Forwarded ported a number of skas-related fixes from 2.4.

arch/um/drivers/harddog_user.c

@@ -11,6 +11,8 @@
 #include "helper.h"
 #include "mconsole.h"
 #include "os.h"
+#include "choose-mode.h"
+#include "mode.h"
 
 struct dog_data {
 	int stdin;
@@ -63,7 +65,8 @@ int start_watchdog(int *in_fd_ret, int *out_fd_ret, char *sock)
 		args = mconsole_args;
 	}
 	else {
-		sprintf(pid_buf, "%d", tracing_pid);
+		/* XXX The os_getpid() is not SMP correct */
+		sprintf(pid_buf, "%d", CHOOSE_MODE(tracing_pid, os_getpid()));
 		args = pid_args;
 	}
 

arch/um/kernel/tt/tracer.c

@@ -120,16 +120,6 @@ static int signal_tramp(void *arg)
 	return((*proc)(NULL));
 }
 
-static void last_ditch_exit(int sig)
-{
-	kmalloc_ok = 0;
-	signal(SIGINT, SIG_DFL);
-	signal(SIGTERM, SIG_DFL);
-	signal(SIGHUP, SIG_DFL);
-	uml_cleanup();
-	exit(1);
-}
-
 static void sleeping_process_signal(int pid, int sig)
 {
 	switch(sig){
@@ -214,9 +204,6 @@ int tracer(int (*init_proc)(void *), void *sp)
 
 	signal(SIGSEGV, (sighandler_t) tracer_segv);
 	signal(SIGUSR1, signal_usr1);
-	set_handler(SIGINT, last_ditch_exit, SA_ONESHOT | SA_NODEFER, -1);
-	set_handler(SIGTERM, last_ditch_exit, SA_ONESHOT | SA_NODEFER, -1);
-	set_handler(SIGHUP, last_ditch_exit, SA_ONESHOT | SA_NODEFER, -1);
 	if(debug_trace){
 		printf("Tracing thread pausing to be attached\n");
 		stop();

arch/um/kernel/um_arch.c

@@ -110,12 +110,14 @@ unsigned long start_vm;
 unsigned long end_vm;
 int ncpus = 1;
 
+#ifdef CONFIG_MODE_TT
 /* Pointer set in linux_main, the array itself is private to each thread,
  * and changed at address space creation time so this poses no concurrency
  * problems.
  */
 static char *argv1_begin = NULL;
 static char *argv1_end = NULL;
+#endif
 
 /* Set in early boot */
 static int have_root __initdata = 0;
@@ -123,6 +125,7 @@ long physmem_size = 32 * 1024 * 1024;
 
 void set_cmdline(char *cmd)
 {
+#ifdef CONFIG_MODE_TT
 	char *umid, *ptr;
 
 	if(CHOOSE_MODE(honeypot, 0)) return;
@@ -139,6 +142,7 @@ void set_cmdline(char *cmd)
 	snprintf(ptr, (argv1_end - ptr) * sizeof(*ptr), " [%s]", cmd);
 	memset(argv1_begin + strlen(argv1_begin), '\0', 
 	       argv1_end - argv1_begin - strlen(argv1_begin));
+#endif
 }
 
 static char *usage_string = 
@@ -199,23 +203,28 @@ static int __init mode_tt_setup(char *line, int *add)
 	return(0);
 }
 
-__uml_setup("mode=tt", mode_tt_setup,
-"mode=tt\n"
-"    When both CONFIG_MODE_TT and CONFIG_MODE_SKAS are enabled, this option\n"
-"    forces UML to run in tt (tracing thread) mode.  It is not the default\n"
-"    because it's slower and less secure than skas mode.\n\n"
-);
-
 #else
 #ifdef CONFIG_MODE_SKAS
 
 #define DEFAULT_TT 0
 
+static int __init mode_tt_setup(char *line, int *add)
+{
+	printk("CONFIG_MODE_TT disabled - 'mode=tt' ignored\n");
+	return(0);
+}
+
 #else
 #ifdef CONFIG_MODE_TT
 
 #define DEFAULT_TT 1
 
+static int __init mode_tt_setup(char *line, int *add)
+{
+	printk("CONFIG_MODE_SKAS disabled - 'mode=tt' redundant\n");
+	return(0);
+}
+
 #else
 
 #error Either CONFIG_MODE_TT or CONFIG_MODE_SKAS must be enabled
@@ -224,6 +233,13 @@ __uml_setup("mode=tt", mode_tt_setup,
 #endif
 #endif
 
