On Thu, Jun 20, 2013 at 8:30 PM, Roland Mainz <[email protected]> wrote:
> On Thu, Jun 20, 2013 at 1:13 PM, Roland Mainz <[email protected]>
> wrote:
>> On Wed, Jun 19, 2013 at 5:49 PM, Cedric Blancher
>> <[email protected]> wrote:
>>> On 19 June 2013 16:16, David Korn <[email protected]> wrote:
>>>> cc: [email protected]
>>>> Subject: Re: [ast-developers] When will the tree reopen for normal patches?
>>>> --------
>>>>
>>>>> cd /dev/fd/$d no longer works
>>>>
>>>> What do you mean that it no longer works, I just did
>>>> exec 9< /tmp
>>>> and was able to do
>>>> cd /dev/fd/9/foo
>>>> to change to /tmp/foo.
>>>>
>>>
>>> /bin/ksh -c 'exec {n}</etc ; cd /dev/fd/$n/ ; true'
>>> /bin/ksh: cd: /dev/fd/11/: [Bad address]
>>>
>>> This has been reported to [email protected] several
>>> times. Search for '[Bad address]'.
>>>
>>> There were also requests for cd -f $n relative_path to allow relative
>>> paths which go above the starting point of fd, e.g. cd -f $n ../../a/b
>>> The other reason for cd -f $fd relative_path was that POSIX does not
>>> standardise absolute paths and that bash and dash developers see it as
>>> a cleaner API to openat() than using /dev/fd
>>
>> Attached (as "astksh_20130613_cd_f_dirfd_002.diff.txt") is the patch
>> to add $ cd -f $fd # ... it's more or less the same solution which was
>> proposed for bash4&&dash, too.
>
> Attached (as "astksh_20130613_cd_f_dirfd_003.diff.txt") is an updated
> patch which fixes the issue that the "pwd" builtin was unable to
> determinate the current cwd location.
>
> The fix works the same way how Sun's Solaris and other OSes with NFSv4
> XATTR support handled the issue in their Bourne shell+csh versions.
>
> Example:
> -- snip --
> $ ksh -c 'redirect {n}<"/etc" ; cd -f $n X11 ; pwd -P; pwd -L ; true'
> -- snip --
> ... will print...
> -- snip --
> /etc/X11
> .
> -- snip --
> ... "/etc/X11" is the physical location... but we use "." as the
> logical location since the logical cwd can not successfully be
> determinated... for example because the directory the descriptor $n is
> pointing to may have moved or the location wasn't know from the
> beginning (David: No... a tracking cache doesn't help if an external
> process or filesystem deamon renames the directory). We can't let
> "pwd" return an error... Sun once determinated that it breaks too many
> scripts (while using "." as logical name seems to work) ... ;-(
>
> More complex example:
> -- snip --
> $ bash -c 'rm -Rf transaction_done ;mkdir transaction1 ; exec
> {n}<"transaction1" ; n=$n ~/bin/ksh -c "mv transaction1
> transaction_done ; cd -f \$n . ; pwd -L ; pwd -P ; true"'
> .
> /home/test001/tmp/l1/transaction_done
> -- snip --
> "." is used as logical name since there is no name associated with the
> file descriptor at the time the shell obtains the fd.
... and finally... in the case David&&Glenn do not like the idea of
"." being returned as logical directory by the "pwd" builtin is a
patch (as
"astksh_20130613_cd_f_dirfd_003_alternative1_no_logicalpwd_dot.diff.txt")
which throws an error if someone wants to access the logical
directory.
