commit b44ac4f4c7a8bbe5eaa2701aa9452eaf2c96e1dd
Author: Florian Weimer <fweimer@redhat.com>
Date: Fri Dec 4 09:13:43 2020 +0100
elf: Process glibc-hwcaps subdirectories in ldconfig
Libraries from these subdirectories are added to the cache
with a special hwcap bit DL_CACHE_HWCAP_EXTENSION, so that
they are ignored by older dynamic loaders.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
diff --git a/elf/cache.c b/elf/cache.c
index f773cacacf26db1c..dde3d7fefa4105f9 100644
--- a/elf/cache.c
+++ b/elf/cache.c
@@ -40,6 +40,105 @@
/* Used to store library names, paths, and other strings. */
static struct stringtable strings;
+/* Keeping track of "glibc-hwcaps" subdirectories. During cache
+ construction, a linear search by name is performed to deduplicate
+ entries. */
+struct glibc_hwcaps_subdirectory
+{
+ struct glibc_hwcaps_subdirectory *next;
+
+ /* Interned string with the subdirectory name. */
+ struct stringtable_entry *name;
+
+ /* Array index in the cache_extension_tag_glibc_hwcaps section in
+ the stored cached file. This is computed after all the
+ subdirectories have been processed, so that subdirectory names in
+ the extension section can be sorted. */
+ uint32_t section_index;
+
+ /* True if the subdirectory is actually used for anything. */
+ bool used;
+};
+
+const char *
+glibc_hwcaps_subdirectory_name (const struct glibc_hwcaps_subdirectory *dir)
+{
+ return dir->name->string;
+}
+
+/* Linked list of known hwcaps subdirecty names. */
+static struct glibc_hwcaps_subdirectory *hwcaps;
+
+struct glibc_hwcaps_subdirectory *
+new_glibc_hwcaps_subdirectory (const char *name)
+{
+ struct stringtable_entry *name_interned = stringtable_add (&strings, name);
+ for (struct glibc_hwcaps_subdirectory *p = hwcaps; p != NULL; p = p->next)
+ if (p->name == name_interned)
+ return p;
+ struct glibc_hwcaps_subdirectory *p = xmalloc (sizeof (*p));
+ p->next = hwcaps;
+ p->name = name_interned;
+ p->section_index = 0;
+ p->used = false;
+ hwcaps = p;
+ return p;
+}
+
+/* Helper for sorting struct glibc_hwcaps_subdirectory elements by
+ name. */
+static int
+assign_glibc_hwcaps_indices_compare (const void *l, const void *r)
+{
+ const struct glibc_hwcaps_subdirectory *left
+ = *(struct glibc_hwcaps_subdirectory **)l;
+ const struct glibc_hwcaps_subdirectory *right
+ = *(struct glibc_hwcaps_subdirectory **)r;
+ return strcmp (glibc_hwcaps_subdirectory_name (left),
+ glibc_hwcaps_subdirectory_name (right));
+}
+
+/* Count the number of hwcaps subdirectories which are actually
+ used. */
+static size_t
+glibc_hwcaps_count (void)
+{
+ size_t count = 0;
+ for (struct glibc_hwcaps_subdirectory *p = hwcaps; p != NULL; p = p->next)
+ if (p->used)
+ ++count;
+ return count;
+}
+
+/* Compute the section_index fields for all */
+static void
+assign_glibc_hwcaps_indices (void)
+{
+ /* Convert the linked list into an array, so that we can use qsort.
