System Calls OS record

8/7/2019 System Calls OS record

1/25

PROGRAM:

/*STAT SYSTEM CALL*/

#include#include#include#includemain(){

char fname[30];struct stat buf;printf("\n enter filename with path");scanf("%s",fname);if(stat(fname,&buf)==0)

{printf("\n filename is %s",fname);printf("\n the user id of the owner is %d",buf.st_uid);printf("\n the size of id is %d bytes",buf.st_size);printf("\n the file permission id %d",buf.st_mode);

}else{

perror("stat");exit(0);

}

}


2/25

OUTPUT:

enter filename with path: test

filename is testthe user id of the owner is 604the size of id is 7587 bytesthe file permission id 33277


3/25

PROGRAM:

/* WAIT SYSTEM CALL*/

#includemain(){

int pid;pid=fork();if(pid


4/25

OUTPUT:

a.out first.c second.c test

c_pgms compile temp

Child Complete


5/25

PROGRAM:

/* FORK SYSTEM CALL*/

#include#includemain(){

pid_t pid;pid=fork();if(pid==0){

printf("\n child process starts");printf("\n the pid of the child process is %d",getpid());printf("\n child process ends");

}

else if(pid>0){

printf("\n parent process atarts");printf("\n the pid of the parent process is %d",getpid());printf("\n parent process ends\n");

}else{

perror("fork");}

}


6/25

OUTPUT:

child process starts

the pid of the child process is 4524child process endsparent process startsthe pid of the parent process is 4523parent process ends


7/25

PROGRAM:

/* I/O SYSTEM CALL FOR CREATE AND CLOSE*/


char fname[30];int fd,filemode;printf("\n enter the file name to be created with the path ");scanf("%s",fname);if(fd=creat(fname)


8/25

OUTPUT:

enter the file name to be created with the path: /home/cs4097/vig3

enter the permission for the file 666

file is successfully createdfilename mode/home/cs4097/vig3 666

file is closed succesfully


9/25

PROGRAM:

/*I/O SYSTEM CALL FOR READ*/

#include#include#include#include#includemain(){

char fn[30];int fd,i=0;int actualbytes, nbytes,pos;char buffer[1000];

printf("\n enter filename with path");scanf("%s",fn);printf("\n opening the file %s \n",fn);if((fd=open(fn,O_RDWR|O_CREAT|O_RDONLY,0644))


10/25

}elseprintf("\n\n the size of the file is %d",pos);

if(close(fd)


11/25

OUTPUT:

enter filename with path /home/cs4097/myfile.c

opening the file /home/cs4097/myfile.c

enter maximum amount of data to be read5

file is opened successfullyreading the first 5 bytes from the files

the contents are

#incl

determining the size of file using lseek

the size of the file is 735

file is closed


12/25

PROGRAM:

/*I/O SYSTEM CALL FOR WRITE*/


char fn[30];int fd,i=0;int actualbytes,bytesstored;char buffer[100];printf("\nenter the filename with path");scanf("%s",fn);if((fd=open(fn,O_RDWR|O_CREAT|O_RDONLY,0611))


13/25

perror("close");exit(0);

}else

{printf("file closed");}

}}


14/25

OUTPUT:

enter the filename with path tamil

enter the contents for the file press ctrl+d at the end of the file

Hello tamil and Hello world

file is opened successfullythe contents are writtenfile closed[root@linuxserver record]# cat tamil

Hello tamil and Hello world


15/25


16/25

OUTPUT:

dshare2.c4038 new a.out .. shmget.cfile3hdhgdhgdhgdgdhfsxgf dir1 s .bash_logout vignesh mr.lesshstirectorypr.ch oustat.comnn.txt .kde jj write.c producerconsumer.c waite.c lsc .bashrc create.c madhuy .zshrc .viminfooi.c balaji m1.c fl2 ipc.c hex . ls.c f2 newfiletamil.c grep.c .bash_history fl1.c fl1 fs.c producer.c wait.c


17/25

PROGRAM:

/*SIMULATION OF GREP COMMAND*/

#include#includemain(){

FILE *fp;char c[100],pat[10];int l,i,j=0,count=0,len,k,flag=0;printf("\n enter the pattern");scanf("%s",pat);len=strlen(pat);

fp=fopen("tamil.c","r");while(!feof(fp)){

fscanf(fp,"%s",c);l=strlen(c);count++;for(i=0;i


18/25

OUTPUT:

enter the pattern sd

the pattern sd present in word 3the pattern sd present in word 4


19/25

PROGRAM:

