exit ********
***********************************************
When i choose 1, "Encode". The function runs but the process exits.
I want when I choose 1, the function to run and then after that, the menu to display again.
Can you help me?
Here is Clientcode:
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <stdlib.h>
#define MAX 1024
// read filename
char *inputString(int size){
int test=0;
char *s=(char*)malloc(size);
do{
if(test!=0){
printf("File not found !!!!!!");
}
fgets(s,size,stdin);
test++;
}while(strlen(s)<=1);
return strtok(s,"\n");
}
int main(int argc, char *argv[]){
int sockfd;
struct sockaddr serverAddr; //server address
char buff[1024];
struct sockaddr_in inAddr;
long int sentBytes,revedBytes;
sockfd=socket(AF_INET,SOCK_STREAM,0); // create socket
if (sockfd == -1)
{
printf("ERROR opening socket\n");
return 1;
}
printf("Socket done\n");
inAddr.sin_family=AF_INET; //default
inAddr.sin_port=htons(5500); // service port
inet_aton("127.0.0.1",&inAddr.sin_addr);
//connectting
if(connect(sockfd,(struct sockaddr *)&inAddr,sizeof(struct sockaddr))<0){
printf("Connect failed.\n");
return 1;
}
printf("Connection accepted\n");
char *FileName; // file input
char *Result; // file return
int choice;
do{
printf("\n*************ENCODE_DECODE_BASE64**************");
printf("\n******* 1. Encode ********");
printf("\n******* 2. Decode ********");
printf("\n******* 3. Exit ********");
printf("\n***********************************************\n");
printf("Choice: ");
choice = getchar();
while(getchar() !='\n');
switch(choice)
{
case '1':
//demo encode////////////////////////////////////////
send(sockfd,"encode",5,0); // send to server when choose 1
printf("File Encode : ");
FileName = inputString(20);
FILE *fpt = fopen(FileName,"r");
if(fpt==NULL){
printf("File not found");
return -1;
}
printf("File Result: ");
Result = inputString(20);
FILE *ft = fopen(Result,"w");
while(!feof(fpt)){
if (fgets(buff,MAX,fpt) != NULL ){
sentBytes=send(sockfd,buff,1024,0);
revedBytes=recv(sockfd,buff,1024,0);
fprintf(ft,"%s\n",buff);
}
}
printf("Encode done!thanks you !\n");
//close(sockfd);
fclose(fpt);fclose(ft);
return 0;
break;
//decode ///////////////////////////////////////////////
case '2':
send(sockfd,"decode",6,0);
printf("File Decode : ");
FileName = inputString(20);
FILE *fpt1 = fopen(FileName,"r");
if(fpt1==NULL){
printf("File not found");
return -1;
}
printf("File Result : ");
Result = inputString(20);
FILE *ft1 = fopen(Result,"w");
while(!feof(fpt1)){
if (fgets(buff,MAX,fpt1) != NULL ){
sentBytes=send(sockfd,buff,1024,0);
revedBytes=recv(sockfd,buff,1024,0);
fprintf(ft1,"%s",buff);
}
}
printf("Decode done ! thanks you !\n");
//close(sockfd);
fclose(fpt1);fclose(ft1);
return 0;
break;
///////////////////////////////////////////////////////
case '3':
printf("Thanks!\n");
break;
default: printf("wrong number, please try again!\n"); break;
//end choice///////////////////////////////////////
}
}while(choice!='3');
//end menu
//close(sockfd);
//return 0;
}
and here is ServerCode:
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/wait.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
char b64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
/* decodeblock - decode 4 '6-bit' characters into 3 8-bit binary bytes */
void decodeblock(unsigned char in[], char *clrstr) {
unsigned char out[4];
out[0] = in[0] << 2 | in[1] >> 4;
out[1] = in[1] << 4 | in[2] >> 2;
out[2] = in[2] << 6 | in[3] >> 0;
out[3] = '\0';
strncat(clrstr, out, sizeof(out));
}
void b64_decode(char *b64src, char *clrdst) {
int c, phase, i;
unsigned char in[4];
char *p;
clrdst[0] = '\0';
phase = 0; i=0;
while(b64src[i]) {
