Add checks to the conversion of Unix file descriptors to I/O channels #1825
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Have these functions fail if the given file descriptor is not suitable for character-oriented I/O, e.g. a block device or a datagram socket. Part of MPR#7238. This is WIP. Needs porting to Windows and testing.
Added Win32 implementation. Changed Unix implementation to report EINVAL in case of non-stream semantics.
| struct stat buf; | ||
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| if (fstat(fd, &buf) == -1) return errno; | ||
| switch (buf.st_mode & S_IFMT) { |
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I think this is sufficient, but someone who can read POSIXese will have to say if one of these is set when the various S_TYPE macros for memory queues and semaphores and the like are true. It may be that one has to check for that separately?
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Actually, thinking about this, if none of those bits are set, the default: case will trigger anyway.
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As far as I know, memory queues and semaphores cannot be opened as file descriptors, e.g. sem_open returns a sem_t *, and is not made available by the OCaml Unix library.
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So my comment was inapplicable two distinct ways.
otherlibs/win32unix/channels.c
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| return 0; | ||
| default: { | ||
| DWORD err = GetLastError(); | ||
| return err == 0 ? ERROR_INVALID_ACCESS : err; |
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I would write NO_ERROR here, which is slightly clearer than 0
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Nice suggestion, implemented in 0724940
Use `NO_ERROR` instead of `0` to mean "no error occurs".
Added Changes entry.
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This GPR adds checks to the
Unix.{in,out}_channel_of_descrfunctions so that they fail if the given file descriptor is not suitable for character-oriented I/O, e.g. a block device or a datagram socket.Without such checks, the I/O channel is created, but will most likely fail in mysterious ways when flushed or refilled.
This addresses part of MPR#7238