From 8e3ba3772cadf6a8292b0da533062dd4d377af67 Mon Sep 17 00:00:00 2001
From: David Herrmann <dh.herrmann@gmail.com>
Date: Thu, 11 Sep 2014 13:25:21 +0200
Subject: [PATCH] udev: allow removing tags via TAG-="foobar"
This extends the udev parser to support OP_REMOVE (-=) and adds support
for TAG-= to remove previously set tags. We don't fail if the tag didn't
exist.
This is pretty handy if we ship default rules for seat-assignments and
users want to exclude specific devices from that. They can easily add
rules that drop any automatically added "seat" tags again.
---
man/udev.xml | 7 ++++
src/libudev/libudev-device.c | 21 +++++++++++-
src/libudev/libudev-private.h | 1 +
src/udev/udev-rules.c | 78 +++++++++++++++++++++++++++++++++++++++++--
4 files changed, 103 insertions(+), 4 deletions(-)
diff --git a/man/udev.xml b/man/udev.xml
index 2948b9ce2b..d77cbb0e6e 100644
--- a/man/udev.xml
+++ b/man/udev.xml
@@ -114,6 +114,13 @@
</varlistentry>
<varlistentry>
+ <term><literal>-=</literal></term>
+ <listitem>
+ <para>Remove the value from a key that holds a list of entries.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
<term><literal>:=</literal></term>
<listitem>
<para>Assign a value to a key finally; disallow any later changes.</para>
diff --git a/src/libudev/libudev-device.c b/src/libudev/libudev-device.c
index f26a4c44b5..d61a2ad8f4 100644
--- a/src/libudev/libudev-device.c
+++ b/src/libudev/libudev-device.c
@@ -1732,9 +1732,14 @@ void udev_device_set_is_initialized(struct udev_device *udev_device)
udev_device->is_initialized = true;
}
+static bool is_valid_tag(const char *tag)
+{
+ return !strchr(tag, ':') && !strchr(tag, ' ');
+}
+
int udev_device_add_tag(struct udev_device *udev_device, const char *tag)
{
- if (strchr(tag, ':') != NULL || strchr(tag, ' ') != NULL)
+ if (!is_valid_tag(tag))
return -EINVAL;
udev_device->tags_uptodate = false;
if (udev_list_entry_add(&udev_device->tags_list, tag, NULL) != NULL)
@@ -1742,6 +1747,20 @@ int udev_device_add_tag(struct udev_device *udev_device, const char *tag)
return -ENOMEM;
}
+void udev_device_remove_tag(struct udev_device *udev_device, const char *tag)
+{
+ struct udev_list_entry *e;
+
+ if (!is_valid_tag(tag))
+ return;
+ e = udev_list_get_entry(&udev_device->tags_list);
+ e = udev_list_entry_get_by_name(e, tag);
+ if (e) {
+ udev_device->tags_uptodate = false;
+ udev_list_entry_delete(e);
+ }
+}
+
void udev_device_cleanup_tags_list(struct udev_device *udev_device)
{
udev_device->tags_uptodate = false;
diff --git a/src/libudev/libudev-private.h b/src/libudev/libudev-private.h
index cd1c1fb8b3..35ea7ba44c 100644
--- a/src/libudev/libudev-private.h
+++ b/src/libudev/libudev-private.h
@@ -73,6 +73,7 @@ const char *udev_device_get_devpath_old(struct udev_device *udev_device);
const char *udev_device_get_id_filename(struct udev_device *udev_device);
void udev_device_set_is_initialized(struct udev_device *udev_device);
int udev_device_add_tag(struct udev_device *udev_device, const char *tag);
+void udev_device_remove_tag(struct udev_device *udev_device, const char *tag);
void udev_device_cleanup_tags_list(struct udev_device *udev_device);