c = (int) b64src[i];
if(c == '=') {
decodeblock(in, clrdst);
break;
}
p = strchr(b64, c);
if(p) {
in[phase] = p - b64;
phase = (phase + 1) % 4;
if(phase == 0) {
decodeblock(in, clrdst);
in[0]=in[1]=in[2]=in[3]=0;
}
}
i++;
}
}
/* encodeblock - encode 3 8-bit binary bytes as 4 '6-bit' characters */
void encodeblock( unsigned char in[], char b64str[], int len ) {
unsigned char out[5];
out[0] = b64[ in[0] >> 2 ];
out[1] = b64[ ((in[0] & 0x03) << 4) | ((in[1] & 0xf0) >> 4) ];
out[2] = (unsigned char) (len > 1 ? b64[ ((in[1] & 0x0f) << 2) |
((in[2] & 0xc0) >> 6) ] : '=');
out[3] = (unsigned char) (len > 2 ? b64[ in[2] & 0x3f ] : '=');
out[4] = '\0';
strncat(b64str, out, sizeof(out));
}
/* encode - base64 encode a stream, adding padding if needed */
void b64_encode(char *clrstr, char *b64dst) {
unsigned char in[3];
int i, len = 0;
int j = 0;
b64dst[0] = '\0';
while(clrstr[j]) {
len = 0;
for(i=0; i<3; i++) {
in[i] = (unsigned char) clrstr[j];
if(clrstr[j]) {
len++; j++;
}
else in[i] = 0;
}
if( len ) {
encodeblock( in, b64dst, len );
}
}
}
void sig_chld(int signo) //child
{
pid_t pid;
int stat;
while((pid = waitpid(-1, &stat, WNOHANG))>0)
printf("child %d terminated\n", pid);
return;
}
int main()
{
int listen_sock, conn_sock;
int server_len, client_len,choice;
struct sockaddr_in server_address;
struct sockaddr_in client_address;
char myb64[1024] = ""; //encode
char mydst[1024] = ""; //decode
int sentBytes,revedBytes,bytes_readi;
char buff[1024]; //buffer to send data
listen_sock = socket(AF_INET, SOCK_STREAM, 0); //create socket
if (listen_sock == -1)
{
printf("ERROR opening socket\n");
return 0;
}
printf("Socket done\n");
//Thiet lap dia chi server
server_address.sin_family = AF_INET; //default
inet_aton("127.0.0.1",&server_address.sin_addr); //ip server
server_address.sin_port = htons(5500); // port server
server_len = sizeof(server_address);
if(bind(listen_sock, (struct sockaddr *)&server_address,server_len)<0)
{
printf("ERROR on binding\n");
return 0;
}
printf("Bind done\n");
int check = listen(listen_sock,10);
if (check == -1)
{
printf("Error connect");
return 0;
}
printf("Waiting connect..\n");
while(1) {
client_len = sizeof(client_address);
conn_sock = accept(listen_sock,(struct sockaddr *)&client_address, &client_len);
if(conn_sock==-1){
printf("Error connect\n");
return 1;
}else{
printf("Accept new connection\n");
}
if(fork() == 0){
close(listen_sock);
do{
revedBytes = recv(conn_sock,buff,1024,0);
buff[revedBytes]='\0';
if(strcmp(buff,"mahoa")==0) choice=1;
else if(strcmp(buff,"giaima")==0) choice=2; else choice = 3;
switch(choice)
{
case 1:
while((revedBytes = recv(conn_sock,buff,1024,0)) > 0){
buff[revedBytes]='\0';
//printf("string send by client encode : %s\n",buff);
b64_encode(buff, myb64); //ma hoa
sentBytes=send(conn_sock,myb64,1024,0); //gui lai string da ma hoa cho client
}
close(conn_sock);//Dong ket noi cua client
exit(0);
break;
case 2:
while((revedBytes = recv(conn_sock,buff,1024,0)) > 0){
buff[revedBytes]='\0';
//printf("string send by client decode: %s\n",buff);
b64_decode(buff,mydst); // giaima
sentBytes=send(conn_sock,mydst,1024,0);
}
close(conn_sock);
exit(0);
break;
case 3:break;
}
}while(choice!=3);
break;
}
signal(SIGCHLD,sig_chld);
close(conn_sock);
}
return 1;
}
I'm writing a TCP server using Lwip Protocol, normally the server can connect to multiple TCP clients. However I have a problem , the server can't connect more than three active connections. The 4th or more clients could not connect for unknown reasons. I looked around the forums and tried increasing the number limit for MEMP_NUM_TCP_PCB in opt.h (lwip-x86_64\include\lwip\opt.h) but it didn't help.
