[05/28] elf: Move ld.so error/help output to _dl_usage

Message ID 82d06d8f60646b8f6e7f13ba42668e3ea10e0268.1601569371.git.fweimer@redhat.com
State New
Headers show
Series
  • glibc-hwcaps support
Related show

Commit Message

Florian Weimer via Libc-alpha Oct. 1, 2020, 4:32 p.m.
Also add a comment to elf/Makefile, explaining why we cannot use
config.status for autoconf template processing.
---
 elf/Makefile   |  9 ++++++++-
 elf/dl-main.h  |  5 +++++
 elf/dl-usage.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++++
 elf/rtld.c     | 26 +------------------------
 4 files changed, 65 insertions(+), 26 deletions(-)
 create mode 100644 elf/dl-usage.c

-- 
Red Hat GmbH, https://de.redhat.com/ , Registered seat: Grasbrunn,
Commercial register: Amtsgericht Muenchen, HRB 153243,
Managing Directors: Charles Cachera, Brian Klemm, Laurie Krebs, Michael O'Neill

Comments

Florian Weimer via Libc-alpha Oct. 6, 2020, 9:06 p.m. | #1
On 01/10/2020 13:32, Florian Weimer via Libc-alpha wrote:
> Also add a comment to elf/Makefile, explaining why we cannot use

> config.status for autoconf template processing.


LGTM, with just a nit below.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>


> ---

>  elf/Makefile   |  9 ++++++++-

>  elf/dl-main.h  |  5 +++++

>  elf/dl-usage.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++++

>  elf/rtld.c     | 26 +------------------------

>  4 files changed, 65 insertions(+), 26 deletions(-)

>  create mode 100644 elf/dl-usage.c

> 

> diff --git a/elf/Makefile b/elf/Makefile

> index ab792d45c2..71602d04c1 100644

> --- a/elf/Makefile

> +++ b/elf/Makefile

> @@ -59,7 +59,7 @@ elide-routines.os = $(all-dl-routines) dl-support enbl-secure dl-origin \

>  # ld.so uses those routines, plus some special stuff for being the program

>  # interpreter and operating independent of libc.

>  rtld-routines	= rtld $(all-dl-routines) dl-sysdep dl-environ dl-minimal \

> -  dl-error-minimal dl-conflict dl-hwcaps

> +  dl-error-minimal dl-conflict dl-hwcaps dl-usage

>  all-rtld-routines = $(rtld-routines) $(sysdep-rtld-routines)

>  

>  CFLAGS-dl-runtime.c += -fexceptions -fasynchronous-unwind-tables


Ok.

> @@ -618,6 +618,12 @@ ldso_install: $(inst_rtlddir)/$(rtld-installed-name)

>  endif

>  

>  

> +# Workarounds for ${exec_prefix} expansion in configure variables.

> +# config.status cannot be used directly for processing ldd.bash.in or

> +# expanding variables such as sysconfdir because the expansion

> +# contains the literal string ${exec_prefix}, which is not valid in C

> +# headers or installed shell scripts.

> +

>  ldd-rewrite = -e 's%@RTLD@%$(rtlddir)/$(rtld-installed-name)%g' \

>  	      -e 's%@VERSION@%$(version)%g' \

>  	      -e 's|@PKGVERSION@|$(PKGVERSION)|g' \

> @@ -655,6 +661,7 @@ 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)

>  

>  cpp-srcs-left := $(all-rtld-routines:=.os)

>  lib := rtld


Ok.

> diff --git a/elf/dl-main.h b/elf/dl-main.h

> index ad9250171f..681f366871 100644

> --- a/elf/dl-main.h

> +++ b/elf/dl-main.h

> @@ -19,7 +19,9 @@

>  #ifndef _DL_MAIN

>  #define _DL_MAIN

>  

> +#include <ldsodefs.h>

>  #include <limits.h>

> +#include <stdlib.h>

>  

>  /* Length limits for names and paths, to protect the dynamic linker,

>     particularly when __libc_enable_secure is active.  */

> @@ -92,4 +94,7 @@ call_init_paths (const struct dl_main_state *state)

>    _dl_init_paths (state->library_path);

>  }

>  

> +/* Print ld.so usage information and exit.  */

> +void _dl_usage (void) attribute_hidden __attribute__ ((__noreturn__));

> +

>  #endif /* _DL_MAIN */


Why not use C11 _Noreturn?

