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8375006: [Linux] Remove obsolete O_CLOEXEC check in os::open
Reviewed-by: dholmes, jsjolen
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@ -4878,31 +4878,8 @@ int os::open(const char *path, int oflag, int mode) {
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// All file descriptors that are opened in the Java process and not
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// specifically destined for a subprocess should have the close-on-exec
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// flag set. If we don't set it, then careless 3rd party native code
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// might fork and exec without closing all appropriate file descriptors,
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// and this in turn might:
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//
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// - cause end-of-file to fail to be detected on some file
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// descriptors, resulting in mysterious hangs, or
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//
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// - might cause an fopen in the subprocess to fail on a system
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// suffering from bug 1085341.
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//
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// (Yes, the default setting of the close-on-exec flag is a Unix
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// design flaw)
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//
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// See:
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// 1085341: 32-bit stdio routines should support file descriptors >255
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// 4843136: (process) pipe file descriptor from Runtime.exec not being closed
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// 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
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//
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// Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open().
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// O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor
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// because it saves a system call and removes a small window where the flag
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// is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored
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// and we fall back to using FD_CLOEXEC (see below).
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#ifdef O_CLOEXEC
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// might fork and exec without closing all appropriate file descriptors.
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oflag |= O_CLOEXEC;
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#endif
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int fd = ::open(path, oflag, mode);
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if (fd == -1) return -1;
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@ -4925,21 +4902,6 @@ int os::open(const char *path, int oflag, int mode) {
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}
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}
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#ifdef FD_CLOEXEC
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// Validate that the use of the O_CLOEXEC flag on open above worked.
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// With recent kernels, we will perform this check exactly once.
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static sig_atomic_t O_CLOEXEC_is_known_to_work = 0;
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if (!O_CLOEXEC_is_known_to_work) {
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int flags = ::fcntl(fd, F_GETFD);
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if (flags != -1) {
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if ((flags & FD_CLOEXEC) != 0)
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O_CLOEXEC_is_known_to_work = 1;
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else
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::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
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}
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}
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#endif
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return fd;
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}
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