Following is my code, and my questions is whether is there a max connection limitation using LWIP ? Maximum number of connections is 3 or more?
//server code
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#define MYPORT 1234 // the port users will be connecting to
#define BACKLOG 2// how many pending connections queue will hold
#define BUF_SIZE 1024
int fd_A[BACKLOG]; // accepted connection fd
int conn_amount; // current connection amount
void showclient()
{
int i;
printf("-----> client amount: %d\n", conn_amount);
for (i = 0; i < BACKLOG; i++) {
printf("BACKLOG%d ---> fd = %d\n", i, fd_A[i]);
}
printf("\n\n");
}
int main(void)
{
sleep(1);
printf("start server\n");
int sock_fd, new_fd; // listen on sock_fd, new connection on new_fd
struct sockaddr_in server_addr; // server address information
struct sockaddr_in client_addr; // connector's address information
socklen_t sin_size;
int yes = 1;
char buf[BUF_SIZE];
int ret;
int i;
if ((sock_fd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
perror("socket");
exit(1);
}
//if (setsockopt(sock_fd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int)) == -1) {
/*if (setsockopt(sock_fd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int)) == -1) {
//perror("setsockopt");
//exit(1);
}
if (fcntl(sock_fd, F_SETFL, O_NONBLOCK) == -1) {
printf("Set server socket nonblock failed\n");
exit(1);
}*/
memset(&server_addr, 0, sizeof(server_addr));
server_addr.sin_family = AF_INET; // host byte order
server_addr.sin_port = htons(MYPORT); // short, network byte order
server_addr.sin_addr.s_addr = htonl(INADDR_ANY); // automatically fill with my IP
//memset(server_addr.sin_zero, '0', sizeof(server_addr.sin_zero));
if (bind(sock_fd, (struct sockaddr *)&server_addr, sizeof(server_addr)) == -1) {
perror("bind");
exit(1);
}
printf("listen...\n");
if (listen(sock_fd, BACKLOG) == -1) {
perror("listen");
exit(1);
}
printf("listen port %d\n", MYPORT);
fd_set fdsr, wfds, efds;
int maxsock;
struct timeval tv;
conn_amount = 0;
sin_size = sizeof(client_addr);
maxsock = sock_fd;
while (1)
{
sleep(1); // it's necessary
// initialize file descriptor set
FD_ZERO(&fdsr);
FD_ZERO(&wfds);
//FD_ZERO(&efds);
FD_SET(sock_fd, &fdsr); // add fd
FD_SET(sock_fd, &wfds); // add fd
//FD_SET(sock_fd, &efds); // add fd
// timeout setting
tv.tv_sec = 30;
tv.tv_usec = 0;
// add active connection to fd set
for (i = 0; i < BACKLOG; i++) {
if (fd_A[i] != 0) {
FD_SET(fd_A[i], &fdsr);
}
}
//printf("before select!!!!!!!!!!!! ret = %d\n", ret);
if ((select(maxsock + 1, &fdsr, &wfds, (fd_set*) 0, (struct timeval*) 0)) < 0) {
perror("select");
break;
}
// check every fd in the set
for (i = 0; i < conn_amount; i++)
{
if (FD_ISSET(fd_A[i], &fdsr)) // check which fd is ready
{
ret = recv(fd_A[i], buf, sizeof(buf), 0);
if (ret <= 0)
{ // client close
printf("ret : %d and client[%d] close\n", ret, i);
close(fd_A[i]);
FD_CLR(fd_A[i], &fdsr); // delete fd
fd_A[i] = 0;
conn_amount--;
}
else
{ // receive data
