Replace the kld_mtx mutex with a kld_sx sx lock and expand it's scope to
protect all linker-related data structures including the contents of linker file objects and the any linker class data as well. Considering how rarely the linker is used I just went with the simple solution of single-threading the whole thing rather than expending a lot of effor on something more fine-grained and complex. Giant is still explicitly acquired while registering and deregistering sysctl's as well as in the elf linker class while calling kmupetext(). The rest of the linker runs without Giant unless it has to acquire Giant while loading files from a non-MPSAFE filesystem.
This commit is contained in:
parent
40bdac68d8
commit
70f3778827
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=159845
@ -62,6 +62,11 @@ __FBSDID("$FreeBSD$");
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int kld_debug = 0;
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#endif
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#define KLD_LOCK() do { sx_xlock(&kld_sx); mtx_lock(&Giant); } while (0)
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#define KLD_UNLOCK() do { mtx_unlock(&Giant); sx_xunlock(&kld_sx); } while (0)
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#define KLD_LOCKED() sx_xlocked(&kld_sx)
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#define KLD_LOCK_ASSERT() do { if (!cold) sx_assert(&kld_sx, SX_XLOCKED); } while (0)
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/*
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* static char *linker_search_path(const char *name, struct mod_depend
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* *verinfo);
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@ -85,7 +90,7 @@ MALLOC_DEFINE(M_LINKER, "linker", "kernel linker");
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linker_file_t linker_kernel_file;
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static struct mtx kld_mtx; /* kernel linker mutex */
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static struct sx kld_sx; /* kernel linker lock */
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static linker_class_list_t classes;
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static linker_file_list_t linker_files;
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@ -95,17 +100,15 @@ static int linker_no_more_classes = 0;
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#define LINKER_GET_NEXT_FILE_ID(a) do { \
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linker_file_t lftmp; \
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\
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KLD_LOCK_ASSERT(); \
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retry: \
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mtx_lock(&kld_mtx); \
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TAILQ_FOREACH(lftmp, &linker_files, link) { \
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if (next_file_id == lftmp->id) { \
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next_file_id++; \
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mtx_unlock(&kld_mtx); \
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goto retry; \
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} \
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} \
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(a) = next_file_id; \
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mtx_unlock(&kld_mtx); /* Hold for safe read of id variable */ \
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} while(0)
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@ -122,6 +125,8 @@ static modlisthead_t found_modules;
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static int linker_file_add_dependency(linker_file_t file,
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linker_file_t dep);
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static caddr_t linker_file_lookup_symbol_internal(linker_file_t file,
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const char* name, int deps);
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static int linker_load_module(const char *kldname,
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const char *modname, struct linker_file *parent,
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struct mod_depend *verinfo, struct linker_file **lfpp);
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@ -141,7 +146,7 @@ static void
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linker_init(void *arg)
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{
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mtx_init(&kld_mtx, "kernel linker", NULL, MTX_DEF);
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sx_init(&kld_sx, "kernel linker");
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TAILQ_INIT(&classes);
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TAILQ_INIT(&linker_files);
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}
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@ -272,8 +277,10 @@ linker_file_register_sysctls(linker_file_t lf)
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if (linker_file_lookup_set(lf, "sysctl_set", &start, &stop, NULL) != 0)
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return;
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mtx_lock(&Giant);
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for (oidp = start; oidp < stop; oidp++)
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sysctl_register_oid(*oidp);
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mtx_unlock(&Giant);
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}
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static void
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@ -287,8 +294,10 @@ linker_file_unregister_sysctls(linker_file_t lf)
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if (linker_file_lookup_set(lf, "sysctl_set", &start, &stop, NULL) != 0)
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return;
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mtx_lock(&Giant);
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for (oidp = start; oidp < stop; oidp++)
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sysctl_unregister_oid(*oidp);
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mtx_unlock(&Giant);
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}
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static int
