[master] meta: scripts - relocation script adapted to support big-endian machines

[master] meta: scripts - relocation script adapted to support big-endian machines

[Sundeep KOKKONDA]

relocate_sdk.py was developed for little-endian architures and when tries
to install SDK for big-endian machines errors like below will be shown.

The changes made in the script to support big-endian architecture.

Signed-off-by: Sundeep KOKKONDA <sundeep.kokkonda@gmail.com>
---
 scripts/relocate_sdk.py | 45 ++++++++++++++++++++++++++++++++---------
 1 file changed, 35 insertions(+), 10 deletions(-)
 mode change 100755 => 100644 scripts/relocate_sdk.py

diff --git a/scripts/relocate_sdk.py b/scripts/relocate_sdk.py
old mode 100755
new mode 100644
index 8c0fdb986a..513b9343d3
--- a/scripts/relocate_sdk.py
+++ b/scripts/relocate_sdk.py
@@ -30,9 +30,10 @@ else:
 old_prefix = re.compile(b("##DEFAULT_INSTALL_DIR##"))
 
 def get_arch():
+    global ei_data
     f.seek(0)
     e_ident =f.read(16)
-    ei_mag0,ei_mag1_3,ei_class = struct.unpack("<B3sB11x", e_ident)
+    ei_mag0,ei_mag1_3,ei_class,ei_data,ei_version = struct.unpack("<B3sBBB9x", e_ident)
 
     if (ei_mag0 != 0x7f and ei_mag1_3 != "ELF") or ei_class == 0:
         return 0
@@ -51,11 +52,17 @@ def parse_elf_header():
 
     if arch == 32:
         # 32bit
-        hdr_fmt = "<HHILLLIHHHHHH"
+        if ei_data == 1: # ei_data = 1, little endian
+            hdr_fmt = "<HHILLLIHHHHHH"
+        else:   # ei_data = 0, big endian
+            hdr_fmt = ">HHILLLIHHHHHH"
         hdr_size = 52
     else:
         # 64bit
-        hdr_fmt = "<HHIQQQIHHHHHH"
+        if ei_data == 1:
+            hdr_fmt = "<HHIQQQIHHHHHH"
+        else:
+            hdr_fmt = ">HHIQQQIHHHHHH"
         hdr_size = 64
 
     e_type, e_machine, e_version, e_entry, e_phoff, e_shoff, e_flags,\
@@ -64,9 +71,15 @@ def parse_elf_header():
 
 def change_interpreter(elf_file_name):
     if arch == 32:
-        ph_fmt = "<IIIIIIII"
+        if ei_data == 1: # ei_data = 1, little endian
+            ph_fmt = "<IIIIIIII"
+        else:   # ei_data = 0, big endian
+            ph_fmt = ">IIIIIIII"
     else:
-        ph_fmt = "<IIQQQQQQ"
+        if ei_data == 1:
+            ph_fmt = "<IIQQQQQQ"
+        else:
+            ph_fmt = ">IIQQQQQQ"
 
     """ look for PT_INTERP section """
     for i in range(0,e_phnum):
@@ -75,7 +88,7 @@ def change_interpreter(elf_file_name):
         if arch == 32:
             # 32bit
             p_type, p_offset, p_vaddr, p_paddr, p_filesz,\
-                p_memsz, p_flags, p_align = struct.unpack(ph_fmt, ph_hdr)
+            p_memsz, p_flags, p_align = struct.unpack(ph_fmt, ph_hdr)
         else:
             # 64bit
             p_type, p_flags, p_offset, p_vaddr, p_paddr, \
@@ -105,17 +118,29 @@ def change_interpreter(elf_file_name):
 
 def change_dl_sysdirs(elf_file_name):
     if arch == 32:
-        sh_fmt = "<IIIIIIIIII"
+        if ei_data == 1: # ei_data = 1, little endian
+            sh_fmt = "<IIIIIIIIII"
+        else:   # ei_data = 0, big endian
+            sh_fmt = ">IIIIIIIIII"
     else:
-        sh_fmt = "<IIQQQQIIQQ"
+        if ei_data == 1:
+            sh_fmt = "<IIQQQQIIQQ"
+        else:
+            sh_fmt = ">IIQQQQIIQQ"
 
