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mount: use the mount syscall directly #10294

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May 21, 2020
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236 changes: 2 additions & 234 deletions cmd/mount_zfs/mount_zfs.c
Original file line number Diff line number Diff line change
Expand Up @@ -42,185 +42,6 @@

libzfs_handle_t *g_zfs;

typedef struct option_map {
const char *name;
unsigned long mntmask;
unsigned long zfsmask;
} option_map_t;

static const option_map_t option_map[] = {
/* Canonicalized filesystem independent options from mount(8) */
{ MNTOPT_NOAUTO, MS_COMMENT, ZS_COMMENT },
{ MNTOPT_DEFAULTS, MS_COMMENT, ZS_COMMENT },
{ MNTOPT_NODEVICES, MS_NODEV, ZS_COMMENT },
{ MNTOPT_DIRSYNC, MS_DIRSYNC, ZS_COMMENT },
{ MNTOPT_NOEXEC, MS_NOEXEC, ZS_COMMENT },
{ MNTOPT_GROUP, MS_GROUP, ZS_COMMENT },
{ MNTOPT_NETDEV, MS_COMMENT, ZS_COMMENT },
{ MNTOPT_NOFAIL, MS_COMMENT, ZS_COMMENT },
{ MNTOPT_NOSUID, MS_NOSUID, ZS_COMMENT },
{ MNTOPT_OWNER, MS_OWNER, ZS_COMMENT },
{ MNTOPT_REMOUNT, MS_REMOUNT, ZS_COMMENT },
{ MNTOPT_RO, MS_RDONLY, ZS_COMMENT },
{ MNTOPT_RW, MS_COMMENT, ZS_COMMENT },
{ MNTOPT_SYNC, MS_SYNCHRONOUS, ZS_COMMENT },
{ MNTOPT_USER, MS_USERS, ZS_COMMENT },
{ MNTOPT_USERS, MS_USERS, ZS_COMMENT },
/* acl flags passed with util-linux-2.24 mount command */
{ MNTOPT_ACL, MS_POSIXACL, ZS_COMMENT },
{ MNTOPT_NOACL, MS_COMMENT, ZS_COMMENT },
{ MNTOPT_POSIXACL, MS_POSIXACL, ZS_COMMENT },
#ifdef MS_NOATIME
{ MNTOPT_NOATIME, MS_NOATIME, ZS_COMMENT },
#endif
#ifdef MS_NODIRATIME
{ MNTOPT_NODIRATIME, MS_NODIRATIME, ZS_COMMENT },
#endif
#ifdef MS_RELATIME
{ MNTOPT_RELATIME, MS_RELATIME, ZS_COMMENT },
#endif
#ifdef MS_STRICTATIME
{ MNTOPT_STRICTATIME, MS_STRICTATIME, ZS_COMMENT },
#endif
#ifdef MS_LAZYTIME
{ MNTOPT_LAZYTIME, MS_LAZYTIME, ZS_COMMENT },
#endif
{ MNTOPT_CONTEXT, MS_COMMENT, ZS_COMMENT },
{ MNTOPT_FSCONTEXT, MS_COMMENT, ZS_COMMENT },
{ MNTOPT_DEFCONTEXT, MS_COMMENT, ZS_COMMENT },
{ MNTOPT_ROOTCONTEXT, MS_COMMENT, ZS_COMMENT },
#ifdef MS_I_VERSION
{ MNTOPT_IVERSION, MS_I_VERSION, ZS_COMMENT },
#endif
#ifdef MS_MANDLOCK
{ MNTOPT_NBMAND, MS_MANDLOCK, ZS_COMMENT },
#endif
/* Valid options not found in mount(8) */
{ MNTOPT_BIND, MS_BIND, ZS_COMMENT },
#ifdef MS_REC
{ MNTOPT_RBIND, MS_BIND|MS_REC, ZS_COMMENT },
#endif
{ MNTOPT_COMMENT, MS_COMMENT, ZS_COMMENT },
#ifdef MS_NOSUB
{ MNTOPT_NOSUB, MS_NOSUB, ZS_COMMENT },
#endif
#ifdef MS_SILENT
{ MNTOPT_QUIET, MS_SILENT, ZS_COMMENT },
#endif
/* Custom zfs options */
{ MNTOPT_XATTR, MS_COMMENT, ZS_COMMENT },
{ MNTOPT_NOXATTR, MS_COMMENT, ZS_COMMENT },
{ MNTOPT_ZFSUTIL, MS_COMMENT, ZS_ZFSUTIL },
{ NULL, 0, 0 } };

