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-rw-r--r--fs/select.c437
1 files changed, 427 insertions, 10 deletions
diff --git a/fs/select.c b/fs/select.c
index e2112270d75a..bd4b2ccfd346 100644
--- a/fs/select.c
+++ b/fs/select.c
@@ -338,6 +338,53 @@ sticky:
return ret;
}
+/*
+ * Scalable version of the fd_set.
+ */
+
+typedef struct {
+ unsigned long *in, *out, *ex;
+ unsigned long *res_in, *res_out, *res_ex;
+} fd_set_bits;
+
+/*
+ * How many longwords for "nr" bits?
+ */
+#define FDS_BITPERLONG (8*sizeof(long))
+#define FDS_LONGS(nr) (((nr)+FDS_BITPERLONG-1)/FDS_BITPERLONG)
+#define FDS_BYTES(nr) (FDS_LONGS(nr)*sizeof(long))
+
+/*
+ * We do a VERIFY_WRITE here even though we are only reading this time:
+ * we'll write to it eventually..
+ *
+ * Use "unsigned long" accesses to let user-mode fd_set's be long-aligned.
+ */
+static inline
+int get_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
+{
+ nr = FDS_BYTES(nr);
+ if (ufdset)
+ return copy_from_user(fdset, ufdset, nr) ? -EFAULT : 0;
+
+ memset(fdset, 0, nr);
+ return 0;
+}
+
+static inline unsigned long __must_check
+set_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
+{
+ if (ufdset)
+ return __copy_to_user(ufdset, fdset, FDS_BYTES(nr));
+ return 0;
+}
+
+static inline
+void zero_fd_set(unsigned long nr, unsigned long *fdset)
+{
+ memset(fdset, 0, FDS_BYTES(nr));
+}
+
#define FDS_IN(fds, n) (fds->in + n)
#define FDS_OUT(fds, n) (fds->out + n)
#define FDS_EX(fds, n) (fds->ex + n)
@@ -401,7 +448,7 @@ static inline void wait_key_set(poll_table *wait, unsigned long in,
wait->_key |= POLLOUT_SET;
}
-int do_select(int n, fd_set_bits *fds, struct timespec64 *end_time)
+static int do_select(int n, fd_set_bits *fds, struct timespec64 *end_time)
{
ktime_t expire, *to = NULL;
struct poll_wqueues table;
@@ -409,7 +456,7 @@ int do_select(int n, fd_set_bits *fds, struct timespec64 *end_time)
int retval, i, timed_out = 0;
u64 slack = 0;
unsigned int busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0;
- unsigned long busy_end = 0;
+ unsigned long busy_start = 0;
rcu_read_lock();
retval = max_select_fd(n, fds);
@@ -512,11 +559,11 @@ int do_select(int n, fd_set_bits *fds, struct timespec64 *end_time)
/* only if found POLL_BUSY_LOOP sockets && not out of time */
if (can_busy_loop && !need_resched()) {
- if (!busy_end) {
- busy_end = busy_loop_end_time();
+ if (!busy_start) {
+ busy_start = busy_loop_current_time();
continue;
}
- if (!busy_loop_timeout(busy_end))
+ if (!busy_loop_timeout(busy_start))
continue;
}
busy_flag = 0;
@@ -800,7 +847,7 @@ static int do_poll(struct poll_list *list, struct poll_wqueues *wait,
int timed_out = 0, count = 0;
u64 slack = 0;
unsigned int busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0;
- unsigned long busy_end = 0;
+ unsigned long busy_start = 0;
/* Optimise the no-wait case */
if (end_time && !end_time->tv_sec && !end_time->tv_nsec) {
@@ -853,11 +900,11 @@ static int do_poll(struct poll_list *list, struct poll_wqueues *wait,
/* only if found POLL_BUSY_LOOP sockets && not out of time */
if (can_busy_loop && !need_resched()) {
- if (!busy_end) {
- busy_end = busy_loop_end_time();
+ if (!busy_start) {
+ busy_start = busy_loop_current_time();
continue;
}
- if (!busy_loop_timeout(busy_end))
+ if (!busy_loop_timeout(busy_start))
continue;
}
busy_flag = 0;
