RE: how to use the function copyout()
I think that could work (only an idea, not tested):
struct Region
{
void * p;
size_t s;
};
#define IOBIG _IOWR ('b', 123, struct Region)
userland:
char data[1000];
struct Region r;
r.p = data;
r.s = sizeof data;
int error = ioctl (fd, IOBIG, r);
kernel:
int my_ioctl(..., caddr_t data, ...)
{
...
char data[1000];
...
return copyout(data, ((struct Region *) data)-p, ((struct Region *)
data)-s);
}
Have a try and tell us if it works.
Norbert
Yes! Now the program works!
I have changed the code in this way:
struct Region
{
void * p;
size_t s;
};
#define IOBIG _IOWR ('b', 123, struct Region)
driver
struct my_softc {
...
short unsigned int B;
};
...
static int
my_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int flag,
struct thread *td)
{
struct my_softc *my_sc;
int unit, error;
unit = minor(dev);
my_sc = (struct my_softc *)devclass_get_softc(my_devclass, unit);
if (my_sc == NULL)
return (ENXIO);
switch(cmd)
{
...
case IOCTL_GET_B:
error = copyout(my_sc-B, (((struct Datas *)data)-d)+0x1850,
sizeof(my_sc-B));
break;
default:
break;
}
return 0;
}
---user program --
...
short unsigned int data[32768];
struct Region r;
int
main(int argc, char *argv[])
{
...
r.p = data;
r.s = sizeof data;
if (ioctl(fd0, IOCTL_GET_B, r) == -1)
err(1, IOCTL_GET_B);
...
}
Now I have access to each element of the array (e.g. 0x1850).
Thank you very much!
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Re: how to use the function copyout()
Felix-KM wrote:
I think that could work (only an idea, not tested):
struct Region
{
void * p;
size_t s;
};
#define IOBIG _IOWR ('b', 123, struct Region)
userland:
char data[1000];
struct Region r;
r.p = data;
r.s = sizeof data;
int error = ioctl (fd, IOBIG, r);
kernel:
int my_ioctl(..., caddr_t data, ...)
{
...
char data[1000];
...
return copyout(data, ((struct Region *) data)-p, ((struct Region *)
data)-s);
}
Have a try and tell us if it works.
Norbert
Yes! Now the program works!
I have changed the code in this way:
struct Region
{
void * p;
size_t s;
};
#define IOBIG _IOWR ('b', 123, struct Region)
Unless your ioctl handler is going to modify values in the Region struct
and pass them back out to userland, you should just use _IOR instead of
_IORW.
Scott
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how to use the function copyout()
I can't understand how to use the function copyout().
It is necessary to write the data from a device driver to the
array defined in user program.
I do it this way:
#define IOCTL_GET_B_IOWR(F, 127, 0x4)
driver
struct my_softc {
...
short unsigned int B;
};
...
static int
my_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int flag,
struct thread *td)
{
struct my_softc *my_sc;
int unit, error;
unit = minor(dev);
my_sc = (struct my_softc *)devclass_get_softc(my_devclass, unit);
if (my_sc == NULL)
return (ENXIO);
switch(cmd)
{
...
case IOCTL_GET_B:
error = copyout(my_sc-B, data, sizeof(my_sc-B));
switch (error)
{
case 0:
printf( IOCTL_GET_B: %d\n, my_sc-B);
break;
case EFAULT:
printf(EFAULT\n);
break;
case EIO:
printf(EIO\n);
break;
case ENOMEM:
printf(ENOMEM\n);
break;
case ENOSPC:
printf(ENOSPC\n);
break;
}
break;
default:
break;
}
return 0;
}
---user program --
...
short unsigned int Data[32768];
int
main(int argc, char *argv[])
{ ...
if (ioctl(fd0, IOCTL_GET_B, Data) == -1)
err(1, IOCTL_GET_B);
...
}
---
Here I get EFAULT.
What have I done wrong? How can I do it correctly?