/*
* Break the mount option in to a name/value pair. The name is
* validated against the option map and mount flags set accordingly.
*/
static int
parse_option(char *mntopt, unsigned long *mntflags,
unsigned long *zfsflags, int sloppy)
{
const option_map_t *opt;
char *ptr, *name, *value = NULL;
int error = 0;

name = strdup(mntopt);
if (name == NULL)
return (ENOMEM);

for (ptr = name; ptr && *ptr; ptr++) {
if (*ptr == '=') {
*ptr = '\0';
value = ptr+1;
VERIFY3P(value, !=, NULL);
break;
}
}

for (opt = option_map; opt->name != NULL; opt++) {
if (strncmp(name, opt->name, strlen(name)) == 0) {
*mntflags |= opt->mntmask;
*zfsflags |= opt->zfsmask;
error = 0;
goto out;
}
}

if (!sloppy)
error = ENOENT;
out:
/* If required further process on the value may be done here */
free(name);
return (error);
}

/*
* Translate the mount option string in to MS_* mount flags for the
* kernel vfs. When sloppy is non-zero unknown options will be ignored
* otherwise they are considered fatal are copied in to badopt.
*/
static int
parse_options(char *mntopts, unsigned long *mntflags, unsigned long *zfsflags,
int sloppy, char *badopt, char *mtabopt)
{
int error = 0, quote = 0, flag = 0, count = 0;
char *ptr, *opt, *opts;

opts = strdup(mntopts);
if (opts == NULL)
return (ENOMEM);

*mntflags = 0;
opt = NULL;

/*
* Scan through all mount options which must be comma delimited.
* We must be careful to notice regions which are double quoted
* and skip commas in these regions. Each option is then checked
* to determine if it is a known option.
*/
for (ptr = opts; ptr && !flag; ptr++) {
if (opt == NULL)
opt = ptr;

if (*ptr == '"')
quote = !quote;

if (quote)
continue;

if (*ptr == '\0')
flag = 1;

if ((*ptr == ',') || (*ptr == '\0')) {
*ptr = '\0';

error = parse_option(opt, mntflags, zfsflags, sloppy);
if (error) {
strcpy(badopt, opt);
goto out;

}

if (!(*mntflags & MS_REMOUNT) &&
!(*zfsflags & ZS_ZFSUTIL)) {
if (count > 0)
strlcat(mtabopt, ",", MNT_LINE_MAX);

strlcat(mtabopt, opt, MNT_LINE_MAX);
count++;
}

opt = NULL;
}
}

out:
free(opts);
return (error);
}

/*
* Return the pool/dataset to mount given the name passed to mount. This
* is expected to be of the form pool/dataset, however may also refer to
Expand Down Expand Up @@ -345,34 +166,6 @@ mtab_update(char *dataset, char *mntpoint, char *type, char *mntopts)
return (MOUNT_SUCCESS);
}

static void
append_mntopt(const char *name, const char *val, char *mntopts,
char *mtabopt, boolean_t quote)
{
char tmp[MNT_LINE_MAX];

snprintf(tmp, MNT_LINE_MAX, quote ? ",%s=\"%s\"" : ",%s=%s", name, val);

if (mntopts)
strlcat(mntopts, tmp, MNT_LINE_MAX);

if (mtabopt)
strlcat(mtabopt, tmp, MNT_LINE_MAX);
}

static void
zfs_selinux_setcontext(zfs_handle_t *zhp, zfs_prop_t zpt, const char *name,
char *mntopts, char *mtabopt)
{
char context[ZFS_MAXPROPLEN];

if (zfs_prop_get(zhp, zpt, context, sizeof (context),
NULL, NULL, 0, B_FALSE) == 0) {
if (strcmp(context, "none") != 0)
append_mntopt(name, context, mntopts, mtabopt, B_TRUE);
}
}

int
main(int argc, char **argv)
{
Expand Down Expand Up @@ -449,7 +242,7 @@ main(int argc, char **argv)
}

/* validate mount options and set mntflags */
error = parse_options(mntopts, &mntflags, &zfsflags, sloppy,
error = zfs_parse_mount_options(mntopts, &mntflags, &zfsflags, sloppy,
badopt, mtabopt);
if (error) {
switch (error) {
Expand Down Expand Up @@ -502,32 +295,7 @@ main(int argc, char **argv)
return (MOUNT_USAGE);
}