@@ -881,7 +928,7 @@ static int do_poll(struct poll_list *list, struct poll_wqueues *wait,
#define N_STACK_PPS ((sizeof(stack_pps) - sizeof(struct poll_list)) / \
sizeof(struct pollfd))
-int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds,
+static int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds,
struct timespec64 *end_time)
{
struct poll_wqueues table;
@@ -1053,3 +1100,373 @@ SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, unsigned int, nfds,
return ret;
}
+
+#ifdef CONFIG_COMPAT
+#define __COMPAT_NFDBITS (8 * sizeof(compat_ulong_t))
+
+static
+int compat_poll_select_copy_remaining(struct timespec *end_time, void __user *p,
+ int timeval, int ret)
+{
+ struct timespec ts;
+
+ if (!p)
+ return ret;
+
+ if (current->personality & STICKY_TIMEOUTS)
+ goto sticky;
+
+ /* No update for zero timeout */
+ if (!end_time->tv_sec && !end_time->tv_nsec)
+ return ret;
+
+ ktime_get_ts(&ts);
+ ts = timespec_sub(*end_time, ts);
+ if (ts.tv_sec < 0)
+ ts.tv_sec = ts.tv_nsec = 0;
+
+ if (timeval) {
+ struct compat_timeval rtv;
+
+ rtv.tv_sec = ts.tv_sec;
+ rtv.tv_usec = ts.tv_nsec / NSEC_PER_USEC;
+
+ if (!copy_to_user(p, &rtv, sizeof(rtv)))
+ return ret;
+ } else {
+ struct compat_timespec rts;
+
+ rts.tv_sec = ts.tv_sec;
+ rts.tv_nsec = ts.tv_nsec;
+
+ if (!copy_to_user(p, &rts, sizeof(rts)))
+ return ret;
+ }
+ /*
+ * If an application puts its timeval in read-only memory, we
+ * don't want the Linux-specific update to the timeval to
+ * cause a fault after the select has completed
+ * successfully. However, because we're not updating the
+ * timeval, we can't restart the system call.
+ */
+
+sticky:
+ if (ret == -ERESTARTNOHAND)
+ ret = -EINTR;
+ return ret;
+}
+
+/*
+ * Ooo, nasty. We need here to frob 32-bit unsigned longs to
+ * 64-bit unsigned longs.
+ */
+static
+int compat_get_fd_set(unsigned long nr, compat_ulong_t __user *ufdset,
+ unsigned long *fdset)
+{
+ nr = DIV_ROUND_UP(nr, __COMPAT_NFDBITS);
+ if (ufdset) {
+ unsigned long odd;
+
+ if (!access_ok(VERIFY_WRITE, ufdset, nr*sizeof(compat_ulong_t)))
+ return -EFAULT;
+
+ odd = nr & 1UL;
+ nr &= ~1UL;
+ while (nr) {
+ unsigned long h, l;
+ if (__get_user(l, ufdset) || __get_user(h, ufdset+1))
+ return -EFAULT;
+ ufdset += 2;
+ *fdset++ = h << 32 | l;
+ nr -= 2;
+ }
+ if (odd && __get_user(*fdset, ufdset))
+ return -EFAULT;
+ } else {
+ /* Tricky, must clear full unsigned long in the
+ * kernel fdset at the end, this makes sure that
+ * actually happens.
+ */
+ memset(fdset, 0, ((nr + 1) & ~1)*sizeof(compat_ulong_t));
+ }
+ return 0;
+}
+
+static
+int compat_set_fd_set(unsigned long nr, compat_ulong_t __user *ufdset,
+ unsigned long *fdset)
+{
+ unsigned long odd;
+ nr = DIV_ROUND_UP(nr, __COMPAT_NFDBITS);
+
+ if (!ufdset)
+ return 0;
+
+ odd = nr & 1UL;
+ nr &= ~1UL;
+ while (nr) {
+ unsigned long h, l;
+ l = *fdset++;
+ h = l >> 32;
+ if (__put_user(l, ufdset) || __put_user(h, ufdset+1))
+ return -EFAULT;
+ ufdset += 2;
+ nr -= 2;
+ }
+ if (odd && __put_user(*fdset, ufdset))
+ return -EFAULT;
+ return 0;
+}
+
+
+/*
+ * This is a virtual copy of sys_select from fs/select.c and probably
+ * should be compared to it from time to time
+ */
+
+/*
+ * We can actually return ERESTARTSYS instead of EINTR, but I'd
+ * like to be certain this leads to no problems. So I return
+ * EINTR just for safety.