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Re: how to use the function copyout()
On Mon, Jul 25, 2005 at 04:35:20PM +0400, Felix-KM wrote: I can't understand how to use the function copyout(). It is necessary to write the data from a device driver to the array defined in user program. I do it this way: #define IOCTL_GET_B_IOWR(F, 127, 0x4) snip Here I get EFAULT. What have I done wrong? How can I do it correctly? You may need to add your ioctl to another middle layer. For example, to add ioctls to network devices, I first added defines to sockio.h only, and it wouldn't work (device not configured). Then I found out that I had to add my ioctls to a rather large switch statement in if.c too. hope this helps, -- stefan http://stsp.in-berlin.de PGP Key: 0xF59D25F0 ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: how to use the function copyout()
Im not sure of the bug in your code, but you have got
to assume that copyout() would fail if the user/kernel
addr passed to it is not accessible.
regards
-kamal
--- Felix-KM [EMAIL PROTECTED] wrote:
I can't understand how to use the function
copyout().
It is necessary to write the data from a device
driver to the
array defined in user program.
I do it this way:
#define IOCTL_GET_B_IOWR(F, 127, 0x4)
driver
struct my_softc {
...
short unsigned int B;
};
...
static int
my_ioctl(struct cdev *dev, u_long cmd, caddr_t data,
int flag,
struct thread *td)
{
struct my_softc *my_sc;
int unit, error;
unit = minor(dev);
my_sc = (struct my_softc
*)devclass_get_softc(my_devclass, unit);
if (my_sc == NULL)
return (ENXIO);
switch(cmd)
{
...
case IOCTL_GET_B:
error = copyout(my_sc-B, data,
sizeof(my_sc-B));
switch (error)
{
case 0:
printf( IOCTL_GET_B: %d\n, my_sc-B);
break;
case EFAULT:
printf(EFAULT\n);
break;
case EIO:
printf(EIO\n);
break;
case ENOMEM:
printf(ENOMEM\n);
break;
case ENOSPC:
printf(ENOSPC\n);
break;
}
break;
default:
break;
}
return 0;
}
---user program --
...
short unsigned int Data[32768];
int
main(int argc, char *argv[])
{ ...
if (ioctl(fd0, IOCTL_GET_B, Data) == -1)
err(1, IOCTL_GET_B);
...
}
---
Here I get EFAULT.
What have I done wrong? How can I do it correctly?
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Kamal R. Prasad
UNIX systems consultant
http://www.kamalprasad.com/
[EMAIL PROTECTED]
In theory, there is no difference between theory and practice. In practice,
there is.
Start your day with Yahoo! - make it your home page
http://www.yahoo.com/r/hs
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RE: how to use the function copyout()
#define IOCTL_GET_B_IOWR(F, 127, 0x4)
I think the third parameter to _IOWR should directly specify a type,
e.g. _IOWR(F, 127, int) or _IOWR(F, 127, struct MyStruct).
driver
struct my_softc {
...
short unsigned int B;
};
...
static int
my_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int flag,
struct thread *td)
{
struct my_softc *my_sc;
int unit, error;
unit = minor(dev);
my_sc = (struct my_softc *)devclass_get_softc(my_devclass, unit);
if (my_sc == NULL)
return (ENXIO);
switch(cmd)
{
...
case IOCTL_GET_B:
error = copyout(my_sc-B, data, sizeof(my_sc-B));
switch (error)
{
case 0:
printf( IOCTL_GET_B: %d\n, my_sc-B);
break;
case EFAULT:
printf(EFAULT\n);
break;
case EIO:
printf(EIO\n);
break;
case ENOMEM:
printf(ENOMEM\n);
break;
case ENOSPC:
printf(ENOSPC\n);
break;
}
break;
default:
break;
}
return 0;
}
---user program --
...
short unsigned int Data[32768];
int
main(int argc, char *argv[])
{ ...
if (ioctl(fd0, IOCTL_GET_B, Data) == -1)
err(1, IOCTL_GET_B);
...
}
---
Here I get EFAULT.
What have I done wrong? How can I do it correctly?
The caddr_t data in your ioctl is already mapped into kernel
memory. Look into the source of other device drivers. You'll
find a lot of *(int *) data = ...
