Re: [PATCH] LoongArch: Add support for ldconfig.

[Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>]

LGTM, some minor remarks below.

On 07/03/23 22:43, caiyinyu wrote:
> ---
>  elf/cache.c                                   |  6 ++
>  sysdeps/generic/ldconfig.h                    |  2 +
>  sysdeps/unix/sysv/linux/loongarch/dl-cache.h  | 82 +++++++++++++++++++
>  .../unix/sysv/linux/loongarch/readelflib.c    | 70 ++++++++++++++++
>  4 files changed, 160 insertions(+)
>  create mode 100644 sysdeps/unix/sysv/linux/loongarch/dl-cache.h
>  create mode 100644 sysdeps/unix/sysv/linux/loongarch/readelflib.c
> 
> diff --git a/elf/cache.c b/elf/cache.c
> index c4c3139264..1a96e770aa 100644
> --- a/elf/cache.c
> +++ b/elf/cache.c
> @@ -225,6 +225,12 @@ print_entry (const char *lib, int flag, uint64_t hwcap,
>      case FLAG_RISCV_FLOAT_ABI_DOUBLE:
>        fputs (",double-float", stdout);
>        break;
> +    case FLAG_LARCH_FLOAT_ABI_SOFT:
> +      fputs (",soft-float", stdout);
> +      break;
> +    case FLAG_LARCH_FLOAT_ABI_DOUBLE:
> +      fputs (",double-float", stdout);
> +      break;
>      case 0:
>        break;
>      default:
> diff --git a/sysdeps/generic/ldconfig.h b/sysdeps/generic/ldconfig.h
> index e9e9e19d0f..864d223745 100644
> --- a/sysdeps/generic/ldconfig.h
> +++ b/sysdeps/generic/ldconfig.h
> @@ -45,6 +45,8 @@
>  #define FLAG_MIPS64_LIBN64_NAN2008	0x0e00
>  #define FLAG_RISCV_FLOAT_ABI_SOFT	0x0f00
>  #define FLAG_RISCV_FLOAT_ABI_DOUBLE	0x1000
> +#define FLAG_LARCH_FLOAT_ABI_SOFT	0x1100
> +#define FLAG_LARCH_FLOAT_ABI_DOUBLE	0x1200
>  
>  /* Name of auxiliary cache.  */
>  #define _PATH_LDCONFIG_AUX_CACHE "/var/cache/ldconfig/aux-cache"
> diff --git a/sysdeps/unix/sysv/linux/loongarch/dl-cache.h b/sysdeps/unix/sysv/linux/loongarch/dl-cache.h
> new file mode 100644
> index 0000000000..cb06feaa83
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/loongarch/dl-cache.h
> @@ -0,0 +1,82 @@
> +/* Support for reading /etc/ld.so.cache files written by Linux ldconfig.
> +   Copyright (C) 2003-2023 Free Software Foundation, Inc.

s/2003/2023 since it is a new file.  Same for the other new file.

> +   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 <ldconfig.h>
> +#include <assert.h>
> +
> +#if defined __loongarch_double_float
> +# define _DL_CACHE_DEFAULT_ID    (FLAG_LARCH_FLOAT_ABI_DOUBLE | FLAG_ELF_LIBC6)
> +#else
> +# define _DL_CACHE_DEFAULT_ID    (FLAG_LARCH_FLOAT_ABI_SOFT | FLAG_ELF_LIBC6)
> +#endif
> +
> +#define _dl_cache_check_flags(flags)                    \
> +  ((flags) == _DL_CACHE_DEFAULT_ID)
> +
> +/* If given a path to one of our library directories, adds every library
> +   directory via add_dir (), otherwise just adds the giver directory.  On
> +   LoongArch, libraries can be found in paths ending in:
> +     - /lib64
> +     - /lib64/sf
> +   so this will add all of those paths.  */
> +
> +#define add_system_dir(dir) 						\
> +  do							    		\
> +    {									\
> +      static const char* lib_dirs[] = {					\
> +	"/lib64",							\
> +	"/lib64/sf",							\
> +	NULL,								\
> +      };								\
> +      const size_t lib_len = sizeof ("/lib") - 1;			\
> +      size_t len = strlen (dir);					\
> +      char path[len + 6];						\
> +      const char **ptr;							\
> +									\
> +      memcpy (path, dir, len + 1);					\
> +									\
> +      for (ptr = lib_dirs; *ptr != NULL; ptr++)				\

I think you can use array_length here and avoid the need to add the final
NULL entry.

