Robert Millan wrote:
On Sat, Nov 10, 2007 at 08:03:57PM +0100, Christian Franke wrote:
This patch fixes this by ignoring the difference. It actually works to
load modules compiled on Linux by a kernel compiled on Cygwin (with
underscores) and vice versa.
[...]
+
+ /* Ignore leading underscore used for C symbols.
+ Done at runtime to allow loading modules compiled on other OS. */
+ if (*name == '_')
+ name++;
Is that something we really want? We never made any efforts at maintaining
ABI between kernel and modules, or in allowing this kind of combinations. If
we go this path, it can mean more work later (e.g. support for building kernel
and modules with different versions of GCC, etc).
Agree.
Should the kernel probably check whether a module is build for the same
target? This would avoid interesting behaviour if a foreign module is
accidentally load for some reason. It could e.g. be done by checking a
symbol derived from $target.
Could you give an example of a situation in which this would be useful?
There probably is none, therefore the (older) patch for the other
variant is attached :-)
Christian
2007-11-11 Christian Franke <[EMAIL PROTECTED]>
* genkernsyms.sh.in: Handle HAVE_ASM_USCORE case.
* genmk.rb: Handle HAVE_ASM_USCORE case in strip command.
Add EXEEXT to CLEANFILES.
* gensymlist.sh.in: Handle HAVE_ASM_USCORE case.
* kern/dl.c (grub_dl_resolve_symbols): Add check for grub_mod_init
and grub_mod_fini for symbols without a type. Handle HAVE_ASM_USCORE
case for these symbols.
(grub_dl_resolve_dependencies): Add check for trailing nullbytes
in symbol table. This fixes an infinite loop if table is zero filled.
diff -rup grub2.orig/genkernsyms.sh.in grub2/genkernsyms.sh.in
--- grub2.orig/genkernsyms.sh.in 2006-07-12 22:42:52.000000000 +0200
+++ grub2/genkernsyms.sh.in 2007-10-06 12:59:29.000000000 +0200
@@ -16,9 +16,12 @@
[EMAIL PROTECTED]@
CC="@CC@"
+u=
+grep "^#define HAVE_ASM_USCORE" config.h >/dev/null 2>&1 && u="_"
+
$CC -DGRUB_SYMBOL_GENERATOR=1 -E -I. -Iinclude -I$srcdir/include $* \
| grep -v '^#' \
| sed -n \
- -e '/EXPORT_FUNC *([a-zA-Z0-9_]*)/{s/.*EXPORT_FUNC *(\([a-zA-Z0-9_]*\)).*/\1 kernel/;p;}' \
- -e '/EXPORT_VAR *([a-zA-Z0-9_]*)/{s/.*EXPORT_VAR *(\([a-zA-Z0-9_]*\)).*/\1 kernel/;p;}' \
+ -e '/EXPORT_FUNC *([a-zA-Z0-9_]*)/{s/.*EXPORT_FUNC *(\([a-zA-Z0-9_]*\)).*/'"$u"'\1 kernel/;p;}' \
+ -e '/EXPORT_VAR *([a-zA-Z0-9_]*)/{s/.*EXPORT_VAR *(\([a-zA-Z0-9_]*\)).*/'"$u"'\1 kernel/;p;}' \
| sort -u
diff -rup grub2.orig/genmk.rb grub2/genmk.rb
--- grub2.orig/genmk.rb 2007-10-20 22:49:38.968750000 +0200
+++ grub2/genmk.rb 2007-11-10 19:37:17.562500000 +0100
@@ -115,7 +115,7 @@ UNDSYMFILES += #{undsym}
[EMAIL PROTECTED]: #{pre_obj} #{mod_obj}
-rm -f $@
$(TARGET_CC) $(#{prefix}_LDFLAGS) $(TARGET_LDFLAGS) -Wl,-r,-d -o $@ $^
- $(STRIP) --strip-unneeded -K grub_mod_init -K grub_mod_fini -R .note -R .comment $@
+ $(STRIP) --strip-unneeded -K grub_mod_init -K grub_mod_fini -K _grub_mod_init -K _grub_mod_fini -R .note -R .comment $@
#{pre_obj}: $(#{prefix}_DEPENDENCIES) #{objs_str}
-rm -f $@
@@ -187,7 +187,7 @@ class Utility
deps = objs.collect {|obj| obj.suffix('d')}
deps_str = deps.join(' ');
- "CLEANFILES += [EMAIL PROTECTED] #{objs_str}
+ "CLEANFILES += [EMAIL PROTECTED](EXEEXT) #{objs_str}