So your copyout() has to fail because it tries to address
memory which is not a part of your application's
memory.
From errno(2): EFAULT: Bad address...
I have no idea if it is possible for ioctls to have mapped more
than a few 100 bytes for data exchange.
You should use read and uiomove() instead.
Norbert
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RE: how to use the function copyout()
#define IOCTL_GET_B_IOWR(F, 127, 0x4)
I think the third parameter to _IOWR should directly specify a type,
e.g. _IOWR(F, 127, int) or _IOWR(F, 127, struct MyStruct).
driver
struct my_softc {
...
short unsigned int B;
};
...
static int
my_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int flag,
struct thread *td)
{
struct my_softc *my_sc;
int unit, error;
unit = minor(dev);
my_sc = (struct my_softc *)devclass_get_softc(my_devclass, unit);
if (my_sc == NULL)
return (ENXIO);
switch(cmd)
{
...
case IOCTL_GET_B:
error = copyout(my_sc-B, data, sizeof(my_sc-B));
switch (error)
{
case 0:
printf( IOCTL_GET_B: %d\n, my_sc-B);
break;
case EFAULT:
printf(EFAULT\n);
break;
case EIO:
printf(EIO\n);
break;
case ENOMEM:
printf(ENOMEM\n);
break;
case ENOSPC:
printf(ENOSPC\n);
break;
}
break;
default:
break;
}
return 0;
}
---user program --
...
short unsigned int Data[32768];
int
main(int argc, char *argv[])
{ ...
if (ioctl(fd0, IOCTL_GET_B, Data) == -1)
err(1, IOCTL_GET_B);
...
}
---
Here I get EFAULT.
What have I done wrong? How can I do it correctly?
The caddr_t data in your ioctl is already mapped into kernel
memory. Look into the source of other device drivers. You'll
find a lot of *(int *) data = ...
So your copyout() has to fail because it tries to address
memory which is not a part of your application's
memory.
From errno(2): EFAULT: Bad address...
I have no idea if it is possible for ioctls to have mapped more
than a few 100 bytes for data exchange.
You should use read and uiomove() instead.
So if I get it right, it's impossible in FreeBSD to gain access to 64KB of
user's program memory with ioctl?
My situation is this - I have a device driver for Linux. My task is port it as
it is (1:1) into FreeBSD.
In the Linux driver Ioctl is realized with the macroses _put_user _get_user all
over it. As I understand in FreeBSD their analogues are functions described in
store(9), copy(9) and fetch(9).
So the problem is that in my user program an array short unsigned int
Data[32768] is defined. I need to gain access to the array(to each element of
it) from device driver with Ioctl handler.
Is it possible to do? If yes, then how it can be done?
Norbert
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Re: how to use the function copyout()
On 2005-07-25 18:14, Felix-KM [EMAIL PROTECTED] wrote: I have no idea if it is possible for ioctls to have mapped more than a few 100 bytes for data exchange. You should use read and uiomove() instead. So if I get it right, it's impossible in FreeBSD to gain access to 64KB of user's program memory with ioctl? My situation is this - I have a device driver for Linux. My task is port it as it is (1:1) into FreeBSD. In the Linux driver Ioctl is realized with the macroses _put_user _get_user all over it. As I understand in FreeBSD their analogues are functions described in store(9), copy(9) and fetch(9). So the problem is that in my user program an array short unsigned int Data[32768] is defined. I need to gain access to the array(to each element of it) from device driver with Ioctl handler. Is it possible to do? If yes, then how it can be done? A better alternative that doesn't involve copying huge amounts of data from userlevel to kernel space and vice versa is probably to pass just the address of the area with an ioctl() and then map the appropriate pages from the address space of the user process to an area where the kernel can access the data directly? ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to [EMAIL PROTECTED]
RE: how to use the function copyout()
So if I get it right, it's impossible in FreeBSD to gain access to
64KB of user's program memory with ioctl?
My situation is this - I have a device driver for Linux. My task is
port it as it is (1:1) into FreeBSD.