if (ret < BUF_SIZE)
memset(&buf[ret], '\0', 1); // add NULL('/0')
printf("client[%d] send:%s\n", i, buf);
}
}
}
// check whether a new connection comes
if (FD_ISSET(sock_fd, &fdsr)) // accept new connection
{
new_fd = accept(sock_fd, (struct sockaddr *)&client_addr, &sin_size);
if (new_fd <= 0)
{
perror("accept");
continue;
}
// add to fd queue
if (conn_amount < BACKLOG)
{
fd_A[conn_amount++] = new_fd;
printf("------> new connection client[%d] %s:%d\n", conn_amount,
inet_ntoa(client_addr.sin_addr), ntohs(client_addr.sin_port));
if (new_fd > maxsock) // update the maxsock fd for select function
maxsock = new_fd;
}
else
{
printf("max connections arrive, exit\n");
send(new_fd, "bye", 4, 0);
close(new_fd);
break;
}
}
//showclient();
}
// close other connections
for (i = 0; i < BACKLOG; i++)
{
if (fd_A[i] != 0)
{
close(fd_A[i]);
}
}
exit(0);
}
//client code
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <malloc.h>
#include <netdb.h>
#include <fcntl.h>
#include <unistd.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#define RES_LENGTH 10240
int connect_socket(char * server,int serverPort);
int send_msg(int sockfd,char * sendBuff);
char * recv_msg(int sockfd);
int close_socket(int sockfd);
int main(int argc, char ** argv)
{
int sockfd[1024] = {0};
char sendMsg[30]="zhangchengfei\r\n\r";
char* res;
int port = 1234;
char ip[128] = {0};
strncpy(ip, "10.107.19.62", 128);
if(argc > 2)
{
strncpy(ip, argv[1], 128);
port = atoi(argv[2]);
printf("Input IP: %s, port : %d\n", ip, port);
}
else if(argc > 1)
{
//port = atoi(argv[1]);
//printf("Input port : %d\n", port);
//
int num_client = atoi(argv[1]);
int i = 0;
for (i = 0; i <= num_client; i++) {
printf("start connect %d\n", i + 1);
sockfd[i]=connect_socket(ip, port);
printf("connect %d OK\n", i + 1);
getchar();
}
for (i = 0; i <= num_client; i++) {
send_msg(sockfd[i], sendMsg);
/* res=recv_msg(sockfd); */
printf("client %d send msg = %s\n", i + 1, sendMsg);
//printf(res);
//free(res);
getchar();
}
for (i = 0; i <= num_client; i++) {
close_socket(sockfd[i]);
printf("close socket %d\n", i + 1);
}
}
return 0;
}
int connect_socket(char * server,int serverPort){
int sockfd=0;
struct sockaddr_in addr;
struct hostent * phost;
if((sockfd=socket(AF_INET,SOCK_STREAM,0))<0){
herror("Init socket error!");
return -1;
}
bzero(&addr,sizeof(addr));
addr.sin_family = AF_INET;
addr.sin_port = htons(serverPort);
addr.sin_addr.s_addr = inet_addr(server);
if(addr.sin_addr.s_addr == INADDR_NONE){
phost = (struct hostent*)gethostbyname(server);
if(phost==NULL){
herror("Init socket s_addr error!");
return -1;
}
addr.sin_addr.s_addr =((struct in_addr*)phost->h_addr)->s_addr;
}
if(connect(sockfd,(struct sockaddr*)&addr, sizeof(addr))<0)
{
perror("Connect server fail!");
return -1;
}
else
return sockfd;
}
int send_msg(int sockfd,char * sendBuff)
{
int sendSize=0;
if((sendSize=send(sockfd,sendBuff,strlen(sendBuff),0))<=0){
herror("Send msg error!");
return -1;
}else
return sendSize;
}
char* recv_msg(int sockfd){
char * response;
int flag=0,recLenth=0;
response=(char *)malloc(RES_LENGTH);
memset(response,0,RES_LENGTH);
for(flag=0;;)
{
printf("======recv data:\n");
if(( recLenth=recv(sockfd,response+flag,RES_LENGTH-flag,0))==-1 )
{
free(response);
printf("Return value : %d\n", recLenth);
perror("Recv msg error : ");
return NULL;
}
else if(recLenth==0)
break;
else
{
printf("%d char recieved data : %s.\n", recLenth, response+flag);
flag+=recLenth;
recLenth=0;
}
}
printf("Return value : %d\n", recLenth);
response[flag]='0';
return response;
}
int close_socket(int sockfd)
{
close(sockfd);
return 0;
}
I have solved this problem caused by a Makefile bug in ./stubdom, after executing make crossclean , I found the .o files still existed in lwip-x86_64 folder. So I add a command find . -name "*.o" | xargs rm -f in Makefile and then anything is OK.
The reason is that lwip configure is given by the macro definition, macro definition have been replaced at the pre-compilation stage, so if I modify the lwip configure and did not delete the .o files, there is no effect. Following is the macro definitions I have modified in opt.h.
MEMP_NUM_TCP_PCB 100
MEMP_NUM_TCP_PCB_LISTEN 100
MEMP_NUM_NETCONN 100
Now the server can break through the connection limitations and more than 3 active TCP connections can be established.
I have a fairly simple code below for processing /proc/* files in solaris to obtain process information and arguments. For the most part it works (meaning it does present arguments correctly on some processes), but on some process arguments (particularly where they are long), it fails and produces the error Value too large for defined data type
Does anyone have any idea perhaps why it fails?
It is the pread() line for the arguments array that fails at line 108.
It is actually some java processes with many arguments where it fails if that helps.
What's interesting too is that:
examining the binary /proc/<pid>/psinfo file, it is very small--the size is clearly not sufficient to contain the kind of long arguments that I am looking at with some processes. Doing hex dump of the contents of the psinfo file confirms that they are not there.
the value of pr_argv when there are long arguments is zero.
On further digging, it looks like the arguments are in /proc/(pid)/object/tmpfs.394.2.71404854. I wonder why.
Code:
#include <dirent.h>
#include <ctype.h>
#include <assert.h>
#include <malloc.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/processor.h>
#include <sys/sysinfo.h>
#include <sys/param.h>
#include <kstat.h>
#include <procfs.h>
#define PROC_ERRNO ((errno == ENOENT) ? ESRCH : errno)
#define my_pread(fd, ptr, type, offset) \
(pread(fd, ptr, sizeof(type), offset) == sizeof(type))
static int proc_psinfo_get(psinfo_t *psinfo, pid_t pid)
{
int fd, retval = 0;
char buffer[BUFSIZ];
sprintf(buffer, "/proc/%d/psinfo", pid);
if ((fd = open(buffer, O_RDONLY)) < 0) {
return ESRCH;
}
