215 lines
7.0 KiB
Diff
215 lines
7.0 KiB
Diff
commit 9ed517b63df35876681e8883388fbf154afda0c1
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Author: Kyle McMartin <kmcmarti@redhat.com>
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Date: Tue Apr 8 10:33:57 2014 +1000
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xfsdump: getdents.c: clean up ifdef-hell around sys_getdents
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Remove the ifdef-hell imported from glibc around getdents64. Everything
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since 2.4.1 supports things properly and this seems like a sensible
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clean up, so lets just assume it exists and handle it by falling back
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if not.
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Additionally, if the old getdents syscall doesn't exist, just stub out
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the actual syscall and return ENOSYS.
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Signed-off-by: Kyle McMartin <kmcmarti@redhat.com>
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Reviewed-by: Christoph Hellwig <hch@lst.de>
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Signed-off-by: Dave Chinner <david@fromorbit.com>
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diff --git a/common/getdents.c b/common/getdents.c
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index e9ba25a..49d0d03 100644
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--- a/common/getdents.c
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+++ b/common/getdents.c
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@@ -35,44 +35,6 @@
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#include <linux/posix_types.h>
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-/* Copied from kernel-features.h for __ASSUME_GETDENTS64_SYSCALL */
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-#ifndef __LINUX_KERNEL_VERSION
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-/* We assume the worst; all kernels should be supported. */
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-# define __LINUX_KERNEL_VERSION 0
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-#endif
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-/* The getdents64 syscall was introduced in 2.4.0-test7. We test for
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- 2.4.1 for the earliest version we know the syscall is available. */
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-#if __LINUX_KERNEL_VERSION >= 132097
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-# define __ASSUME_GETDENTS64_SYSCALL 1
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-#endif
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-/* There are an infinite number of PA-RISC kernel versions numbered
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- 2.4.0. But they've not really been released as such. We require
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- and expect the final version here. */
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-#ifdef __hppa__
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-# define __ASSUME_GETDENTS64_SYSCALL 1
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-#endif
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-
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-#ifndef __set_errno
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-#define __set_errno(e) (errno = (e))
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-#endif
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-
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-
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-#ifdef __NR_getdents64
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-# ifndef __ASSUME_GETDENTS64_SYSCALL
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-# ifndef __GETDENTS
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-/* The variable is shared between all *getdents* calls. */
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-int __have_no_getdents64;
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-# else
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-extern int __have_no_getdents64;
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-# endif
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-# endif
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-/* Earlier versions of glibc don't define SYS_getdents64 at all */
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-# ifndef SYS_getdents64
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-# define SYS_getdents64 __NR_getdents64
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-# endif
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-#endif
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-
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-
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/* For Linux we need a special version of this file since the
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definition of `struct dirent' is not the same for the kernel and
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the libc. There is one additional field which might be introduced
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@@ -97,11 +59,22 @@ struct kernel_dirent64
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char d_name[256];
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};
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-#ifndef DIRENT_TYPE
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-# define DIRENT_TYPE struct dirent
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+#define DIRENT_SET_DP_INO(dp, value) (dp)->d_ino = (value)
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+
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+#define __set_errno(e) (errno = (e))
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+
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+int __have_no_getdents64;
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+
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+#ifdef __NR_getdents64
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+# define __SYS_GETDENTS64(fd, buf, len) (syscall(SYS_getdents64, fd, buf, len))
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+#else
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+# define __SYS_GETDENTS64(fd, buf, len) ({ __set_errno(ENOSYS); -1; })
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#endif
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-#ifndef DIRENT_SET_DP_INO
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-# define DIRENT_SET_DP_INO(dp, value) (dp)->d_ino = (value)
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+
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+#ifdef __NR_getdents
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+# define __SYS_GETDENTS(fd, buf, len) (syscall(SYS_getdents, fd, buf, len))
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+#else
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+# define __SYS_GETDENTS(fd, buf, len) ({ __set_errno(ENOSYS); -1; })
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#endif
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/* The problem here is that we cannot simply read the next NBYTES
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@@ -115,50 +88,43 @@ struct kernel_dirent64
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int
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getdents_wrap (int fd, char *buf, size_t nbytes)
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{
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- DIRENT_TYPE *dp;
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+ struct dirent *dp;
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off64_t last_offset = -1;
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ssize_t retval;
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-#ifdef __NR_getdents64
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-# ifndef __ASSUME_GETDENTS64_SYSCALL
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if (!__have_no_getdents64)
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-# endif
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{
