Date: Mon, 31 May 2010 19:54:24 +0300 From: Andriy Gapon <avg@icyb.net.ua> To: freebsd-fs@FreeBSD.org Subject: nullfs distinct path check: take into account filesystems Message-ID: <4C03E9C0.2010602@icyb.net.ua>
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Right now mount_nullfs doesn't allow to, for example, mount / in /tmp/somedir even if /tmp is a different filesystem. I think there is no reason to do that and thus propose the following patch. diff --git a/sbin/mount_nullfs/mount_nullfs.c b/sbin/mount_nullfs/mount_nullfs.c index abca9fa..4bd426f 100644 --- a/sbin/mount_nullfs/mount_nullfs.c +++ b/sbin/mount_nullfs/mount_nullfs.c @@ -46,6 +46,7 @@ static const char rcsid[] = #include <sys/param.h> #include <sys/mount.h> +#include <sys/stat.h> #include <sys/uio.h> #include <err.h> @@ -62,7 +63,8 @@ struct mntopt mopts[] = { MOPT_END }; -int subdir(const char *, const char *); +static int samefs(const char *p1, const char *p2); +static int subdir(const char *, const char *); static void usage(void) __dead2; int @@ -93,7 +95,8 @@ main(int argc, char *argv[]) (void)checkpath(argv[0], target); (void)checkpath(argv[1], source); - if (subdir(target, source) || subdir(source, target)) + if (samefs(target, source) + && (subdir(target, source) || subdir(source, target))) errx(EX_USAGE, "%s (%s) and %s are not distinct paths", argv[0], target, argv[1]); @@ -116,6 +119,21 @@ main(int argc, char *argv[]) } int +samefs(const char *p1, const char *p2) +{ + struct stat sb; + uint32_t fsid1; + uint32_t fsid2; + + stat(p1, &sb); + fsid1 = sb.st_dev; + stat(p2, &sb); + fsid2 = sb.st_dev; + + return (fsid1 == fsid2); +} + +int subdir(const char *p, const char *dir) { int l; -- Andriy Gapon
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