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| author | Michael Kerrisk <mtk.manpages@gmail.com> | 2016-12-16 11:32:05 +0100 |
|---|---|---|
| committer | Michael Kerrisk <mtk.manpages@gmail.com> | 2016-12-17 10:33:55 +0100 |
| commit | dc4eea68b5652e54a979d346a961971a9957f41b (patch) | |
| tree | 16ec72f6b8a8e08b117f8e679ac01244639f7ca6 | |
| parent | 7df57849a5225fdbb6f883e0181372e856939808 (diff) | |
| download | man-pages-dc4eea68b5652e54a979d346a961971a9957f41b.tar.gz | |
unix.7: Document ETOOMANYREFS for SCM_RIGHTS send exceeding RLIMIT_NOFILE limit
Reviewed-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
| -rw-r--r-- | man7/unix.7 | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/man7/unix.7 b/man7/unix.7 index 05681f0319..3f41ad4ccd 100644 --- a/man7/unix.7 +++ b/man7/unix.7 @@ -534,6 +534,33 @@ versus .TP .B ESOCKTNOSUPPORT Unknown socket type. +.TP +.B ETOOMANYREFS +This error can occur for +.BR sendmsg (2) +when sending a file descriptor as ancilary data over +a UNIX domain socket (see the description of +.BR SCM_RIGHTS , +above). +It occurs if the number of "in-flight" file descriptors exceeds the +.B RLIMIT_NOFILE +resource limit and the caller does not have the +.BR CAP_SYS_RESOURCE +capability. +An in-flight file descriptor is one that has been sent using +.BR sendmsg (2) +but has not yet been accepted in the recipient process using +.BR recvmsg (2). + +This error is diagnosed since Linux 4.5. +.\" commit 712f4aad406bb1ed67f3f98d04c044191f0ff593 +In earlier kernel versions, +it was possible to place an unlimited number of file descriptors in flight, +by sending each file descriptor with +.BR sendmsg (2) +and then closing the file descriptor so that it was not accounted against the +.B RLIMIT_NOFILE +resource limit. .PP Other errors can be generated by the generic socket layer or by the filesystem while generating a filesystem socket object. |