On Thu, Mar 11, 2004 at 02:36:23PM +0100, Kay Sievers wrote:
> On Thu, 2004-03-11 at 15:02, Ananth N Mavinakayanahalli wrote:
> > On Thu, Mar 11, 2004 at 02:04:36PM +0100, Kay Sievers wrote:
> > > On Thu, Mar 11, 2004 at 11:53:50AM +0500, Ananth N Mavinakayanahalli wrote:
> > >
> > > > +#define safestrcpy(to, from) strncpy(to, from, sizeof(to)-1)
> > > > +#define safestrcat(to, from) strncat(to, from, sizeof(to) - strlen(to)-1)
> > >
> > > These strings are not terminated with '\0' if from is longer than
> > > the sizeof to.
> >
> > Did not do it on purpose as the "to" elements are either calloc'd or memset to
> > '0' explicitly in the library. Thats the reason I mentioned "scaled down" :)
>
> Ahh, sounds good.
>
> > > > +#define safestrncpy(to, from, maxsize) \
> > > > +do { \
> > > > + to[maxsize-1] = '\0'; \
> > > > + strncpy(to, from, maxsize-1); \
> > > > +} while (0)
> > > > +
> > > > +#define safestrncat(to, from, maxsize) \
> > > > +do { \
> > > > + to[maxsize-1] = '\0'; \
> > > > + strncat(to, from, maxsize - strlen(to)-1); \
> > > > +} while (0)
> > >
> > > We all expect a similar behavior like strncat/strncpy according to the
> > > names, but these macros are limiting by the target size and do not limit
> > > the count of chars copied.
> > > This is confusing I think and suggest using a different name like
> > > 'safestrcopymax()' or something.
> >
> > Good point.. will make the change
>
> Nice. I've had these *n* names too and I forgot about the logic and only
> 10 days later I introduced a ugly bug cause I can't limit the count of
> copied chars :)
Inlined is the patch for this... applies on the earlier _BIG_ patch.
Please find attached a _BIG_ patch to update udev's libsysfs. Patch applies
on udev-021 and contains:
1. Updates to get udev's libsysfs to the latest (to be released) level.
2. Changes for C++ compatibility (use "char" and not "unsigned char"
unless absolutely necessary).
3. More importantly, take care of buffer overflows. Libsysfs now uses a
scaled down version of Kay's "safe" macros.
Tested using a usb-storage device.
I will send you a doc update shortly.
Ananth released sysfsutils 0.4.0 last night, I'm sure you saw the email.
Here's a patch with the latest changes from the pre-patch I already
gave you. It includes sysfs_get_device_parent(), which you said you
needed. I've run your test scripts and I've built scsi_id. Please
play around with this and check it out.
There are quite a few changes. Please do not access
structure pointers, like sysfs_device's parent, directly like
dev->parent. Please use the "get" function to retrieve. The functions
load things on demand and refresh views under the covers.
I am sending you a pre-release patch. It's everything that's in our
current CVS tree. It adds the functionality you've been looking for. Please
play with this before checking it into your tree, I'd like to know if
it's ok with you or if you find problems. I have tested this out with
test.all and the perl regression test. Let me know what you think.
Still need to do more testing for our work and add some more functions
related to the changes.
I've gone into namedev.c and udev-add.c to make the necessary changes
in line with the library. I have not gone and edited any of the "extras".
Changes:
1) Libsysfs object structures work more as handles now, their included
directories or devices are labeled private. If you need attributes
from a sysfs_class_device, call the available function and don't access
the directory directly. Same holds true for a sysfs_class_device
sysfs_device. Do not access the link directly but call the function
sysfs_get_classdev_device() instead. We only populate entries upon
request, makes things faster and uses less memory.
2) Added sysfs_get_classdev_parent() as requested.
3) Changed getpagesize to sysconf.
4) Added sysfs_refresh_attributes function for refreshing views of
attribute lists. We still need to add refresh for links and subdirs. All
udev needs to do is keep calling sysfs_get_classdev_attr() and that will
internally call the refresh routine.
The quick patch I sent you yesterday fixes it in one location, but
there are other points in the library that calls sysfs_get_mnt_path. We
need to address all the areas in the library where paths are used. The
following patch is a band-aid until we can get a proper path management
in the library.
Here's the patch to up the library to the sysfsutils-0_3_0 level. The
following changes:
1) adds class name to sysfs_class_device structure
2) adds bus to sysfs_device
3) gets rid of code that made assumptions as to bus addresses being
unique across buses, which isn't the case.
I still owe you:
1) change getpagesize->sysconf. This is in the CVS tree and part of other
changes we're currently testing. Patch will follow.
2) you need a function to get a sysfs_class_device's parent. We hadn't
considered class devices to have parents, the one example of a multilevel
is the block class. We will add this function and send the patch to you.
Here's a quick patch to:
1) Add an environment variable "SYSFS_PATH" that libsysfs will check
for when getting mount point before searching system's sysfs mount
point.
2) A quick fix to sysfs_get_link where the bug was.
I have tested this out with libsysfs and with udev. I couldn't test
with klibc because I haven't got the tree to build with klibc without
my changes either. I made the link but get an error finding
linux/linits.h. I will figure that out.
Please have a look at the patch. If it's agreeable, please test it. I
really want to add some generic path manipulation functions for the
sysfs_get_link error, rather than my patch's hack. But, I haven't had
time yet to do that. You really sounded like you needed this for
testing, so I'm sending it out to you. I should probably add a
function to set the env variable(?).
Here's the patch applying the latest libsysfs.
- adds the latest libsysfs code to udev
* new code includes dlist implementation, a generic linked list
implementation. Needed our own because LGPL
* rearranged structures
* provided more functions for accessing directory and attributes
- gets rid of ->directory->path references in namedev.c
- replaces sysfs_get_value_from_attributes with sysfs_get_classdev_attr
