From ddaf24341a512a9891226e85c13d51d7e2cfcb01 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

Related: #2138081

---

 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 142f295f3e..5b096c7ef2 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 f44a174d1f..a8473041c3 100644

--- a/src/udev/udev-rules.c

+++ b/src/udev/udev-rules.c

@@ -79,6 +79,7 @@ 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 */

@@ -411,6 +412,47 @@ 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;

@@ -953,6 +995,12 @@ 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);

@@ -1670,6 +1718,14 @@ 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, NULL);

+                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(rules, token, dev, event);

diff --git a/test/rule-syntax-check.py b/test/rule-syntax-check.py

index ec1c75a854..5543931064 100755

--- a/test/rule-syntax-check.py

+++ b/test/rule-syntax-check.py

@@ -18,7 +18,7 @@ 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