Perform some checking on the requested list of modules to warn people if they

try to load modules by filename out of the current directory where the module
in question may be further up the module path or not in the module path at all.

Also add some text to the man page to help explain what's going on.

Sponsored by:	Redacted Consulting

sbin/kldload/kldload.8

@@ -50,10 +50,22 @@ using
 .Nm .
 It does not hurt to specify it though.
 .Pp
+If a bare filename is requested it will only be loaded if it is found within
+the module path as defined by the sysctl
+.Va kern.module_path .
+To load a module from the current directory it must be specified as a full or
+relative path.
+The
+.Nm
+utility will warn if a module is requested as a bare filename and is present
+in the current directory.
+.Pp
 The following option is available:
 .Bl -tag -width indent
 .It Fl v
 Be more verbose.
+.It Fl q
+Silence any extraneous warnings.
 .El
 .Sh FILES
 .Bl -tag -width /boot/kernel -compact
@@ -64,6 +76,26 @@ Modules must have an extension of
 .El
 .Sh EXIT STATUS
 .Ex -std
+.Sh EXAMPLES
+To load by module name:
+.Bd -literal -offset indent
+\*[Gt] kldload foo
+.Ed
+.Pp
+To load by file name within the module path:
+.Bd -literal -offset indent
+\*[Gt] kldload foo.ko
+.Ed
+.Pp
+To load by relative path:
+.Bd -literal -offset indent
+\*[Gt] kldload ./foo.ko
+.Ed
+.Pp
+To load by full path:
+.Bd -literal -offset indent
+\*[Gt] kldload /boot/kernel/foo.ko
+.Ed
 .Sh AUTOMATICALLY LOADING MODULES
 Some modules (pf, ipfw, ipf, etc.) may be automatically loaded at boot
 time when the corresponding

sbin/kldload/kldload.c

@@ -27,15 +27,105 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
+#include <sys/types.h>
 #include <sys/param.h>
 #include <sys/linker.h>
+#include <sys/sysctl.h>
+#include <sys/stat.h>
 #include <err.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <unistd.h>
 
+#define	PATHCTL	"kern.module_path"
+
+static int	path_check(const char *, int);
 static void	usage(void);
 
+/*
+ * Check to see if the requested module is specified as a filename with no
+ * path.  If so and if a file by the same name exists in the module path,
+ * warn the user that the module in the path will be used in preference.
+ */
+static int
+path_check(const char *kldname, int quiet)
+{
+	int	mib[5], found;
+	size_t	miblen, pathlen;
+	char	kldpath[MAXPATHLEN];
+	char	*path, *tmppath, *element;
+	struct	stat sb;
+	dev_t	dev;
+	ino_t	ino;
+
+	if (strchr(kldname, '/') != NULL) {
+		return (0);
+	}
+	if (strstr(kldname, ".ko") == NULL) {
+		return (0);
+	}
+	if (stat(kldname, &sb) != 0) {
+		return (0);
+	}
+
+	found = 0;
+	dev = sb.st_dev;
+	ino = sb.st_ino;
+
+	miblen = sizeof(mib) / sizeof(mib[0]);
+	if (sysctlnametomib(PATHCTL, mib, &miblen) != 0) {
+		err(1, "sysctlnametomib(%s)", PATHCTL);
+	}
+	if (sysctl(mib, miblen, NULL, &pathlen, NULL, 0) == -1) {
+		err(1, "getting path: sysctl(%s) - size only", PATHCTL);
+	}
+	path = malloc(pathlen + 1);
+	if (path == NULL) {
+		err(1, "allocating %lu bytes for the path",
+		    (unsigned long)pathlen + 1);
+	}
+	if (sysctl(mib, miblen, path, &pathlen, NULL, 0) == -1) {
+		err(1, "getting path: sysctl(%s)", PATHCTL);
+	}
+	tmppath = path;
+
+	while ((element = strsep(&tmppath, ";")) != NULL) {
+		strlcpy(kldpath, element, MAXPATHLEN);
+		if (kldpath[strlen(kldpath) - 1] != '/') {
+			strlcat(kldpath, "/", MAXPATHLEN);
+		}
+		strlcat(kldpath, kldname, MAXPATHLEN);
+				
+		if (stat(kldpath, &sb) == -1) {
+			continue;
+		}	
+
+		found = 1;
+
+		if (sb.st_dev != dev || sb.st_ino != ino) {
+			if (!quiet) {
+				warnx("%s will be loaded from %s, not the "
+				    "current directory", kldname, element);
+			}
+			break;
+		} else if (sb.st_dev == dev && sb.st_ino == ino) {
+			break;
+		}
+	}
+
+	free(path);
+	
+	if (!found) {
+		if (!quiet) {
+			warnx("%s is not in the module path", kldname);
+		}
+		return (-1);
+	}
+	
+	return (0);
+}
+
 static void
 usage(void)
 {
@@ -50,14 +140,21 @@ main(int argc, char** argv)
 	int errors;
 	int fileid;
 	int verbose;
+	int quiet;
 
 	errors = 0;
 	verbose = 0;
-
-	while ((c = getopt(argc, argv, "v")) != -1) {
+	quiet = 0;
+    
+	while ((c = getopt(argc, argv, "qv")) != -1) {
 		switch (c) {
+		case 'q':
+			quiet = 1;
+			verbose = 0;
+			break;
 		case 'v':
 			verbose = 1;
+			quiet = 0;
 			break;
 		default:
 			usage();
@@ -70,14 +167,18 @@ main(int argc, char** argv)
 		usage();
 
 	while (argc-- != 0) {
-		fileid = kldload(argv[0]);
-		if (fileid < 0) {
-			warn("can't load %s", argv[0]);
-			errors++;
-		} else {
-			if (verbose) {
-				printf("Loaded %s, id=%d\n", argv[0], fileid);
+		if (path_check(argv[0], quiet) == 0) {
+			fileid = kldload(argv[0]);
+			if (fileid < 0) {
+				warn("can't load %s", argv[0]);
+				errors++;
+			} else {
+				if (verbose)
+					printf("Loaded %s, id=%d\n", argv[0],
+					    fileid);
 			}
+		} else {
+			errors++;
 		}
 		argv++;
 	}