Questions tagged [dynamic-loading]
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29 questions
0
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dlsym, when run from an LD_PRELOAD interposer, does not find any symbols from the main program
/* dlsym-main.c */
#include <stdio.h>
void doSomething(char const *msg)
{
fprintf(stderr, "Main program is doing %s\n", msg);
}
void (*fnptr)(char const *) = doSomething;
int ...
0
votes
1
answer
489
views
Changing the path opened by openat of a program using LD_PRELOAD
I want to change a path that a program actually opens on filesystem for some paths. The reason is that I want to run a program in parallel, but that program uses /tmp/somedir/ as its temporary ...
- 1,816
0
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1
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110
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tcpdump doesn't appear to call any libpcap's exported function
Digging into tcpdump implementation, I can see that it actually loads the libpcap.so dynamic library in userspace.
However, by use of strace, I can't see any occurrence of calls to any function ...
- 385
0
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1
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827
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Understanding LD_ASSUME_KERNEL usage
I am trying to make sense of the env variable LD_ASSUME_KERNEL on my system (Debian/bullseye+bpo).
Accoring to :
$ man pthreads
I should be able to run something like this, however on my system here ...
- 3,459
4
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0
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341
views
Is there any solution to ltrace calls made by libs opened using dlopen()?
I wrote different two different types of queues. Bundled them in different .sos. I have a driver main.c which tests functions offered by those queues. main.c makes use dlfcn.h to load, unload required ...
- 45
0
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1
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447
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How can I "give" a forked process a diferent dynamic library than the one it "asks" for?
I want to know how I can "give" a forked process a different dynamic library than the one it "asks" for. For example, if the fork "asks" for the library "foo.so"...
0
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0
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395
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What is the best way of finding library conflicts in a large application?
I have a large application (let's call it P) with lots of dependencies to boost, Qt, zlib, libpng, etc. Recently, I have added a feature to P that needs to dynamically load a new shared object (let's ...
- 157
1
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0
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62
views
Why does the address of an internal symbol needs to be recorded in .got?
I am reading the blog https://eli.thegreenplace.net/2011/11/11/position-independent-code-pic-in-shared-libraries-on-x64
In the part "x64 PIC with data references - an example", it seems that the ...
- 1,435
0
votes
2
answers
1k
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$LIB variable does not expand to anything in Ubuntu Server 18.10
I have the same exact problem as this question previously posted, where /etc/ld.so.preload does not intercept the right architecture. A little background: I have compiled a shared object (64-bit) that ...
- 451
6
votes
1
answer
1k
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Are .text sections shared between loaded ELF executables?
If one program, for example grep, is curretly running, and a user executes another instance, do the two instances share the read-only .text sections between them to save memory? Would the sharing of ...
- 429
2
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1
answer
2k
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what are the executable ELF files respectively for static linker, dynamic linker, loader and dynamic loader?
In Linux, what are the executable ELF files respectively for
static linker
dynamic linker
loader
dynamic loader?
Which of them are invoked
by execve()
by dlopen()?
How are they invoked by execve() ...
- 107k
1
vote
1
answer
948
views
What kinds of files can be dynamically loaded?
Operating System Concepts, by Silberschatz A., Galvin P. B., Gagne G. - Operating System Concepts, 9th Edition - 2012 says
8.1.4 Dynamic Loading
In our discussion so far, it has been necessary ...
- 107k
1
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1
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4k
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How does Linux kernel dynamically use a module?
Understanding the Linux Kernel says
The kernel has two key tasks to perform in managing modules. The first task is mak-
ing sure the rest of the kernel can reach the module’s global symbols, such ...
- 107k
5
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1
answer
12k
views
How to run programs with ld-linux.so?
The dynamic linker can be run either indirectly by running some dynamically linked program or shared object (in which case no command-line options to the dynamic linker can be passed and, in the ELF ...
- 3,623
0
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2
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2k
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Will the execution of the binaries that is sitting on a mounted NFS directory fails when network interruption happen?
So I have a Linux machine that acts as an NFS server. Lots of programs has been installed to the folder that is being exported.
On another Linux machine, I've been running one of the program that is ...
- 11