From ac6dc2c2d3eb32443db798003274cbfbd0e4224f Mon Sep 17 00:00:00 2001
From: Alibek Omarov <a1ba.omarov@gmail.com>
Date: Mon, 18 Nov 2024 10:07:10 +0300
Subject: [PATCH] engine: platform: directly call __NR_gettid syscall for
 compatibility with older systems

---
 engine/platform/linux/sys_linux.c | 22 +++++++---------------
 engine/platform/platform.h        | 13 +++++++++----
 2 files changed, 16 insertions(+), 19 deletions(-)

diff --git a/engine/platform/linux/sys_linux.c b/engine/platform/linux/sys_linux.c
index 6ec8f863..1788623e 100644
--- a/engine/platform/linux/sys_linux.c
+++ b/engine/platform/linux/sys_linux.c
@@ -26,32 +26,24 @@ GNU General Public License for more details.
 #include <time.h>
 #include <unistd.h>
 #include <math.h>
+#include <sys/syscall.h>
 #include "platform/platform.h"
 #include <sys/types.h>
 
-#if defined( __GLIBC__ )
-#if ( __GLIBC__ <= 2 ) && ( __GLIBC_MINOR__ <= 30 )
-// Library support was added in glibc 2.30.
-// Earlier glibc versions did not provide a wrapper for this system call,
-// necessitating the use of syscall(2).
-#include <sys/syscall.h>
-
-static pid_t gettid( void )
-{
-	return syscall( SYS_gettid );
-}
-#endif // ( __GLIBC__ <= 2 ) && ( __GLIBC_MINOR__ <= 30 )
-
 // Glibc misses this macro in POSIX headers (bits/types/sigevent_t.h)
 // but it does present in Linux headers (asm-generic/siginfo.h) and musl
 #if !defined( sigev_notify_thread_id )
 #define sigev_notify_thread_id _sigev_un._tid
 #endif // !defined( sigev_notify_thread_id )
-#endif // defined(__GLIBC__)
 
 static void *g_hsystemd;
 static int (*g_pfn_sd_notify)( int unset_environment, const char *state );
 
+int Linux_GetProcessID( void )
+{
+	return syscall( __NR_gettid );
+}
+
 qboolean Platform_DebuggerPresent( void )
 {
 	char buf[4096];
@@ -163,7 +155,7 @@ void Linux_SetTimer( float tm )
 		// this path availiable in POSIX, but may signal wrong thread...
 		// sev.sigev_notify = SIGEV_SIGNAL;
 		sev.sigev_notify = SIGEV_THREAD_ID;
-		sev.sigev_notify_thread_id = gettid();
+		sev.sigev_notify_thread_id = Linux_GetProcessID();
 		sev.sigev_signo = DEBUG_TIMER_SIGNAL;
 		sev.sigev_value.sival_ptr = &timerid;
 		timer_create( CLOCK_REALTIME, &sev, &timerid );
diff --git a/engine/platform/platform.h b/engine/platform/platform.h
index 1605012d..fdbe9ea3 100644
--- a/engine/platform/platform.h
+++ b/engine/platform/platform.h
@@ -101,6 +101,7 @@ void DOS_Shutdown( void );
 void Linux_Init( void );
 void Linux_Shutdown( void );
 void Linux_SetTimer( float time );
+int Linux_GetProcessID( void );
 #endif
 
 static inline void Platform_Init( qboolean con_showalways )
@@ -287,10 +288,12 @@ qboolean VoiceCapture_Lock( qboolean lock );
 	#define INLINE_RAISE(x) asm volatile( "int $3;" );
 	#define INLINE_NANOSLEEP1() // nothing!
 #elif XASH_LINUX && XASH_ARM && !XASH_64BIT
+	#include <sys/syscall.h>
+	#include <sys/types.h>
 	#define INLINE_RAISE(x) do \
 		{ \
 			int raise_pid = getpid(); \
-			int raise_tid = gettid(); \
+			pid_t raise_tid = Linux_GetProcessID(); \
 			int raise_sig = (x); \
 			__asm__ volatile (  \
 				"mov r7,#268\n\t" \
@@ -318,10 +321,12 @@ qboolean VoiceCapture_Lock( qboolean lock );
 			); \
 		} while( 0 )
 #elif XASH_LINUX && XASH_ARM && XASH_64BIT
+	#include <sys/syscall.h>
+	#include <sys/types.h>
 	#define INLINE_RAISE(x) do \
 		{ \
 			int raise_pid = getpid(); \
-			int raise_tid = gettid(); \
+			pid_t raise_tid = Linux_GetProcessID(); \
 			int raise_sig = (x); \
 			__asm__ volatile ( \
 				"mov x8,#131\n\t" \
@@ -349,8 +354,8 @@ qboolean VoiceCapture_Lock( qboolean lock );
 			); \
 		} while( 0 )
 #elif XASH_LINUX
-	#ifdef __NR_tgkill
-		#define INLINE_RAISE(x) syscall( __NR_tgkill, getpid(), gettid(), x )
+	#if defined( __NR_tgkill )
+		#define INLINE_RAISE(x) syscall( __NR_tgkill, getpid(), Linux_GetProcessID(), x )
 	#else // __NR_tgkill
 		#define INLINE_RAISE(x) raise(x)
 	#endif // __NR_tgkill