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glibc/SOURCES/glibc-RHEL-93320-7.patch

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commit b4d4ff8963866367ba861681ef3b1251e122014a
Author: Florian Weimer <fweimer@redhat.com>
Date: Mon Jan 17 09:57:19 2022 +0100
elf: Introduce rtld_setup_main_map
This function collects most of the processing needed to initialize
the link map for the main executable.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
Conflicts:
elf/rtld.c
Updated for minor context changes
diff --git a/elf/rtld.c b/elf/rtld.c
index b5be7674dc1dbf40..a47e105987d87add 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -1129,6 +1129,163 @@ rtld_chain_load (struct link_map *main_map, char *argv0)
rtld_soname, pathname, errcode);
}
+/* Called to complete the initialization of the link map for the main
+ executable. Returns true if there is a PT_INTERP segment. */
+static bool
+rtld_setup_main_map (struct link_map *main_map)
+{
+ /* This have already been filled in right after _dl_new_object, or
+ as part of _dl_map_object. */
+ const ElfW(Phdr) *phdr = main_map->l_phdr;
+ ElfW(Word) phnum = main_map->l_phnum;
+
+ 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. */
+ ++main_map->l_direct_opencount;
+
+ /* Scan the program header table for the dynamic section. */
+ for (const ElfW(Phdr) *ph = phdr; ph < &phdr[phnum]; ++ph)
+ switch (ph->p_type)
+ {
+ case PT_PHDR:
+ /* Find out the load address. */
+ main_map->l_addr = (ElfW(Addr)) phdr - ph->p_vaddr;
+ break;
+ case PT_DYNAMIC:
+ /* This tells us where to find the dynamic section,
+ which tells us everything we need to do. */
+ main_map->l_ld = (void *) main_map->l_addr + ph->p_vaddr;
+ main_map->l_ld_readonly = (ph->p_flags & PF_W) == 0;
+ break;
+ case PT_INTERP:
+ /* This "interpreter segment" was used by the program loader to
+ find the program interpreter, which is this program itself, the
+ dynamic linker. We note what name finds us, so that a future
+ dlopen call or DT_NEEDED entry, for something that wants to link
+ against the dynamic linker as a shared library, will know that
+ the shared object is already loaded. */
+ _dl_rtld_libname.name = ((const char *) main_map->l_addr
+ + ph->p_vaddr);
+ /* _dl_rtld_libname.next = NULL; Already zero. */
+ GL(dl_rtld_map).l_libname = &_dl_rtld_libname;
+
+ /* Ordinarilly, we would get additional names for the loader from
+ our DT_SONAME. This can't happen if we were actually linked as
+ a static executable (detect this case when we have no DYNAMIC).
+ If so, assume the filename component of the interpreter path to
+ be our SONAME, and add it to our name list. */
+ if (GL(dl_rtld_map).l_ld == NULL)
+ {
+ const char *p = NULL;
+ const char *cp = _dl_rtld_libname.name;
+
+ /* Find the filename part of the path. */
+ while (*cp != '\0')
+ if (*cp++ == '/')
+ p = cp;
+
+ if (p != NULL)
+ {
+ _dl_rtld_libname2.name = p;
+ /* _dl_rtld_libname2.next = NULL; Already zero. */
+ _dl_rtld_libname.next = &_dl_rtld_libname2;
+ }
+ }
+
+ has_interp = true;
+ break;
+ case PT_LOAD:
+ {
+ ElfW(Addr) mapstart;
+ ElfW(Addr) allocend;
+
+ /* Remember where the main program starts in memory. */
+ mapstart = (main_map->l_addr
+ + (ph->p_vaddr & ~(GLRO(dl_pagesize) - 1)));
+ if (main_map->l_map_start > mapstart)
+ main_map->l_map_start = mapstart;
+
+ /* Also where it ends. */
+ 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;
+ }
+ break;
+
+ case PT_TLS:
+ if (ph->p_memsz > 0)
+ {
+ /* Note that in the case the dynamic linker we duplicate work
+ here since we read the PT_TLS entry already in
+ _dl_start_final. But the result is repeatable so do not
