Add verbose debug logging to libia2

To print verbose logs of all mprotects and ELF segment computation, build with `-DLIBIA2_DEBUG_LOG=ON`.
immunant · Oct 4, 2024 · bb8fd32 · bb8fd32
1 parent 98fff44
commit bb8fd32
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Showing 3 changed files with 26 additions and 1 deletion.
diff --git a/runtime/libia2/CMakeLists.txt b/runtime/libia2/CMakeLists.txt
@@ -13,6 +13,10 @@ if(LIBIA2_DEBUG)
     target_compile_definitions(libia2 PUBLIC LIBIA2_DEBUG=1)
 endif()
 
+if(LIBIA2_DEBUG_LOG)
+    target_compile_definitions(libia2 PRIVATE LIBIA2_DEBUG_LOG=1)
+endif()
+
 target_link_options(libia2
     INTERFACE
         "-pthread"

diff --git a/runtime/libia2/ia2.c b/runtime/libia2/ia2.c
@@ -351,7 +351,9 @@ int protect_pages(struct dl_phdr_info *info, size_t size, void *data) {
     search_args->found_library_count++;
   }
 
-  // printf("protecting library: %s\n", basename(info->dlpi_name));
+#if LIBIA2_DEBUG_LOG
+  printf("protecting library: %s\n", basename(info->dlpi_name));
+#endif
 
   struct AddressRange shared_ranges[NUM_SHARED_RANGES] = {0};
   size_t shared_range_count = 0;
@@ -379,6 +381,9 @@ int protect_pages(struct dl_phdr_info *info, size_t size, void *data) {
              search_args->shared_sections[i].end);
       exit(-1);
     }
+#if LIBIA2_DEBUG_LOG
+    printf("Shared range %zu: 0x%" PRIx64 "-0x%" PRIx64 "\n", shared_range_count, cur_range->start, cur_range->end);
+#endif
 
     shared_range_count++;
   }
@@ -430,6 +435,9 @@ int protect_pages(struct dl_phdr_info *info, size_t size, void *data) {
 
     Elf64_Addr start = (info->dlpi_addr + phdr.p_vaddr) & ~0xFFFUL;
     Elf64_Addr seg_end = (start + phdr.p_memsz + 0xFFFUL) & ~0xFFFUL;
+#if LIBIA2_DEBUG_LOG
+    printf("Segment %zu: 0x%" PRIx64 "-0x%" PRIx64 "\n", i, start, seg_end);
+#endif
     while (start < seg_end) {
       Elf64_Addr cur_end = seg_end;
 
@@ -440,6 +448,9 @@ int protect_pages(struct dl_phdr_info *info, size_t size, void *data) {
         // and remove the overlapping portion.
         if (shared_ranges[j].start <= start && shared_ranges[j].end > start) {
           start = shared_ranges[j].end;
+#if LIBIA2_DEBUG_LOG
+          printf("Shared range %zu overlaps start of segment %zu, adjusting start to 0x%" PRIx64 "\n", j, i, start);
+#endif
         }
 
         // Look for a shared range overlapping any of the rest of the current
@@ -448,6 +459,9 @@ int protect_pages(struct dl_phdr_info *info, size_t size, void *data) {
         if (shared_ranges[j].start > start &&
             shared_ranges[j].start < cur_end) {
           cur_end = shared_ranges[j].start;
+#if LIBIA2_DEBUG_LOG
+          printf("Shared range %zu overlaps end of segment %zu, adjusting end to 0x%" PRIx64 "\n", j, i, cur_end);
+#endif
         }
       }
 

diff --git a/runtime/libia2/include/ia2_internal.h b/runtime/libia2/include/ia2_internal.h
@@ -300,9 +300,16 @@ works as a reasonable signpost no-op. */
 #if defined(__aarch64__)
 int ia2_mprotect_with_tag(void *addr, size_t len, int prot, int tag);
 #elif defined(__x86_64__)
+#if LIBIA2_DEBUG_LOG
+static int ia2_mprotect_with_tag(void *addr, size_t len, int prot, int tag) {
+  printf("ia2_mprotect_with_tag(addr=%p, len=%zu, prot=%d, tag=%d)\n", addr, len, prot, tag);
+  return pkey_mprotect(addr, len, prot, tag);
+}
+#else
 /* We can't use an alias attribute since this points to a function outside the translation unit */
 #define ia2_mprotect_with_tag pkey_mprotect
 #endif
+#endif
 char *allocate_stack(int i);
 void verify_tls_padding(void);
 void ensure_pkeys_allocated(int *n_to_alloc);