commit 2bf9e641fd50ec34b04b70829679abf64fc0ed78
Author: Florian Weimer <fweimer@redhat.com>
Date: Thu Oct 8 10:57:09 2020 +0200
elf: Extract command-line/environment variables state from rtld.c
Introduce struct dl_main_state and move it to <dl-main.h>. Rename
enum mode to enum rtld_mode and add the rtld_mode_ prefix to the enum
constants.
This avoids the need for putting state that is only needed during
startup into the ld.so data segment.
Conflicts:
elf/rtld.c
(Caused by glibc-fedora-__libc_multiple_libcs.patch.)
diff --git a/elf/dl-main.h b/elf/dl-main.h
new file mode 100644
index 0000000000000000..bcc9bcf2e8fee6e7
--- /dev/null
+++ b/elf/dl-main.h
@@ -0,0 +1,98 @@
+/* Information collection during ld.so startup.
+ 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/>. */
+
+#ifndef _DL_MAIN
+#define _DL_MAIN
+
+#include <limits.h>
+
+/* Length limits for names and paths, to protect the dynamic linker,
+ particularly when __libc_enable_secure is active. */
+#ifdef NAME_MAX
+# define SECURE_NAME_LIMIT NAME_MAX
+#else
+# define SECURE_NAME_LIMIT 255
+#endif
+#ifdef PATH_MAX
+# define SECURE_PATH_LIMIT PATH_MAX
+#else
+# define SECURE_PATH_LIMIT 1024
+#endif
+
+/* Strings containing colon-separated lists of audit modules. */
+struct audit_list
+{
+ /* Array of strings containing colon-separated path lists. Each
+ audit module needs its own namespace, so pre-allocate the largest
+ possible list. */
+ const char *audit_strings[DL_NNS];
+
+ /* Number of entries added to audit_strings. */
+ size_t length;
+
+ /* Index into the audit_strings array (for the iteration phase). */
+ size_t current_index;
+
+ /* Tail of audit_strings[current_index] which still needs
+ processing. */
+ const char *current_tail;
+
+ /* Scratch buffer for returning a name which is part of the strings
+ in audit_strings. */
+ char fname[SECURE_NAME_LIMIT];
+};
+
+/* This is a list of all the modes the dynamic loader can be in. */
+enum rtld_mode
+ {
+ rtld_mode_normal, rtld_mode_list, rtld_mode_verify, rtld_mode_trace,
+ };
+
+/* Aggregated state information extracted from environment variables
+ and the ld.so command line. */
+struct dl_main_state
+{
+ struct audit_list audit_list;
+
+ /* The library search path. */
+ const char *library_path;
+
+ /* The list preloaded objects from LD_PRELOAD. */
+ const char *preloadlist;
+
+ /* The preload list passed as a command argument. */
+ const char *preloadarg;
+
+ enum rtld_mode mode;
+
+ /* True if any of the debugging options is enabled. */
+ bool any_debug;
+
+ /* True if information about versions has to be printed. */
+ bool version_info;
+};
+
+/* Helper function to invoke _dl_init_paths with the right arguments
+ from *STATE. */
+static inline void
+call_init_paths (const struct dl_main_state *state)
+{
+ _dl_init_paths (state->library_path);
+}
+
+#endif /* _DL_MAIN */
diff --git a/elf/rtld.c b/elf/rtld.c
index 4107a215abd554f4..fbfa441bf3b050ff 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -45,6 +45,7 @@
#include <not-cancel.h>
#include <array_length.h>
#include <libc-early-init.h>
+#include <dl-main.h>
#include <assert.h>
@@ -109,42 +110,6 @@ static void print_missing_version (int errcode, const char *objname,
/* Print the various times we collected. */
static void print_statistics (const hp_timing_t *total_timep);
-/* Length limits for names and paths, to protect the dynamic linker,
- particularly when __libc_enable_secure is active. */
-#ifdef NAME_MAX
-# define SECURE_NAME_LIMIT NAME_MAX
