#2969: unix package built wrong on Solaris
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Reporter: duncan | Owner:
Type: bug | Status: new
Priority: normal | Component: Compiler
Version: 6.8.3 | Severity: normal
Keywords: | Testcase:
Os: Solaris | Architecture: sparc
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On Solaris with recent gcc versions the unix package gets built with an
inconsistent state of system header files which results in
`getSymbolicLinkStatus` not working. In turn this breaks darcs.
The problem is that the `HsUnix.h` file contains a bunch of inline
functions. These get inlined into the `.hc` file for the `Files.hs` module
that FFI imports them. The problem is that this `.hc` file `#include`s an
RTS header files which uses some `#define` to get certain API spec
compatibility and for some reason this causes the `lstat()` call to be
directed to the 32bit file ABI whereas the `.hsc` file was compiled for
the 64bit (large file support) ABI. The outcome is that the `.o` file for
the `System.Posix.Files` module is actually calling the `lstat()` function
when it expects to be calling the `lstat64()` function. As a result we get
back the wrong `struct stat` and so of course all the functions like
`isDirectory` etc are then looking at the wrong offsets in the `struct
stat`.
The functions that are being FFI imported are compiled into the
`cbits/HsUnix.c` file anyway (because it `#import`s `HsUnix.h` with a
`#define` to turn off the inlining) so there is no need for them to be
inlined into the `.hc` file. The `cbits/HsUnix.c` gets built correctly
(because it does not `#include` the RTS headers that cause the problem)
and so does call `lstat64` rather than `lstat()`. This can be verified
with `nm`.
So the solution is to remove all the inline calls from `HsUnix.h`,
changing them to simple prototypes, and to put the function bodies in
`HsUnix.c`. This solution works fine. Tested on Solaris 10, ghc-6.8.3. The
files appear to be unchanged in ghc 6.10 and HEAD so the same solution
should work there.
We should add a test case for this. It should test the
`getSymbolicLinkStatus` function with a few things that obviously should
work, like `isDirectory` etc. We might as well test `getFileStatus` too.
The difference is that the FFI wrapper for `getFileStatus` is defined in
the `base` package rather than the `unix` package. This is why it was
unaffected by the above problem.
Generally all the FFI wrappers defined via inlines in `.h` files that get
`#include`d into `.hc` files are rather suspect, but especially so for
wrappers of things defined in system header files. These should instead be
wrapped in very simple .c files that `#include` a minimum of headers so as
to not bump into weird untested combinations of system headers and
standards compatibility `#define`s.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2969>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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