+ *
+ * Update: ERESTARTSYS breaks at least the xview clock binary, so
+ * I'm trying ERESTARTNOHAND which restart only when you want to.
+ */
+static int compat_core_sys_select(int n, compat_ulong_t __user *inp,
+ compat_ulong_t __user *outp, compat_ulong_t __user *exp,
+ struct timespec *end_time)
+{
+ fd_set_bits fds;
+ void *bits;
+ int size, max_fds, ret = -EINVAL;
+ struct fdtable *fdt;
+ long stack_fds[SELECT_STACK_ALLOC/sizeof(long)];
+
+ if (n < 0)
+ goto out_nofds;
+
+ /* max_fds can increase, so grab it once to avoid race */
+ rcu_read_lock();
+ fdt = files_fdtable(current->files);
+ max_fds = fdt->max_fds;
+ rcu_read_unlock();
+ if (n > max_fds)
+ n = max_fds;
+
+ /*
+ * We need 6 bitmaps (in/out/ex for both incoming and outgoing),
+ * since we used fdset we need to allocate memory in units of
+ * long-words.
+ */
+ size = FDS_BYTES(n);
+ bits = stack_fds;
+ if (size > sizeof(stack_fds) / 6) {
+ bits = kmalloc(6 * size, GFP_KERNEL);
+ ret = -ENOMEM;
+ if (!bits)
+ goto out_nofds;
+ }
+ fds.in = (unsigned long *) bits;
+ fds.out = (unsigned long *) (bits + size);
+ fds.ex = (unsigned long *) (bits + 2*size);
+ fds.res_in = (unsigned long *) (bits + 3*size);
+ fds.res_out = (unsigned long *) (bits + 4*size);
+ fds.res_ex = (unsigned long *) (bits + 5*size);
+
+ if ((ret = compat_get_fd_set(n, inp, fds.in)) ||
+ (ret = compat_get_fd_set(n, outp, fds.out)) ||
+ (ret = compat_get_fd_set(n, exp, fds.ex)))
+ goto out;
+ zero_fd_set(n, fds.res_in);
+ zero_fd_set(n, fds.res_out);
+ zero_fd_set(n, fds.res_ex);
+
+ ret = do_select(n, &fds, end_time);
+
+ if (ret < 0)
+ goto out;
+ if (!ret) {
+ ret = -ERESTARTNOHAND;
+ if (signal_pending(current))
+ goto out;
+ ret = 0;
+ }
+
+ if (compat_set_fd_set(n, inp, fds.res_in) ||
+ compat_set_fd_set(n, outp, fds.res_out) ||
+ compat_set_fd_set(n, exp, fds.res_ex))
+ ret = -EFAULT;
+out:
+ if (bits != stack_fds)
+ kfree(bits);
+out_nofds:
+ return ret;
+}
+
+COMPAT_SYSCALL_DEFINE5(select, int, n, compat_ulong_t __user *, inp,
+ compat_ulong_t __user *, outp, compat_ulong_t __user *, exp,
+ struct compat_timeval __user *, tvp)
+{
+ struct timespec end_time, *to = NULL;
+ struct compat_timeval tv;
+ int ret;
+
+ if (tvp) {
+ if (copy_from_user(&tv, tvp, sizeof(tv)))
+ return -EFAULT;
+
+ to = &end_time;
+ if (poll_select_set_timeout(to,
+ tv.tv_sec + (tv.tv_usec / USEC_PER_SEC),
+ (tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC))
+ return -EINVAL;
+ }
+
+ ret = compat_core_sys_select(n, inp, outp, exp, to);
+ ret = compat_poll_select_copy_remaining(&end_time, tvp, 1, ret);
+
+ return ret;
+}
+
+struct compat_sel_arg_struct {
+ compat_ulong_t n;
+ compat_uptr_t inp;
+ compat_uptr_t outp;
+ compat_uptr_t exp;
+ compat_uptr_t tvp;
+};
+
+COMPAT_SYSCALL_DEFINE1(old_select, struct compat_sel_arg_struct __user *, arg)
+{
+ struct compat_sel_arg_struct a;
+
+ if (copy_from_user(&a, arg, sizeof(a)))
+ return -EFAULT;
+ return compat_sys_select(a.n, compat_ptr(a.inp), compat_ptr(a.outp),
+ compat_ptr(a.exp), compat_ptr(a.tvp));
+}
+
+static long do_compat_pselect(int n, compat_ulong_t __user *inp,
+ compat_ulong_t __user *outp, compat_ulong_t __user *exp,
+ struct compat_timespec __user *tsp, compat_sigset_t __user *sigmask,