-#else
-# define SECURE_NAME_LIMIT 255
-#endif
-#ifdef PATH_MAX
-# define SECURE_PATH_LIMIT PATH_MAX
-#else
-# define SECURE_PATH_LIMIT 1024
-#endif
-
-/* Strings containing colon-separated lists of audit modules. */
-struct audit_list
-{
- /* Array of strings containing colon-separated path lists. Each
- audit module needs its own namespace, so pre-allocate the largest
- possible list. */
- const char *audit_strings[DL_NNS];
-
- /* Number of entries added to audit_strings. */
- size_t length;
-
- /* Index into the audit_strings array (for the iteration phase). */
- size_t current_index;
-
- /* Tail of audit_strings[current_index] which still needs
- processing. */
- const char *current_tail;
-
- /* Scratch buffer for returning a name which is part of the strings
- in audit_strings. */
- char fname[SECURE_NAME_LIMIT];
-};
-
/* Creates an empty audit list. */
static void audit_list_init (struct audit_list *);
@@ -165,13 +130,13 @@ static void audit_list_add_dynamic_tag (struct audit_list *,
audit_list_add_dynamic_tags calls. */
static const char *audit_list_next (struct audit_list *);
-/* This is a list of all the modes the dynamic loader can be in. */
-enum mode { normal, list, verify, trace };
+/* Initialize *STATE with the defaults. */
+static void dl_main_state_init (struct dl_main_state *state);
/* Process all environments variables the dynamic linker must recognize.
Since all of them start with `LD_' we are a bit smarter while finding
all the entries. */
-static void process_envvars (enum mode *modep, struct audit_list *);
+static void process_envvars (struct dl_main_state *state);
#ifdef DL_ARGV_NOT_RELRO
int _dl_argc attribute_hidden;
@@ -314,6 +279,18 @@ audit_list_count (struct audit_list *list)
return naudit;
}
+static void
+dl_main_state_init (struct dl_main_state *state)
+{
+ audit_list_init (&state->audit_list);
+ state->library_path = NULL;
+ state->preloadlist = NULL;
+ state->preloadarg = NULL;
+ state->mode = rtld_mode_normal;
+ state->any_debug = false;
+ state->version_info = false;
+}
+
/* Set nonzero during loading and initialization of executable and
libraries, cleared before the executable's entry point runs. This
must not be initialized to nonzero, because the unused dynamic
@@ -896,15 +873,6 @@ security_init (void)
#include "setup-vdso.h"
-/* The library search path. */
-static const char *library_path attribute_relro;
-/* The list preloaded objects. */
-static const char *preloadlist attribute_relro;
-/* Nonzero if information about versions has to be printed. */
-static int version_info attribute_relro;
-/* The preload list passed as a command argument. */
-static const char *preloadarg attribute_relro;
-
/* The LD_PRELOAD environment variable gives list of libraries
separated by white space or colons that are loaded before the
executable's dependencies and prepended to the global scope list.
@@ -1146,7 +1114,6 @@ dl_main (const ElfW(Phdr) *phdr,
ElfW(auxv_t) *auxv)
{
const ElfW(Phdr) *ph;
- enum mode mode;
struct link_map *main_map;
size_t file_size;
char *file;
@@ -1156,8 +1123,8 @@ dl_main (const ElfW(Phdr) *phdr,
bool rtld_is_main = false;
void *tcbp = NULL;
- struct audit_list audit_list;
- audit_list_init (&audit_list);
+ struct dl_main_state state;
+ dl_main_state_init (&state);
GL(dl_init_static_tls) = &_dl_nothread_init_static_tls;
@@ -1172,7 +1139,7 @@ dl_main (const ElfW(Phdr) *phdr,
GL(dl_make_stack_executable_hook) = &_dl_make_stack_executable;
