Trong vớ d映 d逢噂i 8õy, m瓜t ti院n trỡnh t衣o ra m瓜t 嘘ng d磯n, t衣o ra m瓜t ti院n trỡnh con, vi院t m瓜t v<n b違n vào 嘘ng d磯n.Ti院n trỡnh con th瑛a h逢荏ng 嘘ng d磯n và cỏc ký hi羽u mụ t違 c栄a 嘘ng d磯n, th詠c hi羽n 8丑c trong 嘘ng d磯n:
#include <errno. h> #include <stdio. h>
void code_fils(int number) { int fd, nread;
fd=number;
printf(" So hieu mo ta la %d\n",fd);
switch (nread=read(fd, texte, sizeof(texte))) { case -1: perror("Loi doc."); case 0: perror("EOF"); default:
printf("Van ban nhan duoc co %d ky tu: %s\n",fd, texte); } } main() { int fd[2]; char chaine[10]; if (pipe(fd)==-1)
{ perror("Loi khoi tao pipe."); exit(1);
}
switch (fork()) { case -1:
perror(" Loi khoi tao tien trinh."); break; case 0: if (close(fd[1])==-1) perror(" Error."); code_fils(fd[0]); exit(0); } close(fd[0]); if (write(fd[1]),"hello",6)==-1) perror("Loi truyen."); } M院t qu違 ch逢挨ng trỡnh: So hieu mo ta la: 5
Van ban nhan duoc co 6 ky tu: hello
Chỳ ý r茨ng, ti院n trỡnh con 8丑c trong 嘘ng d磯n mà khụng vi院t 荏"8ú nờn nú b逸t 8亥u d茨ng cỏch 8úng ph亥n vi院t fd[1] 8吋 ti院t ki羽m cỏc tớn hi羽u mụ t違 c栄a t鰻 h嬰p. T逢挨ng t詠, vỡ ti院n trỡnh cha ch雨 s穎 d映ng ph亥n vi院t nờn nú 8úng ph亥n 8丑c l衣i (fd[0]). Sau 8ú ti院n trỡnh cha vi院t vào 嘘ng d磯n 6 ký t詠 và ti院n trỡnh con 8ó 8丑c chỳng.
Bài 9 N壱p trỡnh m衣ng TCP/IP
9.1. L壱p trỡnh client /server theo giao th泳c TCP/IP
• Ch⇔￢ng trỡnhtcpClient.c
/ * Khai bỏo cỏc file t h v i゜n c n t hi，t 8； gいi hàm socket * /
#include <sys/types.h> #include <sys/socket.h>
#include <netinet/in.h> / * get host by nam e* /
#include <arpa/inet.h> #include <netdb.h> #include <stdio.h>
#include <unistd.h> / * close * /
#define SERVER_PORT 1500 #define MAX_MSG 100
int main (int argc, char *argv[]) {
/ * Khざi t o cỏc bi，n dựng t r ong ch ng t r ỡnh * /
int sd, rc, i;
struct sockaddr_in localAddr, servAddr; struct hostent *h;
if(argc < 3) {
printf("usage: %s <IPserver> <data1> <data2> ... <dataN>\n",argv[0]); exit(1);
}
/ * Hàm get host byn am e( ) l y v・"8＾a ch｀ I P t h eo t ờn n h p vào t r ong t p t in / et c/ host s * /
h = gethostbyname(argv[1]); if(h==NULL) {
printf("%s: unknown host '%s'\n",argv[0],argv[1]); exit(1);
}
servAddr.sin_family = h->h_addrtype;
memcpy((char *) &servAddr.sin_addr.s_addr, h->h_addr_list[0], h->h_length); servAddr.sin_port = htons(SERVER_PORT);
/ * Gỏn cỏc giỏ t r＾ cho 8えi t ずng socket .
T o socket cho m ỏy Client . L u l i sえ m ụ t socket * /
sd = socket(AF_INET, SOCK_STREAM, 0); if(sd<0) {
perror("cannot open socket "); exit(1);
}
/ * A t t ờn socket cho ch ng t r ỡn h Client
Gỏn 8＾a ch｀ k，t nえi cho socket t heo giao t hだc I nt er net * /
localAddr.sin_family = AF_INET;
localAddr.sin_addr.s_addr = htonl(INADDR_ANY); localAddr.sin_port = htons(0);
/ * Hàm ht ons( ) dựng 8； chu y；n 8がi t r t tと by t e cぞa sえ nguy ờn t r げc kh i gざi 8i ẻ do h゜
t hえng sつ dぜng c ch， giao t i，p TCP/ I P * / / * Ràng buぐc t ờn vげi socket * /
rc = bind(sd, (struct sockaddr *) &localAddr, sizeof(localAddr)); if(rc<0) {
printf("%s: cannot bind port TCP %u\n",argv[0],SERVER_PORT); perror("error ");
exit(1); }
/ * Thとc hi゜n k，t nえi 8，n ser v er t heo t ờn/8＾a ch｀ n h p v ào tぢ dũng l゜nh * /
rc = connect(sd, (struct sockaddr *) &servAddr, sizeof(servAddr)); if(rc<0) {
perror("cannot connect "); exit(1);
}
/ * Sau khi socket 8ó k，t nえi, t hとc h i゜n gつi cỏc dて li゜u 8，n ch ng t r ỡnh Ser v er * /
for(i=2;i<argc;i++) {
rc = send(sd, argv[i], strlen(argv[i]) + 1, 0);
if(rc<0) {
perror("cannot send data "); close(sd);
exit(1);
}/ * if * /
printf("%s: data%u sent (%s)\n",argv[0],i-1,argv[i]);
}/ * for * /
return 0; }/*main*/
• Ch⇔￢ng trỡnh tcpServer.c
/ * Ch u on g t r in h t cpSe r v e r .c * /
/ * Khai bỏo cỏc file t h v i゜n c n t hi，t 8； gいi hàm socket * /
#include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> #include <netdb.h> #include <stdio.h>
#include <unistd.h> / * close * /
#define SUCCESS 0 #define ERROR 1 #define END_LINE 0x0 #define SERVER_PORT 1500 #define MAX_MSG 100 /* function readline */ int read_line();
int main (int argc, char *argv[]) {
int sd, newSd, cliLen;
struct sockaddr_in cliAddr, servAddr; char line[MAX_MSG];
/ * Gỏn cỏc giỏ t r＾ cho 8えi t ずng socket .