+ Only copy the subdirectories which are actually used. */
+ size_t count = glibc_hwcaps_count ();
+ struct glibc_hwcaps_subdirectory **array
+ = xmalloc (sizeof (*array) * count);
+ {
+ size_t i = 0;
+ for (struct glibc_hwcaps_subdirectory *p = hwcaps; p != NULL; p = p->next)
+ if (p->used)
+ {
+ array[i] = p;
+ ++i;
+ }
+ assert (i == count);
+ }
+
+ qsort (array, count, sizeof (*array), assign_glibc_hwcaps_indices_compare);
+
+ /* Assign the array indices. */
+ for (size_t i = 0; i < count; ++i)
+ array[i]->section_index = i;
+
+ free (array);
+}
+
struct cache_entry
{
struct stringtable_entry *lib; /* Library name. */
@@ -48,6 +147,10 @@ struct cache_entry
unsigned int osversion; /* Required OS version. */
uint64_t hwcap; /* Important hardware capabilities. */
int bits_hwcap; /* Number of bits set in hwcap. */
+
+ /* glibc-hwcaps subdirectory. If not NULL, hwcap must be zero. */
+ struct glibc_hwcaps_subdirectory *hwcaps;
+
struct cache_entry *next; /* Next entry in list. */
};
@@ -60,7 +163,7 @@ static const char *flag_descr[] =
/* Print a single entry. */
static void
print_entry (const char *lib, int flag, unsigned int osversion,
- uint64_t hwcap, const char *key)
+ uint64_t hwcap, const char *hwcap_string, const char *key)
{
printf ("\t%s (", lib);
switch (flag & FLAG_TYPE_MASK)
@@ -132,7 +235,9 @@ print_entry (const char *lib, int flag, unsigned int osversion,
printf (",%d", flag & FLAG_REQUIRED_MASK);
break;
}
- if (hwcap != 0)
+ if (hwcap_string != NULL)
+ printf (", hwcap: \"%s\"", hwcap_string);
+ else if (hwcap != 0)
printf (", hwcap: %#.16" PRIx64, hwcap);
if (osversion != 0)
{
@@ -158,6 +263,29 @@ print_entry (const char *lib, int flag, unsigned int osversion,
printf (") => %s\n", key);
}
+/* Returns the string with the name of the glibcs-hwcaps subdirectory
+ associated with ENTRY->hwcap. file_base must be the base address
+ for string table indices. */
+static const char *
+glibc_hwcaps_string (struct cache_extension_all_loaded *ext,
+ const void *file_base, size_t file_size,
+ struct file_entry_new *entry)
+{
+ const uint32_t *hwcaps_array
+ = ext->sections[cache_extension_tag_glibc_hwcaps].base;
+ if (dl_cache_hwcap_extension (entry) && hwcaps_array != NULL)
+ {
+ uint32_t index = (uint32_t) entry->hwcap;
+ if (index < ext->sections[cache_extension_tag_glibc_hwcaps].size / 4)
+ {
+ uint32_t string_table_index = hwcaps_array[index];
+ if (string_table_index < file_size)
+ return file_base + string_table_index;
+ }
+ }
+ return NULL;
+}
+
/* Print an error and exit if the new-file cache is internally
inconsistent. */
static void
@@ -167,9 +295,7 @@ check_new_cache (struct cache_file_new *cache)
error (EXIT_FAILURE, 0, _("Cache file has wrong endianness.\n"));
}
-/* Print the extension information at the cache at start address
- FILE_BASE, of length FILE_SIZE bytes. The new-format cache header
- is at CACHE, and the file name for diagnostics is CACHE_NAME. */
+/* Print the extension information in *EXT. */
static void
print_extensions (struct cache_extension_all_loaded *ext)
{
@@ -266,7 +392,7 @@ print_cache (const char *cache_name)
/* Print everything. */
for (unsigned int i = 0; i < cache->nlibs; i++)
print_entry (cache_data + cache->libs[i].key,
- cache->libs[i].flags, 0, 0,
+ cache->libs[i].flags, 0, 0, NULL,
cache_data + cache->libs[i].value);
}
else if (format == 1)
@@ -281,11 +407,16 @@ print_cache (const char *cache_name)
/* Print everything. */
for (unsigned int i = 0; i < cache_new->nlibs; i++)
- print_entry (cache_data + cache_new->libs[i].key,
- cache_new->libs[i].flags,
- cache_new->libs[i].osversion,
