1 files changed, 293 insertions, 0 deletions
diff --git a/libcutils/abort_socket.c b/libcutils/abort_socket.c
new file mode 100644
index 0000000..d732142
--- /dev/null
+++ b/libcutils/abort_socket.c
@@ -0,0 +1,293 @@
+/*
+ * Copyright 2009, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdlib.h>
+#include <errno.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/socket.h>
+#include <sys/poll.h>
+
+#include "cutils/abort_socket.h"
+
+struct asocket *asocket_init(int fd) {
+    int abort_fd[2];
+    int flags;
+    struct asocket *s;
+
+    /* set primary socket to non-blocking */
+    flags = fcntl(fd, F_GETFL);
+    if (flags == -1)
+        return NULL;
+    if (fcntl(fd, F_SETFL, flags | O_NONBLOCK))
+        return NULL;
+
+    /* create pipe with non-blocking write, so that asocket_close() cannot
+       block */
+    if (pipe(abort_fd))
+        return NULL;
+    flags = fcntl(abort_fd[1], F_GETFL);
+    if (flags == -1)
+        return NULL;
+    if (fcntl(abort_fd[1], F_SETFL, flags | O_NONBLOCK))
+        return NULL;
+
+    s = malloc(sizeof(struct asocket));
+    if (!s)
+        return NULL;
+
+    s->fd = fd;
+    s->abort_fd[0] = abort_fd[0];
+    s->abort_fd[1] = abort_fd[1];
+
+    return s;
+}
+
+int asocket_connect(struct asocket *s, const struct sockaddr *addr,
+        socklen_t addrlen, int timeout) {
+
+    int ret;
+
+    do {
+        ret = connect(s->fd, addr, addrlen);
+    } while (ret && errno == EINTR);
+
+    if (ret && errno == EINPROGRESS) {
+        /* ready to poll() */
+        socklen_t retlen;
+        struct pollfd pfd[2];
+
+        pfd[0].fd = s->fd;
+        pfd[0].events = POLLOUT;
+        pfd[0].revents = 0;
+        pfd[1].fd = s->abort_fd[0];
+        pfd[1].events = POLLIN;
+        pfd[1].revents = 0;
+
+        do {
+            ret = poll(pfd, 2, timeout);
+        } while (ret < 0 && errno == EINTR);
+
+        if (ret < 0)
+            return -1;
+        else if (ret == 0) {
+            /* timeout */
+            errno = ETIMEDOUT;
+            return -1;
+        }
+
+        if (pfd[1].revents) {
+            /* abort due to asocket_abort() */
+            errno = ECANCELED;
+            return -1;
+        }
+
+        if (pfd[0].revents) {
+            if (pfd[0].revents & POLLOUT) {
+                /* connect call complete, read return code */
+                retlen = sizeof(ret);
+                if (getsockopt(s->fd, SOL_SOCKET, SO_ERROR, &ret, &retlen))
+                    return -1;
+                /* got connect() return code */
+                if (ret) {
+                    errno = ret;
+                }
+            } else {
+                /* some error event on this fd */
+                errno = ECONNABORTED;
+                return -1;
+            }
+        }
+    }
+
+    return ret;
+}
+
+int asocket_accept(struct asocket *s, struct sockaddr *addr,
+        socklen_t *addrlen, int timeout) {
+
+    int ret;
+    struct pollfd pfd[2];
+
+    pfd[0].fd = s->fd;
+    pfd[0].events = POLLIN;
+    pfd[0].revents = 0;
+    pfd[1].fd = s->abort_fd[0];
+    pfd[1].events = POLLIN;
+    pfd[1].revents = 0;
+
+    do {
+        ret = poll(pfd, 2, timeout);
+    } while (ret < 0 && errno == EINTR);
+
+    if (ret < 0)
+        return -1;
+    else if (ret == 0) {
+        /* timeout */
+        errno = ETIMEDOUT;
+        return -1;
+    }
+
+    if (pfd[1].revents) {
+        /* abort due to asocket_abort() */
+        errno = ECANCELED;
+        return -1;
+    }
+
+    if (pfd[0].revents) {
+        if (pfd[0].revents & POLLIN) {
+            /* ready to accept() without blocking */
+            do {
+                ret = accept(s->fd, addr, addrlen);
+            } while (ret < 0 && errno == EINTR);
+        } else {
+            /* some error event on this fd */
+            errno = ECONNABORTED;
+            return -1;
+        }
+    }
+
+    return ret;
+}
+
+int asocket_read(struct asocket *s, void *buf, size_t count, int timeout) