svn commit: r208707 - projects/capabilities8/libexec/rtld-elf
Robert Watson
rwatson at FreeBSD.org
Tue Jun 1 14:54:50 UTC 2010
Author: rwatson
Date: Tue Jun 1 14:54:50 2010
New Revision: 208707
URL: http://svn.freebsd.org/changeset/base/208707
Log:
Merge c177160, c177161, c177162, and c177354 from the p4 TrustedBSD
Capabilities branch to capabilities8:
Various rtld capability changes:
Created FDArray structure and methods
Implement and use FDArray, plus remove some #ifdef IN_RTLD_CAP lines
Allow libraries to be named by file descriptor number when in capability
mode. Also, moved the initialization of the library_dirs FDArray.
Allow objects to be loaded by FD number instead of name.
Submitted by: jona
Modified:
projects/capabilities8/libexec/rtld-elf/rtld.c
projects/capabilities8/libexec/rtld-elf/rtld.h
Modified: projects/capabilities8/libexec/rtld-elf/rtld.c
==============================================================================
--- projects/capabilities8/libexec/rtld-elf/rtld.c Tue Jun 1 14:50:00 2010 (r208706)
+++ projects/capabilities8/libexec/rtld-elf/rtld.c Tue Jun 1 14:54:50 2010 (r208707)
@@ -93,6 +93,13 @@ typedef struct Struct_DoneList {
unsigned int num_used; /* Number of array slots used */
} DoneList;
+typedef struct Struct_FDArray {
+ rtld_lock_t lock; /* Mutual exclusion */
+ int *content; /* The file descriptors */
+ int count; /* Number of descriptors in array */
+ int capacity; /* Space available for descriptors */
+} FDArray;
+
/*
* Function declarations.
*/
@@ -106,8 +113,10 @@ static int do_search_info(const Obj_Entr
static bool donelist_check(DoneList *, const Obj_Entry *);
static void errmsg_restore(char *);
static char *errmsg_save(void);
-#ifndef IN_RTLD_CAP
static void *fill_search_info(const char *, size_t, void *);
+#ifdef IN_RTLD_CAP
+static int find_library_fd(const char *name);
+#else
static char *find_library(const char *, const Obj_Entry *);
static const char *gethints(void);
#endif
@@ -121,9 +130,7 @@ static bool is_exported(const Elf_Sym *)
static void linkmap_add(Obj_Entry *);
static void linkmap_delete(Obj_Entry *);
static int load_needed_objects(Obj_Entry *, int);
-#ifndef IN_RTLD_CAP
static int load_preload_objects(void);
-#endif
static Obj_Entry *load_object(const char *, const Obj_Entry *, int);
static Obj_Entry *obj_from_addr(const void *);
static void objlist_call_fini(Objlist *, bool, int *);
@@ -134,9 +141,7 @@ static void objlist_init(Objlist *);
static void objlist_push_head(Objlist *, Obj_Entry *);
static void objlist_push_tail(Objlist *, Obj_Entry *);
static void objlist_remove(Objlist *, Obj_Entry *);
-#ifndef IN_RTLD_CAP
static void *path_enumerate(const char *, path_enum_proc, void *);
-#endif
static int relocate_objects(Obj_Entry *, bool, Obj_Entry *);
static int rtld_dirname(const char *, char *);
static int rtld_dirname_abs(const char *, char *);
@@ -176,25 +181,20 @@ void r_debug_state(struct r_debug *, str
*/
static char *error_message; /* Message for dlerror(), or NULL */
struct r_debug r_debug; /* for GDB; */
-#ifndef IN_RTLD_CAP
static bool libmap_disable; /* Disable libmap */
static char *libmap_override; /* Maps to use in addition to libmap.conf */
-#endif
static bool trust; /* False for setuid and setgid programs */
static bool dangerous_ld_env; /* True if environment variables have been
used to affect the libraries loaded */
static char *ld_bind_now; /* Environment variable for immediate binding */
static char *ld_debug; /* Environment variable for debugging */
-static int *ld_library_dirs = NULL; /* File descriptors of lib path (end: -1) */
-static int ld_library_dirs_done; /* ld_library_dirs has been initialized */
-static int ld_library_dirlen; /* Capacity of ld_library_dirs */
-static int ld_library_dircount; /* Number of entries in ld_library_dirs */
-#ifndef IN_RTLD_CAP
+static FDArray library_dirs; /* File descriptors of library path */
+static FDArray preload_fds; /* File descriptors of preloaded libraries */
+static bool locks_initialized; /* FDArray locks have been initialized */
static char *ld_library_path; /* Environment variable for search path */
static char *ld_preload; /* Environment variable for libraries to
load first */
static char *ld_elf_hints_path; /* Environment variable for alternative hints path */
-#endif
static char *ld_tracing; /* Called from ldd to print libs */
static char *ld_utrace; /* Use utrace() to log events. */