- cache_new->libs[i].hwcap,
- cache_data + cache_new->libs[i].value);
+ {
+ const char *hwcaps_string
+ = glibc_hwcaps_string (&ext, cache, cache_size,
+ &cache_new->libs[i]);
+ print_entry (cache_data + cache_new->libs[i].key,
+ cache_new->libs[i].flags,
+ cache_new->libs[i].osversion,
+ cache_new->libs[i].hwcap, hwcaps_string,
+ cache_data + cache_new->libs[i].value);
+ }
print_extensions (&ext);
}
/* Cleanup. */
@@ -311,8 +442,23 @@ compare (const struct cache_entry *e1, const struct cache_entry *e2)
return 1;
else if (e1->flags > e2->flags)
return -1;
+ /* Keep the glibc-hwcaps extension entries before the regular
+ entries, and sort them by their names. search_cache in
+ dl-cache.c stops searching once the first non-extension entry
+ is found, so the extension entries need to come first. */
+ else if (e1->hwcaps != NULL && e2->hwcaps == NULL)
+ return -1;
+ else if (e1->hwcaps == NULL && e2->hwcaps != NULL)
+ return 1;
+ else if (e1->hwcaps != NULL && e2->hwcaps != NULL)
+ {
+ res = strcmp (glibc_hwcaps_subdirectory_name (e1->hwcaps),
+ glibc_hwcaps_subdirectory_name (e2->hwcaps));
+ if (res != 0)
+ return res;
+ }
/* Sort by most specific hwcap. */
- else if (e2->bits_hwcap > e1->bits_hwcap)
+ if (e2->bits_hwcap > e1->bits_hwcap)
return 1;
else if (e2->bits_hwcap < e1->bits_hwcap)
return -1;
@@ -337,30 +483,65 @@ enum
* sizeof (struct cache_extension_section)))
};
-/* Write the cache extensions to FD. The extension directory is
- assumed to be located at CACHE_EXTENSION_OFFSET. */
+/* Write the cache extensions to FD. The string table is shifted by
+ STRING_TABLE_OFFSET. The extension directory is assumed to be
+ located at CACHE_EXTENSION_OFFSET. assign_glibc_hwcaps_indices
+ must have been called. */
static void
-write_extensions (int fd, uint32_t cache_extension_offset)
+write_extensions (int fd, uint32_t str_offset,
+ uint32_t cache_extension_offset)
{
assert ((cache_extension_offset % 4) == 0);
+ /* The length and contents of the glibc-hwcaps section. */
+ uint32_t hwcaps_count = glibc_hwcaps_count ();
+ uint32_t hwcaps_offset = cache_extension_offset + cache_extension_size;
+ uint32_t hwcaps_size = hwcaps_count * sizeof (uint32_t);
+ uint32_t *hwcaps_array = xmalloc (hwcaps_size);
+ for (struct glibc_hwcaps_subdirectory *p = hwcaps; p != NULL; p = p->next)
+ if (p->used)
+ hwcaps_array[p->section_index] = str_offset + p->name->offset;
+
+ /* This is the offset of the generator string. */
+ uint32_t generator_offset = hwcaps_offset;
+ if (hwcaps_count == 0)
+ /* There is no section for the hwcaps subdirectories. */
+ generator_offset -= sizeof (struct cache_extension_section);
+ else
+ /* The string table indices for the hwcaps subdirectories shift
+ the generator string backwards. */
+ generator_offset += hwcaps_size;
+
struct cache_extension *ext = xmalloc (cache_extension_size);
ext->magic = cache_extension_magic;
- ext->count = cache_extension_count;
- for (int i = 0; i < cache_extension_count; ++i)
- {
- ext->sections[i].tag = i;
- ext->sections[i].flags = 0;
- }
+ /* Extension index current being filled. */
+ size_t xid = 0;
const char *generator
= "ldconfig " PKGVERSION RELEASE " release version " VERSION;
- ext->sections[cache_extension_tag_generator].offset
- = cache_extension_offset + cache_extension_size;
- ext->sections[cache_extension_tag_generator].size = strlen (generator);
+ ext->sections[xid].tag = cache_extension_tag_generator;
+ ext->sections[xid].flags = 0;
+ ext->sections[xid].offset = generator_offset;
+ ext->sections[xid].size = strlen (generator);
+
+ if (hwcaps_count > 0)
