[glibc/fw/glibc-hwcaps] elf: Print the full name of the dynamic loader in the ld.so help message

[glibc/fw/glibc-hwcaps] elf: Print the full name of the dynamic loader in the ld.so help message

[Florian Weimer]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=8b705ed302523cef89fcd2024519b96823b9043c

commit 8b705ed302523cef89fcd2024519b96823b9043c
Author: Florian Weimer <fweimer@redhat.com>
Date:   Mon Jun 8 17:46:28 2020 +0200

    elf: Print the full name of the dynamic loader in the ld.so help message
    
    This requires defining a macro for the full path, matching the
    -Wl,--dynamic-link= arguments used for linking glibc programs,
    and ldd script.

Diff:
---
 elf/Makefile   | 3 ++-
 elf/dl-usage.c | 2 ++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/elf/Makefile b/elf/Makefile
index 71602d04c1..7b97e773a5 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -661,7 +661,8 @@ libof-ldconfig = ldconfig
 CFLAGS-dl-cache.c += $(SYSCONF-FLAGS)
 CFLAGS-cache.c += $(SYSCONF-FLAGS)
 CFLAGS-rtld.c += $(SYSCONF-FLAGS)
-CFLAGS-dl-usage.c += $(SYSCONF-FLAGS)
+CFLAGS-dl-usage.c += $(SYSCONF-FLAGS) \
+  -D'RTLD="$(rtlddir)/$(rtld-installed-name)"'
 
 cpp-srcs-left := $(all-rtld-routines:=.os)
 lib := rtld
diff --git a/elf/dl-usage.c b/elf/dl-usage.c
index 35a1c0c455..0a62e8f7cf 100644
--- a/elf/dl-usage.c
+++ b/elf/dl-usage.c
@@ -76,6 +76,8 @@ setting environment variables (which would be inherted by subprocesses).\n\
   --argv0 STRING        set argv[0] to STRING before running\n\
   --help                display this help and exit\n\
   --version             output version information and exit\n\
+\n\
+This program interpreter self-identifies as: " RTLD "\n\
 ",
               argv0);
   _exit (0);