server: When possible, use tgkill instead of tkill syscall on Linux.

server/context_alpha.c

@@ -341,7 +341,7 @@ int get_thread_single_step( struct thread *thread )
 }
 
 /* send a signal to a specific thread */
-int tkill( int pid, int sig )
+int tkill( int tgid, int pid, int sig )
 {
     /* FIXME: should do something here */
     errno = ENOSYS;

server/context_i386.c

@@ -560,16 +560,24 @@ int get_thread_single_step( struct thread *thread )
 }
 
 /* send a signal to a specific thread */
-int tkill( int pid, int sig )
+int tkill( int tgid, int pid, int sig )
 {
 #ifdef __linux__
     int ret;
+
     __asm__( "pushl %%ebx\n\t"
              "movl %2,%%ebx\n\t"
              "int $0x80\n\t"
              "popl %%ebx\n\t"
              : "=a" (ret)
-             : "0" (238) /*SYS_tkill*/, "r" (pid), "c" (sig) );
+             : "0" (270) /*SYS_tgkill*/, "r" (tgid), "c" (pid), "d" (sig) );
+    if (ret == -ENOSYS)
+        __asm__( "pushl %%ebx\n\t"
+                 "movl %2,%%ebx\n\t"
+                 "int $0x80\n\t"
+                 "popl %%ebx\n\t"
+                 : "=a" (ret)
+                 : "0" (238) /*SYS_tkill*/, "r" (pid), "c" (sig) );
     if (ret >= 0) return ret;
     errno = -ret;
     return -1;

server/context_powerpc.c

@@ -286,7 +286,7 @@ int get_thread_single_step( struct thread *thread )
 }
 
 /* send a signal to a specific thread */
-int tkill( int pid, int sig )
+int tkill( int tgid, int pid, int sig )
 {
     /* FIXME: should do something here */
     errno = ENOSYS;

server/context_sparc.c

@@ -179,7 +179,7 @@ int get_thread_single_step( struct thread *thread )
 }
 
 /* send a signal to a specific thread */
-int tkill( int pid, int sig )
+int tkill( int tgid, int pid, int sig )
 {
     /* FIXME: should do something here */
     errno = ENOSYS;

server/context_x86_64.c

@@ -271,7 +271,7 @@ int get_thread_single_step( struct thread *thread )
 }
 
 /* send a signal to a specific thread */
-int tkill( int pid, int sig )
+int tkill( int tgid, int pid, int sig )
 {
 #ifdef __linux__
     int ret;

server/ptrace.c

@@ -187,7 +187,7 @@ int send_thread_signal( struct thread *thread, int sig )
     {
         if (thread->unix_tid != -1)
         {
-            ret = tkill( thread->unix_tid, sig );
+            ret = tkill( thread->unix_pid, thread->unix_tid, sig );
             if (ret == -1 && errno == ENOSYS) ret = kill( thread->unix_pid, sig );
         }
         else ret = kill( thread->unix_pid, sig );

server/thread.h

@@ -132,7 +132,7 @@ extern void *get_thread_ip( struct thread *thread );
 extern int get_thread_single_step( struct thread *thread );
 extern void get_thread_context( struct thread *thread, CONTEXT *context, unsigned int flags );
 extern void set_thread_context( struct thread *thread, const CONTEXT *context, unsigned int flags );
-extern int tkill( int pid, int sig );
+extern int tkill( int tgid, int pid, int sig );
 extern int send_thread_signal( struct thread *thread, int sig );
 
 extern unsigned int global_error;  /* global error code for when no thread is current */