Add the full module path name to the kld_file_stat structure

for kldstat(2).

This allows libdtrace to determine the exact file from which
a kernel module was loaded without having to guess.

The kldstat(2) API is versioned with the size of the
kld_file_stat structure, so this change creates version 2.

Add the pathname to the verbose output of kldstat(8) too.

MFC: 3 days

1 files changed, 38 insertions, 7 deletions

diff --git a/sys/kern/kern_linker.c b/sys/kern/kern_linker.c
index 7640334..324d349 100644
--- a/sys/kern/kern_linker.c
+++ b/sys/kern/kern_linker.c
@@ -97,6 +97,12 @@ linker_file_t linker_kernel_file;
 
 static struct sx kld_sx;	/* kernel linker lock */
 
+/*
+ * Load counter used by clients to determine if a linker file has been
+ * re-loaded. This counter is incremented for each file load.
+ */
+static int loadcnt;
+
 static linker_class_list_t classes;
 static linker_file_list_t linker_files;
 static int next_file_id = 1;
@@ -534,7 +540,7 @@ linker_make_file(const char *pathname, linker_class_t lc)
 	KLD_LOCK_ASSERT();
 	filename = linker_basename(pathname);
 
-	KLD_DPF(FILE, ("linker_make_file: new file, filename=%s\n", filename));
+	KLD_DPF(FILE, ("linker_make_file: new file, filename='%s' for pathname='%s'\n", filename, pathname));
 	lf = (linker_file_t)kobj_create((kobj_class_t)lc, M_LINKER, M_WAITOK);
 	if (lf == NULL)
 		return (NULL);
@@ -542,9 +548,13 @@ linker_make_file(const char *pathname, linker_class_t lc)
 	lf->userrefs = 0;
 	lf->flags = 0;
 	lf->filename = linker_strdup(filename);
+	lf->pathname = linker_strdup(pathname);
 	LINKER_GET_NEXT_FILE_ID(lf->id);
 	lf->ndeps = 0;
 	lf->deps = NULL;
+	lf->loadcnt = ++loadcnt;
+	lf->sdt_probes = NULL;
+	lf->sdt_nprobes = 0;
 	STAILQ_INIT(&lf->common);
 	TAILQ_INIT(&lf->modules);
 	TAILQ_INSERT_TAIL(&linker_files, lf, link);
@@ -629,6 +639,10 @@ linker_file_unload(linker_file_t file, int flags)
 		free(file->filename, M_LINKER);
 		file->filename = NULL;
 	}
+	if (file->pathname) {
+		free(file->pathname, M_LINKER);
+		file->pathname = NULL;
+	}
 	kobj_delete((kobj_t) file, M_LINKER);
 	return (0);
 }
@@ -920,7 +934,13 @@ kern_kldunload(struct thread *td, int fileid, int flags)
 	lf = linker_find_file_by_id(fileid);
 	if (lf) {
 		KLD_DPF(FILE, ("kldunload: lf->userrefs=%d\n", lf->userrefs));
-		if (lf->userrefs == 0) {
+
+		/* Check if there are DTrace probes enabled on this file. */
+		if (lf->nenabled > 0) {
+			printf("kldunload: attempt to unload file that has"
+			    " DTrace probes enabled\n");
+			error = EBUSY;
+		} else if (lf->userrefs == 0) {
 			/*
 			 * XXX: maybe LINKER_UNLOAD_FORCE should override ?
 			 */
@@ -1041,15 +1061,18 @@ kldstat(struct thread *td, struct kldstat_args *uap)
 {
 	struct kld_file_stat stat;
 	linker_file_t lf;
-	int error, namelen;
+	int error, namelen, version, version_num;
 
 	/*
 	 * Check the version of the user's structure.
 	 */
-	error = copyin(uap->stat, &stat, sizeof(struct kld_file_stat));
-	if (error)
+	if ((error = copyin(&uap->stat->version, &version, sizeof(version))) != 0)
 		return (error);
-	if (stat.version != sizeof(struct kld_file_stat))
+	if (version == sizeof(struct kld_file_stat_1))
+		version_num = 1;
+	else if (version == sizeof(struct kld_file_stat))
+		version_num = 2;
+	else
 		return (EINVAL);
 
 #ifdef MAC
@@ -1065,6 +1088,7 @@ kldstat(struct thread *td, struct kldstat_args *uap)
 		return (ENOENT);
 	}
 
+	/* Version 1 fields: */
 	namelen = strlen(lf->filename) + 1;
 	if (namelen > MAXPATHLEN)
 		namelen = MAXPATHLEN;
@@ -1073,11 +1097,18 @@ kldstat(struct thread *td, struct kldstat_args *uap)
 	stat.id = lf->id;
 	stat.address = lf->address;
 	stat.size = lf->size;
+	if (version_num > 1) {
+		/* Version 2 fields: */
+		namelen = strlen(lf->pathname) + 1;
+		if (namelen > MAXPATHLEN)
+			namelen = MAXPATHLEN;
+		bcopy(lf->pathname, &stat.pathname[0], namelen);
+	}
 	KLD_UNLOCK();
 
 	td->td_retval[0] = 0;
 
-	return (copyout(&stat, uap->stat, sizeof(struct kld_file_stat)));
+	return (copyout(&stat, uap->stat, version));
 }
 
 int