How to use nasm to create gui under linux
I found an example ，https://gist.github.com/nikAizuddin/6fbbc703f1213ab61a8a
but i get an error
nasm main.asm -o main.o -felf64 -w+all -gstabs
ld main.o -o a -melf_x86_64 -dynamic-linker /lib/ld-linux.so.2 -lX11
print zsh: accessing a corrupt shared library: ./a
what happened？
Related
I'm a beginner to learn the basic compiling. I create a very simple c file as below
#include <stdio.h>
int main (void) {
printf("Hello World!\n");
return 0;
}
then I run the commands,
cpp -E helloworld.c -o helloworld.i
gcc -S helloworld.i -o helloworld.s
as helloworld.s -o helloworld.o
ld -shared -o helloworld /usr/lib64/libc.so helloworld.o
in here, I got an error message like this,
ld -shared -o helloworld /usr/lib64/libc.so helloworld.o
ld: helloworld.o: relocation R_X86_64_32 against `.rodata' can not be used when making a shared object; recompile with -fPIC
ld: final link failed: Nonrepresentable section on output
so I rerun the upper but with a -fPIC
cpp -E helloworld.c -o helloworld.i
gcc -S helloworld.i -o helloworld.s -fPIC
as helloworld.s -o helloworld.o
ld -shared -o helloworld /usr/lib64/libc.so helloworld.o
at last, I got my helloworld, but when I try ./helloworld, I got a Segmentation fault.
anyone can help? Thanks in advance!
I try the gcc helloworld.c -Wl,--verbose | grep succeeded and get some output as below,
attempt to open /usr/lib/gcc/x86_64-redhat-linux/4.8.5/../../../../lib64/crt1.o succeeded
attempt to open /usr/lib/gcc/x86_64-redhat-linux/4.8.5/../../../../lib64/crti.o succeeded
attempt to open /usr/lib/gcc/x86_64-redhat-linux/4.8.5/crtbegin.o succeeded
attempt to open /tmp/ccSuIvy2.o succeeded
attempt to open /usr/lib/gcc/x86_64-redhat-linux/4.8.5/libgcc.a succeeded
attempt to open /usr/lib/gcc/x86_64-redhat-linux/4.8.5/libgcc_s.so succeeded
attempt to open /usr/lib/gcc/x86_64-redhat-linux/4.8.5/../../../../lib64/libc.so succeeded
attempt to open /lib64/libc.so.6 succeeded
attempt to open /usr/lib64/libc_nonshared.a succeeded
attempt to open /lib64/ld-linux-x86-64.so.2 succeeded
attempt to open /usr/lib/gcc/x86_64-redhat-linux/4.8.5/libgcc.a succeeded
attempt to open /usr/lib/gcc/x86_64-redhat-linux/4.8.5/libgcc_s.so succeeded
attempt to open /usr/lib/gcc/x86_64-redhat-linux/4.8.5/crtend.o succeeded
attempt to open /usr/lib/gcc/x86_64-redhat-linux/4.8.5/../../../../lib64/crtn.o succeeded
but I still don't know how to do the link, I try this one
ld -shared -o helloworld /usr/lib64/libc.so /usr/lib/gcc/x86_64-redhat-linux/4.8.5/../../../../lib64/crti.o /usr/lib/gcc/x86_64-redhat-linux/4.8.5/libgcc_s.so /usr/lib/gcc/x86_64-redhat-linux/4.8.5/crtend.o /usr/lib64/crtn.o helloworld.o /usr/lib/gcc/x86_64-redhat-linux/4.8.5/libgcc.a /usr/lib64/libc_nonshared.a /usr/lib/gcc/x86_64-redhat-linux/4.8.5/../../../../lib64/crt1.o
but get an error message,
ld: /usr/lib/gcc/x86_64-redhat-linux/4.8.5/../../../../lib64/crt1.o: relocation R_X86_64_32S against undefined symbol `__libc_csu_fini' can not be used when making a shared object; recompile with -fPIC
ld: final link failed: Nonrepresentable section on output
I link a shared library on the command line while building an executable. Running ldd on that executable is not showing the linked shared library.
After looking at some of the output of the linker, I have even tried adding the -Wl,--no-as-needed option and that didn't help either.
foo.c:
#include <stdio.h>
void foo () {
printf ("Hello world\n");
}
main.c:
#include <stdio.h>
int main () {
printf ("In main \n");
foo ();
}
Here's the command I used to compile and link:
$ gcc -Wl,--no-as-needed main.c -o main -L./ -lfoo
/bin/ld: cannot find -lfoo
collect2: error: ld returned 1 exit status
$ gcc -c foo.c -shared -Wl,-soname,libfoo.so -o libfoo.so
$ ls -l libfoo.so
-rw-r--r-- 1 apple eng 1488 Jun 4 04:44 libfoo.so
$ gcc -Wl,--no-as-needed main.c -o main -L./ -lfoo
$ ldd main
linux-vdso.so.1 => (0x00007fffbdd6c000)
libc.so.6 => /lib64/libc.so.6 (0x00007f6367e23000)
/lib64/ld-linux-x86-64.so.2 (0x00005556e268a000)
libfoo.so does not show up above.