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@ -352,6 +361,7 @@ linker_load_file(const char *filename, linker_file_t *result)
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if (securelevel > 0)
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return (EPERM);
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KLD_LOCK_ASSERT();
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lf = linker_find_file_by_name(filename);
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if (lf) {
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KLD_DPF(FILE, ("linker_load_file: file %s is already loaded,"
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@ -418,16 +428,16 @@ linker_reference_module(const char *modname, struct mod_depend *verinfo,
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modlist_t mod;
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int error;
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mtx_lock(&Giant);
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KLD_LOCK();
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if ((mod = modlist_lookup2(modname, verinfo)) != NULL) {
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*result = mod->container;
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(*result)->refs++;
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mtx_unlock(&Giant);
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KLD_UNLOCK();
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return (0);
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}
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error = linker_load_module(NULL, modname, NULL, verinfo, result);
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mtx_unlock(&Giant);
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KLD_UNLOCK();
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return (error);
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}
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@ -438,13 +448,13 @@ linker_release_module(const char *modname, struct mod_depend *verinfo,
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modlist_t mod;
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int error;
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mtx_lock(&Giant);
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KLD_LOCK();
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if (lf == NULL) {
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KASSERT(modname != NULL,
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("linker_release_module: no file or name"));
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mod = modlist_lookup2(modname, verinfo);
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if (mod == NULL) {
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mtx_unlock(&Giant);
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KLD_UNLOCK();
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return (ESRCH);
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}
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lf = mod->container;
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@ -452,7 +462,7 @@ linker_release_module(const char *modname, struct mod_depend *verinfo,
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KASSERT(modname == NULL && verinfo == NULL,
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("linker_release_module: both file and name"));
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error = linker_file_unload(lf, LINKER_UNLOAD_NORMAL);
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mtx_unlock(&Giant);
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KLD_UNLOCK();
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return (error);
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}
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@ -465,14 +475,13 @@ linker_find_file_by_name(const char *filename)
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koname = malloc(strlen(filename) + 4, M_LINKER, M_WAITOK);
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sprintf(koname, "%s.ko", filename);
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mtx_lock(&kld_mtx);
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KLD_LOCK_ASSERT();
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TAILQ_FOREACH(lf, &linker_files, link) {
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if (strcmp(lf->filename, koname) == 0)
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break;
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if (strcmp(lf->filename, filename) == 0)
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break;
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}
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mtx_unlock(&kld_mtx);
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free(koname, M_LINKER);
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return (lf);
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}
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@ -481,12 +490,11 @@ static linker_file_t
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linker_find_file_by_id(int fileid)
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{
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linker_file_t lf;
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mtx_lock(&kld_mtx);
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KLD_LOCK_ASSERT();
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TAILQ_FOREACH(lf, &linker_files, link)
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if (lf->id == fileid)
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break;
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mtx_unlock(&kld_mtx);
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return (lf);
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}
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@ -496,13 +504,13 @@ linker_file_foreach(linker_predicate_t *predicate, void *context)
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linker_file_t lf;
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int retval = 0;
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mtx_lock(&Giant);
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KLD_LOCK();
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TAILQ_FOREACH(lf, &linker_files, link) {
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retval = predicate(lf, context);
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if (retval != 0)
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break;
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}