/*PRODUCER CONSUMER PROBLEM(PCP)*/

#include#include#include#include#include#include#include#include#include

#define EMPTY -2#define TERMINATE -1

int main(){

sem_t* mutex;

sem_unlink("/mutex_lab");

int temp;

mutex = (sem_t*)sem_open("/mutex_lab",O_CREAT,S_IRWXU|S_IRWXG|S_IRWXO,1); //READ WRITE EXECUTE (RWX);

int* buffer = mmap(0, sizeof(int)*50, PROT_READ|PROT_WRITE,MAP_SHARED|MAP_ANONYMOUS, -1, 0);*buffer = EMPTY;

int pid = fork();

setbuf(stdout,0);

if (pid != 0)while(1){sem_wait(mutex);

temp = *buffer;


20/25

printf("\n\n\n");printf("\n(ENTER -1) IN THE PRODUCTION VALUE TO TERMINATE THE

PROGRAM\n");

if(temp == EMPTY){printf("\nEnter the data to be produced!!!!!...\n");scanf("%d",&temp);

if(temp==TERMINATE){

printf("\nPROCESS(ES) TERMINATING NOW!!!!!!!....");kill(0,SIGTERM);exit(1);

}

printf("\nProduced...{ %d }\n",temp);*buffer = temp;}elseprintf("\n {FULL} BUFFER FULL!!!Producer is Waiting For the Consumer...\n\n");

sem_post(mutex);

if(rand()%2)sleep(1);}

elsewhile(1){sem_wait(mutex);

temp = *buffer;

printf("\n\n\n");

if(temp==EMPTY)printf("\n{ EMPTY } No data....consumer is waiting for Producer...\n");elseprintf("\nTHE DATA CONSUMED IS....%d. Now buff is {EMPTY}",temp);


21/25


22/25

OUTPUT:

[root@linuxserver record]$ cc pcs15.c lpthread[root@linuxserver record]$ ./a.out

{ EMPTY } No data....consumer is waiting for Producer...

(ENTER -1) IN THE PRODUCTION VALUE TO TERMINATE THE PROGRAMEnter the data to be produced!!!!!...5Produced...{ 5 }

THE DATA CONSUMED IS....5. Now buff is {EMPTY}

{ EMPTY } No data....consumer is waiting for Producer...


(ENTER -1) IN THE PRODUCTION VALUE TO TERMINATE THE PROGRAM{FULL} BUFFER FULL!!!Producer is Waiting For the Consumer...




(ENTER -1) IN THE PRODUCTION VALUE TO TERMINATE THE PROGRAMEnter the data to be produced!!!!!...-1PROCESS(ES) TERMINATING NOW!!!!!!!....Terminated


23/25

PROGRAM:

/*IPC SHARED MEMORY1 (SENDER)*/

#include#include#include#include#include#include #define K 1024int main(){

int shmid;char *addr1;key_t key;key = ftok("/home/cs4038/share.c",'R');shmid = shmget(key,128*K,IPC_CREAT|SHM_R|SHM_W);addr1=shmat(shmid,0,0);printf("\n IPC using shared memory \n");printf("\n SENDER ADDRESS\n");printf("\n the address is %p",addr1);printf("\n enter the message:");scanf("%s",addr1);printf("\n MESSAGE STORED IN %p is %s",addr1,addr1);return 0;

}


24/25

PROGRAM:

/*IPC SHARED MEMORY2 (RECIEVER)*/

#include#include#include#include#include#include

#define K 1024main(){

int shmid;char *addr1;key_t key;key = ftok("/home/cs4038/share.c",'R');shmid=shmget(key,128*K,SHM_R|SHM_W);addr1=shmat(shmid,0,0);printf("\n ipc using shared memory");printf("\n receiver address\n");printf("\n the address is %p",addr1);printf("\n message retrieved from %pi is %s",addr1,addr1);

}


25/25

OUTPUT:

[root@linuxserver record]$ cc share.c[root@linuxserver record] $./a.out

IPC using shared memory

SENDER ADDRESS

the address is 0x2b48307c9000enter the message:Beautiful

MESSAGE STORED IN 0x2b48307c9000 is Beautiful

[root@linuxserver record]# cc share2.c

[root@linuxserver record]# ./a.out

ipc using shared memoryreceiver address

the address is 0x2b88c8382000message retrieved from 0x2b88c8382000i is Beautiful

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System Calls OS record