In the Linux driver Ioctl is realized with the macroses _put_user
_get_user all over it. As I understand in FreeBSD their analogues are
functions described in store(9), copy(9) and fetch(9).
So the problem is that in my user program an array short unsigned int
Data[32768] is defined. I need to gain access to the array(to each
element of it) from device driver with Ioctl handler.
Is it possible to do? If yes, then how it can be done?
A better alternative that doesn't involve copying huge amounts of data
from userlevel to kernel space and vice versa is probably to pass just
the address of the area with an ioctl() and then map the appropriate
pages from the address space of the user process to an area where the
kernel can access the data directly?
I think that could work (only an idea, not tested):
struct Region
{
void * p;
size_t s;
};
#define IOBIG _IOWR ('b', 123, struct Region)
userland:
char data[1000];
struct Region r;
r.p = data;
r.s = sizeof data;
int error = ioctl (fd, IOBIG, r);
kernel:
int my_ioctl(..., caddr_t data, ...)
{
...
char data[1000];
...
return copyout(data, ((struct Region *) data)-p, ((struct Region *)
data)-s);
}
Have a try and tell us if it works.
Norbert
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RE: how to use the function copyout()
On Mon, 25 Jul 2005, Felix-KM wrote: In the Linux driver Ioctl is realized with the macroses _put_user _get_user all over it. As I understand in FreeBSD their analogues are functions described in store(9), copy(9) and fetch(9). Linux doesn't provide any help for driver IOCTL routines, FreeBSD does. Just declare your IOCTLs correctly and the kernel will perform any copy in/out as specified by the _IOW/_IOR/_IOWR macros. -- 10 40 80 C0 00 FF FF FF FF C0 00 00 00 00 10 AA AA 03 00 00 00 08 00 ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: how to use the function copyout()
Felix-KM wrote:
#define IOCTL_GET_B_IOWR(F, 127, 0x4)
I think the third parameter to _IOWR should directly specify a type,
e.g. _IOWR(F, 127, int) or _IOWR(F, 127, struct MyStruct).
driver
struct my_softc {
...
short unsigned int B;
};
...
static int
my_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int flag,
struct thread *td)
{
struct my_softc *my_sc;
int unit, error;
unit = minor(dev);
my_sc = (struct my_softc *)devclass_get_softc(my_devclass, unit);
if (my_sc == NULL)
return (ENXIO);
switch(cmd)
{
...
case IOCTL_GET_B:
error = copyout(my_sc-B, data, sizeof(my_sc-B));
switch (error)
{
case 0:
printf( IOCTL_GET_B: %d\n, my_sc-B);
break;
case EFAULT:
printf(EFAULT\n);
break;
case EIO:
printf(EIO\n);
break;
case ENOMEM:
printf(ENOMEM\n);
break;
case ENOSPC:
printf(ENOSPC\n);
break;
}
break;
default:
break;
}
return 0;
}
---user program --
...
short unsigned int Data[32768];
int
main(int argc, char *argv[])
{ ...
if (ioctl(fd0, IOCTL_GET_B, Data) == -1)
err(1, IOCTL_GET_B);
...
}
---
Here I get EFAULT.
What have I done wrong? How can I do it correctly?
The caddr_t data in your ioctl is already mapped into kernel
memory. Look into the source of other device drivers. You'll
find a lot of *(int *) data = ...
So your copyout() has to fail because it tries to address
memory which is not a part of your application's
memory.
From errno(2): EFAULT: Bad address...
I have no idea if it is possible for ioctls to have mapped more
than a few 100 bytes for data exchange.
You should use read and uiomove() instead.
So if I get it right, it's impossible in FreeBSD to gain access to 64KB of
user's program memory with ioctl?
no you do not get it right.
you should pass in a pointer to your 64k object.
ioccom.h describes the definition of the ioctl name.
this includes:
#define IOCPARM_MASK0x1fff /* parameter length, at most 13
bits */
so the maximum that the system will AUTOMATICALLY COPYIN() is 8k
For larger amounts you can always have the address as teh parameter and
do the copyin yourself.
in other words the automatically moved data would be only a smal
structure specifying address and size,
and you would use those parameters to copyin the larger structure.
