1 files changed, 58 insertions, 51 deletions

diff --git a/src/coredump/_UCD_access_mem.c b/src/coredump/_UCD_access_mem.c
index 1fdbd128..cdfc6220 100644
--- a/src/coredump/_UCD_access_mem.c
+++ b/src/coredump/_UCD_access_mem.c
@@ -23,76 +23,83 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
 
 #include "_UCD_lib.h"
 #include "_UCD_internal.h"
+#include "ucd_file_table.h"
 
 int
-_UCD_access_mem(unw_addr_space_t as, unw_word_t addr, unw_word_t *val,
-                 int write, void *arg)
+_UCD_access_mem (unw_addr_space_t  as,
+                 unw_word_t        addr,
+                 unw_word_t       *val,
+                 int               write,
+                 void             *arg)
 {
   if (write)
     {
-      Debug(0, "write is not supported\n");
+      Debug (0, "write is not supported\n");
       return -UNW_EINVAL;
     }
 
   struct UCD_info *ui = arg;
 
-  unw_word_t addr_last = addr + sizeof(*val)-1;
-  coredump_phdr_t *phdr;
+  unw_word_t addr_last = addr + sizeof (*val) - 1;
+
   unsigned i;
+
   for (i = 0; i < ui->phdrs_count; i++)
     {
-      phdr = &ui->phdrs[i];
-      if (phdr->p_vaddr <= addr && addr_last < phdr->p_vaddr + phdr->p_memsz)
+      coredump_phdr_t *phdr = &ui->phdrs[i];
+
+      /* First check the (in-memory) backup file image. */
+      if (phdr->p_backing_file_index != ucd_file_no_index)
         {
-          goto found;
-        }
-    }
-  Debug(1, "addr 0x%llx is unmapped\n", (unsigned long long)addr);
-  return -UNW_EINVAL;
+          ucd_file_t *ucd_file = ucd_file_table_at (&ui->ucd_file_table, phdr->p_backing_file_index);
 
- found: ;
+          if (ucd_file == NULL)
+            {
+              Debug (0, "invalid backing file index for phdr[%d]\n", i);
+              return -UNW_EINVAL;
+            }
 
-  const char *filename UNUSED;
-  off_t fileofs;
-  int fd;
-  if (addr_last >= phdr->p_vaddr + phdr->p_filesz)
-    {
-      /* This part of mapped address space is not present in coredump file */
-      /* Do we have it in the backup file? */
-      if (phdr->backing_fd < 0)
+          off_t image_offset = addr - phdr->p_vaddr;
+
+          if (phdr->p_vaddr <= addr && addr_last < phdr->p_vaddr + ucd_file->size)
+            {
+              memcpy (val, ucd_file->image + image_offset, sizeof (*val));
+              Debug (16, "%#010llx <- [addr:%#010llx file:%s]\n",
+                     (unsigned long long) (*val),
+                     (unsigned long long)image_offset,
+                     ucd_file->filename);
+              return UNW_ESUCCESS;
+            }
+        }
+
+      /* Next, check the on-disk corefile. */
+      if (phdr->p_vaddr <= addr && addr_last < phdr->p_vaddr + phdr->p_memsz)
         {
-          Debug(1, "access to not-present data in phdr[%d]: addr:0x%llx\n",
-                                i, (unsigned long long)addr
-                        );
-          return -UNW_EINVAL;
+          off_t fileofs = phdr->p_offset + (addr - phdr->p_vaddr);
+
+          if (lseek (ui->coredump_fd, fileofs, SEEK_SET) != fileofs)
+            {
+              Debug (0, "error %d in lseek(\"%s\", %lld): %s\n",
+                     errno,  ui->coredump_filename, (long long)fileofs, strerror (errno));
+              return -UNW_EINVAL;
+            }
+
+          if (read (ui->coredump_fd, val, sizeof (*val)) != sizeof (*val))
+            {
+              Debug (0, "error %d in read(\"%s\", %lld): %s\n",
+                     errno,  ui->coredump_filename, (long long)sizeof (*val), strerror (errno));
+              return -UNW_EINVAL;
+            }
+
+          Debug (16, "0x%llx <- [addr:0x%llx fileofs:0x%llx file:%s]\n",
+                 (unsigned long long) (*val),
+                 (unsigned long long)addr,
+                 (unsigned long long)fileofs,
+                 ui->coredump_filename);
+          return UNW_ESUCCESS;
         }
-      filename = phdr->backing_filename;
-      fileofs = addr - phdr->p_vaddr;
-      fd = phdr->backing_fd;
-      goto read;
     }
 
-  filename = ui->coredump_filename;
-  fileofs = phdr->p_offset + (addr - phdr->p_vaddr);
-  fd = ui->coredump_fd;
- read:
-  if (lseek(fd, fileofs, SEEK_SET) != fileofs)
-    goto read_error;
-  if (read(fd, val, sizeof(*val)) != sizeof(*val))
-    goto read_error;
-
-  Debug(1, "0x%llx <- [addr:0x%llx fileofs:0x%llx]\n",
-        (unsigned long long)(*val),
-        (unsigned long long)addr,
-        (unsigned long long)fileofs
-  );
-  return 0;
-
- read_error:
-  Debug(1, "access out of file: addr:0x%llx fileofs:%llx file:'%s'\n",
-        (unsigned long long)addr,
-        (unsigned long long)fileofs,
-        filename
-  );
+  Debug (0, "addr %#010llx is unmapped\n", (unsigned long long)addr);
   return -UNW_EINVAL;
 }