tls: in AES-GCM decoding, avoid memmove

[oweals/busybox.git] / util-linux / umount.c

diff --git a/util-linux/umount.c b/util-linux/umount.c
index 5b716c688f83e5957963eda98bae7490820819d6..e2329f8b34c42a383e3ba58b97f17c099c216d7d 100644 (file)
--- a/util-linux/umount.c
+++ b/util-linux/umount.c
@@ -7,6 +7,39 @@
  *
  * Licensed under GPLv2, see file LICENSE in this source tree.
  */
+//config:config UMOUNT
+//config:      bool "umount (4.5 kb)"
+//config:      default y
+//config:      select PLATFORM_LINUX
+//config:      help
+//config:      When you want to remove a mounted filesystem from its current mount
+//config:      point, for example when you are shutting down the system, the
+//config:      'umount' utility is the tool to use. If you enabled the 'mount'
+//config:      utility, you almost certainly also want to enable 'umount'.
+//config:
+//config:config FEATURE_UMOUNT_ALL
+//config:      bool "Support -a (unmount all)"
+//config:      default y
+//config:      depends on UMOUNT
+//config:      help
+//config:      Support -a option to unmount all currently mounted filesystems.
+
+//applet:IF_UMOUNT(APPLET_NOEXEC(umount, umount, BB_DIR_BIN, BB_SUID_DROP, umount))
+/*
+ * On one hand, in some weird situations you'd want umount
+ * to not do anything surprising, to behave as a usual fork+execed executable.
+ *
+ * OTOH, there can be situations where execing would not succeed, or even hang
+ * (say, if executable is on a filesystem which is in trouble and accesses to it
+ * block in kernel).
+ * In this case, you might be actually happy if your standalone bbox shell
+ * does not fork+exec, but only forks and calls umount_main() which it already has!
+ * Let's go with NOEXEC.
+ *
+ * bb_common_bufsiz1 usage here is safe wrt NOEXEC: not expecting it to be zeroed.
+ */
+
+//kbuild:lib-$(CONFIG_UMOUNT) += umount.o
 
 //usage:#define umount_trivial_usage
 //usage:       "[OPTIONS] FILESYSTEM|DIRECTORY"
@@ -24,13 +57,18 @@
 //usage:       IF_FEATURE_MOUNT_LOOP(
 //usage:     "\n       -d      Free loop device if it has been used"
 //usage:       )
+//usage:     "\n       -t FSTYPE[,...] Unmount only these filesystem type(s)"
 //usage:
 //usage:#define umount_example_usage
 //usage:       "$ umount /dev/hdc1\n"
 
 #include <mntent.h>
 #include <sys/mount.h>
+#ifndef MNT_DETACH
+# define MNT_DETACH 0x00000002
+#endif
 #include "libbb.h"
+#include "common_bufsiz.h"
 
 #if defined(__dietlibc__)
 // TODO: This does not belong here.
@@ -44,8 +82,8 @@ static struct mntent *getmntent_r(FILE* stream, struct mntent* result,
 }
 #endif
 
-/* ignored: -v -d -t -i */
-#define OPTION_STRING           "fldnra" "vdt:i"
+/* ignored: -c -v -i */
+#define OPTION_STRING           "fldnrat:" "cvi"
 #define OPT_FORCE               (1 << 0) // Same as MNT_FORCE
 #define OPT_LAZY                (1 << 1) // Same as MNT_DETACH
 #define OPT_FREELOOP            (1 << 2)
@@ -73,8 +111,9 @@ int umount_main(int argc UNUSED_PARAM, char **argv)
        argv += optind;
 
        // MNT_FORCE and MNT_DETACH (from linux/fs.h) must match
-       // OPT_FORCE and OPT_LAZY, otherwise this trick won't work:
-       doForce = MAX((opt & OPT_FORCE), (opt & OPT_LAZY));
+       // OPT_FORCE and OPT_LAZY.
+       BUILD_BUG_ON(OPT_FORCE != MNT_FORCE || OPT_LAZY != MNT_DETACH);
+       doForce = opt & (OPT_FORCE|OPT_LAZY);
 
        /* Get a list of mount points from mtab.  We read them all in now mostly
         * for umount -a (so we don't have to worry about the list changing while
@@ -90,9 +129,10 @@ int umount_main(int argc UNUSED_PARAM, char **argv)
                if (opt & OPT_ALL)
                        bb_error_msg_and_die("can't open '%s'", bb_path_mtab_file);
        } else {
-               while (getmntent_r(fp, &me, bb_common_bufsiz1, sizeof(bb_common_bufsiz1))) {
-                       /* Match fstype if passed */
-                       if (!match_fstype(&me, fstype))
+               setup_common_bufsiz();
+               while (getmntent_r(fp, &me, bb_common_bufsiz1, COMMON_BUFSIZE)) {
+                       /* Match fstype (fstype==NULL matches always) */
+                       if (!fstype_matches(me.mnt_type, fstype))
                                continue;
                        m = xzalloc(sizeof(*m));
                        m->next = mtl;
@@ -104,7 +144,8 @@ int umount_main(int argc UNUSED_PARAM, char **argv)
        }
 
        // If we're not umounting all, we need at least one argument.
-       if (!(opt & OPT_ALL) && !fstype) {
+       // Note: "-t FSTYPE" does not imply -a.
+       if (!(opt & OPT_ALL)) {
                if (!argv[0])
                        bb_show_usage();
                m = NULL;
@@ -139,11 +180,18 @@ int umount_main(int argc UNUSED_PARAM, char **argv)
                // umount the directory even if we were given the block device.
                if (m) zapit = m->dir;
 
+// umount from util-linux 2.22.2 does not do this:
+// umount -f uses umount2(MNT_FORCE) immediately,
+// not trying umount() first.
+// (Strangely, umount -fl ignores -f: it is equivalent to umount -l.
+// We do pass both flags in this case)
+#if 0
                // Let's ask the thing nicely to unmount.
                curstat = umount(zapit);
 
-               // Force the unmount, if necessary.
+               // Unmount with force and/or lazy flags, if necessary.
                if (curstat && doForce)
+#endif
                        curstat = umount2(zapit, doForce);
 
                // If still can't umount, maybe remount read-only?
@@ -160,7 +208,7 @@ int umount_main(int argc UNUSED_PARAM, char **argv)
                                bb_error_msg(msg, m->device);
                        } else {
                                status = EXIT_FAILURE;
-                               bb_perror_msg("can't %sumount %s", (doForce ? "forcibly " : ""), zapit);
+                               bb_perror_msg("can't unmount %s", zapit);
                        }
                } else {
                        // De-allocate the loop device.  This ioctl should be ignored on