/*
* Checks to see if the ZFS_PROP_SELINUX_CONTEXT exists
* if it does, create a tmp variable in case it's needed
* checks to see if the selinux context is set to the default
* if it is, allow the setting of the other context properties
* this is needed because the 'context' property overrides others
* if it is not the default, set the 'context' property
*/
if (zfs_prop_get(zhp, ZFS_PROP_SELINUX_CONTEXT, prop, sizeof (prop),
NULL, NULL, 0, B_FALSE) == 0) {
if (strcmp(prop, "none") == 0) {
zfs_selinux_setcontext(zhp, ZFS_PROP_SELINUX_FSCONTEXT,
MNTOPT_FSCONTEXT, mntopts, mtabopt);
zfs_selinux_setcontext(zhp, ZFS_PROP_SELINUX_DEFCONTEXT,
MNTOPT_DEFCONTEXT, mntopts, mtabopt);
zfs_selinux_setcontext(zhp,
ZFS_PROP_SELINUX_ROOTCONTEXT, MNTOPT_ROOTCONTEXT,
mntopts, mtabopt);
} else {
append_mntopt(MNTOPT_CONTEXT, prop,
mntopts, mtabopt, B_TRUE);
}
}

/* A hint used to determine an auto-mounted snapshot mount point */
append_mntopt(MNTOPT_MNTPOINT, mntpoint, mntopts, NULL, B_FALSE);
zfs_adjust_mount_options(zhp, mntpoint, mntopts, mtabopt);

/* treat all snapshots as legacy mount points */
if (zfs_get_type(zhp) == ZFS_TYPE_SNAPSHOT)
Expand Down
3 changes: 0 additions & 3 deletions cmd/zfs/zfs_main.c
Original file line number Diff line number Diff line change
Expand Up @@ -7319,9 +7319,6 @@ unshare_unmount(int op, int argc, char **argv)
const char *mntarg = NULL;

uu_avl_remove(tree, node);
#ifndef __FreeBSD__
mntarg = node->un_zhp->zfs_name;
#endif
switch (op) {
case OP_SHARE:
if (zfs_unshareall_bytype(node->un_zhp,
Expand Down
7 changes: 7 additions & 0 deletions include/libzfs.h
Original file line number Diff line number Diff line change
Expand Up @@ -801,6 +801,13 @@ extern int zfs_mount_at(zfs_handle_t *, const char *, int, const char *);
extern int zfs_unmount(zfs_handle_t *, const char *, int);
extern int zfs_unmountall(zfs_handle_t *, int);

#if defined(__linux__)
extern int zfs_parse_mount_options(char *mntopts, unsigned long *mntflags,
unsigned long *zfsflags, int sloppy, char *badopt, char *mtabopt);
extern void zfs_adjust_mount_options(zfs_handle_t *zhp, const char *mntpoint,
char *mntopts, char *mtabopt);
#endif

/*
* Share support functions.
*/
Expand Down
3 changes: 2 additions & 1 deletion include/libzfs_impl.h
Original file line number Diff line number Diff line change
Expand Up @@ -246,7 +246,8 @@ typedef struct differ_info {

extern proto_table_t proto_table[PROTO_END];

extern int do_mount(const char *src, const char *mntpt, char *opts, int flags);
extern int do_mount(zfs_handle_t *zhp, const char *mntpt, char *opts,
int flags);
extern int do_unmount(const char *mntpt, int flags);
extern int zfs_mount_delegation_check(void);
extern int zfs_share_proto(zfs_handle_t *zhp, zfs_share_proto_t *proto);
Expand Down
2 changes: 1 addition & 1 deletion lib/libzfs/libzfs_mount.c
Original file line number Diff line number Diff line change
Expand Up @@ -500,7 +500,7 @@ zfs_mount_at(zfs_handle_t *zhp, const char *options, int flags,
}

/* perform the mount */
rc = do_mount(zfs_get_name(zhp), mountpoint, mntopts, flags);
rc = do_mount(zhp, mountpoint, mntopts, flags);
if (rc) {
/*
* Generic errors are nasty, but there are just way too many
Expand Down
7 changes: 4 additions & 3 deletions lib/libzfs/os/freebsd/libzfs_zmount.c
Original file line number Diff line number Diff line change
Expand Up @@ -41,6 +41,7 @@ __FBSDID("$FreeBSD$");
#include <string.h>
#include <sys/mnttab.h>
#include <sys/errno.h>
#include <libzfs.h>

static void
build_iovec(struct iovec **iov, int *iovlen, const char *name, void *val,
Expand Down Expand Up @@ -115,11 +116,11 @@ do_mount_(const char *spec, const char *dir, int mflag, char *fstype,
}

int
do_mount(const char *src, const char *mntpt, char *opts, int flags)
do_mount(zfs_handle_t *zhp, const char *mntpt, char *opts, int flags)
{

return (do_mount_(src, mntpt, flags, MNTTYPE_ZFS, NULL, 0, opts,
sizeof (mntpt)));
return (do_mount_(zfs_get_name(zhp), mntpt, flags, MNTTYPE_ZFS, NULL, 0,
opts, sizeof (mntpt)));
}

int
Expand Down
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