Dup2() help

I'm having issues with dup2(). I can write to a file, however it's classified as no read, no write. I want it to be read-only.

I think I have what I need in this excerpt.
graph[i] is an array holding structs
graph[i].prog is a string of OS commands ie ls, echo.
graph[i].output is the file to write to.

Code:

---

#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <sys/wait.h>
#include <unistd.h>
#include <fcntl.h>
#define CREATE_FLAGS (O_RDWR | O_CREAT | O_APPEND)

 int fileOut=open(graph[i].output, CREATE_FLAGS);
      if(fileOut==-1) {
        perror("Failed to open file");
        return 1;
      }
     
      if(dup2(fileOut, STDOUT_FILENO)==-1) {
        perror("Failed to redirect standard output");
        return 1;
      }


    pid_t childpid;
       
    childpid=fork();
     
      //Fail to fork
      if (childpid==-1) {
        perror("Failed to fork");
        return 1;
      }
     
      //Entered Child
      if (childpid==0) {
        int numArgs;
        char **args;
        numArgs=makeargv(graph[i].prog," ", &args);
        execvp(args[0],args);
        //        fileOut=close(*graph[i].output);
        perror("Child failed to exec\n");
        return 1;
      }

---

Any help would be appreciated, thank you.

So what actual message does your perror line print?

It doesn't print anything, it never gets to it. The file gets written, but I just can't read it without changing permissions later.

If you supply O_CREAT to open(), you must also specify a mode as the third argument. open() is picking up junk and using that as the mode when creating the file, resulting in weird permissions.

Thank you for your help. Got it.

Also, the combination of O_RDWR with O_APPEND seem weird.