cdev/mydev.c

   1 #include <sys/param.h>
   2 #include <sys/systm.h>    /* for uiomove(9) */
   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 /* These macros expand to function prototypes needed for autoconf(9) */
  15 void mydevattach(struct device *parent, struct device *self, void *aux);
  16 static dev_type_open(mydevopen);
  17 static dev_type_close(mydevclose);
  18 static dev_type_read(mydevread);
  19 static dev_type_ioctl(mydevioctl);
  20
  21 static struct mydev_softc {
  22     struct device sc_mydev;    /* generic device info */
  23
  24     unsigned int sc_usage;     /* number of open devices */
  25 } mydev_softc;
  26
  27 /*
  28  * Each device driver must present to the system a standard
  29  * autoconfiguration interface. See driver(9).
  30  */
  31 CFATTACH_DECL(mydev,                        /* driver name */
  32               sizeof (struct mydev_softc),  /* size of instance data */
  33               NULL,                         /* match/probe function */
  34               mydevattach,                  /* attach function */
  35               NULL,                         /* detach function */
  36               NULL);                        /* activate function */
  37
  38 /* Define the character dev handlers */
  39 const struct cdevsw mydev_cdevsw = {
  40     mydevopen,
  41     mydevclose,
  42     mydevread,
  43     nowrite,
  44     mydevioctl,
  45     nostop,
  46     notty,
  47     nopoll,
  48     nommap,
  49     nokqfilter,
  50     D_OTHER,
  51 };
  52
  53 /*
  54  * This private buffer is the pool we draw data from
  55  * and send them over to userspace upon a read() request.
  56  */
  57 static char mybuffer[] = "This is a test";
  58
  59 /*
  60  * Attach for autoconfig to find.
  61  */
  62 void
  63 mydevattach(struct device *parent, struct device *self, void *aux)
  64 {
  65     /*
  66      * This is where resources that need to be allocated/initialised
  67      * can be set up, prior to xxxopen() call.
  68     */
  69     log(LOG_DEBUG, "mydev: pseudo-device attached\n");
  70     mydev_softc.sc_usage = 0;
  71 }
  72
  73 /*
  74  * Handle an open request on the dev.
  75  */
  76 static int
  77 mydevopen(dev_t dev, int flags, int fmt, struct lwp *proc)
  78 {
  79     log(LOG_DEBUG, "mydev: pseudo-device open attempt by "
  80         "uid=%u, pid=%u. (dev=%u, major=%d, minor=%d)\n",
  81         kauth_cred_geteuid(proc->l_cred), proc->l_proc->p_pid,
  82         dev, major(dev), minor(dev));
  83
  84     if (mydev_softc.sc_usage > 0) {
  85         log(LOG_ERR, "mydev: pseudo-device already in use\n");
  86         return EBUSY;
  87     }
  88
  89     mydev_softc.sc_usage++;
  90
  91     return 0;    /* Success */
  92 }
  93
  94 /*
  95  * Handle the close request for the dev.
  96  */
  97 static int
  98 mydevclose(dev_t dev, int flags, int fmt, struct lwp *proc)
  99 {
 100     if (mydev_softc.sc_usage > 0)
 101         mydev_softc.sc_usage--;
 102
 103     log(LOG_DEBUG, "mydev: pseudo-device closed\n");
 104
 105     return 0;    /* Success */
 106 }
 107
 108 /*
 109  * Handle read request on the dev.
 110  */
 111 static int
 112 mydevread(dev_t dev, struct uio *uio, int ioflag)
 113 {
 114     int ret;
 115     size_t nbytes;
 116
 117     log(LOG_DEBUG, "mydev: uio: iov = %p, iovcnt = %d, resid = %u, vmspace = %p\n",
 118         uio->uio_iov, uio->uio_iovcnt, uio->uio_resid, uio->uio_vmspace);
 119
 120     while (uio->uio_resid > 0) {
 121         nbytes = MIN(uio->uio_resid, sizeof mybuffer);
 122         if ((ret = uiomove(mybuffer, nbytes, uio)) != 0)
 123             return ret;    /* Error */
 124     }
 125
 126     return 0;    /* Success */
 127 }
 128
 129
 130 /*
 131  * Handle the ioctl for the dev.
 132  */
 133 static int
 134 mydevioctl(dev_t dev, u_long cmd, void *data, int flags,
 135            struct lwp *proc)
 136 {
 137     const struct mydev_params *params;
 138     const struct plistref *pref;
 139     char *val;
 140     prop_dictionary_t dict;
 141     prop_object_t po;
 142     int error = 0;
 143
 144     switch (cmd) {
 145     case MYDEVOLDIOCTL:
 146         /* Pass data from userspace to kernel in the conventional way */
 147         params = (const struct mydev_params *)data;
 148         log(LOG_DEBUG, "mydev: got number of %d and string of %s\n",
 149             params->number, params->string);
 150         break;
 151
 152     case MYDEVSETPROPS:
 153         /* Use proplib(3) for userspace/kernel communication */
 154         pref = (const struct plistref *)data;
 155         error = prop_dictionary_copyin_ioctl(pref, cmd, &dict);
 156         if (error)
 157             return error;
 158
 159         /* Print dict's count for debugging purposes */
 160         log(LOG_DEBUG, "mydev: dict count = %u\n",
 161             prop_dictionary_count(dict));
 162
 163         /* Retrieve object associated with "key" key */
 164         po = prop_dictionary_get(dict, "key");
 165         if (po == NULL || prop_object_type(po) != PROP_TYPE_STRING) {
 166             log(LOG_DEBUG, "mydev: prop_dictionary_get() failed\n");
 167             prop_object_release(dict);
 168             return -1;
 169         }
 170
 171         /* Print data */
 172         val = prop_string_cstring(po);
 173         if (val == NULL) {
 174             log(LOG_DEBUG, "mydev: prop_string_cstring() failed\n");
 175             prop_object_release(po);
 176             prop_object_release(dict);
 177             return -1;
 178         }
 179         prop_object_release(po);
 180         log(LOG_DEBUG, "mydev: <x, y> = (%s, %s)\n", "key", val);
 181         free(val, M_TEMP);
 182
 183         /* Done */
 184         prop_object_release(dict);
 185         break;
 186
 187     default:
 188         /* Inappropriate ioctl for device */
 189         error = ENOTTY;
 190     }
 191
 192     return error;
 193 }