usec_t udev_device_get_usec_initialized(struct udev_device *udev_device);
void udev_device_set_usec_initialized(struct udev_device *udev_device, usec_t usec_initialized);
diff --git a/src/udev/udev-rules.c b/src/udev/udev-rules.c
index 6de7511c7d..9514dde751 100644
--- a/src/udev/udev-rules.c
+++ b/src/udev/udev-rules.c
@@ -82,7 +82,7 @@ static unsigned int rules_add_string(struct udev_rules *rules, const char *s) {
return strbuf_add_string(rules->strbuf, s, strlen(s));
}
-/* KEY=="", KEY!="", KEY+="", KEY="", KEY:="" */
+/* KEY=="", KEY!="", KEY+="", KEY-="", KEY="", KEY:="" */
enum operation_type {
OP_UNSET,
@@ -91,6 +91,7 @@ enum operation_type {
OP_MATCH_MAX,
OP_ADD,
+ OP_REMOVE,
OP_ASSIGN,
OP_ASSIGN_FINAL,
};
@@ -224,6 +225,7 @@ static const char *operation_str(enum operation_type type) {
[OP_MATCH_MAX] = "MATCH_MAX",
[OP_ADD] = "add",
+ [OP_REMOVE] = "remove",
[OP_ASSIGN] = "assign",
[OP_ASSIGN_FINAL] = "assign-final",
} ;
@@ -761,7 +763,7 @@ static int get_key(struct udev *udev, char **line, char **key, enum operation_ty
break;
if (linepos[0] == '=')
break;
- if ((linepos[0] == '+') || (linepos[0] == '!') || (linepos[0] == ':'))
+ if ((linepos[0] == '+') || (linepos[0] == '-') || (linepos[0] == '!') || (linepos[0] == ':'))
if (linepos[1] == '=')
break;
}
@@ -785,6 +787,9 @@ static int get_key(struct udev *udev, char **line, char **key, enum operation_ty
} else if (linepos[0] == '+' && linepos[1] == '=') {
*op = OP_ADD;
linepos += 2;
+ } else if (linepos[0] == '-' && linepos[1] == '=') {
+ *op = OP_REMOVE;
+ linepos += 2;
} else if (linepos[0] == '=') {
*op = OP_ASSIGN;
linepos++;
@@ -1121,6 +1126,10 @@ static int add_rule(struct udev_rules *rules, char *line,
log_error("error parsing ATTR attribute");
goto invalid;
}
+ if (op == OP_REMOVE) {
+ log_error("invalid ATTR operation");
+ goto invalid;
+ }
if (op < OP_MATCH_MAX) {
rule_add_key(&rule_tmp, TK_M_ATTR, op, value, attr);
} else {
@@ -1135,6 +1144,10 @@ static int add_rule(struct udev_rules *rules, char *line,
log_error("error parsing SECLABEL attribute");
goto invalid;
}
+ if (op == OP_REMOVE) {
+ log_error("invalid SECLABEL operation");
+ goto invalid;
+ }
rule_add_key(&rule_tmp, TK_A_SECLABEL, op, value, attr);
continue;
@@ -1202,6 +1215,10 @@ static int add_rule(struct udev_rules *rules, char *line,
log_error("error parsing ENV attribute");
goto invalid;
}
+ if (op == OP_REMOVE) {
+ log_error("invalid ENV operation");
+ goto invalid;
+ }
if (op < OP_MATCH_MAX) {
if (rule_add_key(&rule_tmp, TK_M_ENV, op, value, attr) != 0)
goto invalid;
@@ -1242,6 +1259,10 @@ static int add_rule(struct udev_rules *rules, char *line,
}
if (streq(key, "PROGRAM")) {
+ if (op == OP_REMOVE) {
+ log_error("invalid PROGRAM operation");
+ goto invalid;
+ }
rule_add_key(&rule_tmp, TK_M_PROGRAM, op, value, NULL);
continue;
}
@@ -1261,6 +1282,10 @@ static int add_rule(struct udev_rules *rules, char *line,
log_error("IMPORT{} type missing, ignoring IMPORT %s:%u", filename, lineno);
continue;
}
+ if (op == OP_REMOVE) {
+ log_error("invalid IMPORT operation");
+ goto invalid;
+ }
if (streq(attr, "program")) {