if (!my_pread(fd, psinfo, psinfo_t, 0)) {
retval = errno;
}
close(fd);
return retval;
}
int main(int argc, char **argv)
{
DIR *dirp = opendir("/proc");
struct dirent *ent;
char *models[] = {
"unknown", "32bit", "64bit"
};
while ((ent = readdir(dirp))) {
pid_t pid;
psinfo_t psinfo;
int retval;
char buffer[BUFSIZ];
char *argvb[56];
char **argvp = argvb;
int n, fd;
size_t nread = 0;
unsigned int argv_size;
if (!isdigit(*ent->d_name)) {
continue;
}
psinfo.pr_dmodel = 0;
pid = strtoul(ent->d_name, NULL, 10);
retval = proc_psinfo_get(&psinfo, pid);
printf("---------------------------------\n");
printf("pid=%d, status=%s, model=%s\n",
pid, retval ? strerror(retval) : "OK",
models[psinfo.pr_dmodel]);
printf("Parent Pid: %ld\n", psinfo.pr_ppid);
printf("UID: %ld\n", psinfo.pr_uid);
printf("size: %ld\n", psinfo.pr_size);
printf("rss: %ld\n", psinfo.pr_rssize);
printf("pcpu: %d\n", psinfo.pr_pctcpu);
printf("pctmem: %d\n", psinfo.pr_pctmem);
printf("zoneid: %d\n", psinfo.pr_zoneid);
printf("pr_sname: %c\n", psinfo.pr_lwp.pr_sname);
printf("Up Start: (%ld, %ld)\n", psinfo.pr_start.tv_sec, psinfo.pr_start.tv_nsec);
printf("Command: %s\n", psinfo.pr_fname);
// print argc
argv_size = sizeof(*argvp) * psinfo.pr_argc;
sprintf(buffer, "/proc/%d/as", pid);
printf("argc=%d, argv_size=%d\n",
psinfo.pr_argc, argv_size);
if ((fd = open(buffer, O_RDONLY)) < 0) {
printf("open(%s) == %s\n",
buffer, strerror(PROC_ERRNO));
if (argvp != argvb) {
free(argvp);
}
continue;
}
if (argv_size > sizeof(argvb)) {
argvp = malloc(argv_size);
}
if ((long int)(nread = pread(fd, argvp, argv_size, (off_t)psinfo.pr_argv)) <= 0) {
close(fd);
printf("error in reading argvp\n");
printf(" pread(%d, 0x%lx, %d, 0x%lx) == %d (%s)\n",
fd, (unsigned long)argvp, argv_size,
(unsigned long)psinfo.pr_argv,
nread, strerror(errno));
continue;
}
// parse the args here
for (n = 0; n < psinfo.pr_argc; n++) {
int alen;
char *arg;
if ((long int)(nread = pread(fd, buffer, sizeof(buffer), (off_t)argvp[n])) <= 0) {
close(fd);
printf("buffer %d argvp as ld %ld argvp as lu %lu ", sizeof(buffer), argvp[n] , argvp[n] );
printf(" %-2d) pread(%d, 0x%lx, %d, 0x%lx) == %d (%s)\n",
n, fd, (unsigned long)&buffer[0], sizeof(buffer),
(unsigned long)argvp[n],
nread, strerror(errno));
break;
}
printf(" %-2d) nread=%-4d, ", n, nread);
fflush(stdout);
alen = strlen(buffer)+1;
printf(" alen=%-4d ", alen);
fflush(stdout);
arg = malloc(alen);
memcpy(arg, buffer, alen);
printf(" {%s}\n", arg);
fflush(stdout);
}
if (argvp != argvb) {
free(argvp);
}
close(fd);
}
closedir(dirp);
return 0;
}
You're trying to read from a starting position past the end of the file.
From the pread man page:
ssize_t pread(int fildes, void *buf, size_t nbyte, off_t offset);
...
EOVERFLOW
The file is a regular file, nbyte is greater than 0, the starting
position is before the end-of-file, and the starting position is
greater than or equal to the offset maximum established in the open
file description associated with fildes.