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mtx_unlock(&Giant);
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KLD_UNLOCK();
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return (retval);
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}
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@ -512,6 +520,7 @@ linker_make_file(const char *pathname, linker_class_t lc)
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linker_file_t lf;
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const char *filename;
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KLD_LOCK_ASSERT();
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filename = linker_basename(pathname);
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KLD_DPF(FILE, ("linker_make_file: new file, filename=%s\n", filename));
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@ -527,9 +536,7 @@ linker_make_file(const char *pathname, linker_class_t lc)
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lf->deps = NULL;
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STAILQ_INIT(&lf->common);
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TAILQ_INIT(&lf->modules);
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mtx_lock(&kld_mtx);
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TAILQ_INSERT_TAIL(&linker_files, lf, link);
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mtx_unlock(&kld_mtx);
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return (lf);
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}
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@ -550,6 +557,7 @@ linker_file_unload(linker_file_t file, int flags)
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return (error);
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#endif
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KLD_LOCK_ASSERT();
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KLD_DPF(FILE, ("linker_file_unload: lf->refs=%d\n", file->refs));
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/* Easy case of just dropping a reference. */
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@ -597,9 +605,7 @@ linker_file_unload(linker_file_t file, int flags)
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linker_file_sysuninit(file);
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linker_file_unregister_sysctls(file);
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}
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mtx_lock(&kld_mtx);
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TAILQ_REMOVE(&linker_files, file, link);
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mtx_unlock(&kld_mtx);
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if (file->deps) {
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for (i = 0; i < file->ndeps; i++)
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@ -627,6 +633,7 @@ linker_file_add_dependency(linker_file_t file, linker_file_t dep)
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{
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linker_file_t *newdeps;
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KLD_LOCK_ASSERT();
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newdeps = malloc((file->ndeps + 1) * sizeof(linker_file_t *),
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M_LINKER, M_WAITOK | M_ZERO);
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if (newdeps == NULL)
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@ -653,12 +660,35 @@ int
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linker_file_lookup_set(linker_file_t file, const char *name,
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void *firstp, void *lastp, int *countp)
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{
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int error, locked;
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return (LINKER_LOOKUP_SET(file, name, firstp, lastp, countp));
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locked = KLD_LOCKED();
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if (!locked)
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KLD_LOCK();
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error = LINKER_LOOKUP_SET(file, name, firstp, lastp, countp);
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if (!locked)
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KLD_UNLOCK();
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return (error);
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}
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caddr_t
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linker_file_lookup_symbol(linker_file_t file, const char *name, int deps)
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{
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caddr_t sym;
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int locked;
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locked = KLD_LOCKED();
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if (!locked)
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KLD_LOCK();
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sym = linker_file_lookup_symbol_internal(file, name, deps);
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if (!locked)
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KLD_UNLOCK();
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return (sym);
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}
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static caddr_t
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linker_file_lookup_symbol_internal(linker_file_t file, const char *name,
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int deps)
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{
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c_linker_sym_t sym;
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linker_symval_t symval;
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@ -666,6 +696,7 @@ linker_file_lookup_symbol(linker_file_t file, const char *name, int deps)
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size_t common_size = 0;
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int i;
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KLD_LOCK_ASSERT();
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KLD_DPF(SYM, ("linker_file_lookup_symbol: file=%p, name=%s, deps=%d\n",
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file, name, deps));
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@ -686,8 +717,8 @@ linker_file_lookup_symbol(linker_file_t file, const char *name, int deps)