static Obj_Entry *obj_list; /* Head of linked list of shared objects */
@@ -454,28 +454,20 @@ _rtld(Elf_Addr *sp, func_ptr_type *exit_
#endif
}
ld_debug = getenv(LD_ "DEBUG");
-#ifndef IN_RTLD_CAP
libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL;
libmap_override = getenv(LD_ "LIBMAP");
ld_library_path = getenv(LD_ "LIBRARY_PATH");
ld_preload = getenv(LD_ "PRELOAD");
ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH");
-#endif
dangerous_ld_env =
-#ifdef IN_RTLD_CAP
- 1;
-#else
libmap_disable || (libmap_override != NULL) ||
(ld_library_path != NULL) || (ld_preload != NULL) ||
(ld_elf_hints_path != NULL);
-#endif
ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS");
ld_utrace = getenv(LD_ "UTRACE");
-#ifndef IN_RTLD_CAP
if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
ld_elf_hints_path = _PATH_ELF_HINTS;
-#endif
if (ld_debug != NULL && *ld_debug != '\0')
debug = 1;
@@ -570,11 +562,16 @@ _rtld(Elf_Addr *sp, func_ptr_type *exit_
#ifndef IN_RTLD_CAP
if (!libmap_disable)
libmap_disable = (bool)lm_init(libmap_override);
+#endif
+
+ /* Initialize FD arrays */
+ library_dirs.content = NULL;
+ preload_fds.content = NULL;
+
dbg("loading LD_PRELOAD libraries");
if (load_preload_objects() == -1)
die();
-#endif
preload_tail = obj_tail;
dbg("loading needed objects");
@@ -631,6 +628,9 @@ _rtld(Elf_Addr *sp, func_ptr_type *exit_
dbg("initializing thread locks");
lockdflt_init();
+ locks_initialized = true;
+ library_dirs.lock = rtld_dirs_lock;
+ preload_fds.lock = rtld_preloads_lock;
/* Make a list of init functions to call. */
objlist_init(&initlist);
@@ -1199,6 +1199,83 @@ elf_hash(const char *name)
return h;
}
+
+
+bool fdarray_init(struct Struct_FDArray *fds) {
+ if (fds == NULL) return false;
+
+ int lockstate = fdarray_lock(fds);
+
+ fds->count = 0;
+ fds->capacity = 8;
+ fds->content = xmalloc(fds->capacity * sizeof(int));
+
+ fdarray_unlock(fds, lockstate);
+
+ return true;
+}
+
+int fdarray_lock(struct Struct_FDArray *fds) {
+ if (!locks_initialized) return 0;
+ else return wlock_acquire(fds->lock);
+}
+
+int fdarray_rlock(struct Struct_FDArray *fds) {
+ if (!locks_initialized) return 0;
+ else return rlock_acquire(fds->lock);
+}
+
+void fdarray_unlock(struct Struct_FDArray *fds, int state) {
+ if (!locks_initialized) return;
+ else wlock_release(fds->lock, state);
+}
+
+void fdarray_runlock(struct Struct_FDArray *fds, int state) {
+ if (!locks_initialized) return;
+ else rlock_release(fds->lock, state);
+}
+bool fdarray_append(struct Struct_FDArray *fds, int fd)
+{
+
+ int lockstate = fdarray_lock(fds);
+
+ /* Do we need to grow? */
+ if (fds->count == fds->capacity) {
+ fds->capacity *= 2;
+ fds->content = realloc(fds->content, fds->capacity * sizeof(int));
+ if (fds->content == NULL) {
+ _rtld_error("add_libdir_fd: realloc failed");
+ fdarray_unlock(fds, lockstate);
+ return false;
+ }
+ }
+
+ /* Add the new fd to the end. */
+ fds->content[fds->count++] = fd;
+
+ fdarray_unlock(fds, lockstate);
+ return true;
+}
+
+int* fdarray_get(struct Struct_FDArray *fds)
+{
+ int bytes, *copy;
+
+ int lockstate = fdarray_rlock(fds);
+
+ bytes = fds->count * sizeof(int);
+
+ copy = xmalloc(bytes);
+ if (copy != NULL)
+ bcopy(fds->content, copy, bytes);
+
+ fdarray_runlock(fds, lockstate);
+
+ return copy;
+}
+
+
+
#ifdef IN_RTLD_CAP
/*
* Find the library with the given name, and return an open file descriptor
@@ -1209,13 +1286,21 @@ find_library_fd(const char *name)
{
int fd, i;
- if (!ld_library_dirs_done)
- init_libdirs();
- for (i = 0; i < ld_library_dircount; i++) {
- fd = openat(ld_library_dirs[i], name, O_RDONLY);
- if (fd >= 0)
+ int lockstate = fdarray_lock(&library_dirs);
+ if (library_dirs.content == NULL) init_libdirs();
+ fdarray_unlock(&library_dirs, lockstate);
+
+
+ lockstate = fdarray_rlock(&library_dirs);
+ for (i = 0; i < library_dirs.count; i++) {
+ fd = openat(library_dirs.content[i], name, O_RDONLY);
+ if (fd >= 0) {
+ fdarray_runlock(&library_dirs, lockstate);
return (fd);
+ }
}
+
+ fdarray_runlock(&library_dirs, lockstate);
return (-1);
}
@@ -1576,7 +1661,6 @@ load_needed_objects(Obj_Entry *first, in
return 0;
}
-#ifndef IN_RTLD_CAP
static int
load_preload_objects(void)
{
@@ -1602,7 +1686,6 @@ load_preload_objects(void)
LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
return 0;
}
-#endif
/*
* Load a shared object into memory, if it is not already loaded.