/* Process the environment variable which control the behaviour. */
- process_envvars (&mode, &audit_list);
+ process_envvars (&state);
/* Set up a flag which tells we are just starting. */
_dl_starting_up = 1;
@@ -1204,7 +1171,7 @@ dl_main (const ElfW(Phdr) *phdr,
while (_dl_argc > 1)
if (! strcmp (_dl_argv[1], "--list"))
{
- mode = list;
+ state.mode = rtld_mode_list;
GLRO(dl_lazy) = -1; /* This means do no dependency analysis. */
++_dl_skip_args;
@@ -1213,7 +1180,7 @@ dl_main (const ElfW(Phdr) *phdr,
}
else if (! strcmp (_dl_argv[1], "--verify"))
{
- mode = verify;
+ state.mode = rtld_mode_verify;
++_dl_skip_args;
--_dl_argc;
@@ -1229,7 +1196,7 @@ dl_main (const ElfW(Phdr) *phdr,
else if (! strcmp (_dl_argv[1], "--library-path")
&& _dl_argc > 2)
{
- library_path = _dl_argv[2];
+ state.library_path = _dl_argv[2];
_dl_skip_args += 2;
_dl_argc -= 2;
@@ -1246,7 +1213,7 @@ dl_main (const ElfW(Phdr) *phdr,
}
else if (! strcmp (_dl_argv[1], "--audit") && _dl_argc > 2)
{
- audit_list_add_string (&audit_list, _dl_argv[2]);
+ audit_list_add_string (&state.audit_list, _dl_argv[2]);
_dl_skip_args += 2;
_dl_argc -= 2;
@@ -1254,7 +1221,7 @@ dl_main (const ElfW(Phdr) *phdr,
}
else if (! strcmp (_dl_argv[1], "--preload") && _dl_argc > 2)
{
- preloadarg = _dl_argv[2];
+ state.preloadarg = _dl_argv[2];
_dl_skip_args += 2;
_dl_argc -= 2;
_dl_argv += 2;
@@ -1322,7 +1289,7 @@ of this helper program; chances are you did not intend to run this program.\n\
break;
}
- if (__builtin_expect (mode, normal) == verify)
+ if (__glibc_unlikely (state.mode == rtld_mode_verify))
{
const char *objname;
const char *err_str = NULL;
@@ -1351,7 +1318,7 @@ of this helper program; chances are you did not intend to run this program.\n\
/* Now the map for the main executable is available. */
main_map = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
- if (__builtin_expect (mode, normal) == normal
+ if (__glibc_likely (state.mode == rtld_mode_normal)
&& GL(dl_rtld_map).l_info[DT_SONAME] != NULL
&& main_map->l_info[DT_SONAME] != NULL
&& strcmp ((const char *) D_PTR (&GL(dl_rtld_map), l_info[DT_STRTAB])
@@ -1592,7 +1559,7 @@ ERROR: '%s': cannot process note segment.\n", _dl_argv[0]);
_dl_setup_hash (main_map);
}
- if (__builtin_expect (mode, normal) == verify)
+ if (__glibc_unlikely (state.mode == rtld_mode_verify))
{
/* We were called just to verify that this is a dynamic
executable using us as the program interpreter. Exit with an
@@ -1619,7 +1586,7 @@ ERROR: '%s': cannot process note segment.\n", _dl_argv[0]);
/* Initialize the data structures for the search paths for shared
objects. */
- _dl_init_paths (library_path);
+ call_init_paths (&state);
/* Initialize _r_debug. */
struct r_debug *r = _dl_debug_initialize (GL(dl_rtld_map).l_addr,
@@ -1684,14 +1651,14 @@ ERROR: '%s': cannot process note segment.\n", _dl_argv[0]);
/* Assign a module ID. Do this before loading any audit modules. */
GL(dl_rtld_map).l_tls_modid = _dl_next_tls_modid ();
- audit_list_add_dynamic_tag (&audit_list, main_map, DT_AUDIT);
- audit_list_add_dynamic_tag (&audit_list, main_map, DT_DEPAUDIT);
+ audit_list_add_dynamic_tag (&state.audit_list, main_map, DT_AUDIT);
+ audit_list_add_dynamic_tag (&state.audit_list, main_map, DT_DEPAUDIT);
/* If we have auditing DSOs to load, do it now. */
bool need_security_init = true;
- if (audit_list.length > 0)
+ if (state.audit_list.length > 0)
{
- size_t naudit = audit_list_count (&audit_list);
+ size_t naudit = audit_list_count (&state.audit_list);
