Re: working GNU/FreeBSD chroot
On Tue, May 06, 2003 at 10:11:42PM +0200, Robert Millan wrote:
>
> hi!
>
> my GNU/FreeBSD chroot jail is finaly self-hosting. i
> could build Glibc 2.3, GCC 3.2.3 and binutils (cvs)
> within the jail, and these worked fine to compile
> other packages like coreutils, etc.
>
> i've uploaded a tarball of the system, you can get
> it from:
>
> http://people.debian.org/~rmh/gnu-freebsd/
>
> (note for those of you interested on a GNU/FreeBSD
> production system: this tarball is _USELESS_ for
> anything other than development or bug fixing.)
>
> there are also some patches you might find useful
> in the patches/ dir (some updated from Bruno's or
> Nathan's, other added myself)
>
> the build environment seems realy sane for being
> in alpha stage, but it's unable to bootstrap Debian
> yet. there are basicaly two problems that prevent
> building and using perl:
>
> - dynamic executables don't work. Glibc's dynamic
> linker triggers a "ELF file OS ABI invalid" error
> (see [glibc]/elf/dl-load.c) when loading an
> executable that is linked against Glibc. i'm
> not sure wether the problem is in ld.so, binutils
> or libc.so itself.
>
> the workaround i used for now is to link
> everything staticaly, by either using [BOOT_]CFLAGS
> variables or a /usr/bin/gcc wrapper.
This IIRC, was simply a bug in the ld.so. I attach a patch that might
fix it.
> - getpw{nam,uid} always fail (return NULL, errno=success)
> this could be a problem in NSS, since other
> NSS services are broken also (hostname resolving)
>
This is probably because of the problem above. DNS is broken, unless
Bruno fixed it, but the NSS uses the dynamic loader.
---Nathan
diff -urN -x manual glibc-20020425/elf/cache.c glibc-20020425-freebsd/elf/cache.c
--- glibc-20020425/elf/cache.c 2002-04-08 18:31:26.000000000 +0000
+++ glibc-20020425-freebsd/elf/cache.c 2002-07-14 00:34:14.000000000 +0000
@@ -104,12 +104,13 @@
[0] = "Linux",
[1] = "Hurd",
[2] = "Solaris",
- [3] = N_("Unknown OS")
+ [3] = "FreeBSD",
+ [4] = N_("Unknown OS")
};
unsigned int os = osversion >> 24;
printf (_(", OS ABI: %s %d.%d.%d"),
- _(abi_tag_os[os > 3 ? 3 : os]),
+ _(abi_tag_os[os > 4 ? 4 : os]),
(osversion >> 16) & 0xff,
(osversion >> 8) & 0xff,
osversion & 0xff);
diff -urN -x manual glibc-20020425/elf/readlib.c glibc-20020425-freebsd/elf/readlib.c
--- glibc-20020425/elf/readlib.c 2001-07-10 20:57:51.000000000 +0000
+++ glibc-20020425-freebsd/elf/readlib.c 2002-07-13 21:57:08.000000000 +0000
@@ -122,8 +122,12 @@
/* First check if this is an aout file. */
aout_header = (struct exec *) file_contents;
+#if defined(QMAGIC)
if (N_MAGIC (*aout_header) == ZMAGIC
|| N_MAGIC (*aout_header) == QMAGIC)
+#else
+ if (N_MAGIC (*aout_header) == ZMAGIC)
+#endif
{
/* Aout files don't have a soname, just return the name
including the major number. */
diff -urN -x manual glibc-20020425/sysdeps/unix/bsd/bsd4.4/freebsd/configure glibc-20020425-freebsd/sysdeps/unix/bsd/bsd4.4/freebsd/configure
--- glibc-20020425/sysdeps/unix/bsd/bsd4.4/freebsd/configure 2002-06-26 21:58:33.000000000 +0000
+++ glibc-20020425-freebsd/sysdeps/unix/bsd/bsd4.4/freebsd/configure 2002-07-13 21:57:08.000000000 +0000
