Re: [PATCH v3 -mm 9/9] netconsole: Support dynamic reconfiguration using configfs
On Mon, 30 Jul 2007, Andrew Morton wrote:
> On Mon, 30 Jul 2007 08:19:10 +0530
> Satyam Sharma <[EMAIL PROTECTED]> wrote:
>
> > +/*
> > + * Wrapper over simple_strtol (base 10) with sanity and range checking.
> > + * We return (signed) long only because we may want to return errors.
> > + * Do not use this to convert numbers that are allowed to be negative.
> > + */
> > +static long strtol10_check_range(const char *cp, long min, long max)
> > +{
> > + long ret;
> > + char *p = (char *) cp;
> > +
> > + WARN_ON(min < 0);
> > + WARN_ON(max < min);
> > +
> > + ret = simple_strtol(p, , 10);
> > +
> > + if (*p && (*p != '\n')) {
> > + printk(KERN_ERR "netconsole: invalid input\n");
> > + return -EINVAL;
> > + }
> > + if ((ret < min) || (ret > max)) {
> > + printk(KERN_ERR "netconsole: input %ld must be between "
> > + "%ld and %ld\n", ret, min, max);
> > + return -EINVAL;
> > + }
> > +
> > + return ret;
> > +}
>
> There's probably other code around the place which does this. It might
> be worth making this function a general-purpose thing.
Probably, yes, I thought along similar lines.
[ BTW somewhere in the 9/9 patch I remember having to define a
__U16_MAX as well. That could be pushed out to some generic
or appropriate header as well, possibly. ]
Satyam
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Re: [PATCH v3 -mm 9/9] netconsole: Support dynamic reconfiguration using configfs
On Mon, 30 Jul 2007 08:19:10 +0530
Satyam Sharma <[EMAIL PROTECTED]> wrote:
> +/*
> + * Wrapper over simple_strtol (base 10) with sanity and range checking.
> + * We return (signed) long only because we may want to return errors.
> + * Do not use this to convert numbers that are allowed to be negative.
> + */
> +static long strtol10_check_range(const char *cp, long min, long max)
> +{
> + long ret;
> + char *p = (char *) cp;
> +
> + WARN_ON(min < 0);
> + WARN_ON(max < min);
> +
> + ret = simple_strtol(p, , 10);
> +
> + if (*p && (*p != '\n')) {
> + printk(KERN_ERR "netconsole: invalid input\n");
> + return -EINVAL;
> + }
> + if ((ret < min) || (ret > max)) {
> + printk(KERN_ERR "netconsole: input %ld must be between "
> + "%ld and %ld\n", ret, min, max);
> + return -EINVAL;
> + }
> +
> + return ret;
> +}
There's probably other code around the place which does this. It might
be worth making this function a general-purpose thing.
-
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the body of a message to [EMAIL PROTECTED]
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Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH v3 -mm 9/9] netconsole: Support dynamic reconfiguration using configfs
On Mon, 30 Jul 2007 08:19:10 +0530
Satyam Sharma [EMAIL PROTECTED] wrote:
+/*
+ * Wrapper over simple_strtol (base 10) with sanity and range checking.
+ * We return (signed) long only because we may want to return errors.
+ * Do not use this to convert numbers that are allowed to be negative.
+ */
+static long strtol10_check_range(const char *cp, long min, long max)
+{
+ long ret;
+ char *p = (char *) cp;
+
+ WARN_ON(min 0);
+ WARN_ON(max min);
+
+ ret = simple_strtol(p, p, 10);
+
+ if (*p (*p != '\n')) {
+ printk(KERN_ERR netconsole: invalid input\n);
+ return -EINVAL;
+ }
+ if ((ret min) || (ret max)) {
+ printk(KERN_ERR netconsole: input %ld must be between
+ %ld and %ld\n, ret, min, max);
+ return -EINVAL;
+ }
+
+ return ret;
+}
There's probably other code around the place which does this. It might
be worth making this function a general-purpose thing.
-
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH v3 -mm 9/9] netconsole: Support dynamic reconfiguration using configfs
On Mon, 30 Jul 2007, Andrew Morton wrote:
On Mon, 30 Jul 2007 08:19:10 +0530
Satyam Sharma [EMAIL PROTECTED] wrote:
+/*
+ * Wrapper over simple_strtol (base 10) with sanity and range checking.
+ * We return (signed) long only because we may want to return errors.
+ * Do not use this to convert numbers that are allowed to be negative.
+ */
+static long strtol10_check_range(const char *cp, long min, long max)
+{
+ long ret;
+ char *p = (char *) cp;
+
+ WARN_ON(min 0);
+ WARN_ON(max min);
+
+ ret = simple_strtol(p, p, 10);
+
+ if (*p (*p != '\n')) {
+ printk(KERN_ERR netconsole: invalid input\n);
+ return -EINVAL;
+ }
+ if ((ret min) || (ret max)) {
+ printk(KERN_ERR netconsole: input %ld must be between
+ %ld and %ld\n, ret, min, max);
+ return -EINVAL;
+ }
+
+ return ret;
+}
There's probably other code around the place which does this. It might
be worth making this function a general-purpose thing.
