Hurd: dup3

2025-08-07 06:43:00 +03:00 · 2012-05-10 13:15:40 -07:00
parent cd9fa98583
commit 5aa3a74a59
5 changed files with 163 additions and 117 deletions
--- a/sysdeps/mach/hurd/dup3.c
+++ b/sysdeps/mach/hurd/dup3.c
@@ -0,0 +1,141 @@
+/* Duplicate a file descriptor to a given number, with flags.  Hurd version.
+   Copyright (C) 1991-2012 Free Software Foundation, Inc.
+
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <hurd.h>
+#include <hurd/fd.h>
+
+/* Duplicate FD to FD2, closing the old FD2 and making FD2 be
+   open on the same file as FD is, and setting FD2's flags according to FLAGS.
+   Return FD2 or -1.  */
+int
+__dup3 (int fd, int fd2, int flags)
+{
+  struct hurd_fd *d;
+
+  /* Both passing flags different from O_CLOEXEC and FD2 being the same as FD
+     are invalid.  */
+  if ((flags & ~O_CLOEXEC
+       || fd2 == fd)
+      /* ... with the exception in case that dup2 behavior is requested: if FD
+	 is valid and FD2 is already the same then just return it.  */
+      && ! (flags == -1
+	    && fd2 == fd))
+    return __hurd_fail (EINVAL);
+
+  /* Extract the ports and flags from FD.  */
+  d = _hurd_fd_get (fd);
+  if (d == NULL)
+    return __hurd_fail (EBADF);
+
+  HURD_CRITICAL_BEGIN;
+
+  __spin_lock (&d->port.lock);
+  if (d->port.port == MACH_PORT_NULL)
+    {
+      __spin_unlock (&d->port.lock);
+      fd2 = __hurd_fail (EBADF);
+    }
+  else if (fd2 == fd)
+    __spin_unlock (&d->port.lock);
+  else
+    {
+      struct hurd_userlink ulink, ctty_ulink;
+      int d_flags = d->flags;
+      io_t ctty = _hurd_port_get (&d->ctty, &ctty_ulink);
+      io_t port = _hurd_port_locked_get (&d->port, &ulink); /* Unlocks D.  */
+
+      if (fd2 < 0)
+	fd2 = __hurd_fail (EBADF);
+      else
+	{
+	  /* Get a hold of the destination descriptor.  */
+	  struct hurd_fd *d2;
+
+	  if (fd2 >= _hurd_dtablesize)
+	    {
+	      /* The table is not large enough to hold the destination
+		 descriptor.  Enlarge it as necessary to allocate this
+		 descriptor.  */
+	      __mutex_unlock (&_hurd_dtable_lock);
+	      /* We still hold FD1's lock, but this is safe because
+		 _hurd_alloc_fd will only examine the cells starting
+		 at FD2.  */
+	      d2 = _hurd_alloc_fd (NULL, fd2);
+	      if (d2)
+		__spin_unlock (&d2->port.lock);
+	      __mutex_lock (&_hurd_dtable_lock);
+	    }
+	  else
+	    {
+	      d2 = _hurd_dtable[fd2];
+	      if (d2 == NULL)
+		{
+		  /* Must allocate a new one.  We don't initialize the port
+		     cells with this call so that if it fails (out of
+		     memory), we will not have already added user
+		     references for the ports, which we would then have to
+		     deallocate.  */
+		  d2 = _hurd_dtable[fd2] = _hurd_new_fd (MACH_PORT_NULL,
+							 MACH_PORT_NULL);
+		}
+	    }
+
+	  if (d2 == NULL)
+	    {
+	      fd2 = -1;
+	      if (errno == EINVAL)
+		errno = EBADF;	/* POSIX.1-1990 6.2.1.2 ll 54-55.  */
+	    }
+	  else
+	    {
+	      /* Give the ports each a user ref for the new descriptor.  */
+	      __mach_port_mod_refs (__mach_task_self (), port,
+				    MACH_PORT_RIGHT_SEND, 1);
+	      if (ctty != MACH_PORT_NULL)
+		__mach_port_mod_refs (__mach_task_self (), ctty,
+				      MACH_PORT_RIGHT_SEND, 1);
+
+	      /* Install the ports and flags in the new descriptor slot.  */
+	      __spin_lock (&d2->port.lock);
+	      if (flags & O_CLOEXEC)
+		d2->flags = d_flags | FD_CLOEXEC;
+	      else
+		/* dup clears FD_CLOEXEC.  */
+		d2->flags = d_flags & ~FD_CLOEXEC;
+	      _hurd_port_set (&d2->ctty, ctty);
+	      _hurd_port_locked_set (&d2->port, port); /* Unlocks D2.  */
+	    }
+	}
+      __mutex_unlock (&_hurd_dtable_lock);
+
+      _hurd_port_free (&d->port, &ulink, port);
+      if (ctty != MACH_PORT_NULL)
+	_hurd_port_free (&d->ctty, &ctty_ulink, port);
+    }
+
+  HURD_CRITICAL_END;
+
+  return fd2;
+}
+libc_hidden_def (__dup3)
+weak_alias (__dup3, dup3)