diff options
| author | cinap_lenrek <cinap_lenrek@felloff.net> | 2020-12-13 16:04:09 +0100 |
|---|---|---|
| committer | cinap_lenrek <cinap_lenrek@felloff.net> | 2020-12-13 16:04:09 +0100 |
| commit | 0b33b3b8adf95bcf6cf0764fe425169ee0b8be0e (patch) | |
| tree | 08aba9ebf384974079de17fffd1c1e3139cfaf38 /sys/man/2 | |
| parent | b2b2d2cb4c5cb3153760084a55584817a2c58a24 (diff) | |
kernel: implement per file descriptor OCEXEC flag, reject ORCLOSE when opening /fd, /srv and /shr
The OCEXEC flag used to be maintained per channel,
making it shared between all the file desciptors.
This has a unexpected side effects with regard to
channel passing drivers such as devdup (/fd),
devsrv (/srv) and devshr (/shr).
For example, opening a /srv file with OCEXEC
makes it impossible to be remounted by exportfs
as it internally does a exec() to mount and
re-export it. There is no way to reset the flag.
This change makes the OCEXEC flag per file descriptor,
so a open with the OCEXEC flag only affects the fd
group of the calling process, and not the channel
itself.
On rfork(RFFDG), the per file descriptor flags get
copied.
On dup(), the per file descriptor flags are reset.
The second modification is that /fd, /srv and /shr
should reject the ORCLOSE flag, as the files that
are returned have already been opend.
Diffstat (limited to 'sys/man/2')
| -rw-r--r-- | sys/man/2/dup | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/sys/man/2/dup b/sys/man/2/dup index cd3414106..1eca0a713 100644 --- a/sys/man/2/dup +++ b/sys/man/2/dup @@ -32,6 +32,19 @@ requires that .I newfd be no greater than 20 more than the highest file descriptor ever used by the program. +.PP +.I Dup +does not copy the per file descriptor +.B OCEXEC +flag, +meaning that +.I newfd +will not be closed on +.IR exec(2) +syscall, +when +.I oldfd +had been previously opend with it. .SH SOURCE .B /sys/src/libc/9syscall .SH SEE ALSO |