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libc: reduce file descriptor lookup exceptions in 'select()'

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Fixes #3908
This commit is contained in:
Christian Prochaska 2020-09-17 16:48:00 +02:00 committed by Christian Helmuth
parent 058f2e687c
commit 5c47fa0d41
2 changed files with 16 additions and 4 deletions
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10
repos/libports/src/lib/libc/socket_fs_plugin.cc
View File

@ -1222,13 +1222,19 @@ int Socket_fs::Plugin::select(int nfds,
for (int fd = 0; fd < nfds; ++fd) { for (int fd = 0; fd < nfds; ++fd) {
bool fd_in_readfds = FD_ISSET(fd, &in_readfds);
bool fd_in_writefds = FD_ISSET(fd, &in_writefds);
if (!fd_in_readfds && !fd_in_writefds)
continue;
File_descriptor *fdo = file_descriptor_allocator()->find_by_libc_fd(fd); File_descriptor *fdo = file_descriptor_allocator()->find_by_libc_fd(fd);
/* handle only fds that belong to this plugin */ /* handle only fds that belong to this plugin */
if (!fdo || (fdo->plugin != this)) if (!fdo || (fdo->plugin != this))
continue; continue;
if (FD_ISSET(fd, &in_readfds)) { if (fd_in_readfds) {
try { try {
Socket_fs::Context *context = dynamic_cast<Socket_fs::Context *>(fdo->context); Socket_fs::Context *context = dynamic_cast<Socket_fs::Context *>(fdo->context);
@ -1239,7 +1245,7 @@ int Socket_fs::Plugin::select(int nfds,
} catch (Socket_fs::Context::Inaccessible) { } } catch (Socket_fs::Context::Inaccessible) { }
} }
if (FD_ISSET(fd, &in_writefds)) { if (fd_in_writefds) {
try { try {
Socket_fs::Context *context = dynamic_cast<Socket_fs::Context *>(fdo->context); Socket_fs::Context *context = dynamic_cast<Socket_fs::Context *>(fdo->context);

10
repos/libports/src/lib/libc/vfs_plugin.cc
View File

@ -2080,6 +2080,12 @@ int Libc::Vfs_plugin::select(int nfds,
auto fn = [&] { auto fn = [&] {
for (int fd = 0; fd < nfds; ++fd) { for (int fd = 0; fd < nfds; ++fd) {
bool fd_in_readfds = FD_ISSET(fd, &in_readfds);
bool fd_in_writefds = FD_ISSET(fd, &in_writefds);
if (!fd_in_readfds && !fd_in_writefds)
continue;
File_descriptor *fdo = File_descriptor *fdo =
file_descriptor_allocator()->find_by_libc_fd(fd); file_descriptor_allocator()->find_by_libc_fd(fd);
@ -2090,7 +2096,7 @@ int Libc::Vfs_plugin::select(int nfds,
Vfs::Vfs_handle *handle = vfs_handle(fdo); Vfs::Vfs_handle *handle = vfs_handle(fdo);
if (!handle) continue; if (!handle) continue;
if (FD_ISSET(fd, &in_readfds)) { if (fd_in_readfds) {
if (handle->fs().read_ready(handle)) { if (handle->fs().read_ready(handle)) {
FD_SET(fd, readfds); FD_SET(fd, readfds);
++nready; ++nready;
@ -2099,7 +2105,7 @@ int Libc::Vfs_plugin::select(int nfds,
} }
} }
if (FD_ISSET(fd, &in_writefds)) { if (fd_in_writefds) {
if (true /* XXX always writeable */) { if (true /* XXX always writeable */) {
FD_SET(fd, writefds); FD_SET(fd, writefds);
++nready; ++nready;