@@ -21,3 +21,4 @@
# sysdeps/unix/sysv/linux/configure.in
# FIXME: Set use_ldconfig=yes once the shared libs work.
+use_ldconfig=yes
diff -urN -x manual glibc-20020425/sysdeps/unix/bsd/bsd4.4/freebsd/i386/readelflib.c glibc-20020425-freebsd/sysdeps/unix/bsd/bsd4.4/freebsd/i386/readelflib.c
--- glibc-20020425/sysdeps/unix/bsd/bsd4.4/freebsd/i386/readelflib.c 1970-01-01 00:00:00.000000000 +0000
+++ glibc-20020425-freebsd/sysdeps/unix/bsd/bsd4.4/freebsd/i386/readelflib.c 2002-07-13 23:28:07.000000000 +0000
@@ -0,0 +1,223 @@
+/* Copyright (C) 1999, 2000, 2001 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Andreas Jaeger <aj@suse.de>, 1999 and
+ Jakub Jelinek <jakub@redhat.com>, 1999.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+/* This code is a heavily simplified version of the readelf program
+ that's part of the current binutils development version. For architectures
+ which need to handle both 32bit and 64bit ELF libraries, this file is
+ included twice for each arch size. */
+
+/* check_ptr checks that a pointer is in the mmaped file and doesn't
+ point outside it. */
+#undef check_ptr
+#define check_ptr(ptr) \
+do \
+ { \
+ if ((void *)(ptr) < file_contents \
+ || (void *)(ptr) > (file_contents+file_length)) \
+ { \
+ error (0, 0, _("file %s is truncated\n"), file_name); \
+ return 1; \
+ } \
+ } \
+ while (0);
+
+/* Returns 0 if everything is ok, != 0 in case of error. */
+int
+process_elf_file (const char *file_name, const char *lib, int *flag,
+ unsigned int *osversion, char **soname, void *file_contents,
+ size_t file_length)
+{
+ int i;
+ unsigned int j;
+ int loadaddr;
+ unsigned int dynamic_addr;
+ size_t dynamic_size;
+ char *program_interpreter;
+
+ ElfW(Ehdr) *elf_header;
+ ElfW(Phdr) *elf_pheader, *segment;
+ ElfW(Dyn) *dynamic_segment, *dyn_entry;
+ char *dynamic_strings;
+
+ elf_header = (ElfW(Ehdr) *) file_contents;
+ *osversion = 0;
+
+ if (elf_header->e_ident [EI_CLASS] != ElfW (CLASS))
+ {
+ if (opt_verbose)
+ {
+ if (ElfW (CLASS) == ELFCLASS32)
+ error (0, 0, _("%s is a 32 bit ELF file.\n"), file_name);
+ else if (ElfW (CLASS) == ELFCLASS64)
+ error (0, 0, _("%s is a 64 bit ELF file.\n"), file_name);
+ else
+ error (0, 0, _("Unknown ELFCLASS in file %s.\n"), file_name);
+ }
+ return 1;
+ }
+
+ /* ld.so.1 is executable on GNU/FreeBSD, so disable this check */
+/* if (elf_header->e_type != ET_DYN)
+ {
+ error (0, 0, _("%s is not a shared object file (Type: %d).\n"), file_name,
+ elf_header->e_type);
+ return 1;
+ }
+ */
+
+ /* Get information from elf program header. */
+ elf_pheader = (ElfW(Phdr) *) (elf_header->e_phoff + file_contents);
+ check_ptr (elf_pheader);
+
+ /* The library is an elf library, now search for soname and
+ libc5/libc6. */
+ *flag = FLAG_ELF;
+
+ loadaddr = -1;
+ dynamic_addr = 0;
+ dynamic_size = 0;
+ program_interpreter = NULL;
+ for (i = 0, segment = elf_pheader;
+ i < elf_header->e_phnum; i++, segment++)
