amd64/132677: error calling fork execvp

[Nate Eldredge]

The following reply was made to PR kern/132677; it has been noted by GNATS.

From: Nate Eldredge <neldredge at math.ucsd.edu>
To: ron <rzo at gmx.de>
Cc: freebsd-gnats-submit at freebsd.org, freebsd-amd64 at freebsd.org
Subject: Re: amd64/132677: error calling fork execvp
Date: Mon, 16 Mar 2009 20:53:49 -0700 (PDT)

 On Sun, 15 Mar 2009, ron wrote:
 
 > hello,
 >
 > calling execvp(2) works fine.
 >
 > however calling
 >
 > pid = fork()
 > if (pid == 0)
 >  execvp(2)
 >
 > returns error 22 (invalid value)
 >
 > calling
 >
 > pid = fork()
 > if (pid == 0)
 >  execve(3)
 >
 > works fine
 
 Can you be more specific?  In particular, could you send a complete source 
 that can be compiled and run, and that shows the problem?
 
 I can't reproduce a problem here.  I am running 7.1 on amd64, and the 
 following program works as expected.
 
 #include <unistd.h>
 #include <stdio.h>
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <stdlib.h>
 
 int main(void) {
    pid_t pid;
    pid = fork();
    if (pid == 0) {
      char *argv[] = { "echo", "Hello, world!", NULL };
      execvp("echo", argv);
      perror("execvp failed");
      _exit(1);
    } else if (pid > 0) {
      int status;
      if (waitpid(pid, &status, 0) == -1) {
        perror("waitpid");
        exit(1);
      }
      if (WIFEXITED(status))
        printf("Child exited with status %d\n", WEXITSTATUS(status));
      else if (WIFSIGNALED(status))
        printf("Child killed by signal %d\n", WTERMSIG(status));
      else
        printf("Impossible status!\n");
    } else if (pid < 0) {
      perror("fork");
      exit(1);
    }
    return 0;
 }
 
 The output is:
 Hello, world!
 Child exited with status 0
 
 Perhaps there is something wrong in a different part of your test program.
 
 -- 
 
 Nate Eldredge
 neldredge at math.ucsd.edu