dt_module.c

Sun Solaris 10 中的 DTrace 组件的源代码。请参看: http://www.sun.com/software/solaris/observability.jsp

		    (dp = elf_getdata(sp, NULL)) != NULL) {
			(void) strlcpy(dmp->dm_file,
			    dp->d_buf, sizeof (dmp->dm_file));
		}
	}

	dmp->dm_flags |= DT_DM_KERNEL;
	dmp->dm_modid = (int)OBJFS_MODID(st.st_ino);

	if (dmp->dm_info.objfs_info_primary)
		dmp->dm_flags |= DT_DM_PRIMARY;

	dt_dprintf("opened %d-bit module %s (%s) [%d]\n",
	    bits, dmp->dm_name, dmp->dm_file, dmp->dm_modid);
}

/*
 * Unload all the loaded modules and then refresh the module cache with the
 * latest list of loaded modules and their address ranges.
 */
void
dtrace_update(dtrace_hdl_t *dtp)
{
	dt_module_t *dmp;
	DIR *dirp;

	for (dmp = dt_list_next(&dtp->dt_modlist);
	    dmp != NULL; dmp = dt_list_next(dmp))
		dt_module_unload(dtp, dmp);

	/*
	 * Open /system/object and attempt to create a libdtrace module for
	 * each kernel module that is loaded on the current system.
	 */
	if (!(dtp->dt_oflags & DTRACE_O_NOSYS) &&
	    (dirp = opendir(OBJFS_ROOT)) != NULL) {
		struct dirent *dp, *ep;

		ep = alloca(sizeof (struct dirent) + PATH_MAX + 1);
		bzero(ep, sizeof (struct dirent) + PATH_MAX + 1);

		while (readdir_r(dirp, ep, &dp) == 0 && dp != NULL) {
			if (dp->d_name[0] != '.')
				dt_module_update(dtp, dp->d_name);
		}

		(void) closedir(dirp);
	}

	/*
	 * Look up all the macro identifiers and set di_id to the latest value.
	 * This code collaborates with dt_lex.l on the use of di_id.  We will
	 * need to implement something fancier if we need to support non-ints.
	 */
	dt_idhash_lookup(dtp->dt_macros, "egid")->di_id = getegid();
	dt_idhash_lookup(dtp->dt_macros, "euid")->di_id = geteuid();
	dt_idhash_lookup(dtp->dt_macros, "gid")->di_id = getgid();
	dt_idhash_lookup(dtp->dt_macros, "pid")->di_id = getpid();
	dt_idhash_lookup(dtp->dt_macros, "pgid")->di_id = getpgid(0);
	dt_idhash_lookup(dtp->dt_macros, "ppid")->di_id = getppid();
	dt_idhash_lookup(dtp->dt_macros, "projid")->di_id = getprojid();
	dt_idhash_lookup(dtp->dt_macros, "sid")->di_id = getsid(0);
	dt_idhash_lookup(dtp->dt_macros, "taskid")->di_id = gettaskid();
	dt_idhash_lookup(dtp->dt_macros, "uid")->di_id = getuid();

	/*
	 * Cache the pointers to the modules representing the base executable
	 * and the run-time linker in the dtrace client handle.  We should
	 * probably have a more generic way of inquiring as to their names.
	 */
	dtp->dt_exec = dt_module_lookup_by_name(dtp, "genunix");
	dtp->dt_rtld = dt_module_lookup_by_name(dtp, "krtld");

