UML kernel reads polling interval from a config file

arch/um/include/shared/aha-defs.h

@@ -0,0 +1,12 @@
+#ifndef __AHA_DEFS__
+#define __AHA_DEFS__
+/* Global variables used for the aha framework */
+
+/* Polling delay for sys_execve. AHA polls the permissions for each system call.
+ * The delay must be expressed in ms
+ * This delay is read once in the main from the conf/polldelay file. Thus one
+ * write. Each sys_execve calls read then this global variable
+ */
+extern int __aha_poll_delay;
+#define AHA_DEF_POLL_DELAY 100
+#endif

arch/um/include/shared/aha.h

@@ -1,6 +1,5 @@
 #ifndef AHA
 #define AHA
-
 #define AHA_DEBUG
 #include "linux/kernel.h" /* printk is declared there */
 //#include "linux/gfp.h" /* GFP_KERNEL */
@@ -18,7 +17,7 @@
 //#include "skas.h"
 #include "os.h"
 #include "linux/delay.h"
-
+#include "aha-defs.h"
 /*FIXME use AHA name space */
 #define MAX_DUMP_BUF 512
 struct ReplyMessage{

arch/um/kernel/aha.c

@@ -170,9 +170,8 @@ void aha_get_reply_message(char* key, struct ReplyMessage *msg)
     filename[0]=0;
 
     snprintf((char*)filename,128,"in/%s",key);
-
     /* Give AHA the time to write the reply */
-    msleep_interruptible(50);
+    msleep_interruptible(__aha_poll_delay);
     fd = os_open_file(filename, of_read(OPENFLAGS()), 0);
     if ( fd < 0 ) {
         AHA_PRINTK("Could not open reply file: %s\n",filename);
@@ -224,3 +223,4 @@ void aha_record_sys_clone(int pid, int ppid)
     #undef filename__size
     #undef buf__size
 }
+

arch/um/os-Linux/Makefile

@@ -9,7 +9,7 @@ obj-y = aio.o elf_aux.o execvp.o file.o helper.o irq.o main.o mem.o process.o \
 
 USER_OBJS := $(user-objs-y) aio.o elf_aux.o execvp.o file.o helper.o irq.o \
 	main.o mem.o process.o registers.o sigio.o signal.o start_up.o time.o \
-	tty.o tls.o uaccess.o umid.o util.o
+	tty.o tls.o uaccess.o umid.o util.o aha.o
 
 CFLAGS_user_syms.o += -DSUBARCH_$(SUBARCH)
 

arch/um/os-Linux/main.c

@@ -16,11 +16,13 @@
 #include "kern_util.h"
 #include "os.h"
 #include "um_malloc.h"
-
+#include "aha-defs.h"
 #define PGD_BOUND (4 * 1024 * 1024)
 #define STACKSIZE (8 * 1024 * 1024)
 #define THREAD_NAME_LEN (256)
 
+int __aha_poll_delay;
+
 static void set_stklim(void)
 {
 	struct rlimit lim;
@@ -38,6 +40,24 @@ static void set_stklim(void)
 	}
 }
 
+/* Read the polling delay from the conf/polldelay file.
+ * On sucess the polling value is returned.
+ * On failure a hardcoded default value is returned.
+ */
+int aha_read_poll_delay(void)
+{
+    FILE *fp;
+    int ret;
+    ret = AHA_DEF_POLL_DELAY; 
+    fp = fopen("conf/polldelay","r");
+    if (fp){
+        if (fscanf(fp,"%d",(int*)&ret)<=0)
+            ret = AHA_DEF_POLL_DELAY;
+        fclose(fp);
+    }
+    return ret;
+}
+
 static __init void do_uml_initcalls(void)
 {
 	initcall_t *call;
@@ -47,6 +67,7 @@ static __init void do_uml_initcalls(void)
 		(*call)();
 		call++;
 	}
+    __aha_poll_delay=aha_read_poll_delay();
 }
 
 static void last_ditch_exit(int sig)