+ check for this special but unimportant case. */
+ main_map->l_tls_blocksize = ph->p_memsz;
+ main_map->l_tls_align = ph->p_align;
+ if (ph->p_align == 0)
+ main_map->l_tls_firstbyte_offset = 0;
+ else
+ main_map->l_tls_firstbyte_offset = (ph->p_vaddr
+ & (ph->p_align - 1));
+ main_map->l_tls_initimage_size = ph->p_filesz;
+ main_map->l_tls_initimage = (void *) ph->p_vaddr;
+
+ /* This image gets the ID one. */
+ GL(dl_tls_max_dtv_idx) = main_map->l_tls_modid = 1;
+ }
+ break;
+
+ case PT_GNU_STACK:
+ GL(dl_stack_flags) = ph->p_flags;
+ break;
+
+ case PT_GNU_RELRO:
+ main_map->l_relro_addr = ph->p_vaddr;
+ main_map->l_relro_size = ph->p_memsz;
+ break;
+ }
+ /* Process program headers again, but scan them backwards so
+ that PT_NOTE can be skipped if PT_GNU_PROPERTY exits. */
+ for (const ElfW(Phdr) *ph = &phdr[phnum]; ph != phdr; --ph)
+ switch (ph[-1].p_type)
+ {
+ case PT_NOTE:
+ _dl_process_pt_note (main_map, -1, &ph[-1]);
+ break;
+ case PT_GNU_PROPERTY:
+ _dl_process_pt_gnu_property (main_map, -1, &ph[-1]);
+ break;
+ }
+
+ /* Adjust the address of the TLS initialization image in case
+ the executable is actually an ET_DYN object. */
+ if (main_map->l_tls_initimage != NULL)
+ main_map->l_tls_initimage
+ = (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
+ PT_INTERP. */
+ _dl_rtld_libname.name = GL(dl_rtld_map).l_name;
+ /* _dl_rtld_libname.next = NULL; Already zero. */
+ GL(dl_rtld_map).l_libname = &_dl_rtld_libname;
+ }
+ else
+ assert (GL(dl_rtld_map).l_libname); /* How else did we get here? */
+
+ return has_interp;
+}
+
/* 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
@@ -1191,11 +1348,9 @@ dl_main (const ElfW(Phdr) *phdr,
ElfW(Addr) *user_entry,
ElfW(auxv_t) *auxv)
{
- const ElfW(Phdr) *ph;
struct link_map *main_map;
size_t file_size;
char *file;
- bool has_interp = false;
unsigned int i;
bool prelinked = false;
bool rtld_is_main = false;
@@ -1397,7 +1552,7 @@ dl_main (const ElfW(Phdr) *phdr,
load the program below unless it has a PT_GNU_STACK indicating
nonexecutable stack is ok. */
- for (ph = phdr; ph < &phdr[phnum]; ++ph)
+ for (const ElfW(Phdr) *ph = phdr; ph < &phdr[phnum]; ++ph)
if (ph->p_type == PT_GNU_STACK)
{
GL(dl_stack_flags) = ph->p_flags;
@@ -1519,147 +1674,7 @@ dl_main (const ElfW(Phdr) *phdr,
information for the program. */
}
- 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. */
- ++main_map->l_direct_opencount;
-
- /* Scan the program header table for the dynamic section. */
- for (ph = phdr; ph < &phdr[phnum]; ++ph)
- switch (ph->p_type)
- {
- case PT_PHDR:
- /* Find out the load address. */
- main_map->l_addr = (ElfW(Addr)) phdr - ph->p_vaddr;
- break;
- case PT_DYNAMIC:
- /* This tells us where to find the dynamic section,
- which tells us everything we need to do. */
- main_map->l_ld = (void *) main_map->l_addr + ph->p_vaddr;
- main_map->l_ld_readonly = (ph->p_flags & PF_W) == 0;
- break;
- case PT_INTERP:
- /* This "interpreter segment" was used by the program loader to
- find the program interpreter, which is this program itself, the
- dynamic linker. We note what name finds us, so that a future
- dlopen call or DT_NEEDED entry, for something that wants to link
- against the dynamic linker as a shared library, will know that
- the shared object is already loaded. */
- _dl_rtld_libname.name = ((const char *) main_map->l_addr
- + ph->p_vaddr);
- /* _dl_rtld_libname.next = NULL; Already zero. */
- GL(dl_rtld_map).l_libname = &_dl_rtld_libname;
-
- /* Ordinarilly, we would get additional names for the loader from
- our DT_SONAME. This can't happen if we were actually linked as
- a static executable (detect this case when we have no DYNAMIC).
