Hello. I was reading open(2) and I have noticed an interesting statement: "The argument flags must include one of the following access modes: O_RDONLY, O_WRONLY, or O_RDWR." Must one of these flags be specified when O_PATH is in use?
O_PATH description says that "Opening a file or directory with the O_PATH flag requires no permissions on the object itself (but does require execute permission on the directories in the path prefix)." I think that this can be a little bit ambiguous. When I first read it, I have thought that this sentence talks about filesystem permissions required on the file, not the access modes.
O_PATH description states that: "When O_PATH is specified in flags, flag bits other than O_CLOEXEC, O_DIRECTORY, and O_NOFOLLOW are ignored." One could think that you must specify an access mode, but it will be ignored.
The O_PATH description actually mentions the O_RDONLY flag, but it compares the difference of opening a file with O_PATH and opening it with (only) O_RDONLY, it doesn't mention the need of O_RDONLY flag when opening a file with O_PATH.
The only part of the manpage that clearly states that using access modes with O_PATH is not mandatory is the code sample included in the O_PATH description, which calls open("some_prog", O_PATH); (but this code sample covers another aspect of O_PATH).
Maybe I'm just dumb and I misread some of the text, but I think this can be ambiguous. I would have sent a patch fixing this, but I'm not a native English speaker and I don't actually know how open() works, so I don't want to make a mistake when modifying its manpage.
Thanks in advance,
Meator
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