On 2012-4-21 0:27, Corinna Vinschen wrote:
On Apr 21 00:17, De-Jian Zhao wrote:
On 2012-4-20 21:07, Václav Zeman wrote:
On 20 April 2012 15:02, De-Jian Zhao wrote:
Hi,
When I type "cyg" and Tab, many executables starting with "cyg" are listed
(Display all 262 possibilities? (y or n) y). I find that many of them are
*.dll libraries under /usr/bin/. This is inconvenient to find the real
executable applications (*.exe). Since *.dll files are only libraries, they
are not necessary to have the attribute of "x". Thus, I run the command
"chmod a-x /usr/bin/*.dll". Unexpectedly, cygwin is corrupted. I closed the
terminal and failed to restart Cygwin. I started my older version of Cygwin
(I did not deleted it after installing a new version), and added "x" to the
previous *.dll files. The dead Cygwin revived.
I am confused why /usr/bin/*.dll should be executable. I thought they were
only library files. When I tried to run a dll file, bash says "cannot
execute binary file". Are there some hidden stories?
DLLs are executables thus they need the +x bit. This is a Windows thing.
If this is a windows thing, removing the x bit should not affect
Cygwin. Instead, Cygwin is corrupted after removing the x bit.
Windows requires the x bit for DLLs to be loadable as executable code
into the address space of a process. As Václav wrote, it's a Windows
thing.
Can Windows see the rwx bits assigned by Cygwin to the files? I tried
removing the x bit of an executable file blastall.exe (chmod a-x
blastall.exe); the file can not be executed under Cygwin, but still can
be executed under cmd console of Windows. It seems that Windows does not
honor the rwx bits assigned by Cygwin.
Is there a detailed description of the starting process of Cygwin
system? Or, how does Cygwin interact with *.dll files?
After starting Cygwin, I ran "chmod a-x /usr/bin/cygperl5_10.dll" and
perl could not be started any more. This could be cured by ran "chmod
a+x /usr/bin/cygperl5_10.dll". It seems to me that the Cygwin binary
executables will communicate with their corresponding *.dll files when
executed. The *.dll provide the required functions and subroutines and
that's enough. There is no need to mark *.dll with an x bit.
I have no strong background of computer science. Maybe there is some
basic knowledge beyond my imagination. Hope you can help disclose it to
me. Thanks.
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