Implement select.

.github/workflows/main.yml

@@ -486,6 +486,7 @@ jobs:
  patch -p1 < $GITHUB_WORKSPACE/ci/tiocgsid.patch
  patch -p1 < $GITHUB_WORKSPACE/ci/more-sockopts.patch
  patch -p1 < $GITHUB_WORKSPACE/ci/pidfd-open.patch
+ patch -p1 < $GITHUB_WORKSPACE/ci/select-setsize.patch
  ./configure --target-list=${{ matrix.qemu_target }} --prefix=${{ runner.tool_cache }}/qemu --disable-tools --disable-slirp --disable-fdt --disable-capstone --disable-docs
  ninja -C build install
  if: matrix.qemu != '' && matrix.os == 'ubuntu-latest'
@@ -624,6 +625,7 @@ jobs:
  patch -p1 < $GITHUB_WORKSPACE/ci/tiocgsid.patch
  patch -p1 < $GITHUB_WORKSPACE/ci/more-sockopts.patch
  patch -p1 < $GITHUB_WORKSPACE/ci/pidfd-open.patch
+ patch -p1 < $GITHUB_WORKSPACE/ci/select-setsize.patch
  ./configure --target-list=${{ matrix.qemu_target }} --prefix=${{ runner.tool_cache }}/qemu --disable-tools --disable-slirp --disable-fdt --disable-capstone --disable-docs
  ninja -C build install
  if: matrix.qemu != '' && matrix.os == 'ubuntu-latest'
@@ -718,6 +720,7 @@ jobs:
  patch -p1 < $GITHUB_WORKSPACE/ci/tiocgsid.patch
  patch -p1 < $GITHUB_WORKSPACE/ci/more-sockopts.patch
  patch -p1 < $GITHUB_WORKSPACE/ci/pidfd-open.patch
+ patch -p1 < $GITHUB_WORKSPACE/ci/select-setsize.patch
  ./configure --target-list=${{ matrix.qemu_target }} --prefix=${{ runner.tool_cache }}/qemu --disable-tools --disable-slirp --disable-fdt --disable-capstone --disable-docs
  ninja -C build install
  if: matrix.qemu != '' && matrix.os == 'ubuntu-latest'

ci/select-setsize.patch

@@ -0,0 +1,269 @@
+From Dan Gohman <[email protected]>
+Subject: [PATCH] Remove the `FD_SETSIZE` limitation in `select`
+
+The `fd_set` type is limited to a fixed `FD_SETSIZE` number of file
+descriptors, however Linux's `select has no such limitation. Change
+the `select` implementation to using manual bit-vector logic to better
+implement the Linux semantics.
+
+diff -ur a/linux-user/syscall.c b/linux-user/syscall.c
+--- a/linux-user/syscall.c
++++ b/linux-user/syscall.c
+@@ -664,8 +664,9 @@
+ char **, argv, char **, envp, int, flags)
+ #if defined(TARGET_NR_select) || defined(TARGET_NR__newselect) || \
+ defined(TARGET_NR_pselect6) || defined(TARGET_NR_pselect6_time64)
+-safe_syscall6(int, pselect6, int, nfds, fd_set *, readfds, fd_set *, writefds, \
+- fd_set *, exceptfds, struct timespec *, timeout, void *, sig)
++safe_syscall6(int, pselect6, int, nfds, unsigned long *, readfds, \
++ unsigned long *, writefds, unsigned long *, exceptfds, \
++ struct timespec *, timeout, void *, sig)
+ #endif
+ #if defined(TARGET_NR_ppoll) || defined(TARGET_NR_ppoll_time64)
+ safe_syscall5(int, ppoll, struct pollfd *, ufds, unsigned int, nfds,
+@@ -861,7 +862,7 @@
+
+ #if defined(TARGET_NR_select) || defined(TARGET_NR__newselect) || \
+ defined(TARGET_NR_pselect6) || defined(TARGET_NR_pselect6_time64)
+-static inline abi_long copy_from_user_fdset(fd_set *fds,
++static inline abi_long copy_from_user_fdset(unsigned long *fds,
+ abi_ulong target_fds_addr,
+ int n)
+ {
+@@ -875,7 +876,8 @@
+ 1)))
+ return -TARGET_EFAULT;
+
+- FD_ZERO(fds);
++ memset(fds, 0, DIV_ROUND_UP(n, sizeof(unsigned long) * 8) *
++ sizeof(unsigned long));
+ k = 0;
