commit 03e187a41d91069543cfcf33469a05912e555447

Author: Florian Weimer <fweimer@redhat.com>

Date:   Wed Apr 29 15:44:03 2020 +0200

    elf: Add initial flag argument to __libc_early_init

    The rseq initialization should happen only for the libc in the base

    namespace (in the dynamic case) or the statically linked libc.  The

    __libc_multiple_libcs flag does not quite cover this case at present,

    so this commit introduces a flag argument to __libc_early_init,

    indicating whether the libc being libc is the primary one (of the main

    program).

    Reviewed-by: Carlos O'Donell <carlos@redhat.com>

diff --git a/csu/libc-start.c b/csu/libc-start.c

index d9c3248219d8f84f..fd0f8640eaeae34c 100644

--- a/csu/libc-start.c

+++ b/csu/libc-start.c

@@ -23,6 +23,7 @@

 #include <exit-thread.h>

 #include <libc-internal.h>

 #include <elf/libc-early-init.h>

+#include <stdbool.h>

 #include <elf/dl-tunables.h>

@@ -241,7 +242,7 @@ LIBC_START_MAIN (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL),

 #ifndef SHARED

   /* Perform early initialization.  In the shared case, this function

      is called from the dynamic loader as early as possible.  */

-  __libc_early_init ();

+  __libc_early_init (true);

   /* Call the initializer of the libc.  This is only needed here if we

      are compiling for the static library in which case we haven't

diff --git a/elf/dl-call-libc-early-init.c b/elf/dl-call-libc-early-init.c

index 41e9ad9aad8b5b46..9a84680a1ceafba2 100644

--- a/elf/dl-call-libc-early-init.c

+++ b/elf/dl-call-libc-early-init.c

@@ -23,7 +23,7 @@

 #include <stddef.h>

 void

-_dl_call_libc_early_init (struct link_map *libc_map)

+_dl_call_libc_early_init (struct link_map *libc_map, _Bool initial)

 {

   /* There is nothing to do if we did not actually load libc.so.  */

   if (libc_map == NULL)

@@ -37,5 +37,5 @@ _dl_call_libc_early_init (struct link_map *libc_map)

   assert (sym != NULL);

   __typeof (__libc_early_init) *early_init

     = DL_SYMBOL_ADDRESS (libc_map, sym);

-  early_init ();

+  early_init (initial);

 }

diff --git a/elf/dl-open.c b/elf/dl-open.c

index 1a77ec833cad6c55..3d49a84596e99bf6 100644

--- a/elf/dl-open.c

+++ b/elf/dl-open.c

@@ -748,9 +748,22 @@ dl_open_worker (void *a)

     LIBC_PROBE (reloc_complete, 3, args->nsid, r, new);

   /* If libc.so was not there before, attempt to call its early

-     initialization routine.  */

+     initialization routine.  Indicate to the initialization routine

+     whether the libc being initialized is the one in the base

+     namespace.  */

   if (!args->libc_already_loaded)

-    _dl_call_libc_early_init (GL(dl_ns)[args->nsid].libc_map);

+    {

+      struct link_map *libc_map = GL(dl_ns)[args->nsid].libc_map;

+#ifdef SHARED

+      bool initial = libc_map->l_ns == LM_ID_BASE;

+#else

+      /* In the static case, there is only one namespace, but it

+	 contains a secondary libc (the primary libc is statically

+	 linked).  */

+      bool initial = false;

+#endif

+      _dl_call_libc_early_init (libc_map, initial);

+    }

 #ifndef SHARED

   DL_STATIC_INIT (new);

diff --git a/elf/libc-early-init.h b/elf/libc-early-init.h

index 5185fa8895c0e11a..8f7836dceaeecd5a 100644

--- a/elf/libc-early-init.h

+++ b/elf/libc-early-init.h

@@ -22,14 +22,17 @@

 struct link_map;

 /* If LIBC_MAP is not NULL, look up the __libc_early_init symbol in it

-   and call this function.  */

-void _dl_call_libc_early_init (struct link_map *libc_map) attribute_hidden;

+   and call this function, with INITIAL as the argument.  */

+void _dl_call_libc_early_init (struct link_map *libc_map, _Bool initial)

+  attribute_hidden;

 /* In the shared case, this function is defined in libc.so and invoked

    from ld.so (or on the fist static dlopen) after complete relocation

    of a new loaded libc.so, but before user-defined ELF constructors

    run.  In the static case, this function is called directly from the

-   startup code.  */

-void __libc_early_init (void);

+   startup code.  If INITIAL is true, the libc being initialized is

+   the libc for the main program.  INITIAL is false for libcs loaded

+   for audit modules, dlmopen, and static dlopen.  */

+void __libc_early_init (_Bool initial);

 #endif /* _LIBC_EARLY_INIT_H */

diff --git a/elf/libc_early_init.c b/elf/libc_early_init.c

index 7f4ca332b805a22c..e6c64fb526600fae 100644

--- a/elf/libc_early_init.c

+++ b/elf/libc_early_init.c

@@ -20,7 +20,7 @@

 #include <libc-early-init.h>

 void

-__libc_early_init (void)

+__libc_early_init (_Bool initial)

 {

   /* Initialize ctype data.  */

   __ctype_init ();

diff --git a/elf/rtld.c b/elf/rtld.c

index a40d5f17db0dac8b..772aff5160359b7b 100644

--- a/elf/rtld.c

+++ b/elf/rtld.c

@@ -2366,8 +2366,10 @@ ERROR: '%s': cannot process note segment.\n", _dl_argv[0]);

       rtld_timer_accum (&relocate_time, start);

     }

-  /* Relocation is complete.  Perform early libc initialization.  */

-  _dl_call_libc_early_init (GL(dl_ns)[LM_ID_BASE].libc_map);

+  /* Relocation is complete.  Perform early libc initialization.  This

+     is the initial libc, even if audit modules have been loaded with

+     other libcs.  */

+  _dl_call_libc_early_init (GL(dl_ns)[LM_ID_BASE].libc_map, true);

   /* Do any necessary cleanups for the startup OS interface code.

      We do these now so that no calls are made after rtld re-relocation