+ {
+ ++xid;
+ ext->sections[xid].tag = cache_extension_tag_glibc_hwcaps;
+ ext->sections[xid].flags = 0;
+ ext->sections[xid].offset = hwcaps_offset;
+ ext->sections[xid].size = hwcaps_size;
+ }
+
+ ++xid;
+ ext->count = xid;
+ assert (xid <= cache_extension_count);
- if (write (fd, ext, cache_extension_size) != cache_extension_size
+ size_t ext_size = (offsetof (struct cache_extension, sections)
+ + xid * sizeof (struct cache_extension_section));
+ if (write (fd, ext, ext_size) != ext_size
+ || write (fd, hwcaps_array, hwcaps_size) != hwcaps_size
|| write (fd, generator, strlen (generator)) != strlen (generator))
error (EXIT_FAILURE, errno, _("Writing of cache extension data failed"));
@@ -373,6 +554,8 @@ save_cache (const char *cache_name)
{
/* The cache entries are sorted already, save them in this order. */
+ assign_glibc_hwcaps_indices ();
+
struct cache_entry *entry;
/* Number of cache entries. */
int cache_entry_count = 0;
@@ -474,7 +657,11 @@ save_cache (const char *cache_name)
struct. */
file_entries_new->libs[idx_new].flags = entry->flags;
file_entries_new->libs[idx_new].osversion = entry->osversion;
- file_entries_new->libs[idx_new].hwcap = entry->hwcap;
+ if (entry->hwcaps == NULL)
+ file_entries_new->libs[idx_new].hwcap = entry->hwcap;
+ else
+ file_entries_new->libs[idx_new].hwcap
+ = DL_CACHE_HWCAP_EXTENSION | entry->hwcaps->section_index;
file_entries_new->libs[idx_new].key
= str_offset + entry->lib->offset;
file_entries_new->libs[idx_new].value
@@ -554,7 +741,7 @@ save_cache (const char *cache_name)
/* Align file position to 4. */
off64_t old_offset = lseek64 (fd, extension_offset, SEEK_SET);
assert ((unsigned long long int) (extension_offset - old_offset) < 4);
- write_extensions (fd, extension_offset);
+ write_extensions (fd, str_offset, extension_offset);
}
/* Make sure user can always read cache file */
@@ -588,27 +775,35 @@ save_cache (const char *cache_name)
/* Add one library to the cache. */
void
-add_to_cache (const char *path, const char *lib, int flags,
- unsigned int osversion, uint64_t hwcap)
+add_to_cache (const char *path, const char *filename, const char *soname,
+ int flags, unsigned int osversion, uint64_t hwcap,
+ struct glibc_hwcaps_subdirectory *hwcaps)
{
struct cache_entry *new_entry = xmalloc (sizeof (*new_entry));
struct stringtable_entry *path_interned;
{
char *p;
- if (asprintf (&p, "%s/%s", path, lib) < 0)
+ if (asprintf (&p, "%s/%s", path, filename) < 0)
error (EXIT_FAILURE, errno, _("Could not create library path"));
path_interned = stringtable_add (&strings, p);
free (p);
}
- new_entry->lib = stringtable_add (&strings, lib);
+ new_entry->lib = stringtable_add (&strings, soname);
new_entry->path = path_interned;
new_entry->flags = flags;
new_entry->osversion = osversion;
new_entry->hwcap = hwcap;
+ new_entry->hwcaps = hwcaps;
new_entry->bits_hwcap = 0;
+ if (hwcaps != NULL)
+ {
+ assert (hwcap == 0);
+ hwcaps->used = true;
+ }
+
/* Count the number of bits set in the masked value. */
for (size_t i = 0;
(~((1ULL << i) - 1) & hwcap) != 0 && i < 8 * sizeof (hwcap); ++i)
diff --git a/elf/ldconfig.c b/elf/ldconfig.c
index 0fa5aef83f9cd86c..8c66d7e5426d8cc4 100644
--- a/elf/ldconfig.c
+++ b/elf/ldconfig.c
@@ -16,6 +16,7 @@
along with this program; if not, see <http://www.gnu.org/licenses/>. */
#define PROCINFO_CLASS static
+#include <assert.h>
#include <alloca.h>
#include <argp.h>
#include <dirent.h>
@@ -41,6 +42,7 @@
#include <ldconfig.h>
#include <dl-cache.h>
+#include <dl-hwcaps.h>
#include <dl-procinfo.h>
@@ -85,6 +87,10 @@ struct dir_entry
dev_t dev;
const char *from_file;