Probably, yes, I thought along similar lines.
[ BTW somewhere in the 9/9 patch I remember having to define a
__U16_MAX as well. That could be pushed out to some generic
or appropriate header as well, possibly. ]
Satyam
-
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[PATCH v3 -mm 9/9] netconsole: Support dynamic reconfiguration using configfs
From: Satyam Sharma <[EMAIL PROTECTED]> [9/9] netconsole: Support dynamic reconfiguration using configfs This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <[EMAIL PROTECTED]> Acked-by: Keiichi Kii <[EMAIL PROTECTED]> --- Documentation/networking/netconsole.txt | 68 drivers/net/Kconfig | 10 + drivers/net/netconsole.c| 605 +-- include/linux/netpoll.h |1 + net/core/netpoll.c | 44 ++- 5 files changed, 683 insertions(+), 45 deletions(-) diff --git a/Documentation/networking/netconsole.txt b/Documentation/networking/netconsole.txt index 1aaa738..3c2f2b3 100644 --- a/Documentation/networking/netconsole.txt +++ b/Documentation/networking/netconsole.txt @@ -3,6 +3,10 @@ started by Ingo Molnar <[EMAIL PROTECTED]>, 2001.09.17 2.6 port and netpoll api by Matt Mackall <[EMAIL PROTECTED]>, Sep 9 2003 Please send bug reports to Matt Mackall <[EMAIL PROTECTED]> +and Satyam Sharma <[EMAIL PROTECTED]> + +Introduction: += This module logs kernel printk messages over UDP allowing debugging of problem where disk logging fails and serial consoles are impractical. @@ -13,6 +17,9 @@ the specified interface as soon as possible. While this doesn't allow capture of early kernel panics, it does capture most of the boot process. +Sender and receiver configuration: +== + It takes a string configuration parameter "netconsole" in the following format: @@ -46,6 +53,67 @@ address. The remote host can run either 'netcat -u -l -p ' or syslogd. +Dynamic reconfiguration: + + +Dynamic reconfigurability is a useful addition to netconsole that enables +remote logging targets to be dynamically added, removed, or have their +parameters reconfigured at runtime from a configfs-based userspace interface. +[ Note that the parameters of netconsole targets that were specified/created +from the boot/module option are not exposed via this interface, and hence +cannot be modified dynamically. ] + +To include this feature, select CONFIG_NETCONSOLE_DYNAMIC when building the +netconsole module (or kernel, if netconsole is built-in). + +Some examples follow (where configfs is mounted at the
[PATCH v3 -mm 9/9] netconsole: Support dynamic reconfiguration using configfs
From: Satyam Sharma [EMAIL PROTECTED] [9/9] netconsole: Support dynamic reconfiguration using configfs This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the config items is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) 1 to the enabled attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the enabled attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma [EMAIL PROTECTED] Acked-by: Keiichi Kii [EMAIL PROTECTED] --- Documentation/networking/netconsole.txt | 68 drivers/net/Kconfig | 10 + drivers/net/netconsole.c| 605 +-- include/linux/netpoll.h |1 + net/core/netpoll.c | 44 ++- 5 files changed, 683 insertions(+), 45 deletions(-) diff --git a/Documentation/networking/netconsole.txt b/Documentation/networking/netconsole.txt index 1aaa738..3c2f2b3 100644 --- a/Documentation/networking/netconsole.txt +++ b/Documentation/networking/netconsole.txt @@ -3,6 +3,10 @@ started by Ingo Molnar [EMAIL PROTECTED], 2001.09.17 2.6 port and netpoll api by Matt Mackall [EMAIL PROTECTED], Sep 9 2003 Please send bug reports to Matt Mackall [EMAIL PROTECTED] +and Satyam Sharma [EMAIL PROTECTED] + +Introduction: += This module logs kernel printk messages over UDP allowing debugging of problem where disk logging fails and serial consoles are impractical. @@ -13,6 +17,9 @@ the specified interface as soon as possible. While this doesn't allow capture of early kernel panics, it does capture most of the boot process. +Sender and receiver configuration: +== + It takes a string configuration parameter netconsole in the following format: @@ -46,6 +53,67 @@ address. The remote host can run either 'netcat -u -l -p port' or syslogd. +Dynamic reconfiguration: + + +Dynamic reconfigurability is a useful addition to netconsole that enables +remote logging targets to be dynamically added, removed, or have their +parameters reconfigured at runtime from a configfs-based userspace interface. +[ Note that the parameters of netconsole targets that were specified/created +from the boot/module option are not exposed via this interface, and hence +cannot be modified dynamically. ] + +To include this feature, select CONFIG_NETCONSOLE_DYNAMIC when building the +netconsole module (or kernel, if netconsole is built-in). + +Some examples follow (where configfs is mounted at the /sys/kernel/config
