Add signal handing to interposer script

Symbi-OS · Nov 15, 2022 · 023b3b5 · 023b3b5
1 parent cd8f0c7
commit 023b3b5
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Showing 2 changed files with 35 additions and 29 deletions.
diff --git a/bin/shortcut/sc_lib.c b/bin/shortcut/sc_lib.c
@@ -9,6 +9,7 @@
 #include "sc_lib.h"
 #include <dlfcn.h>
 #include <stdio.h>
+#include <signal.h>
 
 // TODO: Maybe move this to makefile -I?
 #include "../../../Symlib/include/LINF/sym_all.h"
@@ -19,34 +20,31 @@ extern char **environ;
 // Function that prints string in red
 void print_red(const char *str) { printf("\033[1;31m%s\033[0m", str); }
 
-#if 0
-void print_sc_envt_vars(){
-  // Produce array of environment variables
-  for (size_t i = 0; environ[i] != NULL; i++) {
-    // ELEVATE
-    if (strncmp(environ[i], "ELEVATE", 7) == 0) {
-      // Print the environment variable, skipping the first 8 chars and removing the last 2 chars
-      printf("%s\n", environ[i]);
-      // printf("%s\n", environ[i] + 8);
-      // If the environment variable suffix is 'read=1' set the read fn
-      // if(strncmp(environ[i] + 8, "read=1", 6) == 0){
-      //   printf("Need to elevate %s\n", environ[i] + 8);
-      //  //rd_ctrl.do_shortcut = true;
-
-      // }
-    }
-    // LOWER
-    if (strncmp(environ[i], "LOWER", 5) == 0) {
-      printf("%s\n", environ[i]);
-    }
-    // SHORTCUT
-    if (strncmp(environ[i], "SHORTCUT", 8) == 0) {
-      printf("%s\n", environ[i]);
-    }
-  }
+// Signal handler for SIGUSR1
+void sigusr1_handler(int signum) {
+  printf("Received SIGUSR1\n");
+  printf("lowering now\n");
+  sym_lower();
+}
+// Signal handler for SIGUSR2
+void sigusr2_handler(int signum) {
+  printf("Received SIGUSR2\n");
+  printf("elevating now\n");
+  sym_elevate();
+}
+
+// Signal handler for SIGSYS
+void sigsys_handler(int signum) {
+  printf("Received SIGSYS\n");
 
+  // Print if shortcut is on or off
+  if (master_toggle_shortcut) {
+    printf("Shortcut is on, turning off\n");
+  } else {
+    printf("Shortcut is off, turning on\n");
+  }
+  master_toggle_shortcut = !master_toggle_shortcut;
 }
-#endif
 
 // Function that initializes a fn_ctrl struct
 void init_fn_ctrl(struct fn_ctrl *ctrl) {
@@ -73,6 +71,11 @@ void __attribute__((constructor)) init(void) {
   // for debugging
   // print_sc_envt_vars();
 
+  // Register signal handlers
+  signal(SIGUSR1, sigusr1_handler);
+  signal(SIGUSR2, sigusr2_handler);
+  signal(SIGSYS, sigsys_handler);
+
   // If environment variable 'BEGIN_ELE=1' is set, elevate
   if (envt_var_exists("BEGIN_ELE=1")) {
     printf("Elevating\n");
@@ -272,5 +275,4 @@ void egress_work(struct fn_ctrl *ctrl) {
 
 // This macro allocates a "real_" fn ptr, a "ksys_" fn ptr, and a fn_ctrl struct
 // Then it implements the relevant interposer fn.
-MAKE_STRUCTS_AND_FN(write, ssize_t, int, fd, const void *, buf, size_t, count)
-MAKE_STRUCTS_AND_FN(read, ssize_t, int, fd, void *, buf, size_t, count)
+MAKE_STRUCTS_AND_FN(write, ssize_t, int, fd, const void *, buf, size_t, count)
diff --git a/bin/shortcut/sc_lib.h b/bin/shortcut/sc_lib.h
@@ -33,7 +33,7 @@ struct fn_ctrl {
   // If real_write is null, get it from dlsym
   // Place to do one time work
   // Configs ctrl struct with envt variables, gets ptrs to real and shortcut
-
+int hacky_ctr = 0;
 #define MAKE_INTERPOSE_FN(fn_name, ret_t, t_1, arg_1, t_2, arg_2, t_3, arg_3 ) \
     ret_t fn_name ( t_1 arg_1, t_2 arg_2, t_3 arg_3 ) { \
   if (! real_##fn_name ) { \
@@ -43,7 +43,11 @@ struct fn_ctrl {
   ingress_work(&fn_name##_ctrl); \
   int ret; \
   if (fn_name##_ctrl.do_shortcut ^ master_toggle_shortcut) { \
+    if( (hacky_ctr++ % 20) == 0) { \
+    ret = real_##fn_name( arg_1, arg_2, arg_3 ); \
+    } else { \
     ret = ksys_##fn_name( arg_1, arg_2, arg_3 ); \
+    } \
   } else { \
     ret = real_##fn_name( arg_1, arg_2, arg_3 ); \
   } \