int from_line;
+
+ /* Non-NULL for subdirectories under a glibc-hwcaps subdirectory. */
+ struct glibc_hwcaps_subdirectory *hwcaps;
+
struct dir_entry *next;
};
@@ -338,17 +344,20 @@ new_sub_entry (const struct dir_entry *entry, const char *path,
new_entry->from_line = entry->from_line;
new_entry->path = xstrdup (path);
new_entry->flag = entry->flag;
+ new_entry->hwcaps = NULL;
new_entry->next = NULL;
new_entry->ino = st->st_ino;
new_entry->dev = st->st_dev;
return new_entry;
}
-/* Add a single directory entry. */
-static void
+/* Add a single directory entry. Return true if the directory is
+ actually added (because it is not a duplicate). */
+static bool
add_single_dir (struct dir_entry *entry, int verbose)
{
struct dir_entry *ptr, *prev;
+ bool added = true;
ptr = dir_entries;
prev = ptr;
@@ -368,6 +377,7 @@ add_single_dir (struct dir_entry *entry, int verbose)
ptr->flag = entry->flag;
free (entry->path);
free (entry);
+ added = false;
break;
}
prev = ptr;
@@ -378,6 +388,73 @@ add_single_dir (struct dir_entry *entry, int verbose)
dir_entries = entry;
else if (ptr == NULL)
prev->next = entry;
+ return added;
+}
+
+/* Check if PATH contains a "glibc-hwcaps" subdirectory. If so, queue
+ its subdirectories for glibc-hwcaps processing. */
+static void
+add_glibc_hwcaps_subdirectories (struct dir_entry *entry, const char *path)
+{
+ /* glibc-hwcaps subdirectories do not nest. */
+ assert (entry->hwcaps == NULL);
+
+ char *glibc_hwcaps;
+ if (asprintf (&glibc_hwcaps, "%s/" GLIBC_HWCAPS_SUBDIRECTORY, path) < 0)
+ error (EXIT_FAILURE, errno, _("Could not form glibc-hwcaps path"));
+
+ DIR *dir = opendir (glibc_hwcaps);
+ if (dir != NULL)
+ {
+ while (true)
+ {
+ errno = 0;
+ struct dirent64 *e = readdir64 (dir);
+ if (e == NULL)
+ {
+ if (errno == 0)
+ break;
+ else
+ error (EXIT_FAILURE, errno, _("Listing directory %s"), path);
+ }
+
+ /* Ignore hidden subdirectories, including "." and "..", and
+ regular files. File names containing a ':' cannot be
+ looked up by the dynamic loader, so skip those as
+ well. */
+ if (e->d_name[0] == '.' || e->d_type == DT_REG
+ || strchr (e->d_name, ':') != NULL)
+ continue;
+
+ /* See if this entry eventually resolves to a directory. */
+ struct stat64 st;
+ if (fstatat64 (dirfd (dir), e->d_name, &st, 0) < 0)
+ /* Ignore unreadable entries. */
+ continue;
+
+ if (S_ISDIR (st.st_mode))
+ {
+ /* This is a directory, so it needs to be scanned for
+ libraries, associated with the hwcaps implied by the
+ subdirectory name. */
+ char *new_path;
+ if (asprintf (&new_path, "%s/" GLIBC_HWCAPS_SUBDIRECTORY "/%s",
+ /* Use non-canonicalized path here. */
+ entry->path, e->d_name) < 0)
+ error (EXIT_FAILURE, errno,
+ _("Could not form glibc-hwcaps path"));
+ struct dir_entry *new_entry = new_sub_entry (entry, new_path,
+ &st);
+ free (new_path);
+ new_entry->hwcaps = new_glibc_hwcaps_subdirectory (e->d_name);
+ add_single_dir (new_entry, 0);
+ }
+ }
+
+ closedir (dir);
+ }
+
+ free (glibc_hwcaps);
}
/* Add one directory to the list of directories to process. */
@@ -386,6 +463,7 @@ add_dir_1 (const char *line, const char *from_file, int from_line)
{
unsigned int i;
struct dir_entry *entry = xmalloc (sizeof (struct dir_entry));
+ entry->hwcaps = NULL;
entry->next = NULL;
entry->from_file = strdup (from_file);
@@ -443,7 +521,9 @@ add_dir_1 (const char *line, const char *from_file, int from_line)
entry->ino = stat_buf.st_ino;
entry->dev = stat_buf.st_dev;
- add_single_dir (entry, 1);
+ if (add_single_dir (entry, 1))
+ /* Add glibc-hwcaps subdirectories if present. */
+ add_glibc_hwcaps_subdirectories (entry, path);
