diff options
| -rw-r--r-- | lib/stdopen.c | 52 |
1 files changed, 22 insertions, 30 deletions
diff --git a/lib/stdopen.c b/lib/stdopen.c index 00914307d..c9d674fb6 100644 --- a/lib/stdopen.c +++ b/lib/stdopen.c @@ -30,18 +30,6 @@ #include <unistd.h> #include <errno.h> -#ifndef STDIN_FILENO -# define STDIN_FILENO 0 -#endif - -#ifndef STDOUT_FILENO -# define STDOUT_FILENO 1 -#endif - -#ifndef STDERR_FILENO -# define STDERR_FILENO 2 -#endif - /* Try to ensure that each of the standard file numbers (0, 1, 2) is in use. Without this, each application would have to guard every call to open, dup, fopen, etc. with tests to ensure they @@ -51,25 +39,29 @@ bool stdopen (void) { - int fd = dup (STDIN_FILENO); - - if (0 <= fd) - close (fd); - else if (errno == EBADF) - fd = open ("/dev/null", O_WRONLY); - else - return false; + int fd; + bool ok = true; - if (STDIN_FILENO <= fd && fd <= STDERR_FILENO) + for (fd = 0; fd <= 2; fd++) { - fd = open ("/dev/null", O_RDONLY); - if (fd == STDOUT_FILENO) - fd = dup (fd); - if (fd < 0) - return false; - - if (STDERR_FILENO < fd) - close (fd); + if (fcntl (fd, F_GETFD) < 0) + { + if (errno != EBADF) + ok = false; + else + { + static const int contrary_mode[] + = { O_WRONLY, O_RDONLY, O_RDONLY }; + int new_fd = open ("/dev/null", contrary_mode[fd]); + if (new_fd != fd) + { + if (0 <= new_fd) + close (new_fd); + ok = false; + } + } + } } - return true; + + return ok; } |