mount: helper support + improvements

- helper support (mount.type).
  - helpers need to be in $PATH, if needed we can add a check for
    /sbin/mount.XXXX
  - pass -B, -M, -R to helper, its more reliable to pass these named
    options with -o however.
- allow prefix "no" for which type no action should be taken:
  mount -a -t nonfs,ext4

fix bugs:
- dont modify me->mnt_opts (used strtok).

mount.8

@@ -36,7 +36,23 @@ This is the default action.
 .It Fl o Ar options
 Specify a comma separated string of filesystem specific options.
 .It Fl t Ar fstype
-Set the filesystem type.
+Set the filesystem type. More than one type may be specified in a comma
+separated list. The list of file system types can be prefixed with "no" to
+specify the file system types for which action should not be taken. For
+example, the
+.Nm
+command:
+.Bd -literal
+# mount -a -t nonfs,ext4
+
+.Ed
+mounts all file systems except those of type NFS and EXT4.
+.Nm
+will attempt to execute a program in your
+.Ev PATH
+mount.XXX where XXX is replaced by the type name. For example, NFS file
+systems are mounted by the program
+.Pa mount.nfs .
 .El
 .Sh SEE ALSO
 .Xr mount 2 ,

mount.c

@@ -2,7 +2,9 @@
 #include <sys/mount.h>
 #include <sys/stat.h>
 #include <sys/types.h>
+#include <sys/wait.h>
 
+#include <errno.h>
 #include <limits.h>
 #include <mntent.h>
 #include <stdio.h>
@@ -34,41 +36,117 @@ struct {
 	{ NULL,         NULL,           0              }
 };
 
+static unsigned long argflags = 0;
+static char *argopts = NULL;
+
+static char *
+findtype(const char *types, const char *t)
+{
+	const char *p;
+	size_t len;
+
+	for (len = strlen(t); (p = strstr(types, t)); types = p + len) {
+		if (!strncmp(p, t, len) && (p[len] == '\0' || p[len] == ','))
+			return (char *)p;
+	}
+	return NULL;
+}
+
 static void
-parseopts(char *popts, unsigned long *flags, char *data, size_t datasiz)
+parseopts(const char *popts, unsigned long *flags, char *data, size_t datasiz)
 {
 	unsigned int i, validopt;
 	size_t optlen, dlen = 0;
-	char *name;
+	const char *name, *e;
 
+	name = popts;
 	data[0] = '\0';
-	for (name = strtok(popts, ","); name; name = strtok(NULL, ",")) {
+	do {
+		if ((e = strstr(name, ",")))
+			optlen = e - name;
+		else
+			optlen = strlen(name);
+
 		validopt = 0;
 		for (i = 0; optnames[i].opt; i++) {
-			if (optnames[i].opt && strcmp(name, optnames[i].opt) == 0) {
+			if (optnames[i].opt &&
+			    !strncmp(name, optnames[i].opt, optlen)) {
 				*flags |= optnames[i].v;
 				validopt = 1;
 				break;
 			}
-			if (optnames[i].notopt && strcmp(name, optnames[i].notopt) == 0) {
+			if (optnames[i].notopt &&
+			    !strncmp(name, optnames[i].notopt, optlen)) {
 				*flags &= ~optnames[i].v;
 				validopt = 1;
 				break;
 			}
 		}
-		if (!validopt) {
+
+		if (!validopt && optlen > 0) {
 			/* unknown option, pass as data option to mount() */
-			if ((optlen = strlen(name))) {
-				if (dlen + optlen + 2 >= datasiz)
-					return; /* prevent overflow */
-				if (dlen)
-					data[dlen++] = ',';
-				memcpy(&data[dlen], name, optlen);
-				dlen += optlen;
-				data[dlen] = '\0';
-			}
+			if (dlen + optlen + 2 >= datasiz)
+				return; /* prevent overflow */
+			if (dlen)
+				data[dlen++] = ',';
+			memcpy(&data[dlen], name, optlen);
+			dlen += optlen;
+			data[dlen] = '\0';
 		}
+		name = e + 1;
+	} while (e);
+}
+
+static int
+mounthelper(const char *fsname, const char *dir, const char *fstype)
+{
+	pid_t pid;
+	char eprog[PATH_MAX];
+	char const *eargv[10];
+	int status, i;
+
+	pid = fork();
+	switch(pid) {
+	case -1:
+		break;
+	case 0:
+		snprintf(eprog, sizeof(eprog), "mount.%s", fstype);
+
+		i = 0;
+		eargv[i++] = eprog;
+		if (argflags & MS_BIND)
+			eargv[i++] = "-B";
+		if (argflags & MS_MOVE)
+			eargv[i++] = "-M";
+		if (argflags & MS_REC)
+			eargv[i++] = "-R";
+
+		if (argopts) {
+			eargv[i++] = "-o";
+			eargv[i++] = argopts;
+		}
+		eargv[i++] = fsname;
+		eargv[i++] = dir;
+		eargv[i] = NULL;
+
+		execvp(eprog, (char * const *)eargv);
+		if (errno == ENOENT)
+			_exit(1);
+		weprintf("execvp:");
+		_exit(1);
+		break;
+	default:
+		if (waitpid(pid, &status, 0) < 0) {
+			weprintf("waitpid:");
+			return -1;
+		}
+		if (WIFEXITED(status))
+			return WEXITSTATUS(status);
+		else if (WIFSIGNALED(status))
+			return 1;
+		break;
 	}
+	return 0;
 }
 
