Convert the snp(4) driver to use cdevpriv.
Now we have a single /dev/snp device node, which can be opened by watch(8) multiple times. Even though snp(4) will be dead as of next week, it's nice having this in SVN, because: - We may want to MFC it to RELENG_7. - By the time we fix snp(4) again, it's already there, existing watch(8) binaries should already work. Just like bpf(4), I'm adding a symlink from snp0 to snp to remain binary compatible.
This commit is contained in:
Ed Schouten
parent
854d77bdd6
commit
2e37c8eacb
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=181755
@ -16,8 +16,8 @@
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.Ft int
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.Fn ioctl fd FIONREAD &result
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.Sh DESCRIPTION
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.Pa /dev/snp?
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are snoop devices which allow users to attach to any tty
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.Pa /dev/snp
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is a snoop device which allows users to attach to any tty
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and watch activities on it.
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The kernel must be compiled with
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.Cd "device snp" ,
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@ -36,7 +36,6 @@ __FBSDID("$FreeBSD$");
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static l_close_t snplclose;
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static l_write_t snplwrite;
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static d_open_t snpopen;
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static d_close_t snpclose;
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static d_read_t snpread;
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static d_write_t snpwrite;
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static d_ioctl_t snpioctl;
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@ -46,7 +45,6 @@ static struct cdevsw snp_cdevsw = {
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.d_version = D_VERSION,
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.d_flags = D_PSEUDO | D_NEEDGIANT | D_NEEDMINOR,
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.d_open = snpopen,
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.d_close = snpclose,
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.d_read = snpread,
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.d_write = snpwrite,
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.d_ioctl = snpioctl,
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@ -70,7 +68,6 @@ static struct linesw snpdisc = {
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*/
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struct snoop {
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LIST_ENTRY(snoop) snp_list; /* List glue. */
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int snp_unit; /* Device number. */
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struct cdev *snp_target; /* Target tty device. */
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struct tty *snp_tty; /* Target tty pointer. */
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u_long snp_len; /* Possible length. */
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@ -111,13 +108,11 @@ static MALLOC_DEFINE(M_SNP, "snp", "Snoop device data");
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* module load time.
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*/
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static int snooplinedisc;
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static struct cdev *snoopdev;
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static LIST_HEAD(, snoop) snp_sclist = LIST_HEAD_INITIALIZER(&snp_sclist);
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static struct clonedevs *snpclones;
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static struct tty *snpdevtotty(struct cdev *dev);
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static void snp_clone(void *arg, struct ucred *cred, char *name,
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int namelen, struct cdev **dev);
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static void snp_detach(void *arg);
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static int snp_down(struct snoop *snp);
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static int snp_in(struct snoop *snp, char *buf, int n);
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@ -220,14 +215,17 @@ snpwrite(struct cdev *dev, struct uio *uio, int flag)
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int error, i, len;
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unsigned char c[SNP_INPUT_BUF];
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snp = dev->si_drv1;
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error = devfs_get_cdevpriv((void **)&snp);
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if (error != 0)
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return (error);
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tp = snp->snp_tty;
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if (tp == NULL)
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return (EIO);
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if ((tp->t_state & TS_SNOOP) && tp->t_line == snooplinedisc)
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goto tty_input;
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printf("snp%d: attempt to write to bad tty\n", snp->snp_unit);
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printf("snp: attempt to write to bad tty\n");
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return (EIO);
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tty_input:
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@ -255,7 +253,10 @@ snpread(struct cdev *dev, struct uio *uio, int flag)
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caddr_t from;
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char *nbuf;
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snp = dev->si_drv1;
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error = devfs_get_cdevpriv((void **)&snp);
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if (error != 0)
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return (error);
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KASSERT(snp->snp_len + snp->snp_base <= snp->snp_blen,
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("snoop buffer error"));
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@ -324,12 +325,12 @@ snp_in(struct snoop *snp, char *buf, int n)
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return (0);
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if (snp->snp_flags & SNOOP_DOWN) {
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printf("snp%d: more data to down interface\n", snp->snp_unit);
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printf("snp: more data to down interface\n");
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return (0);
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}
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if (snp->snp_flags & SNOOP_OFLOW) {
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printf("snp%d: buffer overflow\n", snp->snp_unit);
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printf("snp: buffer overflow\n");
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/*
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* On overflow we just repeat the standart close
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* procedure...yes , this is waste of space but.. Then next
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@ -387,18 +388,30 @@ snp_in(struct snoop *snp, char *buf, int n)
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return (n);
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}
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static void
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snp_dtor(void *data)
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{
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struct snoop *snp = data;
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snp->snp_blen = 0;
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LIST_REMOVE(snp, snp_list);
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free(snp->snp_buf, M_SNP);
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snp->snp_flags &= ~SNOOP_OPEN;
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snp_detach(snp);
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}
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static int
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snpopen(struct cdev *dev, int flag, int mode, struct thread *td)
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{
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struct snoop *snp;
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int error;
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if (dev->si_drv1 == NULL) {
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dev->si_flags &= ~SI_CHEAPCLONE;
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dev->si_drv1 = snp = malloc(sizeof(*snp), M_SNP,
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M_WAITOK | M_ZERO);
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snp->snp_unit = dev2unit(dev);
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} else
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return (EBUSY);
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snp = malloc(sizeof(*snp), M_SNP, M_WAITOK | M_ZERO);
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error = devfs_set_cdevpriv(snp, snp_dtor);
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if (error != 0) {
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free(snp, M_SNP);
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return (error);
