What am I overlooking with my library?

**awsdert** · 04-26-2021

The output issue:

Code:

make --no-print-directory CLONED_DIR=.. rebuild
cd ../ && make rebuild
make -f run.mak rebuild
git -C ../mak pull
Already up to date.
rm -f ./bin/*.exe
rm -f ./lib/*.dll
rm -f ./src/*.obj
rm -f ./bin/*.out
rm -f ./lib/*.so
rm -f ./src/*.o
gcc -I ./include -L ./lib  -D PAW_EXPORT -o src/app.c.o -c src/app.c
gcc -I ./include -L ./lib  -D PAW_EXPORT -o src/apps.c.o -c src/apps.c
gcc -I ./include -L ./lib  -D PAW_EXPORT -o src/lib.c.o -c src/lib.c
gcc -I ./include -L ./lib  -D PAW_EXPORT -o src/libs.c.o -c src/libs.c
gcc -I ./include -L ./lib  -D PAW_EXPORT -o src/maps.c.o -c src/maps.c
gcc -I ./include -L ./lib  -D PAW_EXPORT -o src/paw.c.o -c src/paw.c
gcc -I ./include -L ./lib  -D PAW_EXPORT -o src/shared.c.o -c src/shared.c
gcc -I ./include -L ./lib  -o ./lib/libpaw.so src/app.c.o src/apps.c.o src/lib.c.o src/libs.c.o src/maps.c.o src/paw.c.o src/shared.c.o -ldl
gcc -I ./include -L ./lib  -o chkpaw.out ./src/chkpaw.c -lpaw -ldl
/usr/bin/ld: /tmp/ccmy0FBq.o: in function `test':
chkpaw.c:(.text+0x21): undefined reference to `paw_load_app'
/usr/bin/ld: chkpaw.c:(.text+0x5d): undefined reference to `paw_unload_app'
collect2: error: ld returned 1 exit status
make[2]: *** [run.mak:38: chkpaw.out] Error 1
make[1]: *** [GNUmakefile:9: rebuild] Error 2
make: *** [makefile:4: rebuild] Error 2
Compilation failed.

The relevant source code:

Code:

#ifdef _MSC_VER
#	define PAW__EXPORT __declspec(dllexport)
#	define PAW__IMPORT __declspec(dllimport)
#	define PAW_HIDDEN
#elif defined( __GNUC__ ) && __GNUC__ > 4
#	define PAW__EXPORT __attribute__((visibility("default")))
#	define PAW__IMPORT
#	define PAW_HIDDEN __attribute__((visibility("hidden")))
#else
#	define PAW__EXPORT
#	define PAW__IMPORT
#	define PAW_HIDDEN
#endif

#ifdef PAW_EXPORT
#	define PAW_PUBLIC PAW__EXPORT
#elif defined( PAW_STATIC )
#	define PAW_PUBLIC
#else
#	define PAW_PUBLIC PAW__IMPORT
#endif

**Salem** · 04-26-2021

> /usr/bin/ld: chkpaw.c

.text+0x5d): undefined reference to `paw_unload_app'
This usually means
- you didn't implement that function.
- you implemented it, but it's static (or hidden) for some reason.
- you mis-spelled the name between the declaration and the use.

**awsdert** · 04-26-2021

- you implemented it, but it's static (or hidden) for some reason

is all it can be

Code:

#if defined( PAW_BUILD_SHARED ) && defined( PAW_WIN32 )
#	define PAW_SHARED PAW_EXPORT
#else
#	define PAW_SHARED
#endif
...
PAW_SHARED struct paw_app* paw_load_app( void *ud, int pid )
{
	struct paw_app *app = paw__record_app(ud);
	struct paw_text *path;
	
	if ( !app )
		return NULL;
		
	app->pid = pid;
	
	if ( pid == getpid() )
		strcpy( app->proc, "/proc/self" );
	else
		sprintf( app->proc, "/proc/%i", pid );
	
	path = &(app->path);
	path->buff = paw.alloc( ud, NULL, 0, PAW_APP_PATH_DEFAULT_SIZE );
	
	if ( !path->buff )
	{
		paw_unload_app( ud, app );
		return NULL;
	}
	
	path->size = PAW_APP_PATH_DEFAULT_SIZE;

	return app;
}
PAW_HIDDEN void paw__forget_app( void *ud, struct paw_app *app )
{
	struct paw_text *text = &(app->buff);
	
	paw_unhook_app( ud, app );
	
	if ( text->buff )
		(void)paw.alloc( ud, text->buff, text->size, 0 );
		
	text = &(app->path);
	
	if ( text->buff )
		(void)paw.alloc( ud, text->buff, text->size, 0 );
	
	text = &(app->bootpath);
	
	if ( text->buff )
		(void)paw.alloc( ud, text->buff, text->size, 0 );
}

PAW_SHARED void paw_unload_app( void *ud, struct paw_app *app )
{
	paw__forget_app( ud, app );
	(void)paw.alloc( ud, app, sizeof( struct paw_app ), 0 );
}