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}
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if (deps) {
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for (i = 0; i < file->ndeps; i++) {
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address = linker_file_lookup_symbol(file->deps[i],
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name, 0);
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address = linker_file_lookup_symbol_internal(
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file->deps[i], name, 0);
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if (address) {
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KLD_DPF(SYM, ("linker_file_lookup_symbol:"
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" deps value=%p\n", address));
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@ -832,7 +863,7 @@ kern_kldload(struct thread *td, const char *file, int *fileid)
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modname = file;
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}
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mtx_lock(&Giant);
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KLD_LOCK();
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error = linker_load_module(kldname, modname, NULL, NULL, &lf);
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if (error)
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goto unlock;
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@ -845,7 +876,7 @@ kern_kldload(struct thread *td, const char *file, int *fileid)
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if (fileid != NULL)
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*fileid = lf->id;
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unlock:
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mtx_unlock(&Giant);
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KLD_UNLOCK();
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return (error);
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}
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@ -886,7 +917,7 @@ kern_kldunload(struct thread *td, int fileid, int flags)
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if ((error = suser(td)) != 0)
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return (error);
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mtx_lock(&Giant);
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KLD_LOCK();
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lf = linker_find_file_by_id(fileid);
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if (lf) {
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KLD_DPF(FILE, ("kldunload: lf->userrefs=%d\n", lf->userrefs));
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@ -915,7 +946,7 @@ kern_kldunload(struct thread *td, int fileid, int flags)
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if (error == 0)
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PMC_CALL_HOOK(td, PMC_FN_KLD_UNLOAD, (void *) &pkm);
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#endif
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mtx_unlock(&Giant);
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KLD_UNLOCK();
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return (error);
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}
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@ -966,13 +997,13 @@ kldfind(struct thread *td, struct kldfind_args *uap)
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goto out;
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filename = linker_basename(pathname);
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mtx_lock(&Giant);
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KLD_LOCK();
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lf = linker_find_file_by_name(filename);
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if (lf)
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td->td_retval[0] = lf->id;
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else
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error = ENOENT;
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mtx_unlock(&Giant);
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KLD_UNLOCK();
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out:
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free(pathname, M_TEMP);
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return (error);
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@ -993,15 +1024,12 @@ kldnext(struct thread *td, struct kldnext_args *uap)
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return (error);
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#endif
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mtx_lock(&Giant);
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KLD_LOCK();
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if (uap->fileid == 0) {
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mtx_lock(&kld_mtx);
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if (TAILQ_FIRST(&linker_files))
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td->td_retval[0] = TAILQ_FIRST(&linker_files)->id;
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else
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td->td_retval[0] = 0;
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mtx_unlock(&kld_mtx);
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goto out;
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}
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lf = linker_find_file_by_id(uap->fileid);
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@ -1013,7 +1041,7 @@ kldnext(struct thread *td, struct kldnext_args *uap)
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} else
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error = ENOENT;
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out:
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mtx_unlock(&Giant);
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KLD_UNLOCK();
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return (error);
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}
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@ -1042,11 +1070,10 @@ kldstat(struct thread *td, struct kldstat_args *uap)
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return (error);
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#endif
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mtx_lock(&Giant);