----
Bye,
Roland
--
__ . . __
(o.\ \/ /.o) [email protected]
\__\/\/__/ MPEG specialist, C&&JAVA&&Sun&&Unix programmer
/O /==\ O\ TEL +49 641 3992797
(;O/ \/ \O;)
diff -r -u build_i386_64bit_debug/src/cmd/ksh93/bltins/cd_pwd.c
build_i386_64bit_debug_cd_f/src/cmd/ksh93/bltins/cd_pwd.c
--- build_i386_64bit_debug/src/cmd/ksh93/bltins/cd_pwd.c 2013-05-16
16:36:14.000000000 +0200
+++ build_i386_64bit_debug_cd_f/src/cmd/ksh93/bltins/cd_pwd.c 2013-06-20
20:46:33.378961553 +0200
@@ -19,8 +19,8 @@
***********************************************************************/
#pragma prototyped
/*
- * cd [-LP@] [dirname]
- * cd [-LP@] [old] [new]
+ * cd [-LP@] [-f dirfd] [dirname]
+ * cd [-LP@] [-fdirfd] [old] [new]
* pwd [-LP]
*
* David Korn
@@ -114,7 +114,7 @@
{
while(*p=='/')
p++;
- path = *p?(const char*)p:0;
+ path = *p?(const char*)p:e_dot;
dir = fd;
}
}
@@ -169,14 +169,24 @@
register Shell_t *shp = context->shp;
int saverrno=0;
int rval;
- bool flag=false,xattr=false;
+ bool flag=false,xattr=false,unset_pwdnod=false;
char *oldpwd;
+ int dirfd = shp->pwdfd;
int newdirfd;
Namval_t *opwdnod, *pwdnod;
if(sh_isoption(shp,SH_RESTRICTED))
errormsg(SH_DICT,ERROR_exit(1),e_restricted+4);
while((rval = optget(argv,sh_optcd))) switch(rval)
{
+#ifdef AT_FDCWD
+ case 'f':
+ errno = 0;
+ dirfd = strtol(opt_info.arg, (char **)NULL, 10);
+ if ((errno != 0) || (dirfd < 0))
+ errormsg(SH_DICT, ERROR_system(1), "%s: invalid
dir fd", opt_info.arg);
+ unset_pwdnod=true;
+ break;
+#endif
case 'L':
flag = false;
break;
@@ -186,6 +196,7 @@
#ifdef O_XATTR
case '@':
xattr = true;
+ unset_pwdnod=true;
break;
#endif
case ':':
@@ -307,7 +318,7 @@
continue;
#endif /* SHOPT_FS_3D */
}
- rval = newdirfd = sh_diropenat(shp, shp->pwdfd,
+ rval = newdirfd = sh_diropenat(shp, dirfd,
path_relative(shp,stakptr(PATH_OFFSET)), xattr);
if(newdirfd >=0)
{
@@ -346,7 +357,7 @@
if(rval<0 && *dir=='/' &&
*(path_relative(shp,stakptr(PATH_OFFSET)))!='/')
{
rval = newdirfd = sh_diropenat(shp,
- shp->pwdfd,
+ dirfd,
dir, xattr);
if(newdirfd >=0)
{
@@ -403,9 +414,17 @@
/* delete trailing '/' */
while(--flag>0 && dir[flag]=='/')
dir[flag] = 0;
- nv_putval(pwdnod,dir,NV_RDONLY);
- nv_onattr(pwdnod,NV_NOFREE|NV_EXPORT);
- shp->pwd = pwdnod->nvalue.cp;
+ if (unset_pwdnod)
+ {
+ nv_unset(pwdnod);
+ shp->pwd = strdup(e_dot);
+ }
+ else
+ {
+ nv_putval(pwdnod,dir,NV_RDONLY);
+ nv_onattr(pwdnod,NV_NOFREE|NV_EXPORT);
+ shp->pwd = pwdnod->nvalue.cp;
+ }
nv_scan(shp->track_tree,rehash,(void*)0,NV_TAGGED,NV_TAGGED);
path_newdir(shp,shp->pathlist);
path_newdir(shp,shp->cdpathlist);
@@ -416,17 +435,18 @@
int b_pwd(int argc, char *argv[],Shbltin_t *context)
{
- register int n, flag = 0;
- register char *cp;
+ register int n;
+ bool pflag = false;
+ register char *cp, *freecp=NULL;
register Shell_t *shp = context->shp;
NOT_USED(argc);
while((n = optget(argv,sh_optpwd))) switch(n)
{
case 'L':
- flag = 0;
+ pflag = false;
break;
case 'P':
- flag = 1;
+ pflag = true;
break;
case ':':
errormsg(SH_DICT,2, "%s", opt_info.arg);
@@ -437,22 +457,47 @@
}
if(error_info.errors)
errormsg(SH_DICT,ERROR_usage(2),"%s",optusage((char*)0));
- if(*(cp = path_pwd(shp,0)) != '/')
- errormsg(SH_DICT,ERROR_system(1), e_pwd);
- if(flag)
+ cp = path_pwd(shp,0);
+ if(pflag)
{
+ int mc;
+
+ /*
+ * Try the hard way to find the physical location.
