architecture: 0.983
i386: 0.975
user-level: 0.939
files: 0.910
performance: 0.892
x86: 0.858
ppc: 0.858
PID: 0.857
kernel: 0.839
register: 0.831
device: 0.818
arm: 0.806
peripherals: 0.805
graphic: 0.779
permissions: 0.724
mistranslation: 0.700
boot: 0.698
semantic: 0.696
socket: 0.690
TCG: 0.640
debug: 0.625
hypervisor: 0.570
network: 0.556
risc-v: 0.537
VMM: 0.504
vnc: 0.487
assembly: 0.471
KVM: 0.371
virtual: 0.340
--------------------
i386: 0.989
x86: 0.980
virtual: 0.520
hypervisor: 0.335
files: 0.062
TCG: 0.032
PID: 0.018
register: 0.012
debug: 0.007
semantic: 0.006
arm: 0.004
architecture: 0.003
user-level: 0.003
kernel: 0.003
boot: 0.003
performance: 0.003
device: 0.003
network: 0.002
VMM: 0.002
socket: 0.001
permissions: 0.001
KVM: 0.001
peripherals: 0.001
ppc: 0.001
risc-v: 0.001
graphic: 0.001
mistranslation: 0.000
vnc: 0.000
assembly: 0.000

qemu-i386 fails on system(3) with a cross-toolchain from Buildroot

qemu-i386 fails with small C program containing a system().
The C program is cross-compiled with a toolchain created by buildroot (http://buildroot.net/), gcc version 4.6.3, uClibc version 0.9.33.2 .
qemu version 1.2.0 (built with http://git.buildroot.net/buildroot/tree/package/qemu/qemu.mk)
host machine : Ubuntu 12.04 LTS on x86_64.

    $ cat sys.c
    #include <stdio.h>
    #include <stdlib.h>

    int main()
   {
    	int ret = system("echo hello");
    	printf("%d\n", ret);
    }

    $ ../../host/usr/bin/i686-buildroot-linux-uclibc-gcc -o sys sys.c
    $ file sys
    sys: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked (uses shared libs), not stripped
    $ ../../host/usr/bin/qemu-i386 ./sys
    -1

same problem with x86_64 :
    $ ../../host/usr/bin/x86_64-buildroot-linux-uclibc-gcc -o sys sys.c
    $ file sys
    sys: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), not stripped
    $ ../../host/usr/bin/qemu-x86_64 sys
    -1

works fine with arm :
    $ ../../host/usr/bin/arm-buildroot-linux-uclibcgnueabi-gcc -o sys sys.c
    $ file sys
    sys: ELF 32-bit LSB executable, ARM, version 1 (SYSV), dynamically linked (uses shared libs), not stripped
    $ ../../host/usr/bin/qemu-arm ./sys
    hello
    0

works fine with mips :
    $ ../../host/usr/bin/mips-buildroot-linux-uclibc-gcc -o sys sys.c
    $ file sys
    sys: ELF 32-bit MSB executable, MIPS, MIPS32 rel2 version 1 (SYSV), dynamically linked (uses shared libs), with unknown capability 0x41000000 = 0xf676e75, with unknown capability 0x10000 = 0x70403, not stripped
    $ ../../host/usr/bin/qemu-mips sys
    hello
    0

Looks like the long-standing "clone/fork for i386 user mode targets doesn't work" issue. See also discussion in bug 739785...


Fixed in 2013 some time.