     """ read section string table """
     f.seek(e_shoff + e_shstrndx * e_shentsize)
     sh_hdr = f.read(e_shentsize)
     if arch == 32:
-        sh_offset, sh_size = struct.unpack("<16xII16x", sh_hdr)
+        if ei_data == 1:
+            sh_offset, sh_size = struct.unpack("<16xII16x", sh_hdr)
+        else:
+            sh_offset, sh_size = struct.unpack(">16xII16x", sh_hdr)
     else:
-        sh_offset, sh_size = struct.unpack("<24xQQ24x", sh_hdr)
+        if ei_data == 1:
+            sh_offset, sh_size = struct.unpack("<24xQQ24x", sh_hdr)
+        else:
+            sh_offset, sh_size = struct.unpack(">24xQQ24x", sh_hdr)
 
     f.seek(sh_offset)
     sh_strtab = f.read(sh_size)
-- 
2.25.1

Re: [OE-core] [master] meta: scripts - relocation script adapted to support big-endian machines

[Richard Purdie]

On Fri, 2022-04-01 at 09:50 +0530, Sundeep KOKKONDA wrote:
> relocate_sdk.py was developed for little-endian architures and when tries
> to install SDK for big-endian machines errors like below will be shown.
> 
> The changes made in the script to support big-endian architecture.
> 
> Signed-off-by: Sundeep KOKKONDA <sundeep.kokkonda@gmail.com>
> ---
>  scripts/relocate_sdk.py | 45 ++++++++++++++++++++++++++++++++---------
>  1 file changed, 35 insertions(+), 10 deletions(-)
>  mode change 100755 => 100644 scripts/relocate_sdk.py
> 
> diff --git a/scripts/relocate_sdk.py b/scripts/relocate_sdk.py
> old mode 100755
> new mode 100644
> index 8c0fdb986a..513b9343d3
> --- a/scripts/relocate_sdk.py
> +++ b/scripts/relocate_sdk.py
> @@ -30,9 +30,10 @@ else:
>  old_prefix = re.compile(b("##DEFAULT_INSTALL_DIR##"))
>  
>  def get_arch():
> +    global ei_data
>      f.seek(0)
>      e_ident =f.read(16)
> -    ei_mag0,ei_mag1_3,ei_class = struct.unpack("<B3sB11x", e_ident)
> +    ei_mag0,ei_mag1_3,ei_class,ei_data,ei_version = struct.unpack("<B3sBBB9x", e_ident)
>  
>      if (ei_mag0 != 0x7f and ei_mag1_3 != "ELF") or ei_class == 0:
>          return 0
> @@ -51,11 +52,17 @@ def parse_elf_header():
>  
>      if arch == 32:
>          # 32bit
> -        hdr_fmt = "<HHILLLIHHHHHH"
> +        if ei_data == 1: # ei_data = 1, little endian
> +            hdr_fmt = "<HHILLLIHHHHHH"
> +        else:   # ei_data = 0, big endian
> +            hdr_fmt = ">HHILLLIHHHHHH"
>          hdr_size = 52
>      else:
>          # 64bit
> -        hdr_fmt = "<HHIQQQIHHHHHH"
> +        if ei_data == 1:
> +            hdr_fmt = "<HHIQQQIHHHHHH"
> +        else:
> +            hdr_fmt = ">HHIQQQIHHHHHH"
>          hdr_size = 64

I think we can make the change a bit neater, maybe putting ">" or "<" into the
global variable and then doing something like:

hdr_fmt = endian_prefix + "HHIQQQIHHHHHH"

?

Cheers,

Richard

Re: [master] meta: scripts - relocation script adapted to support big-endian machines

[Sundeep KOKKONDA]

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Hello Richard,

Patch updated and resubmitted.
https://lists.openembedded.org/g/openembedded-core/message/164012

Thanks,
Sundeep K.

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