}
if (opt_chroot)
@@ -695,15 +775,27 @@ struct dlib_entry
static void
search_dir (const struct dir_entry *entry)
{
- uint64_t hwcap = path_hwcap (entry->path);
- if (opt_verbose)
+ uint64_t hwcap;
+ if (entry->hwcaps == NULL)
{
- if (hwcap != 0)
- printf ("%s: (hwcap: %#.16" PRIx64 ")", entry->path, hwcap);
- else
- printf ("%s:", entry->path);
- printf (_(" (from %s:%d)\n"), entry->from_file, entry->from_line);
+ hwcap = path_hwcap (entry->path);
+ if (opt_verbose)
+ {
+ if (hwcap != 0)
+ printf ("%s: (hwcap: %#.16" PRIx64 ")", entry->path, hwcap);
+ else
+ printf ("%s:", entry->path);
+ }
}
+ else
+ {
+ hwcap = 0;
+ if (opt_verbose)
+ printf ("%s: (hwcap: \"%s\")", entry->path,
+ glibc_hwcaps_subdirectory_name (entry->hwcaps));
+ }
+ if (opt_verbose)
+ printf (_(" (from %s:%d)\n"), entry->from_file, entry->from_line);
char *dir_name;
char *real_file_name;
@@ -745,13 +837,15 @@ search_dir (const struct dir_entry *entry)
&& direntry->d_type != DT_DIR)
continue;
/* Does this file look like a shared library or is it a hwcap
- subdirectory? The dynamic linker is also considered as
+ subdirectory (if not already processing a glibc-hwcaps
+ subdirectory)? The dynamic linker is also considered as
shared library. */
if (((strncmp (direntry->d_name, "lib", 3) != 0
&& strncmp (direntry->d_name, "ld-", 3) != 0)
|| strstr (direntry->d_name, ".so") == NULL)
&& (direntry->d_type == DT_REG
- || !is_hwcap_platform (direntry->d_name)))
+ || (entry->hwcaps == NULL
+ && !is_hwcap_platform (direntry->d_name))))
continue;
size_t len = strlen (direntry->d_name);
@@ -799,7 +893,7 @@ search_dir (const struct dir_entry *entry)
}
struct stat64 stat_buf;
- int is_dir;
+ bool is_dir;
int is_link = S_ISLNK (lstat_buf.st_mode);
if (is_link)
{
@@ -837,7 +931,10 @@ search_dir (const struct dir_entry *entry)
else
is_dir = S_ISDIR (lstat_buf.st_mode);
- if (is_dir && is_hwcap_platform (direntry->d_name))
+ /* No descending into subdirectories if this directory is a
+ glibc-hwcaps subdirectory (which are not recursive). */
+ if (entry->hwcaps == NULL
+ && is_dir && is_hwcap_platform (direntry->d_name))
{
if (!is_link
&& direntry->d_type != DT_UNKNOWN
@@ -1028,13 +1125,31 @@ search_dir (const struct dir_entry *entry)
struct dlib_entry *dlib_ptr;
for (dlib_ptr = dlibs; dlib_ptr != NULL; dlib_ptr = dlib_ptr->next)
{
- /* Don't create links to links. */
- if (dlib_ptr->is_link == 0)
- create_links (dir_name, entry->path, dlib_ptr->name,
- dlib_ptr->soname);
+ /* The cached file name is the soname for non-glibc-hwcaps
+ subdirectories (relying on symbolic links; this helps with
+ library updates that change the file name), and the actual
+ file for glibc-hwcaps subdirectories. */
+ const char *filename;
+ if (entry->hwcaps == NULL)
+ {
+ /* Don't create links to links. */
+ if (dlib_ptr->is_link == 0)
+ create_links (dir_name, entry->path, dlib_ptr->name,
+ dlib_ptr->soname);
+ filename = dlib_ptr->soname;
+ }
+ else
+ {
+ /* Do not create links in glibc-hwcaps subdirectories, but
+ still log the cache addition. */
+ if (opt_verbose)
+ printf ("\t%s -> %s\n", dlib_ptr->soname, dlib_ptr->name);
+ filename = dlib_ptr->name;
+ }
if (opt_build_cache)
- add_to_cache (entry->path, dlib_ptr->soname, dlib_ptr->flag,
- dlib_ptr->osversion, hwcap);
+ add_to_cache (entry->path, filename, dlib_ptr->soname,
+ dlib_ptr->flag, dlib_ptr->osversion,
+ hwcap, entry->hwcaps);
}
/* Free all resources. */
diff --git a/sysdeps/generic/dl-cache.h b/sysdeps/generic/dl-cache.h
index 259e843724531630..6adbe3c79a32a4ec 100644
--- a/sysdeps/generic/dl-cache.h
+++ b/sysdeps/generic/dl-cache.h
