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Re: miscellaneous patch questions...
- To: drow@false.org
- Subject: Re: miscellaneous patch questions...
- From: Geoff Keating <geoffk@ozemail.com.au>
- Date: Mon, 17 Aug 1998 12:25:37 +1000
- CC: libc-alpha@cygnus.com
- References: <19980816004032.A16595@mindcryme.com>
> Date: Sun, 16 Aug 1998 00:40:32 -0400
> From: Dan Jacobowitz <drow@false.org>
...
> Second, chown. I understand why we do not want to propogate the ugly
> i386 fix to PPC, but without it a glibc built against recent kernel
> headers requires a recent kernel to work. That's a problem; I would
> like for Debian to support the stable powerpc kernel also, which is
> still 2.1.24. So is there a better solution forthcoming?
I have a better solution here, which I'm attaching; but I have never
run this code, so I don't want to put it in the distribution just yet
:-). Feel free to help test it for me.
There are a few other patches in the pipeline. At present, I'm trying
to find a problem with signals in linuxthreads; ex2 deadlocks for no
apparent reason (it's losing a SIGUSR1 signal, which is being sent and
received :-(. ).
> And last, is there a particular reason why the /usr/bin/ldd shell
> script prints an error message if you do not have execute permissions
> for the file in question? Could we either (preferably) remove this
> warning, or at least add the >&2 so it gets sent to stderr? This is
> necessary for the script 'dpkg-shlibdeps' which parses the output of
> ldd on shared libraries, which are not required to have execute
> permission set.
Generally, things that are trying to determine shared library
dependencies should use something like objdump, not ldd:
objdump -p $f | awk '/ NEEDED / { print $2 }'
prints out the libraries required. For a proper dependency-checker,
you should also reference the program's interpreter, and maybe even
handle RPATH entries.
The problem with using ldd is that if an executable uses a shared
library 'libA' that uses another shared library 'libB', libB is noted
as a dependency of the executable. If libA is then upgraded or
changed to require a different library libC, libB still has to be
installed, even if it conflicts with libC.
--
Geoffrey Keating <geoffk@ozemail.com.au>
===File ~/patches/glibc-16.diff=============================
1998-08-09 Geoff Keating <geoffk@ozemail.com.au>
* sysdeps/unix/sysv/linux/powerpc/chown.c: New file.
* sysdeps/unix/sysv/linux/powerpc/lchown.S: New file.
* sysdeps/unix/sysv/linux/powerpc/syscalls.list: Add chown, remove
getresuid, getresgid.
diff -x *~ -urN glibc-2.0.95-old/sysdeps/unix/sysv/linux/powerpc/chown.c glibc-2.0.95/sysdeps/unix/sysv/linux/powerpc/chown.c
--- glibc-2.0.95-old/sysdeps/unix/sysv/linux/powerpc/chown.c Thu Jan 1 10:00:00 1970
+++ glibc-2.0.95/sysdeps/unix/sysv/linux/powerpc/chown.c Mon Aug 10 18:43:48 1998
@@ -0,0 +1,131 @@
+/* chown() compatibility.
+ Copyright (C) 1998 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Library General Public License as
+ published by the Free Software Foundation; either version 2 of the
+ License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Library General Public License for more details.
+
+ You should have received a copy of the GNU Library General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If not,
+ write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+#include <errno.h>
+#include <string.h>
+#include <unistd.h>
+#include <limits.h>
+#include <sys/syscall.h>
+#include <stdlib.h>
+
+/*
+ In Linux 2.1.x the chown functions have been changed. A new function lchown
+ was introduced. The new chown now follows symlinks - the old chown and the
+ new lchown do not follow symlinks.
+ This file emulates chown() under the old kernels.
