Hi,

Thanks for your reply!

I will give it a try to the 0.9.33 stable branch and if it still does not work for me I will start to blame the MIPS port and focus my investigation on _dl_printf :)

I will keep you posted.

Best regards,

Yann

On 01/27/2014 04:37 PM, Filippo Arcidiacono wrote:
Hi,
I'm using uClibc based on 0.9.33 stable branch (uClibc-0.9.33.2), and prelink on SH target until now works fine.
Follow the results i got on my SH4 target:

On 1/24/2014 4:00 PM, Yann Sionneau wrote:
Hello,

I am trying to get prelinking to work on a MIPS target.
I reproduced the issue on OpenWRT (master branch, using uClibc-0.9.33.2) using the "MIPS Malta CoreLV board (qemu)" Target System. At first uClibc Standalone Support was disabled leading to this when trying to run the dynamic linker as an executable:

root@OpenWrt:/# /lib/ld-uClibc.so.0
Standalone execution is not enabled

Then I enabled the following options in uClibc configuration:

LDSO_STANDALONE_SUPPORT=y
LDSO_PRELINK_SUPPORT=y

Afterward I get this when running the dynamic linker as an executable which means the standalone support has been enabled successfully:

root@OpenWrt:/# /lib/ld-uClibc.so.0
root@OpenWrt:/#
Seems you have some wrong declaration of _dl_dprintf.
You should get:

root@arcidiaf:~# /lib/ld-uClibc.so.0
Usage: ld.so [OPTION]... EXECUTABLE-FILE [ARGS-FOR-PROGRAM...]
You have invoked `ld.so', the helper program for shared library executables. This program usually lives in the file `/lib/ld.so', and special directives
in executable files using ELF shared libraries tell the system's program
loader to load the helper program from this file. This helper program loads the shared libraries needed by the program executable, prepares the program to run, and runs it. You may invoke this helper program directly from the command line to load and run an ELF executable file; this is like executing
that file itself, but always uses this helper program from the file you
specified, instead of the helper program file specified in the executable
file you run.  This is mostly of use for maintainers to test new versions
of this helper program; chances are you did not intend to run this program.

--library-path PATH use given PATH instead of content of the environment
                        variable LD_LIBRARY_PATH



Then here comes the issue:

root@OpenWrt:/# LD_WARN= LD_TRACE_PRELINKING=1 LD_TRACE_LOADED_OBJECTS=1 /lib/ld-uClibc.so.0 /bin/busybox
root@OpenWrt:/#


root@arcidiaf:~# LD_WARN= LD_TRACE_PRELINKING=1 LD_TRACE_LOADED_OBJECTS=1 /lib/ld-uClibc.so.0 /bin/busybox
    /bin/busybox => /bin/busybox (0x400000, 0x0)
    libcrypt.so.0 => /lib/libcrypt.so.0 (0x29558000, 0x29558000)
    libm.so.0 => /lib/libm.so.0 (0x2957d000, 0x2957d000)
    libc.so.0 => /lib/libc.so.0 (0x2959f000, 0x2959f000) TLS(0x1, 0x8)
    ld-uClibc.so.0 => /lib/ld-uClibc.so.0 (0x52aac000, 0x52aac000)

This should (should it?) print the list of libraries that busybox depends on (at least eglibc does that on x86), but here it prints nothing. However, if running directly busybox with those environment variables I get what I wanted:

root@OpenWrt:/# LD_WARN= LD_TRACE_PRELINKING=1 LD_TRACE_LOADED_OBJECTS=1 /bin/busybox
    /bin/busybox => /bin/busybox (0x400000, 0x0)
    libcrypt.so.0 => /lib/libcrypt.so.0 (0x77c19000, 0x77c19000)
    libm.so.0 => /lib/libm.so.0 (0x77bf4000, 0x77bf4000)
    libgcc_s.so.1 => /lib/libgcc_s.so.1 (0x77bd0000, 0x77bd0000)
    libc.so.0 => /lib/libc.so.0 (0x77b63000, 0x77b63000) TLS(0x1, 0x0)
    ld-uClibc.so.0 => /lib/ld-uClibc.so.0 (0x77c3d000, 0x77c3d000)

Unfortunately, the prelink tool seems to depend on the eglibc behaviour which is to print those messages even if the dynamic linker is called as an executable, therefore I get those errors when trying to prelink:

root@OpenWrt:/# cat /etc/prelink.conf
-l /lib
-l /usr/lib
-l /bin
-l /sbin
-l /usr/bin
-l /usr/sbin
root@OpenWrt:/# prelink -c /etc/prelink.conf -C /etc/prelink.cache --dynamic-linker=/lib/ld-uClibc.so.0 -mvR --ld-library-path=/lib:/usr/lib -a prelink: /bin/ubus seen 0 times in LD_TRACE_PRELINKING output, expected once prelink: /bin/busybox seen 0 times in LD_TRACE_PRELINKING output, expected once
[...] etc

By looking at prelink source code (src/gather.c) I can see that indeed prelink tries to execute "LD_WARN= LD_TRACE_PRELINKING=1 LD_TRACE_LOADED_OBJECTS=1 /lib/ld-uClibc.so.0 /bin/busybox" and then tries to parse the output to get the dependencies:
For this the dynamic linker has been extended to support the standalone mode.

  argv[i++] = ent_filename;
  argv[i] = NULL;
  envp[0] = "LD_TRACE_LOADED_OBJECTS=1";
  envp[1] = "LD_TRACE_PRELINKING=1";
  envp[2] = "LD_WARN=";
  envp[3] = NULL;
  f = execve_open (dl, (char * const *)argv, (char * const *)envp);

Does anyone encounter this issue as well? Is there a known fix?

Thanks :)

PS: I am using prelink-20130503

So do I.


Regards,





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