[Elftoolchain-developers] Fwd: svn commit: r352875 - head/contrib/elftoolchain/elfcopy

[Ed M. <em...@fr...>]

An elfcopy fix from FreeBSD:

---------- Forwarded message ---------
From: Aleksandr Rybalko <ra...@fr...>
Date: Sun, 29 Sep 2019 at 18:34
Subject: svn commit: r352875 - head/contrib/elftoolchain/elfcopy
To: <src...@fr...>, <svn...@fr...>,
<svn...@fr...>


Author: ray
Date: Sun Sep 29 22:34:01 2019
New Revision: 352875
URL: https://svnweb.freebsd.org/changeset/base/352875

Log:
  Put sections into expected offset in binary format.
  Calculate binary file offset using address field, because software
know only offset to known data, not where to load segment.
  With that patch, kernel .data section can have any alignment/offset
- kernel boot fine.

  PR:           235391
  Reviewed by:  markj
  MFC after:    1 month
  Differential Revision: https://reviews.freebsd.org/D21827

Modified:
  head/contrib/elftoolchain/elfcopy/binary.c

Modified: head/contrib/elftoolchain/elfcopy/binary.c
==============================================================================
--- head/contrib/elftoolchain/elfcopy/binary.c  Sun Sep 29 20:44:13
2019        (r352874)
+++ head/contrib/elftoolchain/elfcopy/binary.c  Sun Sep 29 22:34:01
2019        (r352875)
@@ -49,22 +49,23 @@ create_binary(int ifd, int ofd)
        Elf *e;
        Elf_Scn *scn;
        Elf_Data *d;
+       Elf64_Addr baseaddr;
        GElf_Shdr sh;
-       off_t base, off;
+       off_t baseoff, off;
        int elferr;

        if ((e = elf_begin(ifd, ELF_C_READ, NULL)) == NULL)
                errx(EXIT_FAILURE, "elf_begin() failed: %s",
                    elf_errmsg(-1));

-       base = 0;
-       if (lseek(ofd, base, SEEK_SET) < 0)
+       baseoff = 0;
+       if (lseek(ofd, baseoff, SEEK_SET) < 0)
                err(EXIT_FAILURE, "lseek failed");

        /*
         * Find base offset in the first iteration.
         */
-       base = -1;
+       baseoff = -1;
        scn = NULL;
        while ((scn = elf_nextscn(e, scn)) != NULL) {
                if (gelf_getshdr(scn, &sh) == NULL) {
@@ -76,14 +77,16 @@ create_binary(int ifd, int ofd)
                    sh.sh_type == SHT_NOBITS ||
                    sh.sh_size == 0)
                        continue;
-               if (base == -1 || (off_t) sh.sh_offset < base)
-                       base = sh.sh_offset;
+               if (baseoff == -1 || (off_t) sh.sh_offset < baseoff) {
+                       baseoff = sh.sh_offset;
+                       baseaddr = sh.sh_addr;
+               }
        }
        elferr = elf_errno();
        if (elferr != 0)
                warnx("elf_nextscn failed: %s", elf_errmsg(elferr));

-       if (base == -1)
+       if (baseoff == -1)
                return;

        /*
@@ -110,8 +113,8 @@ create_binary(int ifd, int ofd)
                if (d->d_buf == NULL || d->d_size == 0)
                        continue;

-               /* lseek to section offset relative to `base'. */
-               off = sh.sh_offset - base;
+               /* lseek to section offset relative to `baseaddr'. */
+               off = sh.sh_addr - baseaddr;
                if (lseek(ofd, off, SEEK_SET) < 0)
                        err(EXIT_FAILURE, "lseek failed");