• U
    flag parameters: epoll_create · a0998b50
    Ulrich Drepper 提交于
    This patch adds the new epoll_create2 syscall.  It extends the old epoll_create
    syscall by one parameter which is meant to hold a flag value.  In this
    patch the only flag support is EPOLL_CLOEXEC which causes the close-on-exec
    flag for the returned file descriptor to be set.
    
    A new name EPOLL_CLOEXEC is introduced which in this implementation must
    have the same value as O_CLOEXEC.
    
    The following test must be adjusted for architectures other than x86 and
    x86-64 and in case the syscall numbers changed.
    
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    #include <fcntl.h>
    #include <stdio.h>
    #include <time.h>
    #include <unistd.h>
    #include <sys/syscall.h>
    
    #ifndef __NR_epoll_create2
    # ifdef __x86_64__
    #  define __NR_epoll_create2 291
    # elif defined __i386__
    #  define __NR_epoll_create2 329
    # else
    #  error "need __NR_epoll_create2"
    # endif
    #endif
    
    #define EPOLL_CLOEXEC O_CLOEXEC
    
    int
    main (void)
    {
      int fd = syscall (__NR_epoll_create2, 1, 0);
      if (fd == -1)
        {
          puts ("epoll_create2(0) failed");
          return 1;
        }
      int coe = fcntl (fd, F_GETFD);
      if (coe == -1)
        {
          puts ("fcntl failed");
          return 1;
        }
      if (coe & FD_CLOEXEC)
        {
          puts ("epoll_create2(0) set close-on-exec flag");
          return 1;
        }
      close (fd);
    
      fd = syscall (__NR_epoll_create2, 1, EPOLL_CLOEXEC);
      if (fd == -1)
        {
          puts ("epoll_create2(EPOLL_CLOEXEC) failed");
          return 1;
        }
      coe = fcntl (fd, F_GETFD);
      if (coe == -1)
        {
          puts ("fcntl failed");
          return 1;
        }
      if ((coe & FD_CLOEXEC) == 0)
        {
          puts ("epoll_create2(EPOLL_CLOEXEC) set close-on-exec flag");
          return 1;
        }
      close (fd);
    
      puts ("OK");
    
      return 0;
    }
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    Signed-off-by: NUlrich Drepper <drepper@redhat.com>
    Acked-by: NDavide Libenzi <davidel@xmailserver.org>
    Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
    Cc: <linux-arch@vger.kernel.org>
    Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
    a0998b50
syscalls.h 27.6 KB