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install: don't enforce that .d/ dropin files (and their symlink chain elements) for units must have names that qualify as unit names

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The names of drop-in files can be anything as long as they are suffixed
in ".conf", hence don't be stricter than necessary when validating the
names used in symlink chains of such drop-in files.

Also, drop-in files should not be ale to change the type of unit file
itself, i.e. not affect whether it is considered masked or an alias as a
whole.

This adds a flag SEARCH_DROPIN that is passed whenever we load a drop-in
rather the main unit file, and in that case loosen checks and behaviour
we otherwise enforce for the unit file itself. Specifically:

1. If SEARCH_DROPIN is passed we won't change the unit's info->type
   field anymore, as that field (which can be REGULAR, MASKED, SYMLINK)
   should not be affected by drop-ins, but only by the unit file itself.

2. If SEARCH_DROPIN is passed we will shortcut following of symlink
   chains, and not validate the naming of each element in the chain,
   since that's irrelevant for drop-ins, and only matters for the unit
   file itself.

Or in other words, without this:

1. A symlink /etc/systemd/system/foobar.service.d/20-quux.conf →
   /dev/null might have caused the whole of foobar.service to be
   considered "masked".

2. A symlink /etc/systemd/system/foobar.service.d/20-quux.conf →
   /tmp/miepf might have caused the whole loading of foobar.service to
   fail as EINVAL, as "miepf" is not a valid unit name.
This commit is contained in:
Lennart Poettering 2018-03-28 16:44:19 +02:00
parent 244d2f07b4
commit d04a93864d
1 changed files with 58 additions and 40 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

98
src/shared/install.c
View file

@ -59,8 +59,9 @@
#define UNIT_FILE_FOLLOW_SYMLINK_MAX 64
typedef enum SearchFlags {
SEARCH_LOAD = 1,
SEARCH_FOLLOW_CONFIG_SYMLINKS = 2,
SEARCH_LOAD = 1U << 0,
SEARCH_FOLLOW_CONFIG_SYMLINKS = 1U << 1,
SEARCH_DROPIN = 1U << 2,
} SearchFlags;
typedef struct {
@ -1228,6 +1229,7 @@ static int unit_file_load(
InstallContext *c,
UnitFileInstallInfo *info,
const char *path,
const char *root_dir,
SearchFlags flags) {
const ConfigTableItem items[] = {
@ -1248,40 +1250,57 @@ static int unit_file_load(
assert(info);
assert(path);
type = unit_name_to_type(info->name);
if (unit_name_is_valid(info->name, UNIT_NAME_TEMPLATE|UNIT_NAME_INSTANCE) &&
!unit_type_may_template(type))
return log_error_errno(EINVAL, "Unit type %s cannot be templated.", unit_type_to_string(type));
if (!(flags & SEARCH_DROPIN)) {
/* Loading or checking for the main unit file… */
if (!(flags & SEARCH_LOAD)) {
r = lstat(path, &st);
if (r < 0)
type = unit_name_to_type(info->name);
if (type < 0)
return -EINVAL;
if (unit_name_is_valid(info->name, UNIT_NAME_TEMPLATE|UNIT_NAME_INSTANCE) && !unit_type_may_template(type)) {
log_error("Unit type %s cannot be templated.", unit_type_to_string(type));
return -EINVAL;
}
if (!(flags & SEARCH_LOAD)) {
r = lstat(path, &st);
if (r < 0)
return -errno;
if (null_or_empty(&st))
info->type = UNIT_FILE_TYPE_MASKED;
else if (S_ISREG(st.st_mode))
info->type = UNIT_FILE_TYPE_REGULAR;
else if (S_ISLNK(st.st_mode))
return -ELOOP;
else if (S_ISDIR(st.st_mode))
return -EISDIR;
else
return -ENOTTY;
return 0;
}
fd = open(path, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
if (fd < 0)
return -errno;
} else {
/* Operating on a drop-in file. If we aren't supposed to load the unit file drop-ins don't matter, let's hence shortcut this. */
if (null_or_empty(&st))
info->type = UNIT_FILE_TYPE_MASKED;
else if (S_ISREG(st.st_mode))
info->type = UNIT_FILE_TYPE_REGULAR;
else if (S_ISLNK(st.st_mode))
return -ELOOP;
else if (S_ISDIR(st.st_mode))
return -EISDIR;
else
return -ENOTTY;
if (!(flags & SEARCH_LOAD))
return 0;
return 0;
fd = chase_symlinks_and_open(path, root_dir, 0, O_RDONLY|O_CLOEXEC|O_NOCTTY, NULL);
if (fd < 0)
return fd;
}
/* c is only needed if we actually load the file */
assert(c);
fd = open(path, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
if (fd < 0)
return -errno;
if (fstat(fd, &st) < 0)
return -errno;
if (null_or_empty(&st)) {
info->type = UNIT_FILE_TYPE_MASKED;
if ((flags & SEARCH_DROPIN) == 0)
info->type = UNIT_FILE_TYPE_MASKED;
return 0;
}
@ -1294,6 +1313,9 @@ static int unit_file_load(
return -errno;
fd = -1;
/* c is only needed if we actually load the file (it's referenced from items[] btw, in case you wonder.) */
assert(c);
r = config_parse(info->name, path, f,
NULL,
config_item_table_lookup, items,
@ -1301,7 +1323,8 @@ static int unit_file_load(
if (r < 0)
return log_debug_errno(r, "Failed to parse %s: %m", info->name);
info->type = UNIT_FILE_TYPE_REGULAR;
if ((flags & SEARCH_DROPIN) == 0)
info->type = UNIT_FILE_TYPE_REGULAR;
return
(int) strv_length(info->aliases) +
@ -1319,8 +1342,8 @@ static int unit_file_load_or_readlink(
_cleanup_free_ char *target = NULL;
int r;
r = unit_file_load(c, info, path, flags);
if (r != -ELOOP)
r = unit_file_load(c, info, path, root_dir, flags);
if (r != -ELOOP || (flags & SEARCH_DROPIN))
return r;
/* This is a symlink, let's read it. */
@ -1383,16 +1406,12 @@ static int unit_file_search(
const LookupPaths *paths,
SearchFlags flags) {
const char *dropin_dir_name = NULL, *dropin_template_dir_name = NULL;
_cleanup_strv_free_ char **dirs = NULL, **files = NULL;
_cleanup_free_ char *template = NULL;
_cleanup_strv_free_ char **dirs = NULL;
_cleanup_strv_free_ char **files = NULL;
const char *dropin_dir_name = NULL;
const char *dropin_template_dir_name = NULL;
char **p;
int r;
int result;
bool found_unit = false;
int r, result;
char **p;
assert(info);
assert(paths);
@ -1420,7 +1439,6 @@ static int unit_file_search(
return -ENOMEM;
r = unit_file_load_or_readlink(c, info, path, paths->root_dir, flags);
if (r >= 0) {
info->path = TAKE_PTR(path);
result = r;
@ -1499,7 +1517,7 @@ static int unit_file_search(
return log_debug_errno(r, "Failed to get list of conf files: %m");
STRV_FOREACH(p, files) {
r = unit_file_load_or_readlink(c, info, *p, paths->root_dir, flags);
r = unit_file_load_or_readlink(c, info, *p, paths->root_dir, flags | SEARCH_DROPIN);
if (r < 0)
return log_debug_errno(r, "Failed to load conf file %s: %m", *p);
}