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From e0b6c9706c91a642c781918eea52588ee8dc9f09 Mon Sep 17 00:00:00 2001
From: Florian Weimer <fweimer@redhat.com>
Date: Wed, 18 Oct 2023 14:22:59 +0200
Subject: [PATCH 1/3] Revert "elf: Remove unused l_text_end field from struct
link_map"
This reverts commit 750f19526ae71aac801c77a3f7ef5374890c09b7.
Reason for revert: Restore ABI after revert of commit a3189f66a5f.
---
elf/dl-load.c | 2 +-
elf/dl-load.h | 7 +++++--
elf/rtld.c | 6 ++++++
elf/setup-vdso.h | 4 ++++
include/link.h | 2 ++
5 files changed, 18 insertions(+), 3 deletions(-)
diff --git a/elf/dl-load.c b/elf/dl-load.c
index 2923b1141d..9a87fda9c9 100644
--- a/elf/dl-load.c
+++ b/elf/dl-load.c
@@ -1253,7 +1253,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
/* Now process the load commands and map segments into memory.
This is responsible for filling in:
- l_map_start, l_map_end, l_addr, l_contiguous, l_phdr
+ l_map_start, l_map_end, l_addr, l_contiguous, l_text_end, l_phdr
*/
errstring = _dl_map_segments (l, fd, header, type, loadcmds, nloadcmds,
maplength, has_holes, loader);
diff --git a/elf/dl-load.h b/elf/dl-load.h
index 1d5207694b..ecf6910c68 100644
--- a/elf/dl-load.h
+++ b/elf/dl-load.h
@@ -83,11 +83,14 @@ struct loadcmd
/* This is a subroutine of _dl_map_segments. It should be called for each
load command, some time after L->l_addr has been set correctly. It is
- responsible for setting the l_phdr fields */
+ responsible for setting up the l_text_end and l_phdr fields. */
static __always_inline void
_dl_postprocess_loadcmd (struct link_map *l, const ElfW(Ehdr) *header,
const struct loadcmd *c)
{
+ if (c->prot & PROT_EXEC)
+ l->l_text_end = l->l_addr + c->mapend;
+
if (l->l_phdr == 0
&& c->mapoff <= header->e_phoff
&& ((size_t) (c->mapend - c->mapstart + c->mapoff)
@@ -100,7 +103,7 @@ _dl_postprocess_loadcmd (struct link_map *l, const ElfW(Ehdr) *header,
/* This is a subroutine of _dl_map_object_from_fd. It is responsible
for filling in several fields in *L: l_map_start, l_map_end, l_addr,
- l_contiguous, l_phdr. On successful return, all the
+ l_contiguous, l_text_end, l_phdr. On successful return, all the
segments are mapped (or copied, or whatever) from the file into their
final places in the address space, with the correct page permissions,
and any bss-like regions already zeroed. It returns a null pointer
diff --git a/elf/rtld.c b/elf/rtld.c
index 5107d16fe3..a91e2a4471 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -477,6 +477,7 @@ _dl_start_final (void *arg, struct dl_start_final_info *info)
GL(dl_rtld_map).l_real = &GL(dl_rtld_map);
GL(dl_rtld_map).l_map_start = (ElfW(Addr)) &__ehdr_start;
GL(dl_rtld_map).l_map_end = (ElfW(Addr)) _end;
+ GL(dl_rtld_map).l_text_end = (ElfW(Addr)) _etext;
/* Copy the TLS related data if necessary. */
#ifndef DONT_USE_BOOTSTRAP_MAP
# if NO_TLS_OFFSET != 0
@@ -1118,6 +1119,7 @@ rtld_setup_main_map (struct link_map *main_map)
bool has_interp = false;
main_map->l_map_end = 0;
+ main_map->l_text_end = 0;
/* Perhaps the executable has no PT_LOAD header entries at all. */
main_map->l_map_start = ~0;
/* And it was opened directly. */
@@ -1209,6 +1211,8 @@ rtld_setup_main_map (struct link_map *main_map)
allocend = main_map->l_addr + ph->p_vaddr + ph->p_memsz;
if (main_map->l_map_end < allocend)
main_map->l_map_end = allocend;
+ if ((ph->p_flags & PF_X) && allocend > main_map->l_text_end)
+ main_map->l_text_end = allocend;
/* The next expected address is the page following this load
segment. */
@@ -1268,6 +1272,8 @@ rtld_setup_main_map (struct link_map *main_map)
= (char *) main_map->l_tls_initimage + main_map->l_addr;
if (! main_map->l_map_end)
main_map->l_map_end = ~0;
+ if (! main_map->l_text_end)
+ main_map->l_text_end = ~0;
if (! GL(dl_rtld_map).l_libname && GL(dl_rtld_map).l_name)
{
/* We were invoked directly, so the program might not have a
diff --git a/elf/setup-vdso.h b/elf/setup-vdso.h
index d92b12a7aa..0079842d1f 100644
--- a/elf/setup-vdso.h
+++ b/elf/setup-vdso.h
@@ -51,6 +51,9 @@ setup_vdso (struct link_map *main_map __attribute__ ((unused)),
l->l_addr = ph->p_vaddr;
if (ph->p_vaddr + ph->p_memsz >= l->l_map_end)
l->l_map_end = ph->p_vaddr + ph->p_memsz;
+ if ((ph->p_flags & PF_X)
+ && ph->p_vaddr + ph->p_memsz >= l->l_text_end)
+ l->l_text_end = ph->p_vaddr + ph->p_memsz;
}
else
/* There must be no TLS segment. */
@@ -59,6 +62,7 @@ setup_vdso (struct link_map *main_map __attribute__ ((unused)),
l->l_map_start = (ElfW(Addr)) GLRO(dl_sysinfo_dso);
l->l_addr = l->l_map_start - l->l_addr;
l->l_map_end += l->l_addr;
+ l->l_text_end += l->l_addr;
l->l_ld = (void *) ((ElfW(Addr)) l->l_ld + l->l_addr);
elf_get_dynamic_info (l, false, false);
_dl_setup_hash (l);
diff --git a/include/link.h b/include/link.h
index 686813f281..a02d5f2eba 100644
--- a/include/link.h
+++ b/include/link.h
@@ -253,6 +253,8 @@ struct link_map
/* Start and finish of memory map for this object. l_map_start
need not be the same as l_addr. */
ElfW(Addr) l_map_start, l_map_end;
+ /* End of the executable part of the mapping. */
+ ElfW(Addr) l_text_end;
/* Linked list of objects in reverse ELF constructor execution
order. Head of list is stored in _dl_init_called_list. */
--
2.33.0
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