> +	{								\
> +	  const char *lib_dir = *ptr;					\
> +	  size_t dir_len = strlen (lib_dir);				\
> +									\
> +	  if (len >= dir_len						\
> +	      && !memcmp (path + len - dir_len, lib_dir, dir_len))	\

memcmp (...) == 0

> +	    {								\
> +	      len -= dir_len - lib_len;					\
> +	      path[len] = '\0';						\
> +	      break;							\
> +	    }								\
> +	}								\
> +      add_dir (path);							\
> +      if (len >= lib_len						\
> +	  && !memcmp (path + len - lib_len, "/lib", lib_len))		\

memcmp (...) == 0

> +	for (ptr = lib_dirs; *ptr != NULL; ptr++)			\
> +	  {								\
> +	    const char *lib_dir = *ptr;					\
> +	    size_t dir_len = strlen (lib_dir);				\
> +									\
> +	    assert (dir_len >= lib_len);				\
> +	    memcpy (path + len, lib_dir + lib_len,			\
> +		    dir_len - lib_len + 1);				\
> +	    add_dir (path);						\
> +	  }								\
> +    } while (0)
> +
> +
> +#include_next <dl-cache.h>
> diff --git a/sysdeps/unix/sysv/linux/loongarch/readelflib.c b/sysdeps/unix/sysv/linux/loongarch/readelflib.c
> new file mode 100644
> index 0000000000..87dd4cfce2
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/loongarch/readelflib.c
> @@ -0,0 +1,70 @@
> +/* Support for reading ELF files.
> +   Copyright (C) 1999-2023 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/>.  */
> +
> +
> +int process_elf64_file (const char *file_name, const char *lib,
> +			int *flag, unsigned int *isa_level, char **soname,
> +			void *file_contents, size_t file_length);
> +
> +#define SUPPORTED_ELF_FLAGS \
> +  (EF_LARCH_ABI_DOUBLE_FLOAT | EF_LARCH_ABI_SOFT_FLOAT)
> +
> +/* Returns 0 if everything is ok, != 0 in case of error.  */
> +int
> +process_elf_file (const char *file_name, const char *lib, int *flag,
> +		  unsigned int *isa_level, char **soname, void *file_contents,
> +		  size_t file_length)
> +{
> +  ElfW(Ehdr) *elf_header = (ElfW(Ehdr) *) file_contents;
> +  Elf64_Ehdr *elf64_header = (Elf64_Ehdr *) elf_header;
> +  int ret;
> +  long flags;
> +
> +  /* LoongArch libraries are always libc.so.6+.  */
> +  *flag = FLAG_ELF_LIBC6;
> +
> +  ret = process_elf64_file (file_name, lib, flag, isa_level, soname,
> +				file_contents, file_length);
> +  flags = elf64_header->e_flags;
> +
> +  /* LoongArch linkers encode the floating point ABI as part of the ELF headers.  */
> +  switch (flags & SUPPORTED_ELF_FLAGS)
> +    {
> +      case EF_LARCH_ABI_SOFT_FLOAT:
> +        *flag |= FLAG_LARCH_FLOAT_ABI_SOFT;
> +	break;
> +      case EF_LARCH_ABI_DOUBLE_FLOAT:
> +        *flag |= FLAG_LARCH_FLOAT_ABI_DOUBLE;
> +	break;
> +      default:
> +        return 1;
> +    }
> +
> +  /* If there are any other ELF flags set then glibc doesn't support this
> +     library.  */
> +  if (flags & ~SUPPORTED_ELF_FLAGS)
> +    return 1;
> +
> +  return ret;
> +}
> +
> +#undef __ELF_NATIVE_CLASS
> +#undef process_elf_file
> +#define process_elf_file process_elf64_file
> +#define __ELF_NATIVE_CLASS 64
> +#include "elf/readelflib.c"