> diff --git a/elf/dl-usage.c b/elf/dl-usage.c

> new file mode 100644

> index 0000000000..f3d89d22b7

> --- /dev/null

> +++ b/elf/dl-usage.c

> @@ -0,0 +1,51 @@

> +/* Print usage information and help for ld.so.

> +   Copyright (C) 1995-2020 Free Software Foundation, Inc.

> +   This file is part of the GNU C Library.

> +

> +   The GNU C Library is free software; you can redistribute it and/or

> +   modify it under the terms of the GNU Lesser General Public

> +   License as published by the Free Software Foundation; either

> +   version 2.1 of the License, or (at your option) any later version.

> +

> +   The GNU C Library is distributed in the hope that it will be useful,

> +   but WITHOUT ANY WARRANTY; without even the implied warranty of

> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

> +   Lesser General Public License for more details.

> +

> +   You should have received a copy of the GNU Lesser General Public

> +   License along with the GNU C Library; if not, see

> +   <https://www.gnu.org/licenses/>.  */

> +

> +#include <dl-cache.h>

> +#include <dl-main.h>

> +#include <ldsodefs.h>

> +

> +void

> +_dl_usage (void)

> +{

> +  _dl_fatal_printf ("\

> +Usage: ld.so [OPTION]... EXECUTABLE-FILE [ARGS-FOR-PROGRAM...]\n\

> +You have invoked `ld.so', the helper program for shared library executables.\n\

> +This program usually lives in the file `/lib/ld.so', and special directives\n\

> +in executable files using ELF shared libraries tell the system's program\n\

> +loader to load the helper program from this file.  This helper program loads\n\

> +the shared libraries needed by the program executable, prepares the program\n\

> +to run, and runs it.  You may invoke this helper program directly from the\n\

> +command line to load and run an ELF executable file; this is like executing\n\

> +that file itself, but always uses this helper program from the file you\n\

> +specified, instead of the helper program file specified in the executable\n\

> +file you run.  This is mostly of use for maintainers to test new versions\n\

> +of this helper program; chances are you did not intend to run this program.\n\

> +\n\

> +  --list                list all dependencies and how they are resolved\n\

> +  --verify              verify that given object really is a dynamically linked\n\

> +                        object we can handle\n\

> +  --inhibit-cache       Do not use " LD_SO_CACHE "\n\

> +  --library-path PATH   use given PATH instead of content of the environment\n\

> +                        variable LD_LIBRARY_PATH\n\

> +  --inhibit-rpath LIST  ignore RUNPATH and RPATH information in object names\n\

> +                        in LIST\n\

> +  --audit LIST          use objects named in LIST as auditors\n\

> +  --preload LIST        preload objects named in LIST\n\

> +  --argv0 STRING        set argv[0] to STRING before running\n");

> +}


Ok.

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

> index c1153cb627..f3e1791e2f 100644

> --- a/elf/rtld.c

> +++ b/elf/rtld.c

> @@ -1246,31 +1246,7 @@ dl_main (const ElfW(Phdr) *phdr,

>        /* If we have no further argument the program was called incorrectly.

>  	 Grant the user some education.  */

>        if (_dl_argc < 2)

> -	_dl_fatal_printf ("\

> -Usage: ld.so [OPTION]... EXECUTABLE-FILE [ARGS-FOR-PROGRAM...]\n\

> -You have invoked `ld.so', the helper program for shared library executables.\n\

> -This program usually lives in the file `/lib/ld.so', and special directives\n\

> -in executable files using ELF shared libraries tell the system's program\n\

> -loader to load the helper program from this file.  This helper program loads\n\

> -the shared libraries needed by the program executable, prepares the program\n\

> -to run, and runs it.  You may invoke this helper program directly from the\n\

> -command line to load and run an ELF executable file; this is like executing\n\