My situation is this - I have a device driver for Linux. My task is port it as
it is (1:1) into FreeBSD.
In the Linux driver Ioctl is realized with the macroses _put_user _get_user all over it. As I understand in FreeBSD their analogues are functions described in store(9), copy(9) and fetch(9).
So the problem is that in my user program an array short unsigned int
Data[32768] is defined. I need to gain access to the array(to each element of
it) from device driver with Ioctl handler.
Is it possible to do? If yes, then how it can be done?
Norbert
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Re: how to use the function copyout()
Kamal R. Prasad wrote: Im not sure of the bug in your code, but you have got to assume that copyout() would fail if the user/kernel addr passed to it is not accessible. regards -kamal The whole point of copyin and copyout is to deal with copying to and from user virtual memory that might not be paged in at the moment. Your statement thus makes little sense. Scott ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: how to use the function copyout()
Giorgos Keramidas wrote: On 2005-07-25 18:14, Felix-KM [EMAIL PROTECTED] wrote: I have no idea if it is possible for ioctls to have mapped more than a few 100 bytes for data exchange. You should use read and uiomove() instead. So if I get it right, it's impossible in FreeBSD to gain access to 64KB of user's program memory with ioctl? My situation is this - I have a device driver for Linux. My task is port it as it is (1:1) into FreeBSD. In the Linux driver Ioctl is realized with the macroses _put_user _get_user all over it. As I understand in FreeBSD their analogues are functions described in store(9), copy(9) and fetch(9). So the problem is that in my user program an array short unsigned int Data[32768] is defined. I need to gain access to the array(to each element of it) from device driver with Ioctl handler. Is it possible to do? If yes, then how it can be done? A better alternative that doesn't involve copying huge amounts of data from userlevel to kernel space and vice versa is probably to pass just the address of the area with an ioctl() and then map the appropriate pages from the address space of the user process to an area where the kernel can access the data directly? The kernel can see all of the user address space already, assuming that it's operating in the same process context as the user application (i.e. you haven't defered the ioctl call to a kthread, which is not normally the case). Mapping isn't the problem. Scott ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: how to use the function copyout()
Felix-KM wrote:
I can't understand how to use the function copyout().
It is necessary to write the data from a device driver to the
array defined in user program.
I do it this way:
#define IOCTL_GET_B_IOWR(F, 127, 0x4)
What you've declared here is an ioctl that will copy in 4 bytes of
user data on entry, and copy out 4 bytes back out on exit. The argument
that you supply to the ioctl(2) must be a pointer to a 4 byte word that
you want to copy. This probably isn't what you want. Based on your
code snippets, you want:
#define IOCTL_GET_B _IOW(F, 127, unsigned short)
static int my_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int
flag, struct thread *td)
{
unsigned short data;
[...]
case IOCTL_GET_B:
*(unsigned short *)arg = data;
break;
[...]
Similar code will work for all integral types, as well as simple
structures. The generic ioctl layer will handle all of the copying
magic for you. Copying compound structures (ones that have pointers
to other data that you also want to copy) require explicit copyin
or copyout operations on the pointers that are embedded into the
struct. Likewise, copying arbitrary data that isn't a structure or
integral type (like an array) also requires an explicit copy operation.
You could do something like the following:
struct mysubdata {
int foo;
int bar;
};
struct mystruct {
struct mysubdata *msd;
};
#define IOCTL_SET_COMPOUNT_STRUCT _IOR(F, 123, struct mystruct)
#define IOCTL_SET_BIGDATA _IO(F, 124)
static int my_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int
flag, struct thread *td)
{
struct mystruct *ms;
struct mysubdata msd;
char *bigdata *bd;
[...]
case IOCTL_SET_COMPOUNT_STRUCT:
ms = *(struct mystruct *)arg;
copyin(ms-msd, msd, sizeof(struct mysubdata));
break;
case IOCTL_SET_BIGDATA:
bd = malloc(65536, M_DEVBUF, M_WAITOK);
copyin(arg, bd, 65536);
break;
[...]