MOSTLYCLEANFILES += #{deps_str}
[EMAIL PROTECTED]: $(#{prefix}_DEPENDENCIES) #{objs_str}
diff -rup grub2.orig/gensymlist.sh.in grub2/gensymlist.sh.in
--- grub2.orig/gensymlist.sh.in 2007-07-22 01:32:18.000000000 +0200
+++ grub2/gensymlist.sh.in 2007-10-07 17:47:37.000000000 +0200
@@ -16,6 +16,8 @@
[EMAIL PROTECTED]@
[EMAIL PROTECTED]@
+u=
+grep "^#define HAVE_ASM_USCORE" config.h >/dev/null 2>&1 && u="_"
cat <<EOF
/* This file is automatically generated by gensymlist.sh. DO NOT EDIT! */
@@ -60,8 +62,8 @@ EOF
$CC -DGRUB_SYMBOL_GENERATOR=1 -E -I. -Iinclude -I$srcdir/include $* \
| grep -v '^#' \
| sed -n \
- -e '/EXPORT_FUNC *([a-zA-Z0-9_]*)/{s/.*EXPORT_FUNC *(\([a-zA-Z0-9_]*\)).*/ {"\1", \1},/;p;}' \
- -e '/EXPORT_VAR *([a-zA-Z0-9_]*)/{s/.*EXPORT_VAR *(\([a-zA-Z0-9_]*\)).*/ {"\1", \&\1},/;p;}' \
+ -e '/EXPORT_FUNC *([a-zA-Z0-9_]*)/{s/.*EXPORT_FUNC *(\([a-zA-Z0-9_]*\)).*/ {"'"$u"'\1", \1},/;p;}' \
+ -e '/EXPORT_VAR *([a-zA-Z0-9_]*)/{s/.*EXPORT_VAR *(\([a-zA-Z0-9_]*\)).*/ {"'"$u"'\1", \&\1},/;p;}' \
| sort -u
cat <<EOF
diff -rup grub2.orig/kern/dl.c grub2/kern/dl.c
--- grub2.orig/kern/dl.c 2007-07-22 01:32:26.000000000 +0200
+++ grub2/kern/dl.c 2007-11-11 18:01:50.578125000 +0100
@@ -53,6 +53,12 @@ typedef Elf64_Sym Elf_Sym;
#endif
+#ifdef HAVE_ASM_USCORE
+# define SYM_USCORE "_"
+#else
+# define SYM_USCORE ""
+#endif
+
struct grub_dl_list
@@ -347,6 +353,7 @@ grub_dl_resolve_symbols (grub_dl_t mod,
unsigned char type = ELF_ST_TYPE (sym->st_info);
unsigned char bind = ELF_ST_BIND (sym->st_info);
const char *name = str + sym->st_name;
+ int check_mod_func = 0;
switch (type)
{
@@ -359,6 +366,12 @@ grub_dl_resolve_symbols (grub_dl_t mod,
return grub_error (GRUB_ERR_BAD_MODULE,
"the symbol `%s' not found", name);
}
+ else if (sym->st_name != 0 && bind == STB_LOCAL)
+ { /* Static functions have no type if initial format was not ELF. */
+ sym->st_value += (Elf_Addr) grub_dl_get_section_addr (mod,
+ sym->st_shndx);
+ check_mod_func = 1;
+ }
else
sym->st_value = 0;
break;
@@ -374,14 +387,11 @@ grub_dl_resolve_symbols (grub_dl_t mod,
case STT_FUNC:
sym->st_value += (Elf_Addr) grub_dl_get_section_addr (mod,
sym->st_shndx);
- if (bind != STB_LOCAL)
+ if (bind == STB_LOCAL)
+ check_mod_func = 1;
+ else
if (grub_dl_register_symbol (name, (void *) sym->st_value, mod))
return grub_errno;
-
- if (grub_strcmp (name, "grub_mod_init") == 0)
- mod->init = (void (*) (grub_dl_t)) sym->st_value;
- else if (grub_strcmp (name, "grub_mod_fini") == 0)
- mod->fini = (void (*) (void)) sym->st_value;
break;
case STT_SECTION:
@@ -397,6 +407,13 @@ grub_dl_resolve_symbols (grub_dl_t mod,
return grub_error (GRUB_ERR_BAD_MODULE,
"unknown symbol type `%d'", (int) type);
}
+ if (check_mod_func)
+ {
+ if (grub_strcmp (name, SYM_USCORE "grub_mod_init") == 0)
+ mod->init = (void (*) (grub_dl_t)) sym->st_value;
+ else if (grub_strcmp (name, SYM_USCORE "grub_mod_fini") == 0)
+ mod->fini = (void (*) (void)) sym->st_value;
+ }
}
return GRUB_ERR_NONE;
@@ -454,7 +471,7 @@ grub_dl_resolve_dependencies (grub_dl_t
const char *name = (char *) e + s->sh_offset;
const char *max = name + s->sh_size;
- while (name < max)
+ while (name < max && *name) /* Segment may contain trailing 0. */
{
grub_dl_t m;
grub_dl_dep_t dep;
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