netbsd/cdev/mydev.c

   1 #include <sys/param.h>
   2 #include <sys/systm.h>
   3 #include <sys/proc.h>
   4 #include <sys/errno.h>
   5 #include <sys/ioctl.h>
   6 #include <sys/device.h>
   7 #include <sys/conf.h>
   8 #include <sys/malloc.h>    /* for free(9) */
   9 #include <sys/mydev.h>
  10 #include <sys/kauth.h>
  11 #include <sys/syslog.h>
  12 #include <prop/proplib.h>
  13
  14 struct mydev_softc {
  15     struct device mydev_dev;
  16 };
  17
  18 /* Autoconfiguration glue */
  19 void mydevattach(struct device *parent, struct device *self, void *aux);
  20 int mydevopen(dev_t dev, int flags, int fmt, struct lwp *proc);
  21 int mydevclose(dev_t dev, int flags, int fmt, struct lwp *proc);
  22 int mydevioctl(dev_t dev, u_long cmd, caddr_t data, int flags,
  23                       struct lwp *proc);
  24
  25 /* Just define the character dev handlers because that is all we need */
  26 const struct cdevsw mydev_cdevsw = {
  27     mydevopen,
  28     mydevclose,
  29     noread,
  30     nowrite,
  31     mydevioctl,
  32     nostop,
  33     notty,
  34     nopoll,
  35     nommap,
  36     nokqfilter,
  37     0    /* int d_type; */
  38 };
  39
  40 /* Count of number of times device is open */
  41 static unsigned int mydev_usage = 0;
  42
  43 /*
  44  * Attach for autoconfig to find.
  45  */
  46 void
  47 mydevattach(struct device *parent, struct device *self, void *aux)
  48 {
  49     /*
  50      * This is where resources that need to be allocated/initialised
  51      * before open is called can be set up.
  52     */
  53     mydev_usage = 0;
  54     log(LOG_DEBUG, "mydev: pseudo-device attached\n");
  55 }
  56
  57 /*
  58  * Handle an open request on the dev.
  59  */
  60 int
  61 mydevopen(dev_t dev, int flags, int fmt, struct lwp *proc)
  62 {
  63     log(LOG_DEBUG, "mydev: pseudo-device open attempt by "
  64         "uid=%u, pid=%u. (dev=%u)\n",
  65         kauth_cred_geteuid(proc->l_cred), proc->l_proc->p_pid,
  66         dev);
  67
  68     if (mydev_usage > 0) {
  69         log(LOG_DEBUG, "mydev: pseudo-device already in use\n");
  70         return EBUSY;
  71     }
  72
  73     return 0;    /* Success */
  74 }
  75
  76 /*
  77  * Handle the close request for the dev.
  78  */
  79 int
  80 mydevclose(dev_t dev, int flags, int fmt, struct lwp *proc)
  81 {
  82     if (mydev_usage > 0)
  83         mydev_usage--;
  84
  85     log(LOG_DEBUG, "mydev: pseudo-device closed\n");
  86
  87     return 0;
  88 }
  89
  90 /*
  91  * Handle the ioctl for the dev.
  92  */
  93 int
  94 mydevioctl(dev_t dev, u_long cmd, caddr_t data, int flags,
  95            struct lwp *proc)
  96 {
  97     prop_dictionary_t dict;
  98     prop_string_t ps;
  99     struct mydev_params *params;
 100     const struct plistref *pref;
 101     int error = 0;
 102     char *val;
 103
 104     switch (cmd) {
 105     case MYDEVOLDIOCTL:
 106         /* Pass data from userspace to kernel in the conventional way */
 107         params = (struct mydev_params *)data;
 108         log(LOG_DEBUG, "Got number of %d and string of %s\n",
 109             params->number, params->string);
 110         break;
 111
 112     case MYDEVSETPROPS:
 113         /* Use proplib(3) for userspace/kernel communication */
 114         pref = (const struct plistref *)data;
 115         error = prop_dictionary_copyin_ioctl(pref, cmd, &dict);
 116         if (error)
 117             return error;
 118
 119         /* Print dict's count for debugging purposes */
 120         log(LOG_DEBUG, "mydev: dict count = %u\n",
 121             prop_dictionary_count(dict));
 122
 123         /* Retrieve object associated with "key" key */
 124         ps = prop_dictionary_get(dict, "key");
 125         if (ps == NULL || prop_object_type(ps) != PROP_TYPE_STRING) {
 126             prop_object_release(dict);
 127             log(LOG_DEBUG, "mydev: prop_dictionary_get() failed\n");
 128             return -1;
 129         }
 130
 131         /* Print data */
 132         val = prop_string_cstring(ps);
 133         prop_object_release(ps);
 134         log(LOG_DEBUG, "<x, y> = (%s, %s)\n", "key", val);
 135         free(val, M_TEMP);
 136
 137         /* Done */
 138         prop_object_release(dict);
 139         break;
 140
 141     default:
 142         /* Invalid operation */
 143         error = ENODEV;
 144     }
 145
 146     return error;
 147 }