Linux 进程间通信(IPC)

Linux 进程间通信(IPC):

  Linux系统中除了进程和进程之间通信，我想大家也应该关注用户空间与内核空间是怎样通信的。例如说netlink等等。

除了传统进程间通信外像Socket通信也须要掌握的！

/*--------------------------------------------------------------------------
 * Project: aipc.c
 * Name: zwp
 * Date: 2014/6
 *-------------------------------------------------------------------------*/


#include <sys/types.h>
#include <sys/wait.h>
#include <sys/socket.h>
#include <unistd.h>
#include <signal.h>
#include <stdlib.h>
#include <stdio.h>


#define MAXLINE 1024

static void sig_pipe(int);

int s_pipe(int fd[2]);


int main(void)
{
  int n, fd[2];
  pid_t pid;
  char  line[MAXLINE];

  if(signal(SIGPIPE, sig_pipe) == SIG_ERR)
    printf("signal error...\n");
  if(s_pipe(fd) < 0)
    printf("pipe error...\n");
  else if(pid > 0)
  {
    close(fd[1]);
    while(fgets(line, MAXLINE, stdin) != NULL)
    { 
      n = strlen(line);

      if(write(fd[0], line, MAXLINE) != n)
        printf("write error from pipe...\n");
      if((n = read(fd[0], line, MAXLINE)) < 0)
        printf("read arror from pipe...\n");
      if(n == 0)
      {
        printf("child closed pipe...\n");
        break;
      }
      line[n] = 0;
      if(fputs(line, stdout) == EOF)
        printf("fputs error...\n");
    }
    if(ferror(stdin))
      printf("fgets error on stdin...\n");

    exit(0);


  }
  else
  {
    close(fd[0]);
    if(fd[1] != STDIN_FILENO)
    {
      if(dup2(fd[1], STDIN_FILENO) != STDIN_FILENO)
        printf("dup2 error to stdin...\n");

    }
    if(fd[1] != STDOUT_FILENO)
    {
      if(dup2(fd[1], STDOUT_FILENO) != STDOUT_FILENO)
        printf("dup2 error tostdout..\n");

    }
    if(execl("./add2", "add2", NULL) < 0)
      printf("execl error...\n");


  }

}

int s_pipe(int fd[2])
{
  return (socketpair(AF_UNIX, SOCK_STREAM, 0, fd));

}

static void sig_pipe(int sign)
{
  printf("SIGPIPE caught...\n");
  exit(1);

}