1/* Print usage information and help for ld.so.
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#include <dl-cache.h>
20#include <dl-main.h>
21#include <ldsodefs.h>
22#include <unistd.h>
23#include "version.h"
24
25#include <dl-procinfo.h>
26#include <dl-hwcaps.h>
27
28void
29_dl_usage (const char *argv0, const char *wrong_option)
30{
31 if (wrong_option != NULL)
32 _dl_error_printf ("%s: unrecognized option '%s'\n", argv0, wrong_option);
33 else
34 _dl_error_printf ("%s: missing program name\n", argv0);
35 _dl_error_printf ("Try '%s --help' for more information.\n", argv0);
36 _exit (EXIT_FAILURE);
37}
38
39void
40_dl_version (void)
41{
42 _dl_printf ("\
43ld.so " PKGVERSION RELEASE " release version " VERSION ".\n\
44Copyright (C) 2023 Free Software Foundation, Inc.\n\
45This is free software; see the source for copying conditions.\n\
46There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A\n\
47PARTICULAR PURPOSE.\n\
48");
49 _exit (EXIT_SUCCESS);
50}
51
52/* Print part of the library search path (from a single source). */
53static void
54print_search_path_for_help_1 (struct r_search_path_elem **list)
55{
56 if (list == NULL || list == (void *) -1)
57 /* Path is missing or marked as inactive. */
58 return;
59
60 for (; *list != NULL; ++list)
61 {
62 _dl_write (STDOUT_FILENO, " ", 2);
63 const char *name = (*list)->dirname;
64 size_t namelen = (*list)->dirnamelen;
65 if (namelen == 0)
66 {
67 /* The empty string denotes the current directory. */
68 name = ".";
69 namelen = 1;
70 }
71 else if (namelen > 1)
72 /* Remove the trailing slash. */
73 --namelen;
74 _dl_write (STDOUT_FILENO, name, namelen);
75 _dl_printf (" (%s)\n", (*list)->what);
76 }
77}
78
79/* Prints the library search path. See _dl_init_paths in dl-load.c
80 how this information is populated. */
81static void
82print_search_path_for_help (struct dl_main_state *state)
83{
84 if (__rtld_search_dirs.dirs == NULL)
85 /* The run-time search paths have not yet been initialized. */
86 call_init_paths (state);
87
88 _dl_printf ("\nShared library search path:\n");
89
90 /* The print order should reflect the processing in
91 _dl_map_object. */
92
93 struct link_map *map = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
94 if (map != NULL)
95 print_search_path_for_help_1 (map->l_rpath_dirs.dirs);
96
97 print_search_path_for_help_1 (__rtld_env_path_list.dirs);
98
99 if (map != NULL)
100 print_search_path_for_help_1 (map->l_runpath_dirs.dirs);
101
102 _dl_printf (" (libraries located via %s)\n", LD_SO_CACHE);
103
104 print_search_path_for_help_1 (__rtld_search_dirs.dirs);
105}
106
107/* Print the header for print_hwcaps_subdirectories. */
108static void
109print_hwcaps_subdirectories_header (bool *nothing_printed)
110{
111 if (*nothing_printed)
112 {
113 _dl_printf ("\n\
114Subdirectories of glibc-hwcaps directories, in priority order:\n");
115 *nothing_printed = false;
116 }
117}
118
119/* Print the HWCAP name itself, indented. */
120static void
121print_hwcaps_subdirectories_name (const struct dl_hwcaps_split *split)
122{
123 _dl_write (STDOUT_FILENO, " ", 2);
124 _dl_write (STDOUT_FILENO, split->segment, split->length);
125}
126
127/* Print the list of recognized glibc-hwcaps subdirectories. */
128static void
129print_hwcaps_subdirectories (const struct dl_main_state *state)
130{
131 bool nothing_printed = true;
132 struct dl_hwcaps_split split;
133
134 /* The prepended glibc-hwcaps subdirectories. */
135 _dl_hwcaps_split_init (&split, state->glibc_hwcaps_prepend);
136 while (_dl_hwcaps_split (&split))
137 {
138 print_hwcaps_subdirectories_header (&nothing_printed);
139 print_hwcaps_subdirectories_name (&split);
140 _dl_printf (" (searched)\n");
141 }
142
143 /* The built-in glibc-hwcaps subdirectories. Do the filtering
144 manually, so that more precise diagnostics are possible. */
145 uint32_t mask = _dl_hwcaps_subdirs_active ();
146 _dl_hwcaps_split_init (&split, _dl_hwcaps_subdirs);
147 while (_dl_hwcaps_split (&split))
148 {
149 print_hwcaps_subdirectories_header (&nothing_printed);
150 print_hwcaps_subdirectories_name (&split);
151 bool listed = _dl_hwcaps_contains (state->glibc_hwcaps_mask,
152 split.segment, split.length);
153 if (mask & 1)
154 _dl_printf (" (supported, %s)\n", listed ? "searched" : "masked");
155 else if (!listed)
156 _dl_printf (" (masked)\n");
157 else
158 _dl_printf ("\n");
159 mask >>= 1;
160 }
161
162 if (nothing_printed)
163 _dl_printf ("\n\
164No subdirectories of glibc-hwcaps directories are searched.\n");
165}
166
167void
168_dl_help (const char *argv0, struct dl_main_state *state)
169{
170 _dl_printf ("\
171Usage: %s [OPTION]... EXECUTABLE-FILE [ARGS-FOR-PROGRAM...]\n\
172You have invoked 'ld.so', the program interpreter for dynamically-linked\n\
173ELF programs. Usually, the program interpreter is invoked automatically\n\
174when a dynamically-linked executable is started.\n\
175\n\
176You may invoke the program interpreter program directly from the command\n\
177line to load and run an ELF executable file; this is like executing that\n\
178file itself, but always uses the program interpreter you invoked,\n\
179instead of the program interpreter specified in the executable file you\n\
180run. Invoking the program interpreter directly provides access to\n\
181additional diagnostics, and changing the dynamic linker behavior without\n\
182setting environment variables (which would be inherited by subprocesses).\n\
183\n\
184 --list list all dependencies and how they are resolved\n\
185 --verify verify that given object really is a dynamically linked\n\
186 object we can handle\n\
187 --inhibit-cache Do not use " LD_SO_CACHE "\n\
188 --library-path PATH use given PATH instead of content of the environment\n\
189 variable LD_LIBRARY_PATH\n\
190 --glibc-hwcaps-prepend LIST\n\
191 search glibc-hwcaps subdirectories in LIST\n\
192 --glibc-hwcaps-mask LIST\n\
193 only search built-in subdirectories if in LIST\n\
194 --inhibit-rpath LIST ignore RUNPATH and RPATH information in object names\n\
195 in LIST\n\
196 --audit LIST use objects named in LIST as auditors\n\
197 --preload LIST preload objects named in LIST\n\
198 --argv0 STRING set argv[0] to STRING before running\n\
199 --list-tunables list all tunables with minimum and maximum values\n\
200 --list-diagnostics list diagnostics information\n\
201 --help display this help and exit\n\
202 --version output version information and exit\n\
203\n\
204This program interpreter self-identifies as: " RTLD "\n\
205",
206 argv0);
207 print_search_path_for_help (state);
208 print_hwcaps_subdirectories (state);
209 _exit (EXIT_SUCCESS);
210}
211