(unexec): Consider a section to precede the .bss section

if its addresses overlap that of .bss.
(unexec) [NS_IMPL_GNUSTEP]: Copy ObjC-related data from old file
instead of dumping process.

2 files changed, 68 insertions, 7 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index b8e23d74d41..f68a937aa5e 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,14 @@
+2009-05-06  YAMAMOTO Mitsuharu  <mituharu@math.s.chiba-u.ac.jp>
+
+        * keyboard.h (add_user_signal): Fix typo in extern.
+
+        * lisp.h (add_user_signal): Remove extern.
+
+        * unexelf.c (unexec): Consider a section to precede the .bss section
+        if its addresses overlap that of .bss.
+        (unexec) [NS_IMPL_GNUSTEP]: Copy ObjC-related data from old file
+        instead of dumping process.
+
 2009-05-06  Stefan Monnier  <monnier@iro.umontreal.ca>
 
         * keyboard.c (syms_of_keyboard): Staticpro pending_funcalls.
diff --git a/src/unexelf.c b/src/unexelf.c
index 83e57003759..45de52dffda 100644
--- a/src/unexelf.c
+++ b/src/unexelf.c
@@ -985,9 +985,29 @@ unexec (new_name, old_name, data_start, bss_start, entry_address)
              placed after the .bss section.  Overlap can occur if the
              section just before .bss has less-strict alignment; this
              was observed between .symtab and .bss on Solaris 2.5.1
-             (sparc) with GCC snapshot 960602.  */
+             (sparc) with GCC snapshot 960602.
 
-          if (NEW_SECTION_H (nn).sh_offset >= old_bss_offset)
+> dump -h temacs
+
+temacs:
+
+           **** SECTION HEADER TABLE ****
+[No]    Type    Flags   Addr         Offset       Size          Name
+        Link    Info    Adralgn      Entsize
+
+[22]    1       3       0x335150     0x315150     0x4           .data.rel.local
+        0       0       0x4          0            
+
+[23]    8       3       0x335158     0x315158     0x42720       .bss
+        0       0       0x8          0            
+
+[24]    2       0       0            0x315154     0x1c9d0       .symtab
+        25      1709    0x4          0x10         
+          */
+
+          if (NEW_SECTION_H (nn).sh_offset >= old_bss_offset
+              || (NEW_SECTION_H (nn).sh_offset + NEW_SECTION_H (nn).sh_size
+                  > new_data2_offset))
             NEW_SECTION_H (nn).sh_offset += new_data2_incr;
 
           /* Any section that was originally placed after the section
@@ -1206,11 +1226,41 @@ unexec (new_name, old_name, data_start, bss_start, entry_address)
       symendp = (ElfW(Sym) *) ((byte *)symp + NEW_SECTION_H (n).sh_size);
 
       for (; symp < symendp; symp ++)
-        if (strcmp ((char *) (symnames + symp->st_name), "_end") == 0
-            || strcmp ((char *) (symnames + symp->st_name), "end") == 0
-            || strcmp ((char *) (symnames + symp->st_name), "_edata") == 0
-            || strcmp ((char *) (symnames + symp->st_name), "edata") == 0)
-          memcpy (&symp->st_value, &new_bss_addr, sizeof (new_bss_addr));
+        {
+          if (strcmp ((char *) (symnames + symp->st_name), "_end") == 0
+              || strcmp ((char *) (symnames + symp->st_name), "end") == 0
+              || strcmp ((char *) (symnames + symp->st_name), "_edata") == 0
+              || strcmp ((char *) (symnames + symp->st_name), "edata") == 0)
+            memcpy (&symp->st_value, &new_bss_addr, sizeof (new_bss_addr));
+
+          /* Strictly speaking, #ifdef below is not necessary.  But we
+             keep it to indicate that this kind of change may also be
+             necessary for other unexecs to support GNUstep.  */
+#ifdef NS_IMPL_GNUSTEP
+          /* ObjC runtime modifies the values of some data structures
+             such as classes and selectors in the .data section after
+             loading.  As the dump process copies the .data section
+             from the current process, that causes problems when the
+             modified classes are reinitialized in the dumped
+             executable.  We copy such data from the old file, not
+             from the current process.  */
+          if (strncmp ((char *) (symnames + symp->st_name),
+                       "_OBJC_", sizeof ("_OBJC_") - 1) == 0)
+            {
+              caddr_t old, new;
+
+              new = ((symp->st_value - NEW_SECTION_H (symp->st_shndx).sh_addr)
+                     + NEW_SECTION_H (symp->st_shndx).sh_offset + new_base);
+              /* "Unpatch" index.  */
+              nn = symp->st_shndx;
+              if (nn > old_bss_index)
+                nn--;
+              old = ((symp->st_value - NEW_SECTION_H (symp->st_shndx).sh_addr)
+                     + OLD_SECTION_H (nn).sh_offset + old_base);
+              memcpy (new, old, symp->st_size);
+            }
+#endif
+        }
     }
 
   /* This loop seeks out relocation sections for the data section, so