+ for (i = 0; i < nw; i++) {
+ /* grab the abi_ulong */
+@@ -883,7 +885,8 @@
+ for (j = 0; j < TARGET_ABI_BITS; j++) {
+ /* check the bit inside the abi_ulong */
+ if ((b >> j) & 1)
+- FD_SET(k, fds);
++ fds[k / (sizeof(unsigned long) * 8)] |=
++ 1 << (k % (sizeof(unsigned long) * 8));
+ k++;
+ }
+ }
+@@ -893,7 +896,8 @@
+ return 0;
+ }
+
+-static inline abi_ulong copy_from_user_fdset_ptr(fd_set *fds, fd_set **fds_ptr,
++static inline abi_ulong copy_from_user_fdset_ptr(unsigned long *fds,
++ unsigned long **fds_ptr,
+ abi_ulong target_fds_addr,
+ int n)
+ {
+@@ -908,7 +912,7 @@
+ }
+
+ static inline abi_long copy_to_user_fdset(abi_ulong target_fds_addr,
+- const fd_set *fds,
++ const unsigned long *fds,
+ int n)
+ {
+ int i, nw, j, k;
+@@ -926,7 +930,10 @@
+ for (i = 0; i < nw; i++) {
+ v = 0;
+ for (j = 0; j < TARGET_ABI_BITS; j++) {
+- v |= ((abi_ulong)(FD_ISSET(k, fds) != 0) << j);
++ bool set =
++ (fds[k / (sizeof(unsigned long) * 8)] &
++ (1 << (k % (sizeof(unsigned long) * 8)))) != 0;
++ v |= ((abi_ulong)set << j);
+ k++;
+ }
+ __put_user(v, &target_fds[i]);
+@@ -1295,28 +1302,40 @@
+ abi_ulong rfd_addr, abi_ulong wfd_addr,
+ abi_ulong efd_addr, abi_ulong target_tv_addr)
+ {
+- fd_set rfds, wfds, efds;
+- fd_set *rfds_ptr, *wfds_ptr, *efds_ptr;
++ unsigned long *rfds, *wfds, *efds;
++ unsigned long *rfds_ptr, *wfds_ptr, *efds_ptr;
+ struct timeval tv;
+ struct timespec ts, *ts_ptr;
+ abi_long ret;
+
+- ret = copy_from_user_fdset_ptr(&rfds, &rfds_ptr, rfd_addr, n);
++ rfds = malloc(DIV_ROUND_UP(n, sizeof(unsigned long) * 8) *
++ sizeof(unsigned long));
++ wfds = malloc(DIV_ROUND_UP(n, sizeof(unsigned long) * 8) *
++ sizeof(unsigned long));
++ efds = malloc(DIV_ROUND_UP(n, sizeof(unsigned long) * 8) *
++ sizeof(unsigned long));
++
++ ret = copy_from_user_fdset_ptr(rfds, &rfds_ptr, rfd_addr, n);
+ if (ret) {
++ free(rfds); free(wfds); free(efds);
+ return ret;
+ }
+- ret = copy_from_user_fdset_ptr(&wfds, &wfds_ptr, wfd_addr, n);
++ ret = copy_from_user_fdset_ptr(wfds, &wfds_ptr, wfd_addr, n);
+ if (ret) {
++ free(rfds); free(wfds); free(efds);
+ return ret;
+ }
+- ret = copy_from_user_fdset_ptr(&efds, &efds_ptr, efd_addr, n);
++ ret = copy_from_user_fdset_ptr(efds, &efds_ptr, efd_addr, n);
+ if (ret) {
++ free(rfds); free(wfds); free(efds);
+ return ret;
+ }
+
+ if (target_tv_addr) {
+- if (copy_from_user_timeval(&tv, target_tv_addr))
++ if (copy_from_user_timeval(&tv, target_tv_addr)) {
++ free(rfds); free(wfds); free(efds);
+ return -TARGET_EFAULT;
++ }
+ ts.tv_sec = tv.tv_sec;
+ ts.tv_nsec = tv.tv_usec * 1000;
+ ts_ptr = &ts;
+@@ -1328,22 +1347,30 @@
+ ts_ptr, NULL));
+
+ if (!is_error(ret)) {
+- if (rfd_addr && copy_to_user_fdset(rfd_addr, &rfds, n))
++ if (rfd_addr && copy_to_user_fdset(rfd_addr, rfds, n)) {
++ free(rfds); free(wfds); free(efds);
+ return -TARGET_EFAULT;
+- if (wfd_addr && copy_to_user_fdset(wfd_addr, &wfds, n))
++ }
++ if (wfd_addr && copy_to_user_fdset(wfd_addr, wfds, n)) {
++ free(rfds); free(wfds); free(efds);
+ return -TARGET_EFAULT;
+- if (efd_addr && copy_to_user_fdset(efd_addr, &efds, n))
++ }
++ if (efd_addr && copy_to_user_fdset(efd_addr, efds, n)) {
++ free(rfds); free(wfds); free(efds);
+ return -TARGET_EFAULT;
++ }
+