i installed the usb webcam driver in linux 2.6 version
then i want to capture using V4L please any one reply me how can i write the program to capture using webcam
I work with V4l using the reference of the linuxTV (http://linuxtv.org/downloads/v4l-dvb-apis/). They have the documentation about V4l and some examples. Take a look at the following example (i got from the linuxTV):
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/mman.h>
#include <linux/videodev2.h>
#include "../libv4l/include/libv4l2.h"
#define CLEAR(x) memset(&(x), 0, sizeof(x))
struct buffer {
void *start;
size_t length;
};
static void xioctl(int fh, int request, void *arg)
{
int r;
do {
r = v4l2_ioctl(fh, request, arg);
} while (r == -1 && ((errno == EINTR) || (errno == EAGAIN)));
if (r == -1) {
fprintf(stderr, "error %d, %s\n", errno, strerror(errno));
exit(EXIT_FAILURE);
}
}
int main(int argc, char **argv)
{
struct v4l2_format fmt;
struct v4l2_buffer buf;
struct v4l2_requestbuffers req;
enum v4l2_buf_type type;
fd_set fds;
struct timeval tv;
int r, fd = -1;
unsigned int i, n_buffers;
char *dev_name = "/dev/video0";
char out_name[256];
FILE *fout;
struct buffer *buffers;
fd = v4l2_open(dev_name, O_RDWR | O_NONBLOCK, 0);
if (fd < 0) {
perror("Cannot open device");
exit(EXIT_FAILURE);
}
CLEAR(fmt);
fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
fmt.fmt.pix.width = 640;
fmt.fmt.pix.height = 480;
fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_RGB24;
fmt.fmt.pix.field = V4L2_FIELD_INTERLACED;
xioctl(fd, VIDIOC_S_FMT, &fmt);
if (fmt.fmt.pix.pixelformat != V4L2_PIX_FMT_RGB24) {
printf("Libv4l didn't accept RGB24 format. Can't proceed.\n");
exit(EXIT_FAILURE);
}
if ((fmt.fmt.pix.width != 640) || (fmt.fmt.pix.height != 480))
printf("Warning: driver is sending image at %dx%d\n",
fmt.fmt.pix.width, fmt.fmt.pix.height);
CLEAR(req);
req.count = 2;
req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
req.memory = V4L2_MEMORY_MMAP;
xioctl(fd, VIDIOC_REQBUFS, &req);
buffers = calloc(req.count, sizeof(*buffers));
for (n_buffers = 0; n_buffers < req.count; ++n_buffers) {
CLEAR(buf);
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_MMAP;
buf.index = n_buffers;
xioctl(fd, VIDIOC_QUERYBUF, &buf);
buffers[n_buffers].length = buf.length;
buffers[n_buffers].start = v4l2_mmap(NULL, buf.length,
PROT_READ | PROT_WRITE, MAP_SHARED,
fd, buf.m.offset);
if (MAP_FAILED == buffers[n_buffers].start) {
perror("mmap");
exit(EXIT_FAILURE);
}
}
for (i = 0; i < n_buffers; ++i) {
CLEAR(buf);
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_MMAP;
buf.index = i;
xioctl(fd, VIDIOC_QBUF, &buf);
}
type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
xioctl(fd, VIDIOC_STREAMON, &type);
for (i = 0; i < 20; i++) {
do {
FD_ZERO(&fds);
FD_SET(fd, &fds);
/* Timeout. */
tv.tv_sec = 2;
tv.tv_usec = 0;
r = select(fd + 1, &fds, NULL, NULL, &tv);
} while ((r == -1 && (errno = EINTR)));
if (r == -1) {
perror("select");
return errno;
}
CLEAR(buf);
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_MMAP;
xioctl(fd, VIDIOC_DQBUF, &buf);
sprintf(out_name, "out%03d.ppm", i);
fout = fopen(out_name, "w");
if (!fout) {
perror("Cannot open image");
exit(EXIT_FAILURE);
}
fprintf(fout, "P6\n%d %d 255\n",
fmt.fmt.pix.width, fmt.fmt.pix.height);
fwrite(buffers[buf.index].start, buf.bytesused, 1, fout);
fclose(fout);
xioctl(fd, VIDIOC_QBUF, &buf);
}
type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
xioctl(fd, VIDIOC_STREAMOFF, &type);
for (i = 0; i < n_buffers; ++i)
v4l2_munmap(buffers[i].start, buffers[i].length);
v4l2_close(fd);
return 0;
}