Note that the BIGDATA ioctl doesn't copy in anything on its own. For
ioctls like this, it's often convenient to pass a structure anyway that
contains the size of the data to be copied in and a pointer to the data,
like so:
struct mybigdata {
int datasize;
char*bigdata;
}
#define IOCTL_SET_BIGDATA _IOR(B, 123, struct mybigdata)
case IOCTL_GET_BIGDATA:
mbd = *(struct mybigdata *)arg;
bd = malloc(mbd-datasize, M_DEVBUF, M_WAITOK);
copyin(mbd-bigdata, bd, mbd-datasize);
break;
Does this make sense? Fell free to contact me with questions on this or
anything else.
Scott
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Re: how to use the function copyout()
Scott Long wrote:
Felix-KM wrote:
I can't understand how to use the function copyout().
It is necessary to write the data from a device driver to the
array defined in user program.
I do it this way:
#define IOCTL_GET_B_IOWR(F, 127, 0x4)
What you've declared here is an ioctl that will copy in 4 bytes of
user data on entry, and copy out 4 bytes back out on exit. The argument
that you supply to the ioctl(2) must be a pointer to a 4 byte word that
you want to copy. This probably isn't what you want. Based on your
code snippets, you want:
#define IOCTL_GET_B_IOW(F, 127, unsigned short)
static int my_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int
flag, struct thread *td)
{
unsigned short data;
[...]
case IOCTL_GET_B:
*(unsigned short *)arg = data;
break;
[...]
Similar code will work for all integral types, as well as simple
structures. The generic ioctl layer will handle all of the copying
magic for you. Copying compound structures (ones that have pointers
to other data that you also want to copy) require explicit copyin
or copyout operations on the pointers that are embedded into the
struct. Likewise, copying arbitrary data that isn't a structure or
integral type (like an array) also requires an explicit copy operation.
You could do something like the following:
struct mysubdata {
int foo;
int bar;
};
struct mystruct {
struct mysubdata *msd;
};
#define IOCTL_SET_COMPOUNT_STRUCT_IOR(F, 123, struct mystruct)
#define IOCTL_SET_BIGDATA_IO(F, 124)
static int my_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int
flag, struct thread *td)
{
struct mystruct *ms;
struct mysubdata msd;
char *bigdata *bd;
[...]
case IOCTL_SET_COMPOUNT_STRUCT:
ms = *(struct mystruct *)arg;
copyin(ms-msd, msd, sizeof(struct mysubdata));
break;
case IOCTL_SET_BIGDATA:
bd = malloc(65536, M_DEVBUF, M_WAITOK);
copyin(arg, bd, 65536);
break;
[...]
Note that the BIGDATA ioctl doesn't copy in anything on its own. For
ioctls like this, it's often convenient to pass a structure anyway that
contains the size of the data to be copied in and a pointer to the data,
like so:
struct mybigdata {
intdatasize;
char*bigdata;
}
#define IOCTL_SET_BIGDATA_IOR(B, 123, struct mybigdata)
case IOCTL_GET_BIGDATA:
mbd = *(struct mybigdata *)arg;
bd = malloc(mbd-datasize, M_DEVBUF, M_WAITOK);
copyin(mbd-bigdata, bd, mbd-datasize);
break;
Does this make sense? Fell free to contact me with questions on this or
anything else.
Scott
Oops, I made a small but important mistake in these examples. When you
use _IOR or _IOW, the data argument passed to your routine will be a
pointer (in kernel address space) to the data that you specified, not a
pointer to a pointer. So in the above example, you'd do:
mbd = (struct mybigdata *)arg;
not:
mbd = *(struct mybigdata *)arg;
For integral types, you'd still do:
data = *(unsigned short *)arg;
For ioctls that are specified with merely _IO, the data argument is a
pointer in user address space. Technically you could just use bcopy on
this, but the physical pages backing that address might have been
swapped out in between the time the syscall was started and the time
that your handler got called. The whole point of copyin/copyout is
to safely and transparently handle this situation.
Sorry for the confusion.
Scott
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