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Document file descriptor reopening and current standardization status.

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This commit is contained in:
Garrett Wollman 2002-08-07 18:03:30 +00:00
parent 33559722db
commit 4879739808
1 changed files with 19 additions and 0 deletions
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19
lib/libc/sys/execve.2
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@ -120,6 +120,14 @@ and
.Xr fcntl 2 ) .
Descriptors that remain open are unaffected by
.Fn execve .
If any of the standard descriptors (0, 1, and/or 2) are closed at the
time
.Fn execve
is called, and the process will gain privilege as a result of set-id
semantics, those descriptors will be re-opened automatically.
No programs, whether privileged or not, should assume that these descriptors
will remain closed across a call to
.Fn execve .
.Pp
Signals set to be ignored in the calling process are set to be ignored in
the
@ -278,6 +286,17 @@ of a super-user as well.
.Xr elf 5 ,
.Xr environ 7 ,
.Xr mount 8
.Sh STANDARDS
The
.Fn execve
function conforms to
.St -p1003.1-2001 ,
with the exception of reopening descriptors 0, 1, and/or 2 in certain
circumstances.
A future update of the Standard is expected to require this behavior,
and it may become the default for non-privileged processes as well.
.\" NB: update this caveat when TC1 is blessed.
The support for executing interpreted programs is an extension.
.Sh HISTORY
The
.Fn execve