Dynamically search for /proc/sys/dev/parport/%s/base-addr

[usb-driver] / usb-driver.c

diff --git a/usb-driver.c b/usb-driver.c
index 252e3279c07b5adab1ba68da5cde70990ceb73d8..ed7893262da4be37b5daf90c2b3fb5fe27634b9e 100644 (file)
--- a/usb-driver.c
+++ b/usb-driver.c
@@ -41,6 +41,7 @@
 #include <bits/wordsize.h>
 #include <sys/ipc.h>
 #include <sys/sem.h>
+#include <sys/mman.h>
 #include <syscall.h>
 #include <linux/personality.h>
 #include "usb-driver.h"
@@ -676,29 +677,56 @@ long int _Z14isModuleLoadedPci(char *module_name, int i) {
 /* XilCommNS::CPortResources::Instance() */
 void* _ZN9XilCommNS14CPortResources8InstanceEv() {
        static void* (*func) (void) = NULL;
+       char *filename = NULL;
        void *ret;
+       int i;
 
-       if (!func)
+       if (!func) {
                func = (void* (*) (void)) dlsym(RTLD_NEXT, "_ZN9XilCommNS14CPortResources8InstanceEv");
 
-       DPRINTF("-> XilCommNS::CPortResources::Instance()\n");
+               DPRINTF("Searching for filename starting at %p\n", func);
+               for(i = 0; i < 16384; i++) {
+                       if (!strcmp(((char*)func)+i, "/proc/sys/dev/parport/%s/base-addr")) {
+                               filename = ((char*)func)+i;
+                               DPRINTF("Filename found at offset %p\n", (void*)(filename - ((char*)func)));
+                               break;
+                       }
+               }
+       }
 
-       ret = func();
+       if (filename) {
+               long pagesize;
+               size_t protectlen;
+               void *start;
+               int len = strlen(filename) + 1;
+               int ret;
 
-#ifdef DEBUG
-       hexdump(ret, 0x29, "<-");
-       #if 0
-       {
-               void *portinfo;
-               portinfo = ((unsigned char**)ret+0x00);
-               hexdump(portinfo, 256, "PI");
-               hexdump(portinfo+0x50, 4, "BS");
-               hexdump(portinfo+0x54, 4, "BE");
-               hexdump(portinfo+0x58, 4, "ES");
-               hexdump(portinfo+0x5c, 4, "EE");
+               pagesize = sysconf(_SC_PAGE_SIZE);
+               DPRINTF("You have %lu bytes sized pages!\n", pagesize);
+
+               start = (void*)((long)filename & (~(pagesize-1)));
+
+               protectlen = pagesize;
+               if ((long)(filename + len) > (long)(start + protectlen))
+                       protectlen += pagesize;
+
+               DPRINTF("Unprotecting %zd bytes starting at %p\n", protectlen, start);
+               ret = mprotect(start, protectlen, PROT_READ|PROT_WRITE);
+               if (ret == -1)
+                       perror("mprotect");
+
+               DPRINTF("Replacing %s with /dev/zero\n", filename);
+               strcpy(filename, "/dev/zero");
+
+               DPRINTF("Reprotecting %zd bytes starting at %p\n", protectlen, start);
+               ret = mprotect(start, protectlen, PROT_READ|PROT_EXEC);
+               if (ret == -1)
+                       perror("mprotect");
        }
-       #endif
-#endif
+
+       DPRINTF("-> XilCommNS::CPortResources::Instance()\n");
+
+       ret = func();
 
        DPRINTF("<- XilCommNS::CPortResources::Instance()\n");