Edit: btw I changed the define that checking for from PAW_EXPORT to PAW_BUILD_SHARED and renamed the PAW__EXPORT/PAW__IMPORT to PAW_EXPORT/PAW_IMPORT

**Salem** · 04-26-2021

So how does that differ from all the other public functions in your other source files?

Does 'nm ./lib/libpaw.so' tell you anything about what symbols are present?

**awsdert** · 04-26-2021

nm libpaw.so gave me this:

Code:

000000000000039c r __abi_tag
00000000000050d0 B __bss_start
                 U close@GLIBC_2.2.5
00000000000050d0 b completed.0
                 w __cxa_finalize@GLIBC_2.2.5
00000000000050c0 D __data_start
00000000000050c0 W data_start
00000000000011b0 t deregister_tm_clones
                 U dlopen@GLIBC_2.2.5
0000000000001220 t __do_global_dtors_aux
0000000000004de0 d __do_global_dtors_aux_fini_array_entry
00000000000050c8 D __dso_handle
0000000000004de8 d _DYNAMIC
00000000000050d0 D _edata
00000000000050e0 B _end
                 U __errno_location@GLIBC_2.2.5
                 U fclose@GLIBC_2.2.5
0000000000002368 T _fini
                 U fopen@GLIBC_2.2.5
0000000000001270 t frame_dummy
0000000000004dd0 d __frame_dummy_init_array_entry
000000000000350c r __FRAME_END__
                 U fread@GLIBC_2.2.5
                 U free@GLIBC_2.2.5
                 U fseek@GLIBC_2.2.5
                 U fseeko64@GLIBC_2.2.5
                 U fwrite@GLIBC_2.2.5
                 U getpid@GLIBC_2.2.5
0000000000005000 d _GLOBAL_OFFSET_TABLE_
                 w __gmon_start__
000000000000306c r __GNU_EH_FRAME_HDR
0000000000001000 t _init
00000000000022d3 t init
0000000000004de0 d __init_array_end
0000000000004dd0 d __init_array_start
0000000000003000 R _IO_stdin_used
                 U __isoc99_sscanf@GLIBC_2.7
                 w _ITM_deregisterTMCloneTable
                 w _ITM_registerTMCloneTable
0000000000002360 T __libc_csu_fini
00000000000022f0 T __libc_csu_init
                 U __libc_start_main@GLIBC_2.2.5
00000000000022da T main
                 U malloc@GLIBC_2.2.5
                 U memcpy@GLIBC_2.14
                 U memset@GLIBC_2.2.5
                 U open@GLIBC_2.2.5
00000000000050d8 B paw
00000000000016ab T paw_1st_app
0000000000001da1 T paw__alloc
0000000000001619 T paw_boot_app
0000000000001877 T paw_compare_maps
0000000000001e74 T paw_dump_app_state
00000000000012bd T paw__forget_app
00000000000022be T paw_get_app_boot_bath
00000000000016d1 T paw_have_lib
0000000000001417 T paw_hook_app
0000000000001e14 T paw_init
0000000000001675 T paw_list_apps
0000000000001527 T paw_load_app
00000000000016f4 T paw_load_lib
0000000000001717 T paw_load_maps_file
00000000000019ec T paw_load_maps_text
00000000000016be T paw_nxt_app
0000000000001e5f T paw__perm2native
0000000000001279 T paw__record_app
0000000000001e58 T paw_term
00000000000013e5 T paw_unhook_app
000000000000162c T paw_unlist_apps
00000000000013a0 T paw_unload_app
                 U qsort@GLIBC_2.2.5
                 U realloc@GLIBC_2.2.5
00000000000011e0 t register_tm_clones
                 U sprintf@GLIBC_2.2.5
                 U __stack_chk_fail@GLIBC_2.4
0000000000001180 T _start
                 U strlen@GLIBC_2.2.5
00000000000050d0 D __TMC_END__

What am I looking for? 1st time I hear of nm

**stahta01** · 04-26-2021

This code is likely wrong.