> -that file itself, but always uses this helper program from the file you\n\

> -specified, instead of the helper program file specified in the executable\n\

> -file you run.  This is mostly of use for maintainers to test new versions\n\

> -of this helper program; chances are you did not intend to run this program.\n\

> -\n\

> -  --list                list all dependencies and how they are resolved\n\

> -  --verify              verify that given object really is a dynamically linked\n\

> -			object we can handle\n\

> -  --inhibit-cache       Do not use " LD_SO_CACHE "\n\

> -  --library-path PATH   use given PATH instead of content of the environment\n\

> -			variable LD_LIBRARY_PATH\n\

> -  --inhibit-rpath LIST  ignore RUNPATH and RPATH information in object names\n\

> -			in LIST\n\

> -  --audit LIST          use objects named in LIST as auditors\n\

> -  --preload LIST        preload objects named in LIST\n\

> -  --argv0 STRING        set argv[0] to STRING before running\n");

> +	_dl_usage ();

>  

>        ++_dl_skip_args;

>        --_dl_argc;

> 


Ok.
Florian Weimer via Libc-alpha Oct. 8, 2020, 12:19 p.m. | #2
* Adhemerval Zanella via Libc-alpha:

> On 01/10/2020 13:32, Florian Weimer via Libc-alpha wrote:

>> Also add a comment to elf/Makefile, explaining why we cannot use

>> config.status for autoconf template processing.

>

> LGTM, with just a nit below.

>

> Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>


Thanks, pushed with the _Noreturn change.

Florian
-- 
Red Hat GmbH, https://de.redhat.com/ , Registered seat: Grasbrunn,
Commercial register: Amtsgericht Muenchen, HRB 153243,
Managing Directors: Charles Cachera, Brian Klemm, Laurie Krebs, Michael O'Neill

Patch

diff --git a/elf/Makefile b/elf/Makefile
index ab792d45c2..71602d04c1 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -59,7 +59,7 @@  elide-routines.os = $(all-dl-routines) dl-support enbl-secure dl-origin \
 # ld.so uses those routines, plus some special stuff for being the program
 # interpreter and operating independent of libc.
 rtld-routines	= rtld $(all-dl-routines) dl-sysdep dl-environ dl-minimal \
-  dl-error-minimal dl-conflict dl-hwcaps
+  dl-error-minimal dl-conflict dl-hwcaps dl-usage
 all-rtld-routines = $(rtld-routines) $(sysdep-rtld-routines)
 
 CFLAGS-dl-runtime.c += -fexceptions -fasynchronous-unwind-tables
@@ -618,6 +618,12 @@  ldso_install: $(inst_rtlddir)/$(rtld-installed-name)
 endif
 
 
+# Workarounds for ${exec_prefix} expansion in configure variables.
+# config.status cannot be used directly for processing ldd.bash.in or
+# expanding variables such as sysconfdir because the expansion
+# contains the literal string ${exec_prefix}, which is not valid in C
+# headers or installed shell scripts.
+
 ldd-rewrite = -e 's%@RTLD@%$(rtlddir)/$(rtld-installed-name)%g' \
 	      -e 's%@VERSION@%$(version)%g' \
 	      -e 's|@PKGVERSION@|$(PKGVERSION)|g' \
@@ -655,6 +661,7 @@  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)
 
 cpp-srcs-left := $(all-rtld-routines:=.os)
 lib := rtld
diff --git a/elf/dl-main.h b/elf/dl-main.h
index ad9250171f..681f366871 100644
--- a/elf/dl-main.h
+++ b/elf/dl-main.h
@@ -19,7 +19,9 @@ 
 #ifndef _DL_MAIN
 #define _DL_MAIN
 
+#include <ldsodefs.h>
 #include <limits.h>
+#include <stdlib.h>
 
 /* Length limits for names and paths, to protect the dynamic linker,
    particularly when __libc_enable_secure is active.  */
@@ -92,4 +94,7 @@  call_init_paths (const struct dl_main_state *state)
   _dl_init_paths (state->library_path);
 }
 