|
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|
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KLD_LOCK();
|
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lf = linker_find_file_by_id(uap->fileid);
|
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if (lf == NULL) {
|
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mtx_unlock(&Giant);
|
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KLD_UNLOCK();
|
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return (ENOENT);
|
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}
|
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|
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@ -1058,7 +1085,7 @@ kldstat(struct thread *td, struct kldstat_args *uap)
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stat.id = lf->id;
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stat.address = lf->address;
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stat.size = lf->size;
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mtx_unlock(&Giant);
|
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KLD_UNLOCK();
|
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|
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td->td_retval[0] = 0;
|
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|
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@ -1081,7 +1108,7 @@ kldfirstmod(struct thread *td, struct kldfirstmod_args *uap)
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return (error);
|
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#endif
|
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|
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mtx_lock(&Giant);
|
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KLD_LOCK();
|
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lf = linker_find_file_by_id(uap->fileid);
|
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if (lf) {
|
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MOD_SLOCK;
|
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@ -1093,7 +1120,7 @@ kldfirstmod(struct thread *td, struct kldfirstmod_args *uap)
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MOD_SUNLOCK;
|
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} else
|
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error = ENOENT;
|
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mtx_unlock(&Giant);
|
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KLD_UNLOCK();
|
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return (error);
|
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}
|
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|
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@ -1124,7 +1151,7 @@ kldsym(struct thread *td, struct kldsym_args *uap)
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symstr = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
|
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if ((error = copyinstr(lookup.symname, symstr, MAXPATHLEN, NULL)) != 0)
|
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goto out;
|
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mtx_lock(&Giant);
|
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KLD_LOCK();
|
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if (uap->fileid != 0) {
|
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lf = linker_find_file_by_id(uap->fileid);
|
||||
if (lf == NULL)
|
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@ -1137,7 +1164,6 @@ kldsym(struct thread *td, struct kldsym_args *uap)
|
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} else
|
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error = ENOENT;
|
||||
} else {
|
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mtx_lock(&kld_mtx);
|
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TAILQ_FOREACH(lf, &linker_files, link) {
|
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if (LINKER_LOOKUP_SYMBOL(lf, symstr, &sym) == 0 &&
|
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LINKER_SYMBOL_VALUES(lf, sym, &symval) == 0) {
|
||||
@ -1148,11 +1174,10 @@ kldsym(struct thread *td, struct kldsym_args *uap)
|
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break;
|
||||
}
|
||||
}
|
||||
mtx_unlock(&kld_mtx);
|
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if (lf == NULL)
|
||||
error = ENOENT;
|
||||
}
|
||||
mtx_unlock(&Giant);
|
||||
KLD_UNLOCK();
|
||||
out:
|
||||
free(symstr, M_TEMP);
|
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return (error);
|
||||
@ -1799,6 +1824,7 @@ linker_load_module(const char *kldname, const char *modname,
|
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char *pathname;
|
||||
int error;
|
||||
|
||||
KLD_LOCK_ASSERT();
|
||||
if (modname == NULL) {
|
||||
/*
|
||||
* We have to load KLD
|
||||
@ -1872,6 +1898,7 @@ linker_load_dependencies(linker_file_t lf)
|
||||
/*
|
||||
* All files are dependant on /kernel.
|
||||
*/
|
||||
KLD_LOCK_ASSERT();
|
||||
if (linker_kernel_file) {
|
||||
linker_kernel_file->refs++;
|
||||
error = linker_file_add_dependency(lf, linker_kernel_file);
|
||||
@ -1963,16 +1990,16 @@ sysctl_kern_function_list(SYSCTL_HANDLER_ARGS)
|
||||
error = sysctl_wire_old_buffer(req, 0);
|
||||
if (error != 0)
|
||||
return (error);
|
||||
mtx_lock(&kld_mtx);
|
||||
KLD_LOCK();
|
||||
TAILQ_FOREACH(lf, &linker_files, link) {
|
||||
error = LINKER_EACH_FUNCTION_NAME(lf,
|
||||
sysctl_kern_function_list_iterate, req);
|
||||
if (error) {
|
||||
mtx_unlock(&kld_mtx);
|
||||
KLD_UNLOCK();
|
||||
return (error);
|
||||
}
|
||||
}
|
||||
mtx_unlock(&kld_mtx);
|
||||
KLD_UNLOCK();
|
||||
return (SYSCTL_OUT(req, "", 1));
|
||||
}
|
||||
|
||||
|
@ -559,8 +559,6 @@ link_elf_load_file(linker_class_t cls, const char* filename,
|
||||
int strcnt;
|
||||
int vfslocked;
|
||||
|
||||
GIANT_REQUIRED;
|
||||
|
||||
shdr = NULL;
|
||||
lf = NULL;
|
||||
|
||||
@ -761,8 +759,10 @@ link_elf_load_file(linker_class_t cls, const char* filename,
|
||||
|
||||
#ifdef GPROF
|
||||
/* Update profiling information with the new text segment. */
|
||||
mtx_lock(&Giant);
|
||||
kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr +
|
||||
segs[0]->p_memsz));
|
||||
mtx_unlock(&Giant);
|
||||
#endif
|
||||
|
||||
ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr);
|
||||
|
@ -396,8 +396,6 @@ link_elf_load_file(linker_class_t cls, const char *filename,
|
||||
int alignmask;
|
||||
int vfslocked;
|
||||
|
||||
GIANT_REQUIRED;
|
||||
|
||||
shdr = NULL;
|
||||
lf = NULL;
|
||||
mapsize = 0;
|
||||
|
Loading…
Reference in New Issue
Block a user