On 2024/12/08 13:36, Chris Billington wrote:
> I am attempting to make a port of ctune [https://github.com/An7ar35/ctune],
> an nCurses Internet Radio player written in C.
>
> This seems to be worthwhile, because audio/gradio and audio/curseradio are
> both currently nonfunctional due to API changes in underlying libraries, and
> are based on inactive projects.
>
> I tested ctune on a Linux install and it seems to be both functional,
> low-resource and fast. It also includes support for sndio output.
>
> First steps, getting the program to build, having solved a few type errors I
> have run into the following issue:
>
> [ 23%] Building C object
> plugins/output/pulseaudio/CMakeFiles/ctune_plugin_pulseaudio.dir/__/__/__/src/datastructure/CircularBuffer.c.o
> cd /home/chris/Downloads/build/ctune/plugins/output/pulseaudio && /usr/bin/cc
> -Dctune_plugin_pulseaudio_EXPORTS
> -I/home/chris/Downloads/build/ctune/libraries -I/usr/local/include
> -I/home/chris/Downloads/build/ctune/generated-src -Wextra -O2 -std=gnu99
> -fPIC -MD -MT
> plugins/output/pulseaudio/CMakeFiles/ctune_plugin_pulseaudio.dir/__/__/__/src/datastructure/CircularBuffer.c.o
> -MF
> CMakeFiles/ctune_plugin_pulseaudio.dir/__/__/__/src/datastructure/CircularBuffer.c.o.d
> -o
> CMakeFiles/ctune_plugin_pulseaudio.dir/__/__/__/src/datastructure/CircularBuffer.c.o
> -c /home/chris/Downloads/build/ctune/src/datastructure/CircularBuffer.c
> /home/chris/Downloads/build/ctune/src/datastructure/CircularBuffer.c:36:17:
> warning: call to undeclared function 'syscall'; ISO C99 and later do not
> support implicit function declarations [-Wimplicit-function-declaration]
> long fd = syscall( __NR_memfd_create, name, flags );
> ^
> /home/chris/Downloads/build/ctune/src/datastructure/CircularBuffer.c:36:26:
> error: use of undeclared identifier '__NR_memfd_create'
> long fd = syscall( __NR_memfd_create, name, flags );
> ^
> 1 warning and 1 error generated.
> *** Error 1 in .
> (plugins/output/pulseaudio/CMakeFiles/ctune_plugin_pulseaudio.dir/build.make:107
>
> 'plugins/output/pulseaudio/CMakeFiles/ctune_plugin_pulseaudio.dir/__/__/__/src/datastructure/CircularBuffer.c.o')
> *** Error 2 in . (CMakeFiles/Makefile2:504
> 'plugins/output/pulseaudio/CMakeFiles/ctune_plugin_pulseaudio.dir/all')
> *** Error 2 in /home/chris/Downloads/build/ctune (Makefile:139 'all')
>
> Pulseaudio is installed on my machine because other progams I run require it .
>
> The relevant lines of the file causing the above issue are:
>
> (src/datastructure/CircularBuffer.c)
>
> #include "CircularBuffer.h"
>
> #include <errno.h>
> #include <string.h>
> #include <limits.h>
> #include <sys/mman.h>
> #include <sys/syscall.h>
> #include <unistd.h>
>
> #include "logger/src/Logger.h"
>
> /**
> * [PRIVATE] Gets a string representation of the error enum val for pthread
> returns
> * @param i Error enum integer val
> * @return String
> */
> static const char * CircularBuffer_getPThreadErrStr( int i ) {
> switch( i ) {
> case 0 : return "OK";
> case EINVAL : return "EINVAL";
> case EBUSY : return "EBUSY";
> case EAGAIN : return "EAGAIN";
> case EDEADLK: return "EDEADLK";
> case EPERM : return "EPERM";
> default : return "UNKNOWN";
> }
> }
>
> /**
> * [PRIVATE] Gets a file descriptor for an anonymous file residing in memory
> (replica of https://man7.org/>
> * @param name Name of file
> * @param flags Flags
> * @return File descriptor (-1 or error)
> */
> static int CircularBuffer_memfd_create( const char * name, unsigned int flags
> ) {
> long fd = syscall( __NR_memfd_create, name, flags );
> int cast = 0;
>
> if( fd >= 0 ) {
> if( fd <= INT_MAX ) {
> cast = (int) fd;
>
> } else {
> CTUNE_LOG( CTUNE_LOG_ERROR,
> "[CircularBuffer_memfd_create( \"%s\", %d )] Failed
> cast long->int (%ld)",
> name, flags, fd
> );
>
> cast = -1;
> }
> }
>
> return cast;
> }
>
>
> Can anyone offer some assistance in resolving this 'undeclared function'
> issue please?
As it has sndio support anyway, we don't want to build pulseaudio
support anyway (nor the other plugins really). However this
CircularBuffer data structure is also used in src/ui/EventQueue.c which
looks more of a core thing so I think it will still need an alternative
- try gkoehler's suggestion for that.
To disable - there doesn't seem to be a cmake flag you can use in
CONFIGURE_ARGS to disable these but you can patch CMakeLists.txt - in
the ports framework, extract the files (I usually type "make patch"
for this, even if there aren't any yet), "cd `make show=WRKSRC`", "cp
CMakeLists.txt CMakeLists.txt.orig.port", edit CMakeLists.txt, "cd -",
"make update-patches"
Looking lower in cmakelists we have
target_link_libraries(ctune PRIVATE
ctune_logger #CTUNE_LOG(..)
${JSONC_LIBRARIES} #(json-c/*.h) for `parse/JSON.c`
${NCURSES_LIBRARIES} #(ncurses.h) for `ui/*`
${CURSES_LIBRARIES} #(ncurses.h) for `ui/*`
panel #(panel.h) ncurses panel lib for `ui/*`
form #(form.h) ncurses form lib for `ui/*`
pthread #threading
OpenSSL::SSL #(openssl/*.h) for `network/NetworkUtils.c`
OpenSSL::Crypto #(openssl/*.h) for `network/NetworkUtils.c`
m #(math.h) for `utils/utilities.c`
uuid #(uuid/uuid.h) for `utils/utilities.c`
curl #(curl/curl.h) for `network/NetworkUtils.c`
dl #(dlfcn.h) for `fs/Plugin.c`
)
giving some clues for other libraries you'll need installed - some
are in base, from ports you'll want libjson-c (devel/json-c), libuuid
(it probably wants the one in sysutils/e2fsprogs), curl (net/curl).
OpenBSD doesn't use libdl and you probably need to delete that line
in a patch (the relevant functions are just in libc on OpenBSD,
there is no libdl, so trying to link with it will fail).
> How does one declare the 'syscall' function here, and why is it not needed on
> the Linux platform?
>
> Do we have an equivalent for the Linux macro syscall __NR_memfd_create (which
> seems also to be aliased as SYS_memfd_create)?
IIUC: Linux has this history of adding things to the kernel that glibc
doesn't want to add wrappers for, so in order to use them programs
wanting to use it have to use the syscall directly.
OpenBSD (since recently) doesn't permit using syscall() at all any more
- it's a potent vector for BROP attacks ("ret2syscall"). But because the
kernel and libraries are developed alongside each other and we don't
have a policy of maintaining ABI so that old binaries stay running, its
not a problem to add wrappers for kernel calls to libc if we need them.
That said we don't have memfd support at all hence gkoehler's suggestion
of a workaround.