/* Since we start using the auditing DSOs right away we need to
initialize the data structures now. */
@@ -1704,7 +1671,7 @@ ERROR: '%s': cannot process note segment.\n", _dl_argv[0]);
security_init ();
need_security_init = false;
- load_audit_modules (main_map, &audit_list);
+ load_audit_modules (main_map, &state.audit_list);
/* The count based on audit strings may overestimate the number
of audit modules that got loaded, but not underestimate. */
@@ -1759,19 +1726,21 @@ ERROR: '%s': cannot process note segment.\n", _dl_argv[0]);
struct link_map **preloads = NULL;
unsigned int npreloads = 0;
- if (__glibc_unlikely (preloadlist != NULL))
+ if (__glibc_unlikely (state.preloadlist != NULL))
{
RTLD_TIMING_VAR (start);
rtld_timer_start (&start);
- npreloads += handle_preload_list (preloadlist, main_map, "LD_PRELOAD");
+ npreloads += handle_preload_list (state.preloadlist, main_map,
+ "LD_PRELOAD");
rtld_timer_accum (&load_time, start);
}
- if (__glibc_unlikely (preloadarg != NULL))
+ if (__glibc_unlikely (state.preloadarg != NULL))
{
RTLD_TIMING_VAR (start);
rtld_timer_start (&start);
- npreloads += handle_preload_list (preloadarg, main_map, "--preload");
+ npreloads += handle_preload_list (state.preloadarg, main_map,
+ "--preload");
rtld_timer_accum (&load_time, start);
}
@@ -1878,7 +1847,8 @@ ERROR: '%s': cannot process note segment.\n", _dl_argv[0]);
{
RTLD_TIMING_VAR (start);
rtld_timer_start (&start);
- _dl_map_object_deps (main_map, preloads, npreloads, mode == trace, 0);
+ _dl_map_object_deps (main_map, preloads, npreloads,
+ state.mode == rtld_mode_trace, 0);
rtld_timer_accum (&load_time, start);
}
@@ -1905,7 +1875,7 @@ ERROR: '%s': cannot process note segment.\n", _dl_argv[0]);
rtld_multiple_ref = true;
GL(dl_rtld_map).l_prev = main_map->l_searchlist.r_list[i - 1];
- if (__builtin_expect (mode, normal) == normal)
+ if (__glibc_likely (state.mode == rtld_mode_normal))
{
GL(dl_rtld_map).l_next = (i + 1 < main_map->l_searchlist.r_nlist
? main_map->l_searchlist.r_list[i + 1]
@@ -1938,8 +1908,8 @@ ERROR: '%s': cannot process note segment.\n", _dl_argv[0]);
versions we need. */
{
struct version_check_args args;
- args.doexit = mode == normal;
- args.dotrace = mode == trace;
+ args.doexit = state.mode == rtld_mode_normal;
+ args.dotrace = state.mode == rtld_mode_trace;
_dl_receive_error (print_missing_version, version_check_doit, &args);
}
@@ -1959,7 +1929,7 @@ ERROR: '%s': cannot process note segment.\n", _dl_argv[0]);
earlier. */
security_init ();
- if (__builtin_expect (mode, normal) != normal)
+ if (__glibc_unlikely (state.mode != rtld_mode_normal))
{
/* We were run just to list the shared libraries. It is
important that we do this before real relocation, because the
@@ -2061,7 +2031,7 @@ ERROR: '%s': cannot process note segment.\n", _dl_argv[0]);
(size_t) l->l_map_start);
}
- if (__builtin_expect (mode, trace) != trace)
+ if (__glibc_unlikely (state.mode != rtld_mode_trace))
for (i = 1; i < (unsigned int) _dl_argc; ++i)
{
const ElfW(Sym) *ref = NULL;
@@ -2115,7 +2085,7 @@ ERROR: '%s': cannot process note segment.\n", _dl_argv[0]);
}
}
#define VERNEEDTAG (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (DT_VERNEED))
- if (version_info)
+ if (state.version_info)
{
/* Print more information. This means here, print information
about the versions needed. */
@@ -2477,13 +2447,10 @@ print_missing_version (int errcode __attribute__ ((unused)),
objname, errstring);
}