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-# ifndef __ASSUME_GETDENTS64_SYSCALL
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int saved_errno = errno;
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-# endif
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char *kbuf = buf;
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size_t kbytes = nbytes;
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- if (offsetof (DIRENT_TYPE, d_name)
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+ if (offsetof (struct dirent, d_name)
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< offsetof (struct kernel_dirent64, d_name)
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- && nbytes <= sizeof (DIRENT_TYPE))
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+ && nbytes <= sizeof (struct dirent))
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{
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kbytes = nbytes + offsetof (struct kernel_dirent64, d_name)
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- - offsetof (DIRENT_TYPE, d_name);
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+ - offsetof (struct dirent, d_name);
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kbuf = alloca(kbytes);
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}
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- retval = syscall(SYS_getdents64, fd, kbuf, kbytes);
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-# ifndef __ASSUME_GETDENTS64_SYSCALL
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- if (retval != -1 && errno != -EINVAL)
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-# endif
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+ retval = __SYS_GETDENTS64(fd, kbuf, kbytes);
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+ if (retval != -1)
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{
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struct kernel_dirent64 *kdp;
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const size_t size_diff = (offsetof (struct kernel_dirent64, d_name)
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- - offsetof (DIRENT_TYPE, d_name));
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+ - offsetof (struct dirent, d_name));
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/* If the structure returned by the kernel is identical to what we
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need, don't do any conversions. */
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- if (offsetof (DIRENT_TYPE, d_name)
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+ if (offsetof (struct dirent, d_name)
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== offsetof (struct kernel_dirent64, d_name)
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&& sizeof (dp->d_ino) == sizeof (kdp->d_ino)
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&& sizeof (dp->d_off) == sizeof (kdp->d_off))
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return retval;
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- dp = (DIRENT_TYPE *)buf;
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+ dp = (struct dirent *)buf;
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kdp = (struct kernel_dirent64 *) kbuf;
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while ((char *) kdp < kbuf + retval)
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{
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- const size_t alignment = __alignof__ (DIRENT_TYPE);
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+ const size_t alignment = __alignof__ (struct dirent);
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/* Since kdp->d_reclen is already aligned for the kernel
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structure this may compute a value that is bigger
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than necessary. */
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@@ -194,41 +160,39 @@ getdents_wrap (int fd, char *buf, size_t nbytes)
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memmove (dp->d_name, kdp->d_name,
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old_reclen - offsetof (struct kernel_dirent64, d_name));
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- dp = (DIRENT_TYPE *) ((char *) dp + new_reclen);
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+ dp = (struct dirent *) ((char *) dp + new_reclen);
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kdp = (struct kernel_dirent64 *) ((char *) kdp + old_reclen);
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}
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return (char *) dp - buf;
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}
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-# ifndef __ASSUME_GETDENTS64_SYSCALL
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__set_errno (saved_errno);
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__have_no_getdents64 = 1;
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-# endif
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}
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-#endif
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+
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+ /* fallback to getdents */
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{
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size_t red_nbytes;
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struct kernel_dirent *skdp, *kdp;
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- const size_t size_diff = (offsetof (DIRENT_TYPE, d_name)
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+ const size_t size_diff = (offsetof (struct dirent, d_name)
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- offsetof (struct kernel_dirent, d_name));
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red_nbytes = MIN (nbytes
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- - ((nbytes / (offsetof (DIRENT_TYPE, d_name) + 14))
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+ - ((nbytes / (offsetof (struct dirent, d_name) + 14))
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* size_diff),
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nbytes - size_diff);
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- dp = (DIRENT_TYPE *) buf;
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+ dp = (struct dirent *) buf;
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skdp = kdp = alloca (red_nbytes);
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- retval = syscall(SYS_getdents, fd, kdp, red_nbytes);
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-
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+ retval = __SYS_GETDENTS(fd, kdp, red_nbytes);
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if (retval == -1)
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return -1;
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while ((char *) kdp < (char *) skdp + retval)
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{
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- const size_t alignment = __alignof__ (DIRENT_TYPE);
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+ const size_t alignment = __alignof__ (struct dirent);
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/* Since kdp->d_reclen is already aligned for the kernel structure
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this may compute a value that is bigger than necessary. */
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size_t new_reclen = ((kdp->d_reclen + size_diff + alignment - 1)
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@@ -259,7 +223,7 @@ getdents_wrap (int fd, char *buf, size_t nbytes)
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memcpy (dp->d_name, kdp->d_name,
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kdp->d_reclen - offsetof (struct kernel_dirent, d_name));
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- dp = (DIRENT_TYPE *) ((char *) dp + new_reclen);
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+ dp = (struct dirent *) ((char *) dp + new_reclen);
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kdp = (struct kernel_dirent *) (((char *) kdp) + kdp->d_reclen);
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}
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}
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