oci8lib.c in ruby-oci8-2.2.14

- old
+ new

@@ -7,10 +7,11 @@
 #ifdef HAVE_RUBY_THREAD_H
 #include <ruby/thread.h>
 #endif
 #if defined(HAVE_PLTHOOK) && !defined(WIN32)
 #include <dlfcn.h>
+#include <sys/mman.h>
 #include "plthook.h"
 #endif
 
 ID oci8_id_at_last_error;
 ID oci8_id_get;
@@ -133,10 +134,12 @@
     unsigned int pos = 0;
     const char *name;
     void **addr;
     const char *prefix;
     size_t prefix_len;
+    int prot;
+    size_t page_size = sysconf(_SC_PAGESIZE);
 
 #ifdef RTLD_FIRST
     flags |= RTLD_FIRST; /* for macOS */
 #endif
 
@@ -159,11 +162,11 @@
     if (prefix == NULL) {
         dlclose(handle);
         plthook_close(ph);
         return;
     }
-    while (plthook_enum(ph, &pos, &name, &addr) == 0) {
+    while (plthook_enum_with_prot(ph, &pos, &name, &addr, &prot) == 0) {
         void *funcaddr;
         if (prefix_len != 0) {
             if (strncmp(name, prefix, prefix_len) != 0) {
                 continue;
             }
@@ -177,10 +180,20 @@
         if (funcaddr != NULL && *addr != funcaddr) {
             /* If libclntsh.so exports and imports same functions, their
              * PLT entries are forcedly modified to point to itself not
              * to use functions in other libraries.
              */
+#define ALIGN_ADDR(addr) ((void*)((size_t)(addr) & ~(page_size - 1)))
+            if ((prot & PROT_WRITE) == 0) {
+                /* when the region containing addr isn't writable, make it writable temporarily */
+                if (mprotect(ALIGN_ADDR(addr), page_size, PROT_READ | PROT_WRITE) != 0) {
+                    continue;
+                }
+            }
             *addr = funcaddr;
+            if ((prot & PROT_WRITE) == 0) {
+                mprotect(ALIGN_ADDR(addr), page_size, prot);
+            }
         }
     }
     plthook_close(ph);
     dlclose(handle);
 }