[jdk17u-dev] RFR: 8312065: Socket.connect does not timeout when profiling [v4]

[Paul Hohensee]

On Wed, 6 Sep 2023 02:52:13 GMT, Long Yang <duke at openjdk.org> wrote:

>> Hi all,
>> 
>> This pull request contains a fix for [JDK-8312065](https://bugs.openjdk.org/browse/JDK-8312065).
>> 
>> The old SocketImpl is still present in JDK 17, can be enabled with -Djdk.net.usePlainSocketImpl.
>> 
>> I have verified that this problem exists on Linux and macOS, and I feel that it also exists on AIX, 
>> so I repaired these 3 platforms. Windows implementations are different, so don't have this problem.
>> 
>> All callers of NET_Poll() already check for EINTR, so the fix is to remove do-while loop in the implementation of NET_Poll().
>> 
>> Other methods, such as NET_Read, NET_NonBlockingRead, NET_Accept, NET_Connect, are not affected.
>> Because if Socket has timeout, it will call NET_Timeout first, and then call them. NET_Timeout has a correct timeout implementation and is not affected by profiling signals.
>> If the Socket does not have a timeout, and if the system call is interrupted by a signal, the [Linux Kernel will automatically retry](https://man7.org/linux/man-pages/man7/signal.7.html), and the application code will not be aware of it.
>> 
>> Thanks!
>
> Long Yang has updated the pull request incrementally with one additional commit since the last revision:
> 
>   push to trigger github workflows

Code duplication is the source of many bugs, so instead of duplicating the macro code inline, add a RETRY macro argument, vis,

#define BLOCKING_IO_RETURN_INT(FD, FUNC, RETRY) {     \
    int ret;                                          \
    threadEntry_t self;                               \
    fdEntry_t *fdEntry = getFdEntry(FD);              \
    if (fdEntry == NULL) {                            \
        errno = EBADF;                                \
        return -1;                                    \
    }                                                 \
    do {                                              \
        startOp(fdEntry, &self);                      \
        ret = FUNC;                                   \
        endOp(fdEntry, &self);                        \
    } while ((RETRY) && ret == -1 && errno == EINTR); \
    return ret;                                       \
}

Then, add "true" as the last argument to all invocations of the macro, except the one in NET_Poll, which becomes

int NET_Poll(struct pollfd *ufds, unsigned int nfds, int timeout) {
    BLOCKING_IO_RETURN_INT( ufds[0].fd, poll(ufds, nfds, timeout), false );
}

-------------

Changes requested by phh (Reviewer).

PR Review: https://git.openjdk.org/jdk17u-dev/pull/1639#pullrequestreview-1616030523