- If so, assume the filename component of the interpreter path to
- be our SONAME, and add it to our name list. */
- if (GL(dl_rtld_map).l_ld == NULL)
- {
- const char *p = NULL;
- const char *cp = _dl_rtld_libname.name;
-
- /* Find the filename part of the path. */
- while (*cp != '\0')
- if (*cp++ == '/')
- p = cp;
-
- if (p != NULL)
- {
- _dl_rtld_libname2.name = p;
- /* _dl_rtld_libname2.next = NULL; Already zero. */
- _dl_rtld_libname.next = &_dl_rtld_libname2;
- }
- }
-
- has_interp = true;
- break;
- case PT_LOAD:
- {
- ElfW(Addr) mapstart;
- ElfW(Addr) allocend;
-
- /* Remember where the main program starts in memory. */
- mapstart = (main_map->l_addr
- + (ph->p_vaddr & ~(GLRO(dl_pagesize) - 1)));
- if (main_map->l_map_start > mapstart)
- main_map->l_map_start = mapstart;
-
- /* Also where it ends. */
- 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;
- }
- break;
-
- case PT_TLS:
- if (ph->p_memsz > 0)
- {
- /* Note that in the case the dynamic linker we duplicate work
- here since we read the PT_TLS entry already in
- _dl_start_final. But the result is repeatable so do not
- check for this special but unimportant case. */
- main_map->l_tls_blocksize = ph->p_memsz;
- main_map->l_tls_align = ph->p_align;
- if (ph->p_align == 0)
- main_map->l_tls_firstbyte_offset = 0;
- else
- main_map->l_tls_firstbyte_offset = (ph->p_vaddr
- & (ph->p_align - 1));
- main_map->l_tls_initimage_size = ph->p_filesz;
- main_map->l_tls_initimage = (void *) ph->p_vaddr;
-
- /* This image gets the ID one. */
- GL(dl_tls_max_dtv_idx) = main_map->l_tls_modid = 1;
- }
- break;
-
- case PT_GNU_STACK:
- GL(dl_stack_flags) = ph->p_flags;
- break;
-
- case PT_GNU_RELRO:
- main_map->l_relro_addr = ph->p_vaddr;
- main_map->l_relro_size = ph->p_memsz;
- break;
- }
- /* Process program headers again, but scan them backwards so
- that PT_NOTE can be skipped if PT_GNU_PROPERTY exits. */
- for (ph = &phdr[phnum]; ph != phdr; --ph)
- switch (ph[-1].p_type)
- {
- case PT_NOTE:
- _dl_process_pt_note (main_map, -1, &ph[-1]);
- break;
- case PT_GNU_PROPERTY:
- _dl_process_pt_gnu_property (main_map, -1, &ph[-1]);
- break;
- }
-
- /* Adjust the address of the TLS initialization image in case
- the executable is actually an ET_DYN object. */
- if (main_map->l_tls_initimage != NULL)
- main_map->l_tls_initimage
- = (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
- PT_INTERP. */
- _dl_rtld_libname.name = GL(dl_rtld_map).l_name;
- /* _dl_rtld_libname.next = NULL; Already zero. */
- GL(dl_rtld_map).l_libname = &_dl_rtld_libname;
- }
- else
- assert (GL(dl_rtld_map).l_libname); /* How else did we get here? */
+ bool has_interp = rtld_setup_main_map (main_map);
/* If the current libname is different from the SONAME, add the
latter as well. */
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