+/* Print ld.so usage information and exit.  */
+void _dl_usage (void) attribute_hidden __attribute__ ((__noreturn__));
+
 #endif /* _DL_MAIN */
diff --git a/elf/dl-usage.c b/elf/dl-usage.c
new file mode 100644
index 0000000000..f3d89d22b7
--- /dev/null
+++ b/elf/dl-usage.c
@@ -0,0 +1,51 @@ 
+/* Print usage information and help for ld.so.
+   Copyright (C) 1995-2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <dl-cache.h>
+#include <dl-main.h>
+#include <ldsodefs.h>
+
+void
+_dl_usage (void)
+{
+  _dl_fatal_printf ("\
+Usage: ld.so [OPTION]... EXECUTABLE-FILE [ARGS-FOR-PROGRAM...]\n\
+You have invoked `ld.so', the helper program for shared library executables.\n\
+This program usually lives in the file `/lib/ld.so', and special directives\n\
+in executable files using ELF shared libraries tell the system's program\n\
+loader to load the helper program from this file.  This helper program loads\n\
+the shared libraries needed by the program executable, prepares the program\n\
+to run, and runs it.  You may invoke this helper program directly from the\n\
+command line to load and run an ELF executable file; this is like executing\n\
+that file itself, but always uses this helper program from the file you\n\
+specified, instead of the helper program file specified in the executable\n\
+file you run.  This is mostly of use for maintainers to test new versions\n\
+of this helper program; chances are you did not intend to run this program.\n\
+\n\
+  --list                list all dependencies and how they are resolved\n\
+  --verify              verify that given object really is a dynamically linked\n\
+                        object we can handle\n\
+  --inhibit-cache       Do not use " LD_SO_CACHE "\n\
+  --library-path PATH   use given PATH instead of content of the environment\n\
+                        variable LD_LIBRARY_PATH\n\
+  --inhibit-rpath LIST  ignore RUNPATH and RPATH information in object names\n\
+                        in LIST\n\
+  --audit LIST          use objects named in LIST as auditors\n\
+  --preload LIST        preload objects named in LIST\n\
+  --argv0 STRING        set argv[0] to STRING before running\n");
+}
diff --git a/elf/rtld.c b/elf/rtld.c
index c1153cb627..f3e1791e2f 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -1246,31 +1246,7 @@  dl_main (const ElfW(Phdr) *phdr,
       /* If we have no further argument the program was called incorrectly.
 	 Grant the user some education.  */
       if (_dl_argc < 2)
-	_dl_fatal_printf ("\
-Usage: ld.so [OPTION]... EXECUTABLE-FILE [ARGS-FOR-PROGRAM...]\n\
-You have invoked `ld.so', the helper program for shared library executables.\n\
-This program usually lives in the file `/lib/ld.so', and special directives\n\
-in executable files using ELF shared libraries tell the system's program\n\
-loader to load the helper program from this file.  This helper program loads\n\
-the shared libraries needed by the program executable, prepares the program\n\
-to run, and runs it.  You may invoke this helper program directly from the\n\
-command line to load and run an ELF executable file; this is like executing\n\
-that file itself, but always uses this helper program from the file you\n\
-specified, instead of the helper program file specified in the executable\n\
-file you run.  This is mostly of use for maintainers to test new versions\n\
-of this helper program; chances are you did not intend to run this program.\n\
-\n\
-  --list                list all dependencies and how they are resolved\n\
-  --verify              verify that given object really is a dynamically linked\n\
-			object we can handle\n\
-  --inhibit-cache       Do not use " LD_SO_CACHE "\n\
-  --library-path PATH   use given PATH instead of content of the environment\n\
-			variable LD_LIBRARY_PATH\n\
-  --inhibit-rpath LIST  ignore RUNPATH and RPATH information in object names\n\
-			in LIST\n\
-  --audit LIST          use objects named in LIST as auditors\n\
-  --preload LIST        preload objects named in LIST\n\
-  --argv0 STRING        set argv[0] to STRING before running\n");
+	_dl_usage ();
 
       ++_dl_skip_args;
       --_dl_argc;