+ * This may happen for NFSv4 xattr directories,
+ * Solaris samfs and some other special cases
+ * which may not have a proper logical name when
+ * "cd" was used.
+ */
+ if(*cp != '/')
+ {
+ freecp = cp = getcwd(NULL, 0);
+ if (!cp)
+ errormsg(SH_DICT,ERROR_system(1), e_pwd);
+ }
+
#if SHOPT_FS_3D
- if(shp->gd->lim.fs3d && (flag =
mount(e_dot,NIL(char*),FS3D_GET|FS3D_VIEW,0))>=0)
+ if(shp->gd->lim.fs3d && (mc =
mount(e_dot,NIL(char*),FS3D_GET|FS3D_VIEW,0))>=0)
{
- cp = (char*)stakseek(++flag+PATH_MAX);
- mount(e_dot,cp,FS3D_GET|FS3D_VIEW|FS3D_SIZE(flag),0);
+ cp = (char*)stakseek(++mc+PATH_MAX);
+ mount(e_dot,cp,FS3D_GET|FS3D_VIEW|FS3D_SIZE(mc),0);
}
else
#endif /* SHOPT_FS_3D */
cp = strcpy(stakseek(strlen(cp)+PATH_MAX),cp);
pathcanon(cp,PATH_MAX,PATH_PHYSICAL);
}
+ else
+ {
+ if(*cp != '/')
+ errormsg(SH_DICT,ERROR_system(1), e_pwd);
+ }
+
sfputr(sfstdout,cp,'\n');
+
+ if (freecp)
+ free(freecp);
+
return(0);
}
diff -r -u build_i386_64bit_debug/src/cmd/ksh93/data/builtins.c
build_i386_64bit_debug_cd_f/src/cmd/ksh93/data/builtins.c
--- build_i386_64bit_debug/src/cmd/ksh93/data/builtins.c 2013-05-30
05:34:48.000000000 +0200
+++ build_i386_64bit_debug_cd_f/src/cmd/ksh93/data/builtins.c 2013-06-20
12:52:28.993198173 +0200
@@ -446,7 +446,7 @@
;
const char sh_optcd[] =
-"[-1c?\n@(#)$Id: cd (AT&T Research) 2012-07-10 $\n]"
+"[-1c?\n@(#)$Id: cd (AT&T Research) 2013-06-20 $\n]"
USAGE_LICENSE
"[+NAME?cd - change working directory ]"
"[+DESCRIPTION?\bcd\b changes the current working directory of the "
@@ -482,6 +482,9 @@
"\bPATH_RESOLVE\b. If \bPATH_RESOLVE\b is \bphysical\b, "
"then the behavior will be as if \b-P\b were specified. Otherwise, "
"the behavior will be as if \b-L\b were specified.]"
+#ifdef AT_FDCWD
+"[f]#[dirfd?Path is relative to this directory fd.]"
+#endif
"[L?Handle each pathname component \b..\b in a logical fashion by moving "
"up one level by name in the present working directory.]"
"[P?The present working directory is first converted to an absolute pathname "
Only in build_i386_64bit_debug_cd_f/src/cmd/ksh93/tests: arrays.sh
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