@@ -1623,15 +1706,27 @@ load_object(const char *name, const Obj_
return obj;
#ifdef IN_RTLD_CAP
- if (strchr(name, '/') != NULL) {
- _rtld_error("Paths to shared objects not supported \"%s\"", name);
- return NULL;
- }
path = xstrdup(name);
- if ((fd = find_library_fd(path)) < 0) {
- _rtld_error("Unable to find \"%s\" in LD_LIBRARY_DIRS", path);
- free(path);
- return NULL;
+
+ /* is the name actually a file descriptor? */
+ long long long_fd = strtonum(path, 0, __INT_MAX, NULL);
+ if ((long_fd >= 0) && (fstat((int) long_fd, &sb) == 0))
+ fd = (int) long_fd;
+
+ /* if not, search the library path */
+ else {
+ dbg("preload by name: %s", name);
+ if (strchr(name, '/') != NULL) {
+ _rtld_error("Absolute paths (e.g. \"%s\") not supported", path);
+ free(path);
+ return NULL;
+ }
+
+ if ((fd = find_library_fd(path)) < 0) {
+ _rtld_error("Unable to find \"%s\" in LD_LIBRARY_DIRS", path);
+ free(path);
+ return NULL;
+ }
}
#else
path = find_library(name, refobj);
@@ -1704,7 +1799,7 @@ do_load_object(int fd, const char *name,
if (dangerous_ld_env) {
if (fstatfs(fd, &fs) != 0) {
_rtld_error("Cannot fstatfs \"%s\"", path);
- return NULL;
+ return NULL;
}
if (fs.f_flags & MNT_NOEXEC) {
_rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
@@ -1717,6 +1812,7 @@ do_load_object(int fd, const char *name,
return NULL;
object_add_name(obj, name);
+ obj->fd = fd;
obj->path = path;
digest_dynamic(obj, 0);
if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
@@ -1986,7 +2082,6 @@ rtld_exit(void)
wlock_release(rtld_bind_lock, lockstate);
}
-#ifndef IN_RTLD_CAP
static void *
path_enumerate(const char *path, path_enum_proc callback, void *arg)
{
@@ -2019,7 +2114,6 @@ path_enumerate(const char *path, path_en
return (NULL);
}
-#endif
struct try_library_args {
const char *name;
@@ -2079,52 +2173,15 @@ search_library_path(const char *name, co
#endif
/*
- * Add a file descriptor to ld_library_dirs.
- *
- * XXX: This may be called from either the rtld startup code, or from
- * ld_libdirs. We have no way to distinguish them on error, so die()
- * unconditionally. Perhaps the latter case should allow graceful failure.
- *
- * XXX: Synchronization?
- */
-static void
-add_libdir_fd(int fd)
-{
-
- /* Initialize the FD list. */
- if (!ld_library_dirs_done) {
- ld_library_dirlen = INITIAL_FDLEN;
- ld_library_dircount = 0;
- ld_library_dirs = xmalloc(ld_library_dirlen * sizeof(int));
- ld_library_dirs_done = 1;
- }
-
- /* Do we need to grow? */
- if (ld_library_dirlen == ld_library_dircount) {
- ld_library_dirlen *= 2;
- ld_library_dirs = realloc(ld_library_dirs,
- ld_library_dirlen * sizeof(int));
- if (ld_library_dirs == NULL) {
- _rtld_error("add_libdir_fd: realloc failed");
- die();
- }
- }
-
- /* Add the new library directory fd to the end. */
- ld_library_dirs[ld_library_dircount] = fd;
- ld_library_dircount++;
-}
-
-/*
* Add file descriptors for a path list (e.g. '/lib:/usr/lib') to
* ld_library_dirs.