T o socket cho m ỏy Ser v er . L u l i sえ m ụ t socket * /
sd = socket(AF_INET, SOCK_STREAM, 0); if(sd<0) {
perror("cannot open socket "); return ERROR;
}
/ * A t t ờn socket cho ch ng t r ỡn h Ser v er
Gỏn 8＾a ch｀ k，t nえi cho socket t heo giao t hだc I nt er net * /
servAddr.sin_family = AF_INET;
servAddr.sin_addr.s_addr = htonl(INADDR_ANY); servAddr.sin_port = htons(SERVER_PORT);
if(bind(sd, (struct sockaddr *) &servAddr, sizeof(servAddr))<0) { perror("cannot bind port ");
return ERROR; } /* V o hàng 8ずi l ng n ghe k，t nえi cぞa client Cho phộp hàng 8ずi nh n tえi 8a 5 k，t nえi */ listen(sd,5); / * L p liờn tぜc chご v à lx y k，t nえi cぞa client * / while(1) {
printf("%s: waiting for data on port TCP %u\n",argv[0],SERVER_PORT); cliLen = sizeof(cliAddr);
/* Ch p nh n k，t nえi * /
newSd = accept(sd, (struct sockaddr *) &cliAddr, &cliLen); if(newSd<0) {
perror("cannot accept connection "); return ERROR; } /* init line */ memset(line,0x0,MAX_MSG); /* Aいc dて li゜u do Client gざi 8，n - xつ lý dて li゜u n h n 8 ずc */ while(read_line(newSd,line)!=ERROR) {
printf("%s: received from %s:TCP%d : %s\n", argv[0], inet_ntoa(cliAddr.sin_addr), ntohs(cliAddr.sin_port), line);
/* init line */
} /* while(read_line) */
} /* while (1) */
}
/ * WARNI NG * /
/ * t his funct ion is ex per im ent al. I don't k now y et if it w or ks * /
/ * cor r ect ly or not . Use St ev en's r eadlin e( ) fun ct ion t o hav e som et hing r obust .* / / * r cv _line is m y f unct ion r eadline( ) . Dat a is r ead fr om t he socket w hen * /
/ * needed, but not by t e aft er by t es. All t he r eceiv ed dat a is r ead. * /
/ * Th is m eans only one call t o r ecv ( ) , inst ead of one call for each r eceiv ed by t e. * / / * You can set END_CHAR t o w hat ev er m eans en dofline f or y ou. ( 0x 0A is \ n) * / / * r ead_lin r et ur ns t he num ber of by t es r et u r ned in lin e_t o_r et ur n * /
/* Hàm cú chだc n<ng 8いc dて li゜u tぢ socket*/ int read_line(int newSd, char *line_to_return) {
static int rcv_ptr=0;
static char rcv_msg[MAX_MSG]; static int n;
int offset;
offset=0;
while(1) {
if(rcv_ptr==0) {
/* read data from socket */
memset(rcv_msg,0x0,MAX_MSG); /* init buffer */ n = recv(newSd, rcv_msg, MAX_MSG, 0); /* wait for data */ if (n<0) {
perror(" cannot receive data "); return ERROR;
} else if (n==0) {
printf(" connection closed by client\n"); close(newSd);
return ERROR; }
}
/* if new data read on socket OR if another line is still in buffer */ /* copy line into 'line_to_return' */
while(*(rcv_msg+rcv_ptr)!=END_LINE && rcv_ptr<n) { memcpy(line_to_return+offset,rcv_msg+rcv_ptr,1); offset++;
rcv_ptr++; }
/* end of line + end of buffer => return line */ if(rcv_ptr==n-1) {
/* set last byte to END_LINE */ *(line_to_return+offset)=END_LINE; rcv_ptr=0;
return ++offset; }
/* end of line but still some data in buffer => return line */ if(rcv_ptr <n-1) {
/* set last byte to END_LINE */ *(line_to_return+offset)=END_LINE; rcv_ptr++;
return ++offset; }
/* end of buffer but line is not ended => */ /* wait for more data to arrive on socket */ if(rcv_ptr == n) {
rcv_ptr = 0; }
} / * w hile * /
}/ * m ain* /