[SeaBIOS] [PATCH] ldnoexec: Add script to remove ET_EXEC flag from intermediate build objects

Kevin O'Connor posted 1 patch 3 years, 8 months ago
Patches applied successfully (tree, apply log)
git fetch https://github.com/patchew-project/seabios tags/patchew/20200722153716.2772583-1-kevin@koconnor.net
There is a newer version of this series
Makefile            |  9 +++++----
scripts/ldnoexec.py | 32 ++++++++++++++++++++++++++++++++
2 files changed, 37 insertions(+), 4 deletions(-)
create mode 100755 scripts/ldnoexec.py
[SeaBIOS] [PATCH] ldnoexec: Add script to remove ET_EXEC flag from intermediate build objects
Posted by Kevin O'Connor 3 years, 8 months ago
Add a script to remove the ET_EXEC flag from the 16bit and "32bit
segmented" intermediate objects.  This avoids build failures with some
linkers that will not allow linking these objects again.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
---
 Makefile            |  9 +++++----
 scripts/ldnoexec.py | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+), 4 deletions(-)
 create mode 100755 scripts/ldnoexec.py

diff --git a/Makefile b/Makefile
index c20be15..3d8943e 100644
--- a/Makefile
+++ b/Makefile
@@ -127,9 +127,10 @@ $(Q)printf '$(foreach i,$2,#include "$i"\n)' > $3.tmp.c
 $(Q)$(CC) -I. $1 $(CFLAGSWHOLE) -c $3.tmp.c -o $3
 endef
 
-%.strip.o: %.o
+%.noexec.o: %.o
 	@echo "  Stripping $@"
-	$(Q)$(STRIP) $< -o $@
+	$(Q)$(STRIP) $< -o $<.strip.o
+	$(Q)$(PYTHON) ./scripts/ldnoexec.py $<.strip.o $@
 
 $(OUT)%.s: %.c
 	@echo "  Compiling to assembler $@"
@@ -185,9 +186,9 @@ $(OUT)rom32seg.o: $(OUT)code32seg.o $(OUT)romlayout32seg.lds
 	@echo "  Linking $@"
 	$(Q)$(LD) -T $(OUT)romlayout32seg.lds $< -o $@
 
-$(OUT)rom.o: $(OUT)rom16.strip.o $(OUT)rom32seg.strip.o $(OUT)code32flat.o $(OUT)romlayout32flat.lds
+$(OUT)rom.o: $(OUT)rom16.noexec.o $(OUT)rom32seg.noexec.o $(OUT)code32flat.o $(OUT)romlayout32flat.lds
 	@echo "  Linking $@"
-	$(Q)$(LD) -N -T $(OUT)romlayout32flat.lds $(OUT)rom16.strip.o $(OUT)rom32seg.strip.o $(OUT)code32flat.o -o $@
+	$(Q)$(LD) -N -T $(OUT)romlayout32flat.lds $(OUT)rom16.noexec.o $(OUT)rom32seg.noexec.o $(OUT)code32flat.o -o $@
 
 $(OUT)bios.bin.prep: $(OUT)rom.o scripts/checkrom.py
 	@echo "  Prepping $@"
diff --git a/scripts/ldnoexec.py b/scripts/ldnoexec.py
new file mode 100755
index 0000000..b0b32d4
--- /dev/null
+++ b/scripts/ldnoexec.py
@@ -0,0 +1,32 @@
+#!/usr/bin/env python2
+# Script to remove EXEC flag from an ELF file
+#
+# Copyright (C) 2020  Kevin O'Connor <kevin@koconnor.net>
+#
+# This file may be distributed under the terms of the GNU GPLv3 license.
+import os, optparse, sys
+
+FLAG_OFFSET = 16
+
+def main():
+    # Parse command-line arguments
+    usage = "%prog <input_file> <output_file>"
+    opts = optparse.OptionParser(usage)
+    options, args = opts.parse_args()
+    if len(args) != 2:
+        opts.error("Incorrect number of arguments")
+    infilename, outfilename = args
+    # Read input
+    f = open(infilename, "rb")
+    srcdata = f.read()
+    f.close()
+    # Update
+    outdata = bytearray(srcdata)
+    outdata[FLAG_OFFSET] = 0x01 # change ET_EXEC to ET_REL
+    # Write output
+    f = open(outfilename, "wb")
+    f.write(outdata)
+    f.close()
+
+if __name__ == '__main__':
+    main()
-- 
2.26.2
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[SeaBIOS] Re: [PATCH] ldnoexec: Add script to remove ET_EXEC flag from intermediate build objects
Posted by Gerd Hoffmann 3 years, 8 months ago
  Hi,

> +++ b/scripts/ldnoexec.py
> +#!/usr/bin/env python2

Why "python2"?  All other scripts have just "python" ...

take care,
  Gerd
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[SeaBIOS] Re: [PATCH] ldnoexec: Add script to remove ET_EXEC flag from intermediate build objects
Posted by Kevin O'Connor 3 years, 8 months ago
On Fri, Jul 24, 2020 at 12:55:31PM +0200, Gerd Hoffmann wrote:
>   Hi,
> 
> > +++ b/scripts/ldnoexec.py
> > +#!/usr/bin/env python2
> 
> Why "python2"?  All other scripts have just "python" ...

The script runs on python2 or python3.  I'll make that change.

-Kevin
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