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}
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/*
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* We intentionally do not OR flags with SNOOP_OPEN, but set them so
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@ -444,7 +457,7 @@ snp_detach(void *arg)
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tp->t_state &= ~TS_SNOOP;
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tp->t_line = snp->snp_olddisc;
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} else
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printf("snp%d: bad attached tty data\n", snp->snp_unit);
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printf("snp: bad attached tty data\n");
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snp->snp_tty = NULL;
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snp->snp_target = NULL;
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@ -455,23 +468,6 @@ snp_detach(void *arg)
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free(snp, M_SNP);
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}
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static int
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snpclose(struct cdev *dev, int flags, int fmt, struct thread *td)
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{
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struct snoop *snp;
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snp = dev->si_drv1;
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snp->snp_blen = 0;
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LIST_REMOVE(snp, snp_list);
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free(snp->snp_buf, M_SNP);
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snp->snp_flags &= ~SNOOP_OPEN;
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dev->si_drv1 = NULL;
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snp_detach(snp);
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destroy_dev_sched(dev);
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return (0);
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}
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static int
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snp_down(struct snoop *snp)
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{
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@ -495,9 +491,12 @@ snpioctl(struct cdev *dev, u_long cmd, caddr_t data, int flags,
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struct tty *tp;
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struct cdev *tdev;
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struct file *fp;
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int s;
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int error, s;
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error = devfs_get_cdevpriv((void **)&snp);
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if (error != 0)
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return (error);
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snp = dev->si_drv1;
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switch (cmd) {
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case SNPSTTY:
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s = *(int *)data;
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@ -587,7 +586,10 @@ snppoll(struct cdev *dev, int events, struct thread *td)
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struct snoop *snp;
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int revents;
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snp = dev->si_drv1;
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if (devfs_get_cdevpriv((void **)&snp) != 0)
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return (events &
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(POLLHUP|POLLIN|POLLRDNORM|POLLOUT|POLLWRNORM));
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revents = 0;
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/*
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* If snoop is down, we don't want to poll() forever so we return 1.
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@ -603,44 +605,22 @@ snppoll(struct cdev *dev, int events, struct thread *td)
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return (revents);
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}
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static void
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snp_clone(void *arg, struct ucred *cred, char *name, int namelen,
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struct cdev **dev)
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{
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int u, i;
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if (*dev != NULL)
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return;
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if (dev_stdclone(name, NULL, "snp", &u) != 1)
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return;
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i = clone_create(&snpclones, &snp_cdevsw, &u, dev, 0);
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if (i)
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*dev = make_dev_credf(MAKEDEV_REF, &snp_cdevsw, unit2minor(u),
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NULL, UID_ROOT, GID_WHEEL, 0600, "snp%d", u);
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if (*dev != NULL) {
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(*dev)->si_flags |= SI_CHEAPCLONE;
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}
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}
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static int
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snp_modevent(module_t mod, int type, void *data)
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{
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static eventhandler_tag eh_tag;
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switch (type) {
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case MOD_LOAD:
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/* XXX error checking. */
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clone_setup(&snpclones);
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eh_tag = EVENTHANDLER_REGISTER(dev_clone, snp_clone, 0, 1000);
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snooplinedisc = ldisc_register(LDISC_LOAD, &snpdisc);
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snoopdev = make_dev(&snp_cdevsw, 0, UID_ROOT, GID_WHEEL,
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0600, "snp");
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/* For compatibility */
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make_dev_alias(snoopdev, "snp0");
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break;
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case MOD_UNLOAD:
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if (!LIST_EMPTY(&snp_sclist))
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return (EBUSY);
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EVENTHANDLER_DEREGISTER(dev_clone, eh_tag);
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drain_dev_clone_events();
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clone_cleanup(&snpclones);
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destroy_dev_drain(&snp_cdevsw);
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destroy_dev(snoopdev);
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ldisc_deregister(snooplinedisc);
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break;
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default:
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@ -152,30 +152,21 @@ fatal(int error, const char *buf)
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static int
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open_snp(void)
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{
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char snp[] = {_PATH_DEV "snpXXX"};
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int f, mode, pos, c;
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int f, mode;
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pos = strlen(snp) - 3;
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if (opt_write)
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mode = O_RDWR;
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else
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mode = O_RDONLY;
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if (opt_snpdev == NULL)
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for (c = 0; c <= 999; c++) {
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snprintf(snp+pos, 4, "%d", c);
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if ((f = open(snp, mode)) < 0) {
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if (errno == EBUSY)
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continue;
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err(1, "open %s", snp);
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}
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return f;
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}
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f = open(_PATH_DEV "snp", mode);
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else
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if ((f = open(opt_snpdev, mode)) != -1)
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return (f);
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f = open(opt_snpdev, mode);
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if (f == -1)
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fatal(EX_OSFILE, "cannot open snoop device");
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return (0);
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return (f);
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}
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