More robust search for filename in memory at runtime

[usb-driver] / usb-driver.c

diff --git a/usb-driver.c b/usb-driver.c
index 3bfeee5558f4c507b79f8e7a89679694c4b7e900..3b8b51d4747d2f8c9edf631f627171000268d78d 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"
@@ -61,13 +62,15 @@ static int modules_read = 0;
 #define NO_WINDRVR 1
 
 void hexdump(unsigned char *buf, int len, char *prefix) {
-       int i;
+       int i = 0;
 
-       fprintf(stderr, "%s ", prefix);
-       for(i=0; i<len; i++) {
+       fprintf(stderr, "%s %03x: ", prefix, i);
+       for(i = 0; i<len; i++) {
                fprintf(stderr,"%02x ", buf[i]);
-               if ((i % 16) == 15)
-                       fprintf(stderr,"\n%s ", prefix);
+               if ((i % 16) == 7)
+                       fprintf(stderr," ");
+               if (((i % 16) == 15) && ((i+1) < len))
+                       fprintf(stderr,"\n%s %03x: ", prefix, i+1);
        }
        fprintf(stderr,"\n");
 }
@@ -659,8 +662,10 @@ int semop (int __semid, struct sembuf *__sops, size_t __nsops) {
 #endif
 
 /*
- * Ugly hack for ISE 12. They don't seem to open /proc/modules with
- * open() anymore...
+ * Ugly hack for ISE 12. Preload doesn't seem to work correctly for
+ * libImpactComm.so. Even though the file is still read with fopen(),
+ * the version from libc is used and not the one from this file.
+ * Replace the function calling fopen() instead...
  * echo '_Z14isModuleLoadedPci' | c++filt
  */
 long int _Z14isModuleLoadedPci(char *module_name, int i) {
@@ -669,16 +674,122 @@ long int _Z14isModuleLoadedPci(char *module_name, int i) {
        return 1;
 }
 
+void cpr_segv_handler(int sig, siginfo_t *info, void *context) {
+       void *newmem;
+
+       DPRINTF("SEGV at %p, mapping memory\n", info->si_addr);
+       errno = 0;
+       newmem = mmap(info->si_addr, 1, PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, -1, 0);
+       if (newmem != info->si_addr) {
+               perror("libusb-driver.so: Can't map memory, crashing now");
+               exit(EXIT_FAILURE);
+       }
+}
+
+/* XilCommNS::CPortResources::Instance() */
+void* _ZN9XilCommNS14CPortResources8InstanceEv() {
+       static void* (*func) (void) = NULL;
+       char *filename = NULL;
+       void *ret;
+       int i;
+
+       if (!func) {
+               struct sigaction act, oldact;
+               int sighand_installed = 0;
+
+               func = (void* (*) (void)) dlsym(RTLD_NEXT, "_ZN9XilCommNS14CPortResources8InstanceEv");
+
+               DPRINTF("Installing signal-handler for SIGSEGV\n");
+               bzero(&act, sizeof(struct sigaction));
+               act.sa_sigaction = cpr_segv_handler;
+               act.sa_flags = SA_SIGINFO;
+               if (sigaction(SIGSEGV, &act, &oldact) == 0) {
+                       sighand_installed = 1;
+               }
+
+               DPRINTF("Searching for filename starting at %p\n", func);
+               for(i = 0; i < 32768; 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;
+                       }
+               }
+               if (sighand_installed) {
+                       DPRINTF("Restoring signal-handler for SIGSEGV\n");
+                       sigaction(SIGSEGV, &oldact, NULL);
+               }
+               if (!filename)
+                       fprintf(stderr, "libusb-driver.so: Can't find memory to patch, parallel cables will probably not work!\n");
+       }
+
+       if (filename) {
+               long pagesize;
+               size_t protectlen;
+               void *start;
+               int len = strlen(filename) + 1;
+               int ret;
+
+               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");
+       }
+
+       DPRINTF("-> XilCommNS::CPortResources::Instance()\n");
+
+       ret = func();
+
+       DPRINTF("<- XilCommNS::CPortResources::Instance()\n");
+
+       return ret;
+}
+
 static void __attribute__ ((constructor)) libusbdriver_init(void) {
+       int i;
+       char buf[256];
+       char buf2[256];
+
+       for (i = 0; i < 4; i++) {
+               snprintf(buf, sizeof(buf), "XIL_IMPACT_ENV_LPT%d_BASE_ADDRESS", i+1);
+               snprintf(buf2, sizeof(buf2), "%x", 0x10*i);
+               setenv(buf, buf2, 1);
+               snprintf(buf, sizeof(buf), "XIL_IMPACT_ENV_LPT%d_ECP_ADDRESS", i+1);
+               snprintf(buf2, sizeof(buf2), "%x", (0x10*i)+0x400);
+               setenv(buf, buf2, 1);
+       }
+
+       setenv("XIL_IMPACT_USE_LIBUSB", "0", 1);
+       setenv("XIL_IMPACT_USE_WINDRIVER", "1", 1);
+
        #if __WORDSIZE == 32
-       struct utsname un;
-       int ret;
+       {
+               struct utsname un;
+               int ret;
 
-       ret = uname(&un);
+               ret = uname(&un);
 
-       if (ret == 0 && (!strcmp(un.machine, "x86_64"))) {
-               DPRINTF("setting 32bit personality\n");
-               (long)syscall(SYS_personality, PER_LINUX32);
+               if (ret == 0 && (!strcmp(un.machine, "x86_64"))) {
+                       DPRINTF("setting 32bit personality\n");
+                       (long)syscall(SYS_personality, PER_LINUX32);
+               }
        }
        #endif
 }