+ {
+ check_ptr (segment);
+
+ switch (segment->p_type)
+ {
+ case PT_LOAD:
+ if (loadaddr == -1)
+ loadaddr = (segment->p_vaddr & 0xfffff000)
+ - (segment->p_offset & 0xfffff000);
+ break;
+
+ case PT_DYNAMIC:
+ if (dynamic_addr)
+ error (0, 0, _("more than one dynamic segment\n"));
+
+ dynamic_addr = segment->p_offset;
+ dynamic_size = segment->p_filesz;
+ break;
+
+ case PT_INTERP:
+ program_interpreter = (char *) (file_contents + segment->p_offset);
+ check_ptr (program_interpreter);
+
+ /* Check if this is enough to classify the binary. */
+ for (j = 0; j < sizeof (interpreters) / sizeof (interpreters [0]);
+ ++j)
+ if (strcmp (program_interpreter, interpreters[j].soname) == 0)
+ {
+ *flag = interpreters[j].flag;
+ break;
+ }
+ break;
+
+ case PT_NOTE:
+ if (!*osversion && segment->p_filesz == 32 && segment->p_align >= 4)
+ {
+ ElfW(Word) *abi_note = (ElfW(Word) *) (file_contents
+ + segment->p_offset);
+ if (abi_note [0] == 4 && abi_note [1] == 16 && abi_note [2] == 1
+ && memcmp (abi_note + 3, "GNU", 4) == 0)
+ *osversion = (abi_note [4] << 24) |
+ ((abi_note [5] & 0xff) << 16) |
+ ((abi_note [6] & 0xff) << 8) |
+ (abi_note [7] & 0xff);
+ }
+ break;
+
+ default:
+ break;
+ }
+
+ }
+ if (loadaddr == -1)
+ {
+ /* Very strange. */
+ loadaddr = 0;
+ }
+
+ /* Now we can read the dynamic sections. */
+ if (dynamic_size == 0)
+ return 1;
+
+ dynamic_segment = (ElfW(Dyn) *) (file_contents + dynamic_addr);
+ check_ptr (dynamic_segment);
+
+ /* Find the string table. */
+ dynamic_strings = NULL;
+ for (dyn_entry = dynamic_segment; dyn_entry->d_tag != DT_NULL;
+ ++dyn_entry)
+ {
+ check_ptr (dyn_entry);
+ if (dyn_entry->d_tag == DT_STRTAB)
+ {
+ dynamic_strings = (char *) (file_contents + dyn_entry->d_un.d_val - loadaddr);
+ check_ptr (dynamic_strings);
+ break;
+ }
+ }
+
+ if (dynamic_strings == NULL)
+ return 1;
+
+ /* Now read the DT_NEEDED and DT_SONAME entries. */
+ for (dyn_entry = dynamic_segment; dyn_entry->d_tag != DT_NULL;
+ ++dyn_entry)
+ {
+ if (dyn_entry->d_tag == DT_NEEDED || dyn_entry->d_tag == DT_SONAME)
+ {
+ char *name = dynamic_strings + dyn_entry->d_un.d_val;
+ check_ptr (name);
+
+ if (dyn_entry->d_tag == DT_NEEDED)
+ {
+
+ if (*flag == FLAG_ELF)
+ {
+ /* Check if this is enough to classify the binary. */
+ for (j = 0;
+ j < sizeof (known_libs) / sizeof (known_libs [0]);
+ ++j)
+ if (strcmp (name, known_libs [j].soname) == 0)
+ {
+ *flag = known_libs [j].flag;
+ break;
+ }
+ }
+ }
+
+ else if (dyn_entry->d_tag == DT_SONAME)
+ *soname = xstrdup (name);
+
+ /* Do we have everything we need? */
+ if (*soname && *flag != FLAG_ELF)
+ return 0;
+ }
+ }
+
+ /* We reach this point only if the file doesn't contain a DT_SONAME
+ or if we can't classify the library. If it doesn't have a
+ soname, return the name of the library. */
+ if (*soname == NULL)
+ *soname = xstrdup (lib);
+
+ return 0;
+}
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