1  /* Information collection during ld.so startup.
       2     Copyright (C) 1995-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; if not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #ifndef _DL_MAIN
      20  #define _DL_MAIN
      21  
      22  #include <ldsodefs.h>
      23  #include <limits.h>
      24  #include <stdlib.h>
      25  
      26  /* Length limits for names and paths, to protect the dynamic linker,
      27     particularly when __libc_enable_secure is active.  */
      28  #ifdef NAME_MAX
      29  # define SECURE_NAME_LIMIT NAME_MAX
      30  #else
      31  # define SECURE_NAME_LIMIT 255
      32  #endif
      33  #ifdef PATH_MAX
      34  # define SECURE_PATH_LIMIT PATH_MAX
      35  #else
      36  # define SECURE_PATH_LIMIT 1024
      37  #endif
      38  
      39  /* Strings containing colon-separated lists of audit modules.  */
      40  struct audit_list
      41  {
      42    /* Array of strings containing colon-separated path lists.  Each
      43       audit module needs its own namespace, so pre-allocate the largest
      44       possible list.  */
      45    const char *audit_strings[DL_NNS];
      46  
      47    /* Number of entries added to audit_strings.  */
      48    size_t length;
      49  
      50    /* Index into the audit_strings array (for the iteration phase).  */
      51    size_t current_index;
      52  
      53    /* Tail of audit_strings[current_index] which still needs
      54       processing.  */
      55    const char *current_tail;
      56  
      57    /* Scratch buffer for returning a name which is part of the strings
      58       in audit_strings.  */
      59    char fname[SECURE_NAME_LIMIT];
      60  };
      61  
      62  /* This is a list of all the modes the dynamic loader can be in.  */
      63  enum rtld_mode
      64    {
      65      rtld_mode_normal, rtld_mode_list, rtld_mode_verify, rtld_mode_trace,
      66      rtld_mode_list_tunables, rtld_mode_list_diagnostics, rtld_mode_help,
      67    };
      68  
      69  /* Aggregated state information extracted from environment variables
      70     and the ld.so command line.  */
      71  struct dl_main_state
      72  {
      73    struct audit_list audit_list;
      74  
      75    /* The library search path.  */
      76    const char *library_path;
      77  
      78    /* Where library_path comes from.  LD_LIBRARY_PATH or --library-path.  */
      79    const char *library_path_source;
      80  
      81    /* The list preloaded objects from LD_PRELOAD.  */
      82    const char *preloadlist;
      83  
      84    /* The preload list passed as a command argument.  */
      85    const char *preloadarg;
      86  
      87    /* Additional glibc-hwcaps subdirectories to search first.
      88       Colon-separated list.  */
      89    const char *glibc_hwcaps_prepend;
      90  
      91    /* Mask for the internal glibc-hwcaps subdirectories.
      92       Colon-separated list.  */
      93    const char *glibc_hwcaps_mask;
      94  
      95    enum rtld_mode mode;
      96  
      97    /* True if program should be also printed for rtld_mode_trace.  */
      98    bool mode_trace_program;
      99  
     100    /* True if any of the debugging options is enabled.  */
     101    bool any_debug;
     102  
     103    /* True if information about versions has to be printed.  */
     104    bool version_info;
     105  };
     106  
     107  /* Helper function to invoke _dl_init_paths with the right arguments
     108     from *STATE.  */
     109  static inline void
     110  call_init_paths (const struct dl_main_state *state)
     111  {
     112    _dl_init_paths (state->library_path, state->library_path_source,
     113                    state->glibc_hwcaps_prepend, state->glibc_hwcaps_mask);
     114  }
     115  
     116  /* Print ld.so usage information and exit.  */
     117  _Noreturn void _dl_usage (const char *argv0, const char *wrong_option)
     118    attribute_hidden;
     119  
     120  /* Print ld.so version information and exit.  */
     121  _Noreturn void _dl_version (void) attribute_hidden;
     122  
     123  /* Print ld.so --help output and exit.  */
     124  _Noreturn void _dl_help (const char *argv0, struct dl_main_state *state)
     125    attribute_hidden;
     126  
     127  /* Print a diagnostics dump.  */
     128  _Noreturn void _dl_print_diagnostics (char **environ) attribute_hidden;
     129  
     130  #endif /* _DL_MAIN */