+*/
+
+extern int __syscall_chown (const char *__file,
+ uid_t __owner, gid_t __group);
+
+int
+__chown (const char *file, uid_t owner, gid_t group)
+{
+ int err;
+ int old_errno;
+ char link[PATH_MAX+2];
+ char path[2*PATH_MAX+4];
+ int loopct;
+ int filelen;
+ static int libc_old_chown = 0 /* -1=old linux, 1=new linux, 0=unknown */;
+
+ if (libc_old_chown == 1)
+ return __syscall_chown (file, owner, group);
+
+ old_errno = errno;
+
+#ifdef __NR_lchown
+ if (libc_old_chown == 0)
+ {
+ err = __syscall_chown (file, owner, group);
+ if (err != -1 || errno != ENOSYS)
+ {
+ libc_old_chown = 1;
+ return err;
+ }
+ libc_old_chown = -1;
+ }
+#endif
+
+ err = __readlink (file, link, PATH_MAX+1);
+ if (err == -1)
+ {
+ errno = old_errno;
+ return __lchown(file, owner, group);
+ }
+
+ filelen = strlen (file) + 1;
+ if (filelen > sizeof(path))
+ {
+ errno = ENAMETOOLONG;
+ return -1;
+ }
+ memcpy (path, file, filelen);
+
+ /* 'The system has an arbitrary limit...' In practise, we'll hit
+ ENAMETOOLONG before this, usually. */
+ for (loopct = 0; loopct < 128; loopct++)
+ {
+ int linklen;
+
+ if (err >= PATH_MAX+1)
+ {
+ errno = ENAMETOOLONG;
+ return -1;
+ }
+
+ link[err] = 0; /* Null-terminate string, just-in-case. */
+
+ linklen = strlen (link) + 1;
+
+ if (link[0] == '/')
+ memcpy (path, link, linklen);
+ else
+ {
+ filelen = strlen (path);
+
+ while (filelen > 1 && path[filelen-1] == '/')
+ filelen--;
+ while (filelen > 0 && path[filelen-1] != '/')
+ filelen--;
+ if (filelen + linklen > sizeof(path))
+ {
+ errno = ENAMETOOLONG;
+ return -1;
+ }
+ memcpy (path+filelen, link, linklen);
+ }
+
+ err = __readlink(path, link, PATH_MAX+1);
+
+ if (err == -1)
+ {
+ errno = old_errno;
+ return __lchown(path, owner, group);
+ }
+ }
+ errno = ELOOP;
+ return -1;
+}
+
+#if defined PIC && defined DO_VERSIONING
+default_symbol_version (__chown, chown, GLIBC_2.1);
+#else
+weak_alias (__chown, chown)
+#endif
diff -x *~ -urN glibc-2.0.95-old/sysdeps/unix/sysv/linux/powerpc/lchown.S glibc-2.0.95/sysdeps/unix/sysv/linux/powerpc/lchown.S
--- glibc-2.0.95-old/sysdeps/unix/sysv/linux/powerpc/lchown.S Thu Jan 1 10:00:00 1970
+++ glibc-2.0.95/sysdeps/unix/sysv/linux/powerpc/lchown.S Mon Aug 10 18:43:34 1998
@@ -0,0 +1,35 @@
+/* lchown system call.
+ Copyright (C) 1998 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Library General Public License as
+ published by the Free Software Foundation; either version 2 of the
+ License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Library General Public License for more details.
+
+ You should have received a copy of the GNU Library General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If not,
+ write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+/* Some old kernel headers call lchown() 'chown'. The number is
+ the same. */
+
+#include <sysdep.h>
+
+#ifdef __NR_lchown
+ PSEUDO (__lchown, lchown, 3)
+#else
+ PSEUDO (__lchown, chown, 3)
+#endif
+ ret
+ PSEUDO_END(__lchown)
+ weak_alias (__lchown, lchown)
+#if defined PIC && defined DO_VERSIONING
+ symbol_version (__lchown, chown, GLIBC_2.0);
+#endif
diff -x *~ -urN glibc-2.0.95-old/sysdeps/unix/sysv/linux/powerpc/syscalls.list glibc-2.0.95/sysdeps/unix/sysv/linux/powerpc/syscalls.list
--- glibc-2.0.95-old/sysdeps/unix/sysv/linux/powerpc/syscalls.list Fri Mar 13 04:16:02 1998
+++ glibc-2.0.95/sysdeps/unix/sysv/linux/powerpc/syscalls.list Sun Aug 9 14:24:58 1998
@@ -1,6 +1,4 @@
# File name Caller Syscall name # args Strong name Weak names
s_llseek llseek _llseek 5 __sys_llseek
-
-getresuid - getresuid 3 getresuid
-getresgid - getresgid 3 getresgid
+s_chown chown chown 3 __syscall_chown
============================================================