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fstab-generator: split out several functions from parse_fstab()
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No functional changes, just refactoring and preparation for later
commits.

(cherry picked from commit cfeb4d378ecd1ea50c0a0248c384e49983511fa8)

Related: #2190228
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@yuwata @dtardon
yuwata authored and dtardon committed Jul 18, 2023
1 parent 0813100 commit 0bbebc5
Showing 1 changed file with 123 additions and 96 deletions.
219 changes: 123 additions & 96 deletions src/fstab-generator/fstab-generator.c
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Original file line number Diff line number Diff line change
Expand Up @@ -81,15 +81,14 @@ static int write_what(FILE *f, const char *what) {

static int add_swap(
const char *what,
struct mntent *me,
const char *options,
MountpointFlags flags) {

_cleanup_free_ char *name = NULL;
_cleanup_fclose_ FILE *f = NULL;
int r;

assert(what);
assert(me);

if (access("/proc/swaps", F_OK) < 0) {
log_info("Swap not supported, ignoring fstab swap entry for %s.", what);
Expand Down Expand Up @@ -119,7 +118,7 @@ static int add_swap(
if (r < 0)
return r;

r = write_options(f, me->mnt_opts);
r = write_options(f, options);
if (r < 0)
return r;

Expand All @@ -128,7 +127,7 @@ static int add_swap(
return log_error_errno(r, "Failed to write unit file %s: %m", name);

/* use what as where, to have a nicer error message */
r = generator_write_timeouts(arg_dest, what, what, me->mnt_opts, NULL);
r = generator_write_timeouts(arg_dest, what, what, options, NULL);
if (r < 0)
return r;

Expand All @@ -152,18 +151,14 @@ static int add_swap(
return 0;
}

static bool mount_is_network(struct mntent *me) {
assert(me);

return fstab_test_option(me->mnt_opts, "_netdev\0") ||
fstype_is_network(me->mnt_type);
static bool mount_is_network(const char *fstype, const char *options) {
return fstab_test_option(options, "_netdev\0") ||
(fstype && fstype_is_network(fstype));
}

static bool mount_in_initrd(struct mntent *me) {
assert(me);

return fstab_test_option(me->mnt_opts, "x-initrd.mount\0") ||
streq(me->mnt_dir, "/usr");
static bool mount_in_initrd(const char *where, const char *options) {
return fstab_test_option(options, "x-initrd.mount\0") ||
(where && path_equal(where, "/usr"));
}

static int write_timeout(FILE *f, const char *where, const char *opts,
Expand Down Expand Up @@ -501,11 +496,120 @@ static int add_mount(
return 0;
}

static MountpointFlags fstab_options_to_flags(const char *options, bool is_swap) {
MountpointFlags flags = 0;

if (fstab_test_option(options, "x-systemd.makefs\0"))
flags |= MAKEFS;
if (fstab_test_option(options, "x-systemd.growfs\0"))
flags |= GROWFS;
if (fstab_test_yes_no_option(options, "noauto\0" "auto\0"))
flags |= NOAUTO;
if (fstab_test_yes_no_option(options, "nofail\0" "fail\0"))
flags |= NOFAIL;

if (!is_swap) {
if (fstab_test_option(options,
"comment=systemd.automount\0"
"x-systemd.automount\0"))
flags |= AUTOMOUNT;
}

return flags;
}

static int parse_fstab_one(
const char *source,
const char *what_original,
const char *where_original,
const char *fstype,
const char *options,
int passno,
bool initrd) {

_cleanup_free_ char *where = NULL, *what = NULL, *canonical_where = NULL;
const char *post;
MountpointFlags flags;
int r;

assert(what_original);
assert(where_original);
assert(fstype);
assert(options);

if (initrd && !mount_in_initrd(where_original, options))
return 0;

what = fstab_node_to_udev_node(what_original);
if (!what)
return log_oom();

if (is_device_path(what) && path_is_read_only_fs("sys") > 0) {
log_info("Running in a container, ignoring fstab device entry for %s.", what);
return 0;
}

where = strdup(where_original);
if (!where)
return log_oom();

if (is_path(where)) {
path_simplify(where, false);

/* Follow symlinks here; see 5261ba901845c084de5a8fd06500ed09bfb0bd80 which makes sense for
* mount units, but causes problems since it historically worked to have symlinks in e.g.
* /etc/fstab. So we canonicalize here. Note that we use CHASE_NONEXISTENT to handle the case
* where a symlink refers to another mount target; this works assuming the sub-mountpoint
* target is the final directory. */
r = chase_symlinks(where, initrd ? "/sysroot" : NULL,
CHASE_PREFIX_ROOT | CHASE_NONEXISTENT,
&canonical_where);
if (r < 0) /* If we can't canonicalize we continue on as if it wasn't a symlink */
log_debug_errno(r, "Failed to read symlink target for %s, ignoring: %m", where);
else if (streq(canonical_where, where)) /* If it was fully canonicalized, suppress the change */
canonical_where = mfree(canonical_where);
else
log_debug("Canonicalized what=%s where=%s to %s", what, where, canonical_where);
}

