Re: DEVLINKS and DEVNAME variables in RUN rules

[Andrey Borzenkov <arvidjaar@mail.ru>]

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On Tuesday 24 January 2006 19:24, Olivier Blin wrote:
> Hi,
>
> I'd like to use the DEVNAME and DEVLINKS (thanks Kay) environment
> variables in a RUN rule. Unfortunately, they're not exported yet when
> the command to be executed is computed (i.e. when the format is
> applied). So, for now, I'm using a dumb trick:
> RUN+="/bin/sh -c '/sbin/pam_console_setowner $$DEVICE $$DEVNAME
> $$DEVLINKS'"
>
> Would it be possible to have the format applied right before the RUN
> command is run?
>

Like this? This seems to work for me:

Jan 24 21:04:24 cooker udevd-event[16049]: name_list_add: adding 
'/sbin/pam_console_setowner $env{DEVICE} $env{DEVNAME} $env{DEVLINKS}'
Jan 24 21:04:25 cooker udevd-event[16049]: apply_format: format=14, 
string='/sbin/pam_console_setowner ', tail=' $env{DEVNAME} $env{DEVLINKS}'
Jan 24 21:04:25 cooker udevd-event[16049]: apply_format: format=14, 
string='/sbin/pam_console_setowner  ', tail=' $env{DEVLINKS}'
Jan 24 21:04:25 cooker udevd-event[16049]: apply_format: format=14, 
string='/sbin/pam_console_setowner  /dev/adsp ', tail=''
Jan 24 21:04:25 cooker udevd-event[16049]: run_program: arg[0] 
'/sbin/pam_console_setowner'
Jan 24 21:04:25 cooker udevd-event[16049]: run_program: 
'/sbin/pam_console_setowner  /dev/adsp /dev/sound/adsp'
Jan 24 21:04:25 cooker udevd-event[16049]: run_program: 
'/sbin/pam_console_setowner' returned with status 0


-andrey

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Subject: [PATCH] Allow substitution of environment variables in RUN commands

Apply substitutions immediately before running program, not when rule
is parsed. It allows use environment variables set by udev during
rule processing as command arguments.

---

 udev.c       |    9 +++++++--
 udev_rules.c |    3 +--
 udev_rules.h |    2 +-
 udevd.c      |    9 +++++++--
 udevstart.c  |    9 +++++++--
 5 files changed, 23 insertions(+), 9 deletions(-)

c1d4190501d381ac2d6987e84b680907c93c0b4d
diff --git a/udev.c b/udev.c
index 4762ab1..f808abf 100644
--- a/udev.c
+++ b/udev.c
@@ -161,8 +161,13 @@ int main(int argc, char *argv[], char *e
 		list_for_each_entry(name_loop, &udev->run_list, node) {
 			if (strncmp(name_loop->name, "socket:", strlen("socket:")) == 0)
 				pass_env_to_socket(&name_loop->name[strlen("socket:")], devpath, action);
-			else
-				run_program(name_loop->name, udev->dev->subsystem, NULL, 0, NULL, (udev_log_priority >= LOG_INFO));
+			else {
+				char program[PATH_SIZE];
+
+				strlcpy(program, name_loop->name, sizeof(program));
+				apply_format(udev, program, sizeof(program));
+				run_program(program, udev->dev->subsystem, NULL, 0, NULL, (udev_log_priority >= LOG_INFO));
+			}
 		}
 	}
 
diff --git a/udev_rules.c b/udev_rules.c
index e9d8d75..fbcbbe0 100644
--- a/udev_rules.c
+++ b/udev_rules.c
@@ -362,7 +362,7 @@ static int wait_for_sysfs(struct udevice
 	return -1;
 }
 
-static void apply_format(struct udevice *udev, char *string, size_t maxsize)
+void apply_format(struct udevice *udev, char *string, size_t maxsize)
 {
 	char temp[PATH_SIZE];
 	char temp2[PATH_SIZE];
@@ -1017,7 +1017,6 @@ int udev_rules_get_name(struct udev_rule
 					name_list_cleanup(&udev->run_list);
 				}
 				strlcpy(program, key_val(rule, &rule->run), sizeof(program));
-				apply_format(udev, program, sizeof(program));
 				dbg("add run '%s'", program);
 				name_list_add(&udev->run_list, program, 0);
 			}
diff --git a/udev_rules.h b/udev_rules.h
index 125babf..b183d9b 100644
--- a/udev_rules.h
+++ b/udev_rules.h
@@ -105,7 +105,7 @@ struct udev_rules {
 extern int udev_rules_init(struct udev_rules *rules, int resolve_names);
 extern void udev_rules_cleanup(struct udev_rules *rules);
 
-extern void udev_apply_format(struct udevice *udev, char *string, size_t maxsize);
+extern void apply_format(struct udevice *udev, char *string, size_t maxsize);
 
 extern void udev_rules_iter_init(struct udev_rules *rules);
 extern struct udev_rule *udev_rules_iter_next(struct udev_rules *rules);
diff --git a/udevd.c b/udevd.c
index c45d3a4..af5685c 100644
--- a/udevd.c
+++ b/udevd.c
@@ -123,10 +123,15 @@ static int udev_event_process(struct uev
 		list_for_each_entry(name_loop, &udev->run_list, node) {
 			if (strncmp(name_loop->name, "socket:", strlen("socket:")) == 0)
 				pass_env_to_socket(&name_loop->name[strlen("socket:")], msg->devpath, msg->action);
-			else
-				if (run_program(name_loop->name, udev->dev->subsystem, NULL, 0, NULL,
+			else {
+				char program[PATH_SIZE];
+
+				strlcpy(program, name_loop->name, sizeof(program));
+				apply_format(udev, program, sizeof(program));
+				if (run_program(program, udev->dev->subsystem, NULL, 0, NULL,
 						(udev_log_priority >= LOG_INFO)))
 					retval = -1;
+			}
 		}
 	}
 
diff --git a/udevstart.c b/udevstart.c
index 8c414f1..11bdf79 100644
--- a/udevstart.c
+++ b/udevstart.c
@@ -160,8 +160,13 @@ run:
 		list_for_each_entry(name_loop, &udev->run_list, node) {
 			if (strncmp(name_loop->name, "socket:", strlen("socket:")) == 0)
 				pass_env_to_socket(&name_loop->name[strlen("socket:")], udev->dev->devpath, "add");
-			else
-				run_program(name_loop->name, udev->dev->subsystem, NULL, 0, NULL, (udev_log_priority >= LOG_INFO));
+			else {
+				char program[PATH_SIZE];
+
+				strlcpy(program, name_loop->name, sizeof(program));
+				apply_format(udev, program, sizeof(program));
+				run_program(program, udev->dev->subsystem, NULL, 0, NULL, (udev_log_priority >= LOG_INFO));
+			}
 		}
 	}
 exit:
-- 
1.1.4

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