1copyin(9F) Kernel Functions for Drivers copyin(9F)
2
6 copyin - copy data from a user program to a driver buffer
7
9 #include <sys/types.h>
10 #include <sys/ddi.h>
11 int copyin(const void *userbuf, void *driverbuf, size_t cn);
15
18 This interface is obsolete. ddi_copyin(9F) should be used instead.
19
21 userbuf User program source address from which data is trans‐
22 ferred.
23 driverbuf Driver destination address to which data is transferred.
26 cn Number of bytes transferred.
29
32 copyin() copies data from a user program source address to a driver
33 buffer. The driver developer must ensure that adequate space is allo‐
34 cated for the destination address.
35 Addresses that are word-aligned are moved most efficiently. However,
38 the driver developer is not obligated to ensure alignment. This func‐
39 tion automatically finds the most efficient move according to address
40 alignment.
41
43 Under normal conditions, a 0 is returned indicating a successful copy.
44 Otherwise, a −1 is returned if one of the following occurs:
45 o Paging fault; the driver tried to access a page of memory
47 for which it did not have read or write access.
48 o Invalid user address, such as a user area or stack area.
50 o Invalid address that would have resulted in data being
52 copied into the user block.
53 o Hardware fault; a hardware error prevented access to the
55 specified user memory. For example, an uncorrectable parity
56 or ECC error occurred.
57 If a −1 is returned to the caller, driver entry point routines should
60 return EFAULT.
61
63 copyin() can be called from user context only.
64
66 Example 1 An ioctl() Routine
67 A driver ioctl(9E) routine (line 10) can be used to get or set device
70 attributes or registers. In the XX_GETREGS condition (line 17), the
71 driver copies the current device register values to a user data area
72 (line 18). If the specified argument contains an invalid address, an
73 error code is returned.
74 1 struct device { /* layout of physical device registers */
78 2 int control; /* physical device control word */
79 3 int status; /* physical device status word */
80 4 short recv_char; /* receive character from device */
81 5 short xmit_char; /* transmit character to device */
82 6 };
83 7
84 8 extern struct device xx_addr[]; /* phys. device regs. location */
85 9 . . .
86 10 xx_ioctl(dev_t dev, int cmd, int arg, int mode,
87 11 cred_t *cred_p, int *rval_p)
88 12 ...
89 13 {
90 14 register struct device *rp = &xx_addr[getminor(dev) >> 4];
91 15 switch (cmd) {
92 16
93 17 case XX_GETREGS: /* copy device regs. to user program */
94 18 if (copyin(arg, rp, sizeof(struct device)))
95 19 return(EFAULT);
96 20 break;
97 21 ...
98 22 }
99 23 ...
100 24 }
101
104 See attributes(5) for a description of the following attributes:
105 ┌─────────────────────────────┬─────────────────────────────┐
110 │ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
111 ├─────────────────────────────┼─────────────────────────────┤
112 │Stability Level │Obsolete │
113 └─────────────────────────────┴─────────────────────────────┘
114
116 attributes(5), ioctl(9E), bcopy(9F), copyout(9F), ddi_copyin(9F),
117 ddi_copyout(9F), uiomove(9F).
118 Writing Device Drivers
121
123 Driver writers who intend to support layered ioctls in their ioctl(9E)
124 routines should use ddi_copyin(9F) instead.
125 Driver defined locks should not be held across calls to this function.
128 copyin() should not be used from a streams driver. See M_COPYIN and
131 M_COPYOUT in STREAMS Programming Guide.
132SunOS 5.11 27 Sep 2002 copyin(9F)