Code:

#ifdef PAW_EXPORT
#   define PAW_PUBLIC PAW__EXPORT
#elif defined( PAW_STATIC )
#   define PAW_PUBLIC
#else
#   define PAW_PUBLIC PAW__IMPORT
#endif

Likely more correct is

Code:

#if defined( PAW_STATIC )
#   define PAW_PUBLIC export
#elif defined( PAW_EXPORT )
#   define PAW_PUBLIC PAW__EXPORT
#else
#   define PAW_PUBLIC PAW__IMPORT
#endif

**awsdert** · 04-26-2021

Aside from the "extern" bit that looks like it amounts to the same deal though? I'll try anyways

Edit: Nope, didn't resolve it, what it looks like now btw:

Code:

#ifdef PAW_BUILD_STATIC
#	define PAW_PUBLIC extern
#elif defined( PAW_BUILD_SHARED )
#	define PAW_PUBLIC PAW_EXPORT
#else
#	define PAW_PUBLIC PAW_IMPORT
#endif

**awsdert** · 04-26-2021

Found out what I overlooked, the library needed to be linked with -shared option set, the code needed to be compiled with the -fPIC option set

**awsdert** · 04-27-2021

Another problem being experienced, tried to actually run the app I was compiling and linking to libpaw (one that checks that libpaw does as expected) and ld or whatever it was couldn't find libpaw, I tried setting -Wl,--rpath=. during compile, tried setting LD_LIBRARY_PATH=.:$(LD_LIBRARY_PATH) on the same line I execute the binary, still nothing, any ideas?

Code:

make --no-print-directory CLONED_DIR=.. run (in directory: .../gitlab/gasp/cloned/paw)
make -f run.mak run
git -C ../mak pull
Already up to date.
cp ./lib/libpaw.so ./bin/libpaw.so
LD_LIBRARY_PATH=.: && ./bin/chkpaw.out
./bin/chkpaw.out: error while loading shared libraries: libpaw.so: cannot open shared object file: No such file or directory
make[1]: *** [run.mak:28: run] Error 127
make: *** [GNUmakefile:9: run] Error 2
Compilation failed.

Code:

make --no-print-directory CLONED_DIR=.. rebuild (in directory: /mnt/MEDIA/HOME/gitlab/gasp/cloned/paw)
make -f run.mak rebuild
git -C ../mak pull
Already up to date.
rm -f ./bin/*.exe
rm -f ./lib/*.dll
rm -f ./src/*.obj
rm -f ./bin/*.out
rm -f ./lib/*.so
rm -f ./src/*.o
gcc -I ./include -L ./lib  -fPIC -D PAW_BUILD_SHARED -o src/app.c.o -c src/app.c
gcc -I ./include -L ./lib  -fPIC -D PAW_BUILD_SHARED -o src/apps.c.o -c src/apps.c
gcc -I ./include -L ./lib  -fPIC -D PAW_BUILD_SHARED -o src/lib.c.o -c src/lib.c
gcc -I ./include -L ./lib  -fPIC -D PAW_BUILD_SHARED -o src/libs.c.o -c src/libs.c
gcc -I ./include -L ./lib  -fPIC -D PAW_BUILD_SHARED -o src/maps.c.o -c src/maps.c
gcc -I ./include -L ./lib  -fPIC -D PAW_BUILD_SHARED -o src/paw.c.o -c src/paw.c
gcc -I ./include -L ./lib  -fPIC -D PAW_BUILD_SHARED -o src/shared.c.o -c src/shared.c
gcc -I ./include -L ./lib  -fPIC -shared -o lib/libpaw.so src/app.c.o src/apps.c.o src/lib.c.o src/libs.c.o src/maps.c.o src/paw.c.o src/shared.c.o -ldl
gcc -I ./include -L ./lib  -fPIC -o bin/chkpaw.out ./src/chkpaw.c -lpaw -Wl,--rpath=.
Compilation finished successfully.

**stahta01** · 04-27-2021

Originally Posted by awsdert

Another problem being experienced, tried to actually run the app I was compiling and linking to libpaw (one that checks that libpaw does as expected) and ld or whatever it was couldn't find libpaw, I tried setting -Wl,--rpath=. during compile, tried setting LD_LIBRARY_PATH=.:$(LD_LIBRARY_PATH) on the same line I execute the binary, still nothing, any ideas?