 static int
@@ -96,6 +174,7 @@ mounted(const char *dir)
 			return 1;
 	}
 	endmntent(fp);
+
 	return 0;
 }
 
@@ -103,37 +182,37 @@ static void
 usage(void)
 {
 	eprintf("usage: %s [-BMRan] [-t fstype] [-o options] [source] [target]\n",
-		argv0);
+	        argv0);
 }
 
 int
 main(int argc, char *argv[])
 {
-	int aflag = 0, oflag = 0, status = 0, i;
-	unsigned long flags = 0;
 	char *types = NULL, data[512] = "", *resolvpath = NULL;
 	char *files[] = { "/proc/mounts", "/etc/fstab", NULL };
-	size_t datasiz = sizeof(data);
 	const char *source, *target;
 	struct mntent *me = NULL;
+	int aflag = 0, oflag = 0, status = 0, i, r;
+	unsigned long flags = 0;
 	FILE *fp;
 
 	ARGBEGIN {
 	case 'B':
-		flags |= MS_BIND;
+		argflags |= MS_BIND;
 		break;
 	case 'M':
-		flags |= MS_MOVE;
+		argflags |= MS_MOVE;
 		break;
 	case 'R':
-		flags |= MS_REC;
+		argflags |= MS_REC;
 		break;
 	case 'a':
 		aflag = 1;
 		break;
 	case 'o':
 		oflag = 1;
-		parseopts(EARGF(usage()), &flags, data, datasiz);
+		argopts = EARGF(usage());
+		parseopts(argopts, &flags, data, sizeof(data));
 		break;
 	case 't':
 		types = EARGF(usage());
@@ -182,7 +261,7 @@ main(int argc, char *argv[])
 					source = me->mnt_fsname;
 				}
 				if (!oflag)
-					parseopts(me->mnt_opts, &flags, data, datasiz);
+					parseopts(me->mnt_opts, &flags, data, sizeof(data));
 				if (!types)
 					types = me->mnt_type;
 				goto mountsingle;
@@ -195,7 +274,10 @@ main(int argc, char *argv[])
 		eprintf("can't find %s in /etc/fstab\n", target);
 
 mountsingle:
-	if (mount(source, target, types, flags, data) < 0) {
+	r = mounthelper(source, target, types);
+	if (r == -1)
+		status = 1;
+	if (r > 0 && mount(source, target, types, argflags | flags, data) < 0) {
 		weprintf("mount: %s:", source);
 		status = 1;
 	}
@@ -208,14 +290,23 @@ mountall:
 	if (!(fp = setmntent("/etc/fstab", "r")))
 		eprintf("setmntent %s:", "/etc/fstab");
 	while ((me = getmntent(fp))) {
-		if (hasmntopt(me, MNTOPT_NOAUTO))
-			continue;
-		/* already mounted, skip */
-		if (mounted(me->mnt_dir))
+		/* has "noauto" option or already mounted: skip */
+		if (hasmntopt(me, MNTOPT_NOAUTO) || mounted(me->mnt_dir))
 			continue;
 		flags = 0;
-		parseopts(me->mnt_opts, &flags, data, datasiz);
-		if (mount(me->mnt_fsname, me->mnt_dir, me->mnt_type, flags, data) < 0) {
+		parseopts(me->mnt_opts, &flags, data, sizeof(data));
+		/* if -t types specified:
+		 * if non-match, skip
+		 * if match and prefixed with "no", skip */
+		if (types &&
+		    ((types[0] == 'n' && types[1] == 'o' &&
+		     findtype(types + 2, me->mnt_type)) ||
+		     (!findtype(types, me->mnt_type))))
+			continue;
+
+		r = mounthelper(me->mnt_fsname, me->mnt_dir, me->mnt_type);
+		if (r > 0 && mount(me->mnt_fsname, me->mnt_dir, me->mnt_type,
+		                   argflags | flags, data) < 0) {
 			weprintf("mount: %s:", me->mnt_fsname);
 			status = 1;
 		}