View of xos/usr/lib/libc/fcntl.c

/* Copyright (C) 2008  Emmanuel Varoquaux
 
   This file is part of XOS.
 
   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
 
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
 
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>. */
 
#include "fcntl.h"
 
#include "xos.h"
 
#include <stdarg.h>
#include <errno.h>
 
int __attribute__ ((weak, visibility ("default"))) fcntl(int fd, int cmd, ...)
{
  va_list ap;
  long arg;
 
  va_start(ap, cmd);
  arg = va_arg(ap, long);
  va_end(ap);
  return __syscall_fcntl(fd, cmd, arg);
}
typeof (fcntl) __fcntl __attribute__ ((alias ("fcntl")));
 
int __attribute__ ((weak, visibility ("default"))) open(const char *path, int oflag, ...)
{
  int flags;
  int fd;
  struct _xos_stat_struct statbuf;
  int errnum;
 
  flags = 0;
  switch (oflag & O_ACCMODE) {
  case O_RDONLY:
    flags |= _XOS_O_READ;
    break;
  case O_RDWR:
    flags |= _XOS_O_READ | _XOS_O_WRITE;
    break;
  case O_WRONLY:
    flags |= _XOS_O_WRITE;
    break;
  }
  if ((fd = __syscall_open(path, flags)) != -1) {
    if (oflag & O_CREAT && oflag & O_EXCL) {
      errnum = EEXIST;
      goto error_close;
    }
  }
  else {
    if (oflag & O_CREAT && errno == ENOENT) {
      if (__syscall_create(path) == -1)
        return -1;
      if ((fd = __syscall_open(path, flags)) == -1)
        return -1;
    }
    else
      return -1;
  }
  if ((oflag & O_ACCMODE) == O_RDWR || (oflag & O_ACCMODE) == O_WRONLY) {
    if (__syscall_stat(fd, &statbuf) == -1) {
      errnum = errno;
      goto error_close;
    }
    if (statbuf.type == _XOS_FT_DIR) {
      errnum = EISDIR;
      goto error_close;
    }
    if (oflag & O_TRUNC) {
      if (__syscall_stat(fd, &statbuf) == -1) {
        errnum = errno;
        goto error_close;
      }
      if (statbuf.type == _XOS_FT_REG) {
        if (__syscall_close(fd) == -1)
          return -1;
        if (__syscall_remove(path) == -1)
          return -1;
        if (__syscall_create(path) == -1)
          return -1;
        if ((fd = __syscall_open(path, flags)) == -1)
          return -1;
      }
    }
  }
  return fd;
 
 error_close:
  __syscall_close(fd);
  errno = errnum;
  return -1;
}
typeof (open) __open __attribute__ ((alias ("open")));
 
int __attribute__ ((weak, visibility ("default"))) creat(const char *path, mode_t mode)
{
  return __open(path, O_WRONLY | O_CREAT | O_TRUNC, mode);
}
typeof (creat) __creat __attribute__ ((alias ("creat")));