Code:

make --no-print-directory CLONED_DIR=.. run (in directory: .../gitlab/gasp/cloned/paw)
make -f run.mak run
git -C ../mak pull
Already up to date.
cp ./lib/libpaw.so ./bin/libpaw.so
LD_LIBRARY_PATH=.: && ./bin/chkpaw.out
./bin/chkpaw.out: error while loading shared libraries: libpaw.so: cannot open shared object file: No such file or directory
make[1]: *** [run.mak:28: run] Error 127
make: *** [GNUmakefile:9: run] Error 2
Compilation failed.

Code:

make --no-print-directory CLONED_DIR=.. rebuild (in directory: /mnt/MEDIA/HOME/gitlab/gasp/cloned/paw)
make -f run.mak rebuild
git -C ../mak pull
Already up to date.
rm -f ./bin/*.exe
rm -f ./lib/*.dll
rm -f ./src/*.obj
rm -f ./bin/*.out
rm -f ./lib/*.so
rm -f ./src/*.o
gcc -I ./include -L ./lib  -fPIC -D PAW_BUILD_SHARED -o src/app.c.o -c src/app.c
gcc -I ./include -L ./lib  -fPIC -D PAW_BUILD_SHARED -o src/apps.c.o -c src/apps.c
gcc -I ./include -L ./lib  -fPIC -D PAW_BUILD_SHARED -o src/lib.c.o -c src/lib.c
gcc -I ./include -L ./lib  -fPIC -D PAW_BUILD_SHARED -o src/libs.c.o -c src/libs.c
gcc -I ./include -L ./lib  -fPIC -D PAW_BUILD_SHARED -o src/maps.c.o -c src/maps.c
gcc -I ./include -L ./lib  -fPIC -D PAW_BUILD_SHARED -o src/paw.c.o -c src/paw.c
gcc -I ./include -L ./lib  -fPIC -D PAW_BUILD_SHARED -o src/shared.c.o -c src/shared.c
gcc -I ./include -L ./lib  -fPIC -shared -o lib/libpaw.so src/app.c.o src/apps.c.o src/lib.c.o src/libs.c.o src/maps.c.o src/paw.c.o src/shared.c.o -ldl
gcc -I ./include -L ./lib  -fPIC -o bin/chkpaw.out ./src/chkpaw.c -lpaw -Wl,--rpath=.
Compilation finished successfully.

Why does your post suggest you are both running your code from the "./bin" folder and not running your code from the "./bin" folder?

Decide which folder is "." when you are running the commands and either do an CD to it or another fix!

Tim S.

**stahta01** · 04-27-2021

Originally Posted by stahta01

Why does your post suggest you are both running your code from the "./bin" folder and not running your code from the "./bin" folder?

Decide which folder is "." when you are running the commands and either do an CD to it or another fix!

Tim S.

In other words, the proper thing to try was likely.

Code:

LD_LIBRARY_PATH=./bin:$(LD_LIBRARY_PATH)

Tim S.

**awsdert** · 04-27-2021

Originally Posted by stahta01

Why does your post suggest you are both running your code from the "./bin" folder and not running your code from the "./bin" folder?

Decide which folder is "." when you are running the commands and either do an CD to it or another fix!

Tim S.

There's makefiles in each directory that simply launch a new instance of make in either the directory above or if in the project directory the main *.mak file which holds all the targets, this is to force make to use the correct PWD/CWD for the *.mak files so ./ in all cases means the project root, in the case of paw that happens to be inside .../gasp/cloned/paw because that's where I cloned it as I'm planning to use it in gasp (only recently remember the paw project of mine and decided to move everything related from gasp into it and then make a lpaw library for lua), in the case of gasp ./ means .../gasp, ./bin is always in the project root and if it isn't it is made prior to running the *.mak files ensuring the directories become a dependency for those files to be run correctly

**awsdert** · 04-27-2021

Originally Posted by stahta01

In other words, the proper thing to try was likely.

Code:

LD_LIBRARY_PATH=./bin:$(LD_LIBRARY_PATH)

Tim S.

Thank you, I'll give that a try

Edit: Went with a variant, cd'd into the directory and ran with the prior command I had already tried, got a segmentation fault so gonna see if I can track down where that came from.

Code:

make --no-print-directory CLONED_DIR=.. run (in directory: .../gasp/cloned/paw)
make -f run.mak run
git -C ../mak pull
Already up to date.
cp ./lib/libpaw.so ./bin/libpaw.so
cd ./bin && LD_LIBRARY_PATH=.: && ./chkpaw.out
make[1]: *** [run.mak:28: run] Segmentation fault (core dumped)
make: *** [GNUmakefile:20: run] Error 2
Compilation failed.

