File _service:tar_scm:backport-elfcompress-Don-t-com... of Package elfutils

File _service:tar_scm:backport-elfcompress-Don-t-compress-if-section-already-compre.patch of Package elfutils (Revision e7872672e8c83ba7fd70acba8c627e91)

Currently displaying revision e7872672e8c83ba7fd70acba8c627e91 , Show latest

From 6cad4e56a930034765f8e79ba2eaa2ff1cd8394f Mon Sep 17 00:00:00 2001
From: Mark Wielaard <mark@klomp.org>
Date: Sat, 22 Apr 2023 01:45:43 +0200
Subject: [PATCH] elfcompress: Don't compress if section already compressed
 unless forced

Before commit a5b07cdf9 "support ZSTD compression algorithm"
elfcompress would not try to compress a section if it already
had the requested compression type (or was already uncompressed)
unless the --force flag was given. An else if construct was changed
to an if in the commit causing elfcompress to warn (in verbose mode)
but then still try to (re)compress the section.

Add an explicit check so if nothing needs (un)compressing, the file
isn't changed.

The diff looks large, but git diff -b -w is just:

+     if (force || type != schtype)
+       {
          if (shdr->sh_type != SHT_NOBITS
              && (shdr->sh_flags & SHF_ALLOC) == 0)
            {
@@ -554,6 +556,7 @@ process_file (const char *fname)
              printf ("[%zd] %s ignoring %s section\n", ndx, sname,
                      (shdr->sh_type == SHT_NOBITS ? "no bits" : "allocated"));
        }
+   }

Signed-off-by: Mark Wielaard <mark@klomp.org>
---
 src/elfcompress.c | 43 +++++++++++++++++++++++--------------------
 1 file changed, 23 insertions(+), 20 deletions(-)

diff --git a/src/elfcompress.c b/src/elfcompress.c
index 18ade66f..f771b92a 100644
--- a/src/elfcompress.c
+++ b/src/elfcompress.c
@@ -529,30 +529,33 @@ process_file (const char *fname)
 		  }
 	    }
 
-	  if (shdr->sh_type != SHT_NOBITS
-	      && (shdr->sh_flags & SHF_ALLOC) == 0)
+	  if (force || type != schtype)
 	    {
-	      set_section (sections, ndx);
-	      /* Check if we might want to change this section name.  */
-	      if (! adjust_names
-		  && ((type != ZLIB_GNU
-		       && startswith (sname, ".zdebug"))
-		      || (type == ZLIB_GNU
-			  && startswith (sname, ".debug"))))
-		adjust_names = true;
-
-	      /* We need a buffer this large if we change the names.  */
-	      if (adjust_names)
+	      if (shdr->sh_type != SHT_NOBITS
+		  && (shdr->sh_flags & SHF_ALLOC) == 0)
 		{
-		  size_t slen = strlen (sname);
-		  if (slen > maxnamelen)
-		    maxnamelen = slen;
+		  set_section (sections, ndx);
+		  /* Check if we might want to change this section name.  */
+		  if (! adjust_names
+		      && ((type != ZLIB_GNU
+			   && startswith (sname, ".zdebug"))
+			  || (type == ZLIB_GNU
+			      && startswith (sname, ".debug"))))
+		    adjust_names = true;
+
+		  /* We need a buffer this large if we change the names.  */
+		  if (adjust_names)
+		    {
+		      size_t slen = strlen (sname);
+		      if (slen > maxnamelen)
+			maxnamelen = slen;
+		    }
 		}
+	      else
+		if (verbose >= 0)
+		  printf ("[%zd] %s ignoring %s section\n", ndx, sname,
+			  (shdr->sh_type == SHT_NOBITS ? "no bits" : "allocated"));
 	    }
-	  else
-	    if (verbose >= 0)
-	      printf ("[%zd] %s ignoring %s section\n", ndx, sname,
-		      (shdr->sh_type == SHT_NOBITS ? "no bits" : "allocated"));
 	}
 
       if (shdr->sh_type == SHT_SYMTAB)
-- 
2.27.0