1 files changed, 64 insertions, 15 deletions

diff --git a/src/coredump/_UCD_get_proc_name.c b/src/coredump/_UCD_get_proc_name.c
index cd5ee892..aeec3c9b 100644
--- a/src/coredump/_UCD_get_proc_name.c
+++ b/src/coredump/_UCD_get_proc_name.c
@@ -24,6 +24,57 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
 #include "_UCD_lib.h"
 #include "_UCD_internal.h"
 
+#if defined(HAVE_ELF_H)
+# include <elf.h>
+#elif defined(HAVE_SYS_ELF_H)
+# include <sys/elf.h>
+#endif
+
+
+static off_t
+_get_text_offset (uint8_t *image)
+{
+  off_t offset = 0;
+  typedef union
+  {
+    Elf32_Ehdr h32;
+    Elf64_Ehdr h64;
+  } elf_header_t;
+
+  elf_header_t *elf_header = (elf_header_t *)image;
+  bool _64bits     = (elf_header->h32.e_ident[EI_CLASS] == ELFCLASS64);
+  off_t e_phofs    = _64bits ? elf_header->h64.e_phoff  : elf_header->h32.e_phoff;
+  unsigned e_phnum = _64bits ? elf_header->h64.e_phnum  : elf_header->h32.e_phnum;
+
+  for (unsigned i = 0; i < e_phnum; ++i)
+    {
+      if (_64bits)
+        {
+          Elf64_Phdr *phdr = (Elf64_Phdr *) (image + e_phofs);
+
+          if (phdr[i].p_type == PT_LOAD && (phdr[i].p_flags & PF_X) == PF_X)
+            {
+              offset = phdr[i].p_offset;
+              break;
+            }
+        }
+
+      else
+        {
+          Elf32_Phdr *phdr = (Elf32_Phdr *) (image + e_phofs);
+
+          if ((phdr[i].p_flags & PF_X) == PF_X)
+            {
+              offset = phdr[i].p_offset;
+              break;
+            }
+        }
+    }
+
+  Debug (4, "returning offset %ld\n", (long)offset);
+  return offset;
+}
+
 
 /* Find the ELF image that contains IP and return the "closest"
    procedure name, if there is one.  With some caching, this could be
@@ -31,30 +82,29 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
    sensitive to the performance of this routine, why bother...  */
 static int
 elf_w (CD_get_proc_name) (struct UCD_info *ui, unw_addr_space_t as, unw_word_t ip,
-                       char *buf, size_t buf_len, unw_word_t *offp)
+                          char *buf, size_t buf_len, unw_word_t *offp)
 {
   unsigned long segbase, mapoff;
   int ret;
-
-  /* We're about to map an elf image. If there is an elf image currently mapped,
-     then make sure to unmap it. */
-  invalidate_edi(&ui->edi);
-
+  /* We're about to map an elf image.
+     The call will unmap memory it doesn't own, so just null it out and avoid
+     that. */
+  ui->edi.ei.image = NULL;
+  invalidate_edi (&ui->edi);
   /* Used to be tdep_get_elf_image() in ptrace unwinding code */
-  coredump_phdr_t *cphdr = _UCD_get_elf_image(ui, ip);
+  coredump_phdr_t *cphdr = _UCD_get_elf_image (ui, ip);
+
   if (!cphdr)
     {
-      Debug(1, "returns error: _UCD_get_elf_image failed\n");
+      Debug (1, "returns error: _UCD_get_elf_image failed\n");
       return -UNW_ENOINFO;
     }
-  /* segbase: where it is mapped in virtual memory */
-  /* mapoff: offset in the file */
-  segbase = cphdr->p_vaddr;
-  /*mapoff  = phdr->p_offset; WRONG! phdr->p_offset is the offset in COREDUMP file */
-  mapoff  = 0;
 
+  segbase = 0; /* everything is relative to the beginning of the ELF file */
+  mapoff  = 0;
+  /* Adjust IP to be relative to start of the .text section of the ELF file */
+  ip = ip - cphdr->p_vaddr + _get_text_offset (ui->edi.ei.image);
   ret = elf_w (get_proc_name_in_image) (as, &ui->edi.ei, segbase, mapoff, ip, buf, buf_len, offp);
-
   return ret;
 }
 
@@ -63,7 +113,6 @@ _UCD_get_proc_name (unw_addr_space_t as, unw_word_t ip,
                     char *buf, size_t buf_len, unw_word_t *offp, void *arg)
 {
   struct UCD_info *ui = arg;
-
 #if UNW_ELF_CLASS == UNW_ELFCLASS64
   return _Uelf64_CD_get_proc_name (ui, as, ip, buf, buf_len, offp);
 #elif UNW_ELF_CLASS == UNW_ELFCLASS32