This is my writeup of a basic description of /dev/fuse after
playing with it for a few hours today. It is of course woefully
incomplete, and since I neither have a use case nor am working
on this code, I will not be in a position to expand it in the
near future. However, I'm hoping this could still serve as a
handy reference for others looking at this interface.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
The FDs returned by NS_GET_USERNS and NS_GET_PAREENT must be
tested by comparing to both the 'st_dev' and 'st_ino' fields
returned by fstat(2).
Reported-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
This section material in the user_namespaces(7) page was written
before the creation of the mount_namespaces(7) manual page.
Nowadays, this material properly belongs in the newer page.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Add note regarding the size of the output user space buffer
for PR_GET_TID_ADDRESS operation on x32/n32.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
The changes in commit 2ae4c26dec were a mistake.
The System V behavior was always the default for setjmp(3).
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
[mtk] I did a little code spelunking and found the following:
1. In glibc 1.09 (tagged 1995-03-02 in the git history),
__USE_REENTRANT, _THREAD_SAFE, and _REENTRANT do not appear.
2. In glibc-1.93 (tagged 1996-08-29 in the git history),
__USE_REENTRANT governs the exposure of some "_r()"
functions from about a dozen header files. However, it is
defined in <features.h> via
#if defined (__USE_GNU) || defined (__USE_MISC)
#define __USE_REENTRANT 1
#endif
_REENTRANT and _THREAD_SAFE solely govern declarations in
<stdio.h>, where they expose declarations of a few "unlocked"
stdio functions and use #define to redirect a few stdio
function names to "locked" versions.
3. THREAD_SAFE and _REENTRANT first appear in the git logs
1996-05-09.
4. About 9 months later, glibc 2.0.1 arrives on 1997-02-04
(timestamp and tarball taken from
https://ftp.gnu.org/gnu/libc/, since there is no tag in the
git history; casual inspection of the logs suggests the
glibc 2.0 release was about a week earlier.
By now we have the following in <features.h>:
#if defined _REENTRANT || defined _THREAD_SAFE
#define __USE_REENTRANT 1
#endif
And _THREAD_SAFE, and _REENTRANT do not appear appear in
other headers. However, by now, __USE_REENTRANT governs only
the declarations of tmpnam_r() and getlogin_r()
In other words, the window of time where _REENTRANT and
_THREAD_SAFE did anything much in glibc was quite short, IIUC.
Cowritten-by: Zack Weinberg <zackw@panix.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Give the reader a clue that there is another policy()
available that can't be set via sched_setscheduler(2).
See https://bugzilla.redhat.com/show_bug.cgi?id=1390546
Reported-by: Daniel Berrange <berrange@redhat.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
The discussion of 'socklen_t' editorializes and is repeated
across several pages. Replace it with a reference to accept(2),
where some details about this type are provided.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Keno Fischer