Help with Mkfifo and exec Post: 302469573

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Homework and Emergencies Homework & Coursework Questions Help with Mkfifo and exec Post 302469573 by dano88 on Sunday 7th of November 2010 03:28:18 AM

11-07-2010

Registered User

Help with Mkfifo and exec

Hello guys!

I am doing a project for the university and I have to do that a process has to create several children through fork(). The father process sends a pathname to each one through exec and the children must send to the father a list with the files from each directory.

The father is waiting and the children don't send anything. I must to do the pipe with mkfifo. I am trying to send text from the children but nothing happens. This is the code that I have wroten:

Code:

struct stat buf;
 mkfifo(NOMBREFIFO, S_IRWXU);
    while (--argc>0){
        stat (argv[argc], &buf);
        if (S_ISDIR(buf.st_mode)){
            pid = fork();
            
            if (pid<0) fprintf (stderr, "error %d", errno); 
            if (pid==0) printf ("hhhhhhhhh");
            if (pid==0 && (exec=execl ("./listarordenado", argv[argc], NULL))<0) fprintf (stderr, "error %d", errno);
            if (pid>0 && wait(&status) && waitpid (pid, &status, 0)){
                printf ("ssssssssss");
                 while(TRUE) {
                      fp=open(NOMBREFIFO,O_RDONLY);
                      nbytes=read(fp,buffer,TAM_BUF-1);
                      buffer[nbytes]='\0';
                      printf("%d Cadena recibida: %s \n",i, buffer);
                      close(fp);
                      i++;
                }
                 }
         }
      } 


/////***code of listarordenado*//


for (i=0; i<50; i++){
        if ((fp=open(NOMBREFIFO,O_WRONLY))==-1)
            perror("fopen");
          else {    
                descr=write(fp,argv[1],strlen(argv[1]));
        }
         
      close(fp);
    }

4. Complete Name of School (University), City (State), Country, Name of Professor, and Course Number (Link to Course):

University: Universidad de Castilla-La Mancha (Ciudad Real, spain)
Professor: Carlos Gonzalez Morcillo :: Personal Web Page www. inf-cr.uclm.es/www/cglez/
Degree: "Computer engineering"
Subject: "Ampliaci�n de Sistemas Operativos" + info: www. esi.uclm.es:8081/www/GuiaDocente/GuiaDocente0910/guias/42534_0910.pdf

dano88

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getexecname

getexecname(3C) 					   Standard C Library Functions 					   getexecname(3C)

NAME

       getexecname - return pathname of executable

SYNOPSIS

       #include <stdlib.h>

       const char *getexecname(void);

DESCRIPTION

       The  getexecname() function returns the pathname (the first argument of one of the exec family of functions; see exec(2)) of the executable
       that started the process.

       Normally this is an absolute pathname, as the majority of commands are executed by the shells that append the command name  to  the  user's
       PATH  components.   If this is not an absolute path, the output of getcwd(3C) can be prepended to it to create an absolute path, unless the
       process or one of its ancestors has changed its root directory or current working directory since the last successful call to  one  of  the
       exec family of functions.

RETURN VALUES

       If successful, getexecname() returns a pointer to the executables pathname; otherwise, it returns 0.

USAGE

       The getexecname() function obtains the executable pathname from the AT_SUN_EXECNAME aux vector.	These vectors are made available to dynam-
       ically linked processes only.

       A successful call to one of the exec family of functions will always have AT_SUN_EXECNAME in the aux vector.  The  associated  pathname	is
       guaranteed to be less than or equal to PATH_MAX, not counting the trailing null byte that is always present.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |Safe			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       exec(2), getcwd(3C), attributes(5)

SunOS 5.10							    17 Dec 1997 						   getexecname(3C)

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