[05/28] elf: Move ld.so error/help output to _dl_usage
Commit Message
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
Comments
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.
* 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
@@ -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
@@ -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 */
new file mode 100644
@@ -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");
+}
@@ -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;