/* find known built-in command */
if (value[0] != '/') {
@@ -1316,6 +1341,10 @@ static int add_rule(struct udev_rules *rules, char *line,
attr = get_key_attribute(rules->udev, key + strlen("RUN"));
if (attr == NULL)
attr = "program";
+ if (op == OP_REMOVE) {
+ log_error("invalid RUN operation");
+ goto invalid;
+ }
if (streq(attr, "builtin")) {
enum udev_builtin_cmd cmd = udev_builtin_lookup(value);
@@ -1336,21 +1365,37 @@ static int add_rule(struct udev_rules *rules, char *line,
}
if (streq(key, "WAIT_FOR") || streq(key, "WAIT_FOR_SYSFS")) {
+ if (op == OP_REMOVE) {
+ log_error("invalid WAIT_FOR/WAIT_FOR_SYSFS operation");
+ goto invalid;
+ }
rule_add_key(&rule_tmp, TK_M_WAITFOR, 0, value, NULL);
continue;
}
if (streq(key, "LABEL")) {
+ if (op == OP_REMOVE) {
+ log_error("invalid LABEL operation");
+ goto invalid;
+ }
rule_tmp.rule.rule.label_off = rules_add_string(rules, value);
continue;
}
if (streq(key, "GOTO")) {
+ if (op == OP_REMOVE) {
+ log_error("invalid GOTO operation");
+ goto invalid;
+ }
rule_add_key(&rule_tmp, TK_A_GOTO, 0, value, NULL);
continue;
}
if (startswith(key, "NAME")) {
+ if (op == OP_REMOVE) {
+ log_error("invalid NAME operation");
+ goto invalid;
+ }
if (op < OP_MATCH_MAX) {
rule_add_key(&rule_tmp, TK_M_NAME, op, value, NULL);
} else {
@@ -1371,6 +1416,10 @@ static int add_rule(struct udev_rules *rules, char *line,
}
if (streq(key, "SYMLINK")) {
+ if (op == OP_REMOVE) {
+ log_error("invalid SYMLINK operation");
+ goto invalid;
+ }
if (op < OP_MATCH_MAX)
rule_add_key(&rule_tmp, TK_M_DEVLINK, op, value, NULL);
else
@@ -1383,6 +1432,11 @@ static int add_rule(struct udev_rules *rules, char *line,
uid_t uid;
char *endptr;
+ if (op == OP_REMOVE) {
+ log_error("invalid OWNER operation");
+ goto invalid;
+ }
+
uid = strtoul(value, &endptr, 10);
if (endptr[0] == '\0') {
rule_add_key(&rule_tmp, TK_A_OWNER_ID, op, NULL, &uid);
@@ -1400,6 +1454,11 @@ static int add_rule(struct udev_rules *rules, char *line,
gid_t gid;
char *endptr;
+ if (op == OP_REMOVE) {
+ log_error("invalid GROUP operation");
+ goto invalid;
+ }
+
gid = strtoul(value, &endptr, 10);
if (endptr[0] == '\0') {
rule_add_key(&rule_tmp, TK_A_GROUP_ID, op, NULL, &gid);
@@ -1417,6 +1476,11 @@ static int add_rule(struct udev_rules *rules, char *line,
mode_t mode;
char *endptr;
+ if (op == OP_REMOVE) {
+ log_error("invalid MODE operation");
+ goto invalid;
+ }
+
mode = strtol(value, &endptr, 8);
if (endptr[0] == '\0')
rule_add_key(&rule_tmp, TK_A_MODE_ID, op, NULL, &mode);
@@ -1429,6 +1493,11 @@ static int add_rule(struct udev_rules *rules, char *line,
if (streq(key, "OPTIONS")) {
const char *pos;
+ if (op == OP_REMOVE) {
+ log_error("invalid OPTIONS operation");
+ goto invalid;
+ }
+
pos = strstr(value, "link_priority=");
if (pos != NULL) {
int prio = atoi(&pos[strlen("link_priority=")]);
@@ -2320,7 +2389,10 @@ int udev_rules_apply_to_event(struct udev_rules *rules,
log_error("ignoring invalid tag name '%s'", tag);
break;
}
- udev_device_add_tag(event->dev, tag);
+ if (cur->key.op == OP_REMOVE)
+ udev_device_remove_tag(event->dev, tag);
+ else
+ udev_device_add_tag(event->dev, tag);
break;
}
case TK_A_NAME: {