	/*
	 * If this is the first time we are initializing the module list,
	 * remove the module for genunix from the module list and then move it
	 * to the front of the module list.  We do this so that type and symbol
	 * queries encounter genunix and thereby optimize for the common case
	 * in dtrace_lookup_by_name() and dtrace_lookup_by_type(), below.
	 */
	if (dtp->dt_exec != NULL &&
	    dtp->dt_cdefs == NULL && dtp->dt_ddefs == NULL) {
		dt_list_delete(&dtp->dt_modlist, dtp->dt_exec);
		dt_list_prepend(&dtp->dt_modlist, dtp->dt_exec);
	}
}

static dt_module_t *
dt_module_from_object(dtrace_hdl_t *dtp, const char *object)
{
	int err = EDT_NOMOD;
	dt_module_t *dmp;

	switch ((uintptr_t)object) {
	case (uintptr_t)DTRACE_OBJ_EXEC:
		dmp = dtp->dt_exec;
		break;
	case (uintptr_t)DTRACE_OBJ_RTLD:
		dmp = dtp->dt_rtld;
		break;
	case (uintptr_t)DTRACE_OBJ_CDEFS:
		dmp = dtp->dt_cdefs;
		break;
	case (uintptr_t)DTRACE_OBJ_DDEFS:
		dmp = dtp->dt_ddefs;
		break;
	default:
		dmp = dt_module_create(dtp, object);
		err = EDT_NOMEM;
	}

	if (dmp == NULL)
		(void) dt_set_errno(dtp, err);

	return (dmp);
}

/*
 * Exported interface to look up a symbol by name.  We return the GElf_Sym and
 * complete symbol information for the matching symbol.
 */
int
dtrace_lookup_by_name(dtrace_hdl_t *dtp, const char *object, const char *name,
    GElf_Sym *symp, dtrace_syminfo_t *sip)
{
	dt_module_t *dmp;
	dt_ident_t *idp;
	uint_t n, id;
	GElf_Sym sym;

	uint_t mask = 0; /* mask of dt_module flags to match */
	uint_t bits = 0; /* flag bits that must be present */

	if (object != DTRACE_OBJ_EVERY &&
	    object != DTRACE_OBJ_KMODS &&
	    object != DTRACE_OBJ_UMODS) {
		if ((dmp = dt_module_from_object(dtp, object)) == NULL)
			return (-1); /* dt_errno is set for us */

		if (dt_module_load(dtp, dmp) == -1)
			return (-1); /* dt_errno is set for us */
		n = 1;

	} else {
		if (object == DTRACE_OBJ_KMODS)
			mask = bits = DT_DM_KERNEL;
		else if (object == DTRACE_OBJ_UMODS)
			mask = DT_DM_KERNEL;

		dmp = dt_list_next(&dtp->dt_modlist);
		n = dtp->dt_nmods;
	}

	if (symp == NULL)
		symp = &sym;

	for (; n > 0; n--, dmp = dt_list_next(dmp)) {
		if ((dmp->dm_flags & mask) != bits)
			continue; /* failed to match required attributes */

		if (dt_module_load(dtp, dmp) == -1)
			continue; /* failed to load symbol table */

		if (dmp->dm_ops->do_symname(dmp, name, symp, &id) != NULL) {
			if (sip != NULL) {
				sip->dts_object = dmp->dm_name;
				sip->dts_name = (const char *)
				    dmp->dm_strtab.cts_data + symp->st_name;
				sip->dts_id = id;
			}
			return (0);
		}

		if (dmp->dm_extern != NULL &&
		    (idp = dt_idhash_lookup(dmp->dm_extern, name)) != NULL) {
			if (symp != &sym) {
				symp->st_name = (uintptr_t)idp->di_name;
				symp->st_info =
				    GELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
				symp->st_other = 0;
				symp->st_shndx = SHN_UNDEF;
				symp->st_value = 0;
				symp->st_size =
				    ctf_type_size(idp->di_ctfp, idp->di_type);
			}

			if (sip != NULL) {
				sip->dts_object = dmp->dm_name;
				sip->dts_name = idp->di_name;
				sip->dts_id = idp->di_id;
			}

			return (0);
		}
	}

	return (dt_set_errno(dtp, EDT_NOSYM));
}

/*
 * Exported interface to look up a symbol by address.  We return the GElf_Sym
 * and complete symbol information for the matching symbol.
 */
int
dtrace_lookup_by_addr(dtrace_hdl_t *dtp, GElf_Addr addr,
    GElf_Sym *symp, dtrace_syminfo_t *sip)
{
	dt_module_t *dmp;
	uint_t id;
	const dtrace_vector_t *v = dtp->dt_vector;

