On Fri, Jan 09, 2015 at 04:47:31PM +0100, Michael Kerrisk (man-pages) wrote:
On 11/24/2014 12:53 PM, David Drysdale wrote:
quoted
Signed-off-by: David Drysdale <redacted>
---
man2/execveat.2 | 153 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 153 insertions(+)
create mode 100644 man2/execveat.2
David,
Thanks for the very nicely prepared man page. I've done
a few very light edits, and will release the version below
with the next man-pages release.
I have one question. In the message accompanying
commit 51f39a1f0cea1cacf8c787f652f26dfee9611874 you wrote:
The filename fed to the executed program as argv[0] (or the name of the
script fed to a script interpreter) will be of the form "/dev/fd/<fd>"
(for an empty filename) or "/dev/fd/<fd>/<filename>", effectively
reflecting how the executable was found. This does however mean that
execution of a script in a /proc-less environment won't work; also, script
execution via an O_CLOEXEC file descriptor fails (as the file will not be
accessible after exec).
How does one produce this situation where the execed program sees
argv[0] as a /dev/fd path? (i.e., what would the execveat()
call look like?) I tried to produce this scenario, but could not.
I think this is wrong. argv[0] is an arbitrary string provided by the
caller and would never be derived from the fd passed. It's AT_EXECFN,
/proc/self/exe, and filenames shown elsewhere in /proc that may be
derived in odd ways.
I would also move the text about O_CLOEXEC to a BUGS or NOTES section
rather than the main description. The long-term intent should be that
script execution this way should work. IIRC this was discussed earlier
in the thread.
Rich