From ba508dc60d5f62d8821242eebf50efcfbddd1428 Mon Sep 17 00:00:00 2001
From: David Tardon <dtardon@redhat.com>
Date: Tue, 10 Aug 2021 14:46:16 +0200
Subject: [PATCH] Revert "udev: remove WAIT_FOR key"
This reverts commit f2b8052fb648b788936dd3e85be6a9aca90fbb2f.
RHEL-only
Resolves: #1982666
---
man/udev.xml | 9 +++++++
src/udev/udev-rules.c | 56 +++++++++++++++++++++++++++++++++++++++
test/rule-syntax-check.py | 2 +-
3 files changed, 66 insertions(+), 1 deletion(-)
diff --git a/man/udev.xml b/man/udev.xml
index f6ea2abc12..ce96e201e4 100644
--- a/man/udev.xml
+++ b/man/udev.xml
@@ -592,6 +592,15 @@
</listitem>
</varlistentry>
+ <varlistentry>
+ <term><varname>WAIT_FOR</varname></term>
+ <listitem>
+ <para>Wait for a file to become available or until a timeout of
+ 10 seconds expires. The path is relative to the sysfs device;
+ if no path is specified, this waits for an attribute to appear.</para>
+ </listitem>
+ </varlistentry>
+
<varlistentry>
<term><varname>OPTIONS</varname></term>
<listitem>
diff --git a/src/udev/udev-rules.c b/src/udev/udev-rules.c
index bf997fc0ed..a02a7a1bc6 100644
--- a/src/udev/udev-rules.c
+++ b/src/udev/udev-rules.c
@@ -78,6 +78,7 @@ typedef enum {
TK_M_TAG, /* strv, sd_device_get_tag_first(), sd_device_get_tag_next() */
TK_M_SUBSYSTEM, /* string, sd_device_get_subsystem() */
TK_M_DRIVER, /* string, sd_device_get_driver() */
+ TK_M_WAITFOR,
TK_M_ATTR, /* string, takes filename through attribute, sd_device_get_sysattr_value(), udev_resolve_subsys_kernel(), etc. */
TK_M_SYSCTL, /* string, takes kernel parameter through attribute */
@@ -415,6 +416,47 @@ static void rule_line_append_token(UdevRuleLine *rule_line, UdevRuleToken *token
rule_line->current_token = token;
}
+#define WAIT_LOOP_PER_SECOND 50
+static int wait_for_file(sd_device *dev, const char *file, int timeout) {
+ char filepath[UDEV_PATH_SIZE];
+ char devicepath[UDEV_PATH_SIZE];
+ struct stat stats;
+ int loop = timeout * WAIT_LOOP_PER_SECOND;
+
+ /* a relative path is a device attribute */
+ devicepath[0] = '\0';
+ if (file[0] != '/') {
+ const char *val;
+ int r;
+
+ r = sd_device_get_syspath(dev, &val);
+ if (r < 0)
+ return r;
+ strscpyl(devicepath, sizeof(devicepath), val, NULL);
+ strscpyl(filepath, sizeof(filepath), devicepath, "/", file, NULL);
+ file = filepath;
+ }
+
+ while (--loop) {
+ const struct timespec duration = { 0, 1000 * 1000 * 1000 / WAIT_LOOP_PER_SECOND };
+
+ /* lookup file */
+ if (stat(file, &stats) == 0) {
+ log_debug("file '%s' appeared after %i loops", file, (timeout * WAIT_LOOP_PER_SECOND) - loop-1);
+ return 0;
+ }
+ /* make sure, the device did not disappear in the meantime */
+ if (devicepath[0] != '\0' && stat(devicepath, &stats) != 0) {
+ log_debug("device disappeared while waiting for '%s'", file);
+ return -2;
+ }
+ log_debug("wait for '%s' for %i mseconds", file, 1000 / WAIT_LOOP_PER_SECOND);
+ nanosleep(&duration, NULL);
+ }
+ log_debug("waiting for '%s' failed", file);
+ return -1;
+}
+
static int rule_line_add_token(UdevRuleLine *rule_line, UdevRuleTokenType type, UdevRuleOperatorType op, char *value, void *data) {
UdevRuleToken *token;
UdevRuleMatchType match_type = _MATCH_TYPE_INVALID;
@@ -957,6 +999,12 @@ static int parse_token(UdevRules *rules, const char *key, char *attr, UdevRuleOp
r = rule_line_add_token(rule_line, TK_A_RUN_BUILTIN, op, value, UDEV_BUILTIN_CMD_TO_PTR(cmd));
} else
return log_token_invalid_attr(rules, key);
+ } else if (streq(key, "WAIT_FOR") || streq(key, "WAIT_FOR_SYSFS")) {
+ if (op == OP_REMOVE)
+ return log_token_invalid_op(rules, key);
+
+ rule_line_add_token(rule_line, TK_M_WAITFOR, 0, value, NULL);
+ return 1;
} else if (streq(key, "GOTO")) {
if (attr)
return log_token_invalid_attr(rules, key);
@@ -1643,6 +1691,14 @@ static int udev_rule_apply_token_to_event(
return token_match_string(token, val);
}
+ case TK_M_WAITFOR: {
+ char filename[UDEV_PATH_SIZE];
+ int found;
+
+ udev_event_apply_format(event, token->value, filename, sizeof(filename), false);
+ found = (wait_for_file(event->dev, filename, 10) == 0);
+ return found || (token->op == OP_NOMATCH);
+ }
case TK_M_ATTR:
case TK_M_PARENTS_ATTR:
return token_match_attr(token, dev, event);
diff --git a/test/rule-syntax-check.py b/test/rule-syntax-check.py
index 9a9e4d1658..0649bcf58e 100755
--- a/test/rule-syntax-check.py
+++ b/test/rule-syntax-check.py
@@ -20,7 +20,7 @@ no_args_tests = re.compile(r'(ACTION|DEVPATH|KERNELS?|NAME|SYMLINK|SUBSYSTEMS?|D
# PROGRAM can also be specified as an assignment.
program_assign = re.compile(r'PROGRAM\s*=\s*' + quoted_string_re + '$')
args_tests = re.compile(r'(ATTRS?|ENV|CONST|TEST){([a-zA-Z0-9/_.*%-]+)}\s*(?:=|!)=\s*' + quoted_string_re + '$')
-no_args_assign = re.compile(r'(NAME|SYMLINK|OWNER|GROUP|MODE|TAG|RUN|LABEL|GOTO|OPTIONS|IMPORT)\s*(?:\+=|:=|=)\s*' + quoted_string_re + '$')
+no_args_assign = re.compile(r'(NAME|SYMLINK|OWNER|GROUP|MODE|TAG|RUN|LABEL|GOTO|WAIT_FOR|OPTIONS|IMPORT)\s*(?:\+=|:=|=)\s*' + quoted_string_re + '$')
args_assign = re.compile(r'(ATTR|ENV|IMPORT|RUN){([a-zA-Z0-9/_.*%-]+)}\s*(=|\+=)\s*' + quoted_string_re + '$')
# Find comma-separated groups, but allow commas that are inside quoted strings.
# Using quoted_string_re + '?' so that strings missing the last double quote