	if (v != NULL)
		return (v->dtv_lookup_by_addr(dtp->dt_varg, addr, symp, sip));

	for (dmp = dt_list_next(&dtp->dt_modlist); dmp != NULL;
	    dmp = dt_list_next(dmp)) {
		if (addr - dmp->dm_text_va < dmp->dm_text_size ||
		    addr - dmp->dm_data_va < dmp->dm_data_size ||
		    addr - dmp->dm_bss_va < dmp->dm_bss_size)
			break;
	}

	if (dmp == NULL)
		return (dt_set_errno(dtp, EDT_NOSYMADDR));

	if (dt_module_load(dtp, dmp) == -1)
		return (-1); /* dt_errno is set for us */

	if (symp != NULL) {
		if (dmp->dm_ops->do_symaddr(dmp, addr, symp, &id) == NULL)
			return (dt_set_errno(dtp, EDT_NOSYMADDR));
	}

	if (sip != NULL) {
		sip->dts_object = dmp->dm_name;

		if (symp != NULL) {
			sip->dts_name = (const char *)
			    dmp->dm_strtab.cts_data + symp->st_name;
			sip->dts_id = id;
		} else {
			sip->dts_name = NULL;
			sip->dts_id = 0;
		}
	}

	return (0);
}

int
dtrace_lookup_by_type(dtrace_hdl_t *dtp, const char *object, const char *name,
    dtrace_typeinfo_t *tip)
{
	dtrace_typeinfo_t ti;
	dt_module_t *dmp;
	int found = 0;
	ctf_id_t id;
	uint_t n;

	uint_t mask = 0; /* mask of dt_module flags to match */
	uint_t bits = 0; /* flag bits that must be present */

	if (object != DTRACE_OBJ_EVERY &&
	    object != DTRACE_OBJ_KMODS &&
	    object != DTRACE_OBJ_UMODS) {
		if ((dmp = dt_module_from_object(dtp, object)) == NULL)
			return (-1); /* dt_errno is set for us */

		if (dt_module_load(dtp, dmp) == -1)
			return (-1); /* dt_errno is set for us */
		n = 1;

	} else {
		if (object == DTRACE_OBJ_KMODS)
			mask = bits = DT_DM_KERNEL;
		else if (object == DTRACE_OBJ_UMODS)
			mask = DT_DM_KERNEL;

		dmp = dt_list_next(&dtp->dt_modlist);
		n = dtp->dt_nmods;
	}

	if (tip == NULL)
		tip = &ti;

	for (; n > 0; n--, dmp = dt_list_next(dmp)) {
		if ((dmp->dm_flags & mask) != bits)
			continue; /* failed to match required attributes */

		/*
		 * If we can't load the CTF container, continue on to the next
		 * module.  If our search was scoped to only one module (n = 1)
		 * then return immediately, leaving dt_errno set to the error
		 * from dt_module_getctf() on the module given by the caller.
		 */
		if (dt_module_getctf(dtp, dmp) == NULL) {
			if (n == 1)
				return (-1);
			continue;
		}

		/*
		 * Look up the type in the module's CTF container.  If our
		 * match is a forward declaration tag, save this choice in
		 * 'tip' and keep going in the hope that we will locate the
		 * underlying structure definition.  Otherwise just return.
		 */
		if ((id = ctf_lookup_by_name(dmp->dm_ctfp, name)) != CTF_ERR) {
			tip->dtt_object = dmp->dm_name;
			tip->dtt_ctfp = dmp->dm_ctfp;
			tip->dtt_type = id;

			if (ctf_type_kind(dmp->dm_ctfp, ctf_type_resolve(
			    dmp->dm_ctfp, id)) != CTF_K_FORWARD)
				return (0);

			found++;
		}
	}

	if (found == 0)
		return (dt_set_errno(dtp, EDT_NOTYPE));