+ compat_size_t sigsetsize)
+{
+ compat_sigset_t ss32;
+ sigset_t ksigmask, sigsaved;
+ struct compat_timespec ts;
+ struct timespec end_time, *to = NULL;
+ int ret;
+
+ if (tsp) {
+ if (copy_from_user(&ts, tsp, sizeof(ts)))
+ return -EFAULT;
+
+ to = &end_time;
+ if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
+ return -EINVAL;
+ }
+
+ if (sigmask) {
+ if (sigsetsize != sizeof(compat_sigset_t))
+ return -EINVAL;
+ if (copy_from_user(&ss32, sigmask, sizeof(ss32)))
+ return -EFAULT;
+ sigset_from_compat(&ksigmask, &ss32);
+
+ sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
+ sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
+ }
+
+ ret = compat_core_sys_select(n, inp, outp, exp, to);
+ ret = compat_poll_select_copy_remaining(&end_time, tsp, 0, ret);
+
+ if (ret == -ERESTARTNOHAND) {
+ /*
+ * Don't restore the signal mask yet. Let do_signal() deliver
+ * the signal on the way back to userspace, before the signal
+ * mask is restored.
+ */
+ if (sigmask) {
+ memcpy(&current->saved_sigmask, &sigsaved,
+ sizeof(sigsaved));
+ set_restore_sigmask();
+ }
+ } else if (sigmask)
+ sigprocmask(SIG_SETMASK, &sigsaved, NULL);
+
+ return ret;
+}
+
+COMPAT_SYSCALL_DEFINE6(pselect6, int, n, compat_ulong_t __user *, inp,
+ compat_ulong_t __user *, outp, compat_ulong_t __user *, exp,
+ struct compat_timespec __user *, tsp, void __user *, sig)
+{
+ compat_size_t sigsetsize = 0;
+ compat_uptr_t up = 0;
+
+ if (sig) {
+ if (!access_ok(VERIFY_READ, sig,
+ sizeof(compat_uptr_t)+sizeof(compat_size_t)) ||
+ __get_user(up, (compat_uptr_t __user *)sig) ||
+ __get_user(sigsetsize,
+ (compat_size_t __user *)(sig+sizeof(up))))
+ return -EFAULT;
+ }
+ return do_compat_pselect(n, inp, outp, exp, tsp, compat_ptr(up),
+ sigsetsize);
+}
+
+COMPAT_SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds,
+ unsigned int, nfds, struct compat_timespec __user *, tsp,
+ const compat_sigset_t __user *, sigmask, compat_size_t, sigsetsize)
+{
+ compat_sigset_t ss32;
+ sigset_t ksigmask, sigsaved;
+ struct compat_timespec ts;
+ struct timespec end_time, *to = NULL;
+ int ret;
+
+ if (tsp) {
+ if (copy_from_user(&ts, tsp, sizeof(ts)))
+ return -EFAULT;
+
+ to = &end_time;
+ if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
+ return -EINVAL;
+ }
+
+ if (sigmask) {
+ if (sigsetsize != sizeof(compat_sigset_t))
+ return -EINVAL;
+ if (copy_from_user(&ss32, sigmask, sizeof(ss32)))
+ return -EFAULT;
+ sigset_from_compat(&ksigmask, &ss32);
+
+ sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
+ sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
+ }
+
+ ret = do_sys_poll(ufds, nfds, to);
+
+ /* We can restart this syscall, usually */
+ if (ret == -EINTR) {
+ /*
+ * Don't restore the signal mask yet. Let do_signal() deliver
+ * the signal on the way back to userspace, before the signal
+ * mask is restored.
+ */
+ if (sigmask) {
+ memcpy(&current->saved_sigmask, &sigsaved,
+ sizeof(sigsaved));
+ set_restore_sigmask();
+ }
+ ret = -ERESTARTNOHAND;
+ } else if (sigmask)
+ sigprocmask(SIG_SETMASK, &sigsaved, NULL);
+
+ ret = compat_poll_select_copy_remaining(&end_time, tsp, 0, ret);
+
+ return ret;
+}
+#endif
generated by cgit v1.2.3 (git 2.39.0) at 2024-12-17 09:29:40 +0300