flags = fstab_options_to_flags(options, streq_ptr(fstype, "swap"));

log_debug("Found entry what=%s where=%s type=%s makefs=%s noauto=%s nofail=%s",
what, where, strna(fstype),
yes_no(flags & MAKEFS),
yes_no(flags & NOAUTO), yes_no(flags & NOFAIL));

if (streq(fstype, "swap"))
return add_swap(what, options, flags);

if (initrd)
post = SPECIAL_INITRD_FS_TARGET;
else if (mount_is_network(fstype, options))
post = SPECIAL_REMOTE_FS_TARGET;
else
post = SPECIAL_LOCAL_FS_TARGET;

r = add_mount(arg_dest,
what,
canonical_where ?: where,
canonical_where ? where: NULL,
fstype,
options,
passno,
flags,
post,
source);
if (r < 0)
return log_oom();

return 1;
}

static int parse_fstab(bool initrd) {
_cleanup_endmntent_ FILE *f = NULL;
const char *fstab_path;
struct mntent *me;
int r = 0;
int r, ret = 0;

fstab_path = initrd ? "/sysroot/etc/fstab" : "/etc/fstab";
f = setmntent(fstab_path, "re");
Expand All @@ -517,89 +621,12 @@ static int parse_fstab(bool initrd) {
}

while ((me = getmntent(f))) {
_cleanup_free_ char *where = NULL, *what = NULL, *canonical_where = NULL;
bool makefs, growfs, noauto, nofail;
int k;

if (initrd && !mount_in_initrd(me))
continue;

what = fstab_node_to_udev_node(me->mnt_fsname);
if (!what)
return log_oom();

if (is_device_path(what) && path_is_read_only_fs("sys") > 0) {
log_info("Running in a container, ignoring fstab device entry for %s.", what);
continue;
}

where = strdup(me->mnt_dir);
if (!where)
return log_oom();

if (is_path(where)) {
path_simplify(where, false);

/* Follow symlinks here; see 5261ba901845c084de5a8fd06500ed09bfb0bd80 which makes sense for
* mount units, but causes problems since it historically worked to have symlinks in e.g.
* /etc/fstab. So we canonicalize here. Note that we use CHASE_NONEXISTENT to handle the case
* where a symlink refers to another mount target; this works assuming the sub-mountpoint
* target is the final directory. */
r = chase_symlinks(where, initrd ? "/sysroot" : NULL,
CHASE_PREFIX_ROOT | CHASE_NONEXISTENT,
&canonical_where);
if (r < 0) /* If we can't canonicalize we continue on as if it wasn't a symlink */
log_debug_errno(r, "Failed to read symlink target for %s, ignoring: %m", where);
else if (streq(canonical_where, where)) /* If it was fully canonicalized, suppress the change */
canonical_where = mfree(canonical_where);
else
log_debug("Canonicalized what=%s where=%s to %s", what, where, canonical_where);
}

makefs = fstab_test_option(me->mnt_opts, "x-systemd.makefs\0");
growfs = fstab_test_option(me->mnt_opts, "x-systemd.growfs\0");
noauto = fstab_test_yes_no_option(me->mnt_opts, "noauto\0" "auto\0");
nofail = fstab_test_yes_no_option(me->mnt_opts, "nofail\0" "fail\0");

log_debug("Found entry what=%s where=%s type=%s makefs=%s noauto=%s nofail=%s",
what, where, me->mnt_type,
yes_no(makefs),
yes_no(noauto), yes_no(nofail));

if (streq(me->mnt_type, "swap"))
k = add_swap(what, me,
makefs*MAKEFS | growfs*GROWFS | noauto*NOAUTO | nofail*NOFAIL);
else {
bool automount;
const char *post;

automount = fstab_test_option(me->mnt_opts,
"comment=systemd.automount\0"
"x-systemd.automount\0");
if (initrd)
post = SPECIAL_INITRD_FS_TARGET;
else if (mount_is_network(me))
post = SPECIAL_REMOTE_FS_TARGET;
else
post = SPECIAL_LOCAL_FS_TARGET;

k = add_mount(arg_dest,
what,
canonical_where ?: where,
canonical_where ? where: NULL,
me->mnt_type,
me->mnt_opts,
me->mnt_passno,
makefs*MAKEFS | growfs*GROWFS | noauto*NOAUTO | nofail*NOFAIL | automount*AUTOMOUNT,
post,
fstab_path);
}

if (r >= 0 && k < 0)
r = k;
r = parse_fstab_one(fstab_path, me->mnt_fsname, me->mnt_dir, me->mnt_type, me->mnt_opts, me->mnt_passno, initrd);
if (r < 0 && ret >= 0)
ret = r;
}

return r;
return ret;
}

static int add_sysroot_mount(void) {
Expand Down

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