+__uml_setup("mode=tt", mode_tt_setup,
+"mode=tt\n"
+"    When both CONFIG_MODE_TT and CONFIG_MODE_SKAS are enabled, this option\n"
+"    forces UML to run in tt (tracing thread) mode.  It is not the default\n"
+"    because it's slower and less secure than skas mode.\n\n"
+);
+
 int mode_tt = DEFAULT_TT;
 
 static int __init Usage(char *line, int *add)
@@ -307,8 +323,10 @@ int linux_main(int argc, char **argv)
 
 	setup_machinename(system_utsname.machine);
 
+#ifdef CONFIG_MODE_TT
 	argv1_begin = argv[1];
 	argv1_end = &argv[1][strlen(argv[1])];
+#endif
   
 	set_usable_vm(uml_physmem, get_kmem_end());
 

arch/um/main.c

@@ -15,10 +15,12 @@
 #include "user_util.h"
 #include "kern_util.h"
 #include "mem_user.h"
+#include "signal_user.h"
 #include "user.h"
 #include "init.h"
 #include "mode.h"
 #include "choose-mode.h"
+#include "uml-config.h"
 
 /* Set in set_stklim, which is called from main and __wrap_malloc.  
  * __wrap_malloc only calls it if main hasn't started.
@@ -32,11 +34,6 @@ char *linux_prog;
 #define STACKSIZE (8 * 1024 * 1024)
 #define THREAD_NAME_LEN (256)
 
-/* Never changed */
-static char padding[THREAD_NAME_LEN] = { 
-	[ 0 ...  THREAD_NAME_LEN - 2] = ' ', '\0' 
-};
-
 static void set_stklim(void)
 {
 	struct rlimit lim;
@@ -66,26 +63,43 @@ static __init void do_uml_initcalls(void)
 	}
 }
 
+static void last_ditch_exit(int sig)
+{
+	CHOOSE_MODE(kmalloc_ok = 0, (void) 0);
+	signal(SIGINT, SIG_DFL);
+	signal(SIGTERM, SIG_DFL);
+	signal(SIGHUP, SIG_DFL);
+	uml_cleanup();
+	exit(1);
+}
+
 extern int uml_exitcode;
 
 int main(int argc, char **argv, char **envp)
 {
+	char **new_argv;
 	sigset_t mask;
 	int ret, i;
-	char **new_argv;
 
-	/* Enable all signals - in some environments, we can enter with
-	 * some signals blocked
+	/* Enable all signals except SIGIO - in some environments, we can 
+	 * enter with some signals blocked
 	 */
 
 	sigemptyset(&mask);
+	sigaddset(&mask, SIGIO);
 	if(sigprocmask(SIG_SETMASK, &mask, NULL) < 0){
 		perror("sigprocmask");
 		exit(1);
 	}
 
+#ifdef CONFIG_MODE_TT
 	/* Allocate memory for thread command lines */
 	if(argc < 2 || strlen(argv[1]) < THREAD_NAME_LEN - 1){
+
+		char padding[THREAD_NAME_LEN] = { 
+			[ 0 ...  THREAD_NAME_LEN - 2] = ' ', '\0' 
+		};
+
 		new_argv = malloc((argc + 2) * sizeof(char*));
 		if(!new_argv) {
 			perror("Allocating extended argv");
@@ -103,6 +117,7 @@ int main(int argc, char **argv, char **envp)
 		perror("execing with extended args");
 		exit(1);
 	}	
+#endif
 
 	linux_prog = argv[0];
 
@@ -120,6 +135,10 @@ int main(int argc, char **argv, char **envp)
 	}
 	new_argv[argc] = NULL;
 
+	set_handler(SIGINT, last_ditch_exit, SA_ONESHOT | SA_NODEFER, -1);
+	set_handler(SIGTERM, last_ditch_exit, SA_ONESHOT | SA_NODEFER, -1);
+	set_handler(SIGHUP, last_ditch_exit, SA_ONESHOT | SA_NODEFER, -1);
+
 	do_uml_initcalls();
 	ret = linux_main(argc, argv);
 	
@@ -141,8 +160,10 @@ extern void *__real_malloc(int);
 
 void *__wrap_malloc(int size)
 {
-	if(CAN_KMALLOC()) return(um_kmalloc(size));
-	else return(__real_malloc(size));
+	if(CAN_KMALLOC())
+		return(um_kmalloc(size));
+	else
+		return(__real_malloc(size));
 }
 
 void *__wrap_calloc(int n, int size)