107 lines
3.7 KiB
Diff
107 lines
3.7 KiB
Diff
commit 2cac9559e06044ba520e785c151fbbd25011865f
|
|
Author: Florian Weimer <fweimer@redhat.com>
|
|
Date: Fri Aug 1 10:20:23 2025 +0200
|
|
|
|
elf: Extract rtld_setup_phdr function from dl_main
|
|
|
|
Remove historic binutils reference from comment and update
|
|
how this data is used by applications.
|
|
|
|
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
|
|
|
|
Conflicts:
|
|
elf/rtld.
|
|
(missing __ehdr_start cleanup downstream)
|
|
|
|
diff --git a/elf/rtld.c b/elf/rtld.c
|
|
index 667880e18ae816d8..a9073d4e14b07410 100644
|
|
--- a/elf/rtld.c
|
|
+++ b/elf/rtld.c
|
|
@@ -1306,6 +1306,45 @@ rtld_setup_main_map (struct link_map *main_map)
|
|
return has_interp;
|
|
}
|
|
|
|
+/* Set up the program header information for the dynamic linker
|
|
+ itself. It can be accessed via _r_debug and dl_iterate_phdr
|
|
+ callbacks. */
|
|
+static void
|
|
+rtld_setup_phdr (void)
|
|
+{
|
|
+ const ElfW(Ehdr) *rtld_ehdr;
|
|
+
|
|
+ /* Starting from binutils-2.23, the linker will define the magic symbol
|
|
+ __ehdr_start to point to our own ELF header if it is visible in a
|
|
+ segment that also includes the phdrs. If that's not available, we use
|
|
+ the old method that assumes the beginning of the file is part of the
|
|
+ lowest-addressed PT_LOAD segment. */
|
|
+#ifdef HAVE_EHDR_START
|
|
+ extern const ElfW(Ehdr) __ehdr_start __attribute__ ((visibility ("hidden")));
|
|
+ rtld_ehdr = &__ehdr_start;
|
|
+#else
|
|
+ rtld_ehdr = (void *) GL(dl_rtld_map).l_map_start;
|
|
+#endif
|
|
+ assert (rtld_ehdr->e_ehsize == sizeof *rtld_ehdr);
|
|
+ assert (rtld_ehdr->e_phentsize == sizeof (ElfW(Phdr)));
|
|
+
|
|
+ const ElfW(Phdr) *rtld_phdr = (const void *) rtld_ehdr + rtld_ehdr->e_phoff;
|
|
+
|
|
+ GL(dl_rtld_map).l_phdr = rtld_phdr;
|
|
+ GL(dl_rtld_map).l_phnum = rtld_ehdr->e_phnum;
|
|
+
|
|
+
|
|
+ /* PT_GNU_RELRO is usually the last phdr. */
|
|
+ size_t cnt = rtld_ehdr->e_phnum;
|
|
+ while (cnt-- > 0)
|
|
+ if (rtld_phdr[cnt].p_type == PT_GNU_RELRO)
|
|
+ {
|
|
+ GL(dl_rtld_map).l_relro_addr = rtld_phdr[cnt].p_vaddr;
|
|
+ GL(dl_rtld_map).l_relro_size = rtld_phdr[cnt].p_memsz;
|
|
+ break;
|
|
+ }
|
|
+}
|
|
+
|
|
/* Adjusts the contents of the stack and related globals for the user
|
|
entry point. The ld.so processed skip_args arguments and bumped
|
|
_dl_argv and _dl_argc accordingly. Those arguments are removed from
|
|
@@ -1790,39 +1829,7 @@ dl_main (const ElfW(Phdr) *phdr,
|
|
if (GLRO(dl_use_load_bias) == (ElfW(Addr)) -2)
|
|
GLRO(dl_use_load_bias) = main_map->l_addr == 0 ? -1 : 0;
|
|
|
|
- /* Set up the program header information for the dynamic linker
|
|
- itself. It is needed in the dl_iterate_phdr callbacks. */
|
|
- const ElfW(Ehdr) *rtld_ehdr;
|
|
-
|
|
- /* Starting from binutils-2.23, the linker will define the magic symbol
|
|
- __ehdr_start to point to our own ELF header if it is visible in a
|
|
- segment that also includes the phdrs. If that's not available, we use
|
|
- the old method that assumes the beginning of the file is part of the
|
|
- lowest-addressed PT_LOAD segment. */
|
|
-#ifdef HAVE_EHDR_START
|
|
- extern const ElfW(Ehdr) __ehdr_start __attribute__ ((visibility ("hidden")));
|
|
- rtld_ehdr = &__ehdr_start;
|
|
-#else
|
|
- rtld_ehdr = (void *) GL(dl_rtld_map).l_map_start;
|
|
-#endif
|
|
- assert (rtld_ehdr->e_ehsize == sizeof *rtld_ehdr);
|
|
- assert (rtld_ehdr->e_phentsize == sizeof (ElfW(Phdr)));
|
|
-
|
|
- const ElfW(Phdr) *rtld_phdr = (const void *) rtld_ehdr + rtld_ehdr->e_phoff;
|
|
-
|
|
- GL(dl_rtld_map).l_phdr = rtld_phdr;
|
|
- GL(dl_rtld_map).l_phnum = rtld_ehdr->e_phnum;
|
|
-
|
|
-
|
|
- /* PT_GNU_RELRO is usually the last phdr. */
|
|
- size_t cnt = rtld_ehdr->e_phnum;
|
|
- while (cnt-- > 0)
|
|
- if (rtld_phdr[cnt].p_type == PT_GNU_RELRO)
|
|
- {
|
|
- GL(dl_rtld_map).l_relro_addr = rtld_phdr[cnt].p_vaddr;
|
|
- GL(dl_rtld_map).l_relro_size = rtld_phdr[cnt].p_memsz;
|
|
- break;
|
|
- }
|
|
+ rtld_setup_phdr ();
|
|
|
|
/* Add the dynamic linker to the TLS list if it also uses TLS. */
|
|
if (GL(dl_rtld_map).l_tls_blocksize != 0)
|