On 29 August 2012 14:35, Cedric Blancher <cedric.blanc...@googlemail.com> wrote:
> On 29 August 2012 10:01, Roland Mainz <roland.ma...@nrubsig.org> wrote:
>> [Forwarding email since somehow the ast-developers@ list has issues
>> with postings from Olga's address... ;-( ]
>> ---------- Forwarded message ----------
>> From: ольга крыжановская <olga.kryzhanov...@gmail.com>
>> Date: Wed, Aug 29, 2012 at 7:36 AM
>> Subject: Fwd: Per thread open(), stat(), rename() and so on, and *at() API
>> To: Roland Mainz <roland.ma...@nrubsig.org>
>>
>>
>> Wenn du wach bist schick es bitte nochmal an
>> ast-developers@research.att.com. Meine mail ist im spam-filter
>> hangengeblieben.
>> ---------- Forwarded message ----------
>> From: ольга крыжановская <olga.kryzhanov...@gmail.com>
>> Date: Wed, Aug 29, 2012 at 6:54 AM
>> Subject: Per thread open(), stat(), rename() and so on, and *at() API
>> To: Glenn Fowler <g...@research.att.com>, David Korn
>> <d...@research.att.com>, Phong Vo <k...@research.att.com>
>> Cc: ast-developers@research.att.com
>>
>>
>> Glenn, I have an alternative for your per thread open(), stat(),
>> rename() and so on API plans:
>>
>> Instead of creating AST wrapper code for open(), stat(), rename() and
>> so we could use the following macros, defined in <ast/fcntl.h>:
>>
>> ------------------cutme------------------------
>> #define unlink(path)
>> unlinkat(AST_GET_CURRENT_THREAD_CWD_FD(), (path), 0)
>> #define rmdir(path)
>> unlinkat(AST_GET_CURRENT_THREAD_CWD_FD(),
>> (path), AT_REMOVEDIR)
>> #define chown(path, uid,
>> gid) fchownat(AST_GET_CURRENT_THREAD_CWD_FD(), (path), (uid),
>> (gid),
>> 0)
>> #define lchown(path, uid, gid)
>> fchownat(AST_GET_CURRENT_THREAD_CWD_FD(), (path), (uid), (gid),
>> AT_SYMLINK_NOFOLLOW)
>> #define stat(path, sb)
>> fstatat(AST_GET_CURRENT_THREAD_CWD_FD(),
>> (path), (sb), 0)
>> #define lstat(path, sb)
>> fstatat(AST_GET_CURRENT_THREAD_CWD_FD(),
>> (path), (sb), AT_SYMLINK_NOFOLLOW)
>> #define rename(oldname,
>> newname) renameat(AST_GET_CURRENT_THREAD_CWD_FD(), (oldname),
>> AST_GET_CURRENT_THREAD_CWD_FD(), (newname))
>> #define access(path,
>> amode) faccessat(AST_GET_CURRENT_THREAD_CWD_FD(), (path), (amode),
>> 0)
>> #define eaccess(path,
>> amode) faccessat(AST_GET_CURRENT_THREAD_CWD_FD(), (path), (amode),
>> AT_EACCESS)
>> #define mkdir(path, amode)
>> mkdirat(AST_GET_CURRENT_THREAD_CWD_FD(),
>> (path), (amode))
>> #define mkfifo(path, amode)
>> mkfifoat(AST_GET_CURRENT_THREAD_CWD_FD(),
>> (path), (amode))
>> #define mknod(path, amode,
>> adev) mknodat(AST_GET_CURRENT_THREAD_CWD_FD(), (path), (amode),
>> (adev))
>> #define readlink(path, buf,
>> bufsize) readlinkat(AST_GET_CURRENT_THREAD_CWD_FD(), (path), (buf),
>> (bufsize))
>> #define symlink(oldpath, newpath) symlinkat((oldpath),
>> AST_GET_CURRENT_THREAD_CWD_FD(), (newpath))
>> ------------------cutme------------------------
>>
>> AST_GET_CURRENT_THREAD_CWD_FD() would be defined to be a preprocessor
>> macro, which will be a function returning the current thread's cwd fd;
>> if there is none allocated for this thread yet it will be done by
>> within that function, using open(".", O_search).
>>
>> However, consumers of the <ast/fcntl.h> header are _free_ to redefine
>> this macro, for example src/cmd/ksh93/include/defs.h could define
>> AST_GET_CURRENT_THREAD_CWD_FD() as
>> #define AST_GET_CURRENT_THREAD_CWD_FD() (shp->pwdfd)
>> This would, at least, save the function call overhead, and finally
>> make use of (shp->pwdfd) as it was intended.
>>
>> What do you think? It would make things easier for you to implement,
>> i.e. you only have to implement the per thread
>> AST_GET_CURRENT_THREAD_CWD_FD(), and applications are free to use the
>> *at() API if they wish to.
>
> What do you intend to do for platforms which do not have the POSIX
> openat() and friends API? Old Solaris, old Linux comes in mind (not
> that I care about any OS older than four years)...
Search your inbox for emails with the title "[ast-developers]
|*at()|-emulation, 3rd prototype...". It contains emulation functions
for all *at() calls, using the old POSIX functions to emulate them.
Lionel
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