$ objdump -x main | grep NEEDED
NEEDED libc.so.6
Why isn't libfoo.so showing up as NEEDED?
By using the gcc option -c you're telling it to create only object from foo.c, so the only product you're getting from this gcc command is an object file. The fact that its suffix is .so is only because you forced it using -o option. If you run this command without -o you'd see that the output is just foo.o - an object file.
If you omit the -c from the gcc command you'd get the shared object you wanted.
Running file on the output file shows the difference (note that I'm not setting the output name using -o and letting gcc use its default names):
With -c:
> gcc -c foo.c -shared
> file foo.o
foo.o: ELF 64-bit LSB relocatable, x86-64, version 1 (SYSV), not stripped
Without -c:
> gcc foo.c -shared
> file a.out
a.out: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, BuildID[sha1]=a63581bfc45f845c501ffb6635, not stripped
^^^
|||
This command does not generate a shared library:
gcc -c foo.c -shared -Wl,-soname,libfoo.so -o libfoo.so
It generates an object file libfoo.so that is later statically linked with your code. Proof: remove the lib file, the program will still run.
Solution:
Compile the object file separately, then convert it into a shared library. You will have to tell the loader where to search for the shared libraries by setting LD_LIBRARY_PATH:
gcc -c foo.c
gcc foo.o -shared -o libfoo.so
gcc main.c -o main -L./ -lfoo
export LD_LIBRARY_PATH=`pwd`
ldd ./main
# linux-vdso.so.1 (0x00007ffe0f7cb000)
# libfoo.so => /home/---/tmp/libfoo.so (0x00007f9bab6ec000)
# libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f9bab2fb000)
# /lib64/ld-linux-x86-64.so.2 (0x00007f9babaf0000)
I am currently using the following method to create shared libraries:
gcc -c test1.c -fPIC -o test1.o
gcc -c test2.c -fPIC -o test2.o
...
gcc test1.o test2.o ... -shared -o libtest.so
How can I do this same task with libtool? This is what I have done so far:
libtool compile gcc -c test1.c -o test1.o
libtool compile gcc -c test2.c -o test2.o
...
libtool link gcc test1.lo test2.lo ... -o libtest.la
However, this only creates libtest.la and libtest.a. I need the shared library libtest.so.
Try to add -rpath option like:
libtool --mode=link gcc -o libtest.la test1.lo -rpath /tmp
-rpath option tells Libtool where to install the library
If the path's missed, it won't generate the shared library.
I was bothered by this problem for quite a while until later I read carefully through the log file from configure, the script detects that LD was not able to generate dynamic linked file (.so). The problem was my environment variable LD was set to g++. Unset it or change to ld fixed the problem.
I am following a tutorial online made a while back and it says to use
ld -s -o testing test.o
to create an output file.
I'm getting the error of
ld: i386 architecture of input file 'test.o' is incompatible with i386:x86-64 output
when trying to run that line.
Test.o was created by nasm -f elf test.asm. It can't be created in 64-bit format sadly.
How should I go about combating this? Thanks so much for your time!!
You can't make a 64bit executable with 32bit code.
If you want to make a 32bit executable, you can use -m elf_i386:
$ ld -s -o test test.o
ld: i386 architecture of input file `test.o' is incompatible
with i386:x86-64 output
$ ld -s -o test test.o -m elf_i386
$
I am using Linux 2.6.31-14 on Intel 32-bit processor.
C file:
#include <stdio.h>
main()
{
printf("Hello World!\n");
}
Linker script:
SECTIONS{
.text 0x00000100 :{
*(.text)
}
}
Output:
$ gcc -S test.c
$ as -o test.o test.s
$ ld -T linker.ld -dynamic-linker /lib/ld-linux.so.2 -o test test.o
test.o: In function `main':
test.c:(.text+0x11): undefined reference to `puts'
What is wrong? How can I make the linker script use the dynamic C library?
I think that you should link your program with C standard library (libc.so) by adding -lc option to ld arguments.
ld -T linker.ld -lc -dynamic-linker /lib/ld-linux.so.2 -o test test.o
Also you may have some problems with running your program (segmentation faults) because your test.o have no program entry point (_start symbol). So you will need additional object file with entry point that is calling your main() function inside test.o and than termitates code execution by calling exit() system call.
Here is start.s code
# Linux system calls constants
.equ SYSCALL_EXIT, 1
.equ INTERRUPT_LINUX_SYSCALL, 0x80
# Code section
.section .text
.globl _start
_start: # Program entry point
call main # Calling main function
# Now calling exit() system call
movl %eax, %ebx # Saving return value for exit() argument
movl $SYSCALL_EXIT, %eax # System call number
int $INTERRUPT_LINUX_SYSCALL # Raising programm interrupt
Then you should build your program
gcc test.c -S
as test.s -o test.o
as start.s -o start.o
ld start.o test.o -o test -lc --dynamic-linker=/lib/ld-linux.so.2
You may also want to check out this article https://blogs.oracle.com/ksplice/entry/hello_from_a_libc_free to learn more about how C compiler and standard library works.
You are not linking in the c library.
On my 64bit system it's:
-dynamic-linker /lib64/ld-linux-x86-64.so.2 /lib64/libc.so.6