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Merged
stgraber merged 2 commits into from
May 10, 2025
Merged

Mount options (lxc.mount.entry) handling improvements #4547

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2e08794
lxc/conf: support nosymfollow mount flag
mihalicyn May 5, 2025
afb35f3
lxc/conf: support flag kind of mount options in lxc.mount.entry options
mihalicyn May 5, 2025
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33 changes: 20 additions & 13 deletions src/lxc/conf.c
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Original file line number Diff line number Diff line change
Expand Up @@ -140,6 +140,7 @@ static struct mount_opt mount_opt[] = {
{ "noexec", 0, false, MOUNT_ATTR_NOEXEC, MS_NOEXEC },
{ "norelatime", 1, false, MOUNT_ATTR_RELATIME, MS_RELATIME },
{ "nostrictatime", 1, false, MOUNT_ATTR_STRICTATIME, MS_STRICTATIME },
{ "nosymfollow", 0, false, MOUNT_ATTR_NOSYMFOLLOW, MS_NOSYMFOLLOW },
{ "nosuid", 0, false, MOUNT_ATTR_NOSUID, MS_NOSUID },
{ "relatime", 0, false, MOUNT_ATTR_RELATIME, MS_RELATIME },
{ "ro", 0, false, MOUNT_ATTR_RDONLY, MS_RDONLY },
Expand Down Expand Up @@ -2034,6 +2035,11 @@ int parse_mntopts_legacy(const char *mntopts, unsigned long *mntflags, char **mn
return 0;
}

/* Parses generic VFS option (opt) and puts results into (opts).
*
* @return 1 if opt is not a generic VFS option
* @return 0 if opt was processed
*/
static int parse_vfs_attr(struct lxc_mount_options *opts, char *opt, size_t size)
{
/*
Expand Down Expand Up @@ -2090,7 +2096,8 @@ static int parse_vfs_attr(struct lxc_mount_options *opts, char *opt, size_t size
return 0;
}

return 0;
/* opt was skipped */
return 1;
}

int parse_mount_attrs(struct lxc_mount_options *opts, const char *mntopts)
Expand All @@ -2116,22 +2123,22 @@ int parse_mount_attrs(struct lxc_mount_options *opts, const char *mntopts)
return ret_errno(ENOMEM);

lxc_iterate_parts(mntopt_cur, mntopts_dup, ",") {
/* This is a filesystem specific option. */
if (strchr(mntopt_cur, '=')) {
if (!end) {
end = stpcpy(mntopts_new, mntopt_cur);
} else {
end = stpcpy(end, ",");
end = stpcpy(end, mntopt_cur);
}

continue;
}

/* This is a generic vfs option. */
ret = parse_vfs_attr(opts, mntopt_cur, size);
if (ret < 0)
return syserror("Failed to parse mount attributes: \"%s\"", mntopt_cur);

/* (mntopt_cur) was processed in parse_vfs_attr() */
if (ret == 0)
continue;

/* This is a filesystem specific option. */
if (!end) {
end = stpcpy(mntopts_new, mntopt_cur);
} else {
end = stpcpy(end, ",");
end = stpcpy(end, mntopt_cur);
}
}

if (*mntopts_new)
Expand Down
4 changes: 4 additions & 0 deletions src/lxc/macro.h
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Original file line number Diff line number Diff line change
Expand Up @@ -626,6 +626,10 @@ enum {
#define MS_REC 16384
#endif

#ifndef MS_NOSYMFOLLOW
#define MS_NOSYMFOLLOW 256 /* Do not follow symlinks */
#endif

/* open */
#ifndef O_PATH
#define O_PATH 010000000
Expand Down
4 changes: 4 additions & 0 deletions src/lxc/mount_utils.h
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Original file line number Diff line number Diff line change
Expand Up @@ -176,6 +176,10 @@ struct lxc_rootfs;
#define MOUNT_ATTR_IDMAP 0x00100000
#endif

#ifndef MOUNT_ATTR_NOSYMFOLLOW
#define MOUNT_ATTR_NOSYMFOLLOW 0x00200000 /* Do not follow symlinks */
#endif

#if !HAVE_MOVE_MOUNT
static inline int move_mount_lxc(int from_dfd, const char *from_pathname,
int to_dfd, const char *to_pathname,
Expand Down