+ if (target_tv_addr) {
+ tv.tv_sec = ts.tv_sec;
+ tv.tv_usec = ts.tv_nsec / 1000;
+ if (copy_to_user_timeval(target_tv_addr, &tv)) {
++ free(rfds); free(wfds); free(efds);
+ return -TARGET_EFAULT;
+ }
+ }
+ }
+
++ free(rfds); free(wfds); free(efds);
+ return ret;
+ }
+
+@@ -1377,8 +1404,8 @@
+ bool time64)
+ {
+ abi_long rfd_addr, wfd_addr, efd_addr, n, ts_addr;
+- fd_set rfds, wfds, efds;
+- fd_set *rfds_ptr, *wfds_ptr, *efds_ptr;
++ unsigned long *rfds, *wfds, *efds;
++ unsigned long *rfds_ptr, *wfds_ptr, *efds_ptr;
+ struct timespec ts, *ts_ptr;
+ abi_long ret;
+
+@@ -1399,16 +1426,26 @@
+ efd_addr = arg4;
+ ts_addr = arg5;
+
+- ret = copy_from_user_fdset_ptr(&rfds, &rfds_ptr, rfd_addr, n);
++ rfds = malloc(DIV_ROUND_UP(n, sizeof(unsigned long) * 8) *
++ sizeof(unsigned long));
++ wfds = malloc(DIV_ROUND_UP(n, sizeof(unsigned long) * 8) *
++ sizeof(unsigned long));
++ efds = malloc(DIV_ROUND_UP(n, sizeof(unsigned long) * 8) *
++ sizeof(unsigned long));
++
++ ret = copy_from_user_fdset_ptr(rfds, &rfds_ptr, rfd_addr, n);
+ if (ret) {
++ free(rfds); free(wfds); free(efds);
+ return ret;
+ }
+- ret = copy_from_user_fdset_ptr(&wfds, &wfds_ptr, wfd_addr, n);
++ ret = copy_from_user_fdset_ptr(wfds, &wfds_ptr, wfd_addr, n);
+ if (ret) {
++ free(rfds); free(wfds); free(efds);
+ return ret;
+ }
+- ret = copy_from_user_fdset_ptr(&efds, &efds_ptr, efd_addr, n);
++ ret = copy_from_user_fdset_ptr(efds, &efds_ptr, efd_addr, n);
+ if (ret) {
++ free(rfds); free(wfds); free(efds);
+ return ret;
+ }
+
+@@ -1419,10 +1456,12 @@
+ if (ts_addr) {
+ if (time64) {
+ if (target_to_host_timespec64(&ts, ts_addr)) {
++ free(rfds); free(wfds); free(efds);
+ return -TARGET_EFAULT;
+ }
+ } else {
+ if (target_to_host_timespec(&ts, ts_addr)) {
++ free(rfds); free(wfds); free(efds);
+ return -TARGET_EFAULT;
+ }
+ }
+@@ -1436,6 +1475,7 @@
+ if (arg6) {
+ arg7 = lock_user(VERIFY_READ, arg6, sizeof(*arg7) * 2, 1);
+ if (!arg7) {
++ free(rfds); free(wfds); free(efds);
+ return -TARGET_EFAULT;
+ }
+ arg_sigset = tswapal(arg7[0]);
+@@ -1445,6 +1485,7 @@
+ if (arg_sigset) {
+ ret = process_sigsuspend_mask(&sig.set, arg_sigset, arg_sigsize);
+ if (ret != 0) {
++ free(rfds); free(wfds); free(efds);
+ return ret;
+ }
+ sig_ptr = &sig;
+@@ -1460,25 +1501,31 @@
+ }
+
+ if (!is_error(ret)) {
+- if (rfd_addr && copy_to_user_fdset(rfd_addr, &rfds, n)) {
++ if (rfd_addr && copy_to_user_fdset(rfd_addr, rfds, n)) {
++ free(rfds); free(wfds); free(efds);
+ return -TARGET_EFAULT;
+ }
+- if (wfd_addr && copy_to_user_fdset(wfd_addr, &wfds, n)) {
++ if (wfd_addr && copy_to_user_fdset(wfd_addr, wfds, n)) {
++ free(rfds); free(wfds); free(efds);
+ return -TARGET_EFAULT;
+ }
+- if (efd_addr && copy_to_user_fdset(efd_addr, &efds, n)) {
++ if (efd_addr && copy_to_user_fdset(efd_addr, efds, n)) {
++ free(rfds); free(wfds); free(efds);
+ return -TARGET_EFAULT;
+ }
+ if (time64) {
+ if (ts_addr && host_to_target_timespec64(ts_addr, &ts)) {
++ free(rfds); free(wfds); free(efds);
+ return -TARGET_EFAULT;
+ }
+ } else {
+ if (ts_addr && host_to_target_timespec(ts_addr, &ts)) {
++ free(rfds); free(wfds); free(efds);
+ return -TARGET_EFAULT;
+ }
+ }
+ }
++ free(rfds); free(wfds); free(efds);
+ return ret;
+ }
+ #endif