	return (0);
}

int
dtrace_symbol_type(dtrace_hdl_t *dtp, const GElf_Sym *symp,
    const dtrace_syminfo_t *sip, dtrace_typeinfo_t *tip)
{
	dt_module_t *dmp;

	tip->dtt_object = NULL;
	tip->dtt_ctfp = NULL;
	tip->dtt_type = CTF_ERR;

	if ((dmp = dt_module_lookup_by_name(dtp, sip->dts_object)) == NULL)
		return (dt_set_errno(dtp, EDT_NOMOD));

	if (symp->st_shndx == SHN_UNDEF && dmp->dm_extern != NULL) {
		dt_ident_t *idp =
		    dt_idhash_lookup(dmp->dm_extern, sip->dts_name);

		if (idp == NULL)
			return (dt_set_errno(dtp, EDT_NOSYM));

		tip->dtt_ctfp = idp->di_ctfp;
		tip->dtt_type = idp->di_type;

	} else if (GELF_ST_TYPE(symp->st_info) != STT_FUNC) {
		if (dt_module_getctf(dtp, dmp) == NULL)
			return (-1); /* errno is set for us */

		tip->dtt_ctfp = dmp->dm_ctfp;
		tip->dtt_type = ctf_lookup_by_symbol(dmp->dm_ctfp, sip->dts_id);

		if (tip->dtt_type == CTF_ERR) {
			dtp->dt_ctferr = ctf_errno(tip->dtt_ctfp);
			return (dt_set_errno(dtp, EDT_CTF));
		}

	} else {
		tip->dtt_ctfp = DT_FPTR_CTFP(dtp);
		tip->dtt_type = DT_FPTR_TYPE(dtp);
	}

	tip->dtt_object = dmp->dm_name;
	return (0);
}

static dtrace_objinfo_t *
dt_module_info(const dt_module_t *dmp, dtrace_objinfo_t *dto)
{
	dto->dto_name = dmp->dm_name;
	dto->dto_file = dmp->dm_file;
	dto->dto_id = dmp->dm_modid;
	dto->dto_flags = 0;

	if (dmp->dm_flags & DT_DM_KERNEL)
		dto->dto_flags |= DTRACE_OBJ_F_KERNEL;
	if (dmp->dm_flags & DT_DM_PRIMARY)
		dto->dto_flags |= DTRACE_OBJ_F_PRIMARY;

	dto->dto_text_va = dmp->dm_text_va;
	dto->dto_text_size = dmp->dm_text_size;
	dto->dto_data_va = dmp->dm_data_va;
	dto->dto_data_size = dmp->dm_data_size;
	dto->dto_bss_va = dmp->dm_bss_va;
	dto->dto_bss_size = dmp->dm_bss_size;

	return (dto);
}

int
dtrace_object_iter(dtrace_hdl_t *dtp, dtrace_obj_f *func, void *data)
{
	const dt_module_t *dmp = dt_list_next(&dtp->dt_modlist);
	dtrace_objinfo_t dto;
	int rv;

	for (; dmp != NULL; dmp = dt_list_next(dmp)) {
		if ((rv = (*func)(dtp, dt_module_info(dmp, &dto), data)) != 0)
			return (rv);
	}

	return (0);
}

int
dtrace_object_info(dtrace_hdl_t *dtp, const char *object, dtrace_objinfo_t *dto)
{
	dt_module_t *dmp;

	if (object == DTRACE_OBJ_EVERY || object == DTRACE_OBJ_KMODS ||
	    object == DTRACE_OBJ_UMODS || dto == NULL)
		return (dt_set_errno(dtp, EINVAL));

	if ((dmp = dt_module_from_object(dtp, object)) == NULL)
		return (-1); /* dt_errno is set for us */

	if (dt_module_load(dtp, dmp) == -1)
		return (-1); /* dt_errno is set for us */

	(void) dt_module_info(dmp, dto);
	return (0);
}