@@ -99,6 +99,23 @@ struct file_entry_new
uint64_t hwcap; /* Hwcap entry. */
};
+/* This bit in the hwcap field of struct file_entry_new indicates that
+ the lower 32 bits contain an index into the
+ cache_extension_tag_glibc_hwcaps section. Older glibc versions do
+ not know about this HWCAP bit, so they will ignore these
+ entries. */
+#define DL_CACHE_HWCAP_EXTENSION (1ULL << 62)
+
+/* Return true if the ENTRY->hwcap value indicates that
+ DL_CACHE_HWCAP_EXTENSION is used. */
+static inline bool
+dl_cache_hwcap_extension (struct file_entry_new *entry)
+{
+ /* If DL_CACHE_HWCAP_EXTENSION is set, but other bits as well, this
+ is a different kind of extension. */
+ return (entry->hwcap >> 32) == (DL_CACHE_HWCAP_EXTENSION >> 32);
+}
+
/* See flags member of struct cache_file_new below. */
enum
{
@@ -182,6 +199,17 @@ enum cache_extension_tag
cache file. */
cache_extension_tag_generator,
+ /* glibc-hwcaps subdirectory information. An array of uint32_t
+ values, which are indices into the string table. The strings
+ are sorted lexicographically (according to strcmp). The extra
+ level of indirection (instead of using string table indices
+ directly) allows the dynamic loader to compute the preference
+ order of the hwcaps names more efficiently.
+
+ For this section, 4-byte alignment is required, and the section
+ size must be a multiple of 4. */
+ cache_extension_tag_glibc_hwcaps,
+
/* Total number of known cache extension tags. */
cache_extension_count
};
@@ -236,6 +264,27 @@ struct cache_extension_all_loaded
struct cache_extension_loaded sections[cache_extension_count];
};
+/* Performs basic data validation based on section tag, and removes
+ the sections which are invalid. */
+static void
+cache_extension_verify (struct cache_extension_all_loaded *loaded)
+{
+ {
+ /* Section must not be empty, it must be aligned at 4 bytes, and
+ the size must be a multiple of 4. */
+ struct cache_extension_loaded *hwcaps
+ = &loaded->sections[cache_extension_tag_glibc_hwcaps];
+ if (hwcaps->size == 0
+ || ((uintptr_t) hwcaps->base % 4) != 0
+ || (hwcaps->size % 4) != 0)
+ {
+ hwcaps->base = NULL;
+ hwcaps->size = 0;
+ hwcaps->flags = 0;
+ }
+ }
+}
+
static bool __attribute__ ((unused))
cache_extension_load (const struct cache_file_new *cache,
const void *file_base, size_t file_size,
@@ -282,6 +331,7 @@ cache_extension_load (const struct cache_file_new *cache,
loaded->sections[tag].size = ext->sections[i].size;
loaded->sections[tag].flags = ext->sections[i].flags;
}
+ cache_extension_verify (loaded);
return true;
}
diff --git a/sysdeps/generic/ldconfig.h b/sysdeps/generic/ldconfig.h
index b15b142511829436..a8d22f143f867a3e 100644
--- a/sysdeps/generic/ldconfig.h
+++ b/sysdeps/generic/ldconfig.h
@@ -57,8 +57,22 @@ extern void init_cache (void);
extern void save_cache (const char *cache_name);
-extern void add_to_cache (const char *path, const char *lib, int flags,
- unsigned int osversion, uint64_t hwcap);
+struct glibc_hwcaps_subdirectory;
+
+/* Return a struct describing the subdirectory for NAME. Reuse an
+ existing struct if it exists. */
+struct glibc_hwcaps_subdirectory *new_glibc_hwcaps_subdirectory
+ (const char *name);
+
+/* Returns the name that was specified when
+ add_glibc_hwcaps_subdirectory was called. */
+const char *glibc_hwcaps_subdirectory_name
+ (const struct glibc_hwcaps_subdirectory *);
+
+extern void add_to_cache (const char *path, const char *filename,
+ const char *soname,
+ int flags, unsigned int osversion, uint64_t hwcap,
+ struct glibc_hwcaps_subdirectory *);
extern void init_aux_cache (void);