diff options
author | jilles <jilles@FreeBSD.org> | 2016-09-07 21:09:44 +0000 |
---|---|---|
committer | jilles <jilles@FreeBSD.org> | 2016-09-07 21:09:44 +0000 |
commit | 595191c4ea58a782473f4396aa34b53867c70aac (patch) | |
tree | a177024a6425568d8e034aa1210e530c25be0b05 /lib | |
parent | 87621d8c31cedd07df80d71e85939e7ef4d3cd52 (diff) | |
download | FreeBSD-src-595191c4ea58a782473f4396aa34b53867c70aac.zip FreeBSD-src-595191c4ea58a782473f4396aa34b53867c70aac.tar.gz |
MFC r305154: directory(3): Deprecate readdir_r(). Clarify dirent buffers.
In existing implementations including FreeBSD, there is no reason to use
readdir_r() in the common case where potentially multiple threads each list
their own directory. Code using readdir() is simpler.
What's more, although readdir_r() can safely be used on FreeBSD because
NAME_MAX is forced to 255, it cannot be used safely on systems where
{NAME_MAX} is not fixed. As a concrete example, FAT/NTFS filenames can be up
to 255 UTF-16 code units long, which can be up to 765 UTF-8 bytes.
Deprecating readdir_r() in POSIX has been proposed in
http://www.austingroupbugs.net/view.php?id=696
and glibc wants to deprecate it as well.
Diffstat (limited to 'lib')
-rw-r--r-- | lib/libc/gen/directory.3 | 26 |
1 files changed, 24 insertions, 2 deletions
diff --git a/lib/libc/gen/directory.3 b/lib/libc/gen/directory.3 index f0d0f4b..b732863 100644 --- a/lib/libc/gen/directory.3 +++ b/lib/libc/gen/directory.3 @@ -28,7 +28,7 @@ .\" @(#)directory.3 8.1 (Berkeley) 6/4/93 .\" $FreeBSD$ .\" -.Dd May 6, 2015 +.Dd August 31, 2016 .Dt DIRECTORY 3 .Os .Sh NAME @@ -69,6 +69,15 @@ .Ft int .Fn dirfd "DIR *dirp" .Sh DESCRIPTION +.Bf -symbolic +The +.Fn readdir_r +interface is deprecated +because it cannot be used correctly unless +.Brq Va NAME_MAX +is a fixed value. +.Ef +.Pp The .Fn opendir function @@ -123,7 +132,13 @@ The .Fn readdir function returns a pointer to the next directory entry. -It returns +The directory entry remains valid until the next call to +.Fn readdir +or +.Fn closedir +on the same +.Em directory stream . +The function returns .Dv NULL upon reaching the end of the directory or on error. In the event of an error, @@ -140,6 +155,13 @@ provides the same functionality as but the caller must provide a directory .Fa entry buffer to store the results in. +The buffer must be large enough for a +.Vt struct dirent +with a +.Va d_name +array with +.Brq Va NAME_MAX ++ 1 elements. If the read succeeds, .Fa result is pointed at the |