Edit 2: Btw, do any of you know how to open a terminal window from a makefile (cross platform solution is preferred), I've tried variants of the below but to no avail:

Code:

X_TERMINAL:=x-terminal-emulator DISPLAY=$(DISPLAY)--working-directory=$(PWD)
TERMINAL:=$(if $(filter cmd.exe,$(SHELL)),cmd.exe,$(X_TERMINAL))

**awsdert** · 04-27-2021

For anyone wandering the segfault was caused by me forgetting to call paw_init( NULL ) which sets the allocator function pointer, paw_load_app() relied on that function but the pointer started as NULL so it just hit a segfault from the word go

**awsdert** · 04-28-2021

New problem, same library, might as well post here.
Hitting a segfault but I'm not seeing what I did wrong, I'm assuming I miss-allocated but I rather than just throw memory at the problem to shut it up I'd rather understand it 1st, here's the relevant code:

Code:

PAW_HIDDEN int paw_compare_maps( void const * _one, void const * _two )
{
	struct paw_map const *one = _one, *two = _two;
	int ret = (one->first > two->final) - (two->first > one->final);
	
	if ( ret )
		return ret;
		
	ret = (two->first < one->first) - (two->first > one->first);
	
	if ( ret )
		return ret;
	
	ret = (two->final < one->final) - (two->final > one->final);
	
	if ( ret )
		return ret;
		
	ret = (one->perm[0] == 'r') - (two->perm[0] == 'r');
	
	if ( ret )
		return ret;
	
	ret = (one->perm[0] == 'w') - (two->perm[0] == 'w');
	
	if ( ret )
		return ret;
	
	return (one->perm[0] == 'x') - (two->perm[0] == 'x');
}

PAW_SHARED int paw_load_maps_text( void *ud, struct paw_text *text, struct paw_maps *maps )
{
	struct paw_text *sources = &(maps->sources);
	struct paw_map *_maps = maps->buff, *map;
	size_t want = 0, done = 0;
	char *line = text->buff, *source, *_sources = sources->buff, *temp;
	
	want = (text->size / sizeof(struct paw_map)) * sizeof(struct paw_map);
	
	if ( maps->size < want )
	{
		_maps = paw.alloc( ud, _maps, maps->size, want );
		if ( !_maps )
			return ENOMEM;
			
		maps->buff = _maps;
		maps->size = want;
	}
	
	memset( _maps, 0, want );
	
	if ( sources->size < text->size )
	{
		_sources = paw.alloc( ud, _sources, sources->size, text->size );
		
		if ( !_sources )
			return ENOMEM;
		
		sources->buff = _sources;
		sources->size = text->size;
	}
	
	sources->used = 0;
	memset( _sources, 0, sources->size );
	
	for ( maps->used = 0; *line; maps->used++ )
	{
		map = _maps + maps->used;
		
		sscanf
		(
			line
			, "%jx-%jx %s %jx %u:%u %lu%n"
			, &(map->first)
			, &(map->final)
			, map->perm
			, &(map->faddr)
			, &(map->major)
			, &(map->minor)
			, &(map->inode)
			, &done
		);
		
		for ( source = line + done; *source == ' '; ++source );
		for ( line = source; *line && *line != '\n' && *line != '\r'; ++line );
		
		temp = _sources + sources->used;
		map->index = sources->used;
		map->count = (size_t)(line - source);
		
		if ( map->count )
			(void)memcpy( temp, source, map->count );
		
		sources->used += map->count + 1;
	}
	
	/* Downsize now we no longer need the optimization */
	sources->buff = paw.alloc( ud, _sources, sources->size, sources->used );
	sources->size = sources->used;
	
	/* Same with mappings */
	want = maps->used * sizeof(struct paw_map);
	maps->buff = paw.alloc( ud, _maps, maps->size, want );
	maps->size = want;
	
	qsort( maps->buff, maps->size, sizeof(struct paw_map), paw_compare_maps );
	
	return 0;
}

The text parameter only has the 3 members you can see so skip that question, it's preloaded by another function with the contents of /proc/<PID>/maps, in this case it's actually /proc/self/maps (The function that loads app details just fills in the directory to use as an optimization)
According to gede the segfault occured in paw_compare_apps() but only after successfully comparing a number of them so the error is surely with what I hand qsort(), I gave the rest of paw_load_maps_text() for context, the main area I'm looking at is at the bottom of that function

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