-/* Nonzero if any of the debugging options is enabled. */
-static int any_debug attribute_relro;
-
/* Process the string given as the parameter which explains which debugging
options are enabled. */
static void
-process_dl_debug (const char *dl_debug)
+process_dl_debug (struct dl_main_state *state, const char *dl_debug)
{
/* When adding new entries make sure that the maximal length of a name
is correctly handled in the LD_DEBUG_HELP code below. */
@@ -2540,7 +2507,7 @@ process_dl_debug (const char *dl_debug)
&& memcmp (dl_debug, debopts[cnt].name, len) == 0)
{
GLRO(dl_debug_mask) |= debopts[cnt].mask;
- any_debug = 1;
+ state->any_debug = true;
break;
}
@@ -2594,11 +2561,10 @@ extern char **_environ attribute_hidden;
static void
-process_envvars (enum mode *modep, struct audit_list *audit_list)
+process_envvars (struct dl_main_state *state)
{
char **runp = _environ;
char *envline;
- enum mode mode = normal;
char *debug_output = NULL;
/* This is the default place for profiling data file. */
@@ -2630,25 +2596,25 @@ process_envvars (enum mode *modep, struct audit_list *audit_list)
/* Debugging of the dynamic linker? */
if (memcmp (envline, "DEBUG", 5) == 0)
{
- process_dl_debug (&envline[6]);
+ process_dl_debug (state, &envline[6]);
break;
}
if (memcmp (envline, "AUDIT", 5) == 0)
- audit_list_add_string (audit_list, &envline[6]);
+ audit_list_add_string (&state->audit_list, &envline[6]);
break;
case 7:
/* Print information about versions. */
if (memcmp (envline, "VERBOSE", 7) == 0)
{
- version_info = envline[8] != '\0';
+ state->version_info = envline[8] != '\0';
break;
}
/* List of objects to be preloaded. */
if (memcmp (envline, "PRELOAD", 7) == 0)
{
- preloadlist = &envline[8];
+ state->preloadlist = &envline[8];
break;
}
@@ -2697,7 +2663,7 @@ process_envvars (enum mode *modep, struct audit_list *audit_list)
if (!__libc_enable_secure
&& memcmp (envline, "LIBRARY_PATH", 12) == 0)
{
- library_path = &envline[13];
+ state->library_path = &envline[13];
break;
}
@@ -2739,7 +2705,7 @@ process_envvars (enum mode *modep, struct audit_list *audit_list)
/* The mode of the dynamic linker can be set. */
if (memcmp (envline, "TRACE_PRELINKING", 16) == 0)
{
- mode = trace;
+ state->mode = rtld_mode_trace;
GLRO(dl_verbose) = 1;
GLRO(dl_debug_mask) |= DL_DEBUG_PRELINK;
GLRO(dl_trace_prelink) = &envline[17];
@@ -2749,7 +2715,7 @@ process_envvars (enum mode *modep, struct audit_list *audit_list)
case 20:
/* The mode of the dynamic linker can be set. */
if (memcmp (envline, "TRACE_LOADED_OBJECTS", 20) == 0)
- mode = trace;
+ state->mode = rtld_mode_trace;
break;
/* We might have some extra environment variable to handle. This
@@ -2762,9 +2728,6 @@ process_envvars (enum mode *modep, struct audit_list *audit_list)
}
}
- /* The caller wants this information. */
- *modep = mode;
-
/* Extra security for SUID binaries. Remove all dangerous environment
variables. */
if (__builtin_expect (__libc_enable_secure, 0))
@@ -2793,13 +2756,13 @@ process_envvars (enum mode *modep, struct audit_list *audit_list)
GLRO(dl_debug_mask) = 0;
}
- if (mode != normal)
+ if (state->mode != rtld_mode_normal)
_exit (5);
}
/* If we have to run the dynamic linker in debugging mode and the
LD_DEBUG_OUTPUT environment variable is given, we write the debug
messages to this file. */
- else if (any_debug && debug_output != NULL)
+ else if (state->any_debug && debug_output != NULL)
{
const int flags = O_WRONLY | O_APPEND | O_CREAT | O_NOFOLLOW;
size_t name_len = strlen (debug_output);