*/
-static void
+static bool
add_libdir_paths(const char *path)
{
if (path == NULL)
- return;
+ return false;
char *pathcopy, *dirname, *tokcontext;
int pathlen = strnlen(path, PATH_MAX);
@@ -2132,6 +2189,7 @@ add_libdir_paths(const char *path)
pathcopy = malloc(pathlen + 1);
strncpy(pathcopy, path, pathlen + 1);
+ bool success = true;
for (dirname = strtok_r(pathcopy, ":", &tokcontext); dirname;
dirname = strtok_r(NULL, ":", &tokcontext)) {
struct try_library_args arg;
@@ -2152,10 +2210,14 @@ add_libdir_paths(const char *path)
}
if (fd >= 0)
- add_libdir_fd(fd);
+ if (!fdarray_append(&library_dirs, fd)) {
+ success = false;
+ break;
+ }
}
free(pathcopy);
+ return success;
}
/*
@@ -2164,6 +2226,8 @@ add_libdir_paths(const char *path)
static void
init_libdirs(void)
{
+ fdarray_init(&library_dirs);
+
#ifdef IN_RTLD_CAP
char *envvar = getenv(LD_ "LIBRARY_DIRS");
@@ -2181,27 +2245,33 @@ init_libdirs(void)
/*
* Return an array of file descriptors for the library search paths.
- *
- * XXX: synchronization of ld_library_dirs?
*/
int
ld_libdirs(int *fds, int *fdcount)
{
-
if (fdcount == NULL)
return (-1);
else if (fds == NULL) {
*fdcount = -1;
return (-1);
}
- if (!ld_library_dirs_done)
+
+ int lockstate = rlock_acquire(library_dirs.lock);
+
+ if (library_dirs.content == NULL)
init_libdirs();
- if (*fdcount < ld_library_dircount) {
- *fdcount = ld_library_dircount;
+
+ if (*fdcount < library_dirs.count) {
+ *fdcount = library_dirs.count;
+ rlock_release(library_dirs.lock, lockstate);
return (-1);
}
- *fdcount = ld_library_dircount;
- memcpy(fds, ld_library_dirs, ld_library_dircount * sizeof(int));
+
+ *fdcount = library_dirs.count;
+ memcpy(fds, library_dirs.content, *fdcount * sizeof(int));
+
+ rlock_release(library_dirs.lock, lockstate);
+
return (0);
}
@@ -2648,7 +2718,6 @@ struct fill_search_info_args {
char *strspace;
};
-#ifndef IN_RTLD_CAP
static void *
fill_search_info(const char *dir, size_t dirlen, void *param)
{
@@ -2675,24 +2744,21 @@ fill_search_info(const char *dir, size_t
return (NULL);
}
-#endif
static int
do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
{
struct dl_serinfo _info;
-#ifndef IN_RTLD_CAP
struct fill_search_info_args args;
args.request = RTLD_DI_SERINFOSIZE;
args.serinfo = &_info;
-#endif
_info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
_info.dls_cnt = 0;
-#ifndef IN_RTLD_CAP
path_enumerate(ld_library_path, fill_search_info, &args);
+#ifndef IN_RTLD_CAP
path_enumerate(obj->rpath, fill_search_info, &args);
path_enumerate(gethints(), fill_search_info, &args);
path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
Modified: projects/capabilities8/libexec/rtld-elf/rtld.h
==============================================================================
--- projects/capabilities8/libexec/rtld-elf/rtld.h Tue Jun 1 14:50:00 2010 (r208706)
+++ projects/capabilities8/libexec/rtld-elf/rtld.h Tue Jun 1 14:54:50 2010 (r208707)
@@ -255,6 +255,11 @@ typedef struct Struct_SymCache {
const Obj_Entry *obj; /* Shared object which defines it */
} SymCache;
+/*
+ * Storage for arrays of file descriptors.
+ */
+struct Struct_FDArray;
+
extern void _rtld_error(const char *, ...) __printflike(1, 2);
extern Obj_Entry *map_object(int, const char *, const struct stat *);
extern void *xcalloc(size_t);
@@ -287,6 +292,11 @@ void *allocate_module_tls(int index);
bool allocate_tls_offset(Obj_Entry *obj);
void free_tls_offset(Obj_Entry *obj);
const Ver_Entry *fetch_ventry(const Obj_Entry *obj, unsigned long);
+bool fdarray_init(struct Struct_FDArray*);
+bool fdarray_append(struct Struct_FDArray*, int);
+int* fdarray_get(struct Struct_FDArray*);
+int fdarray_lock(struct Struct_FDArray*);
+void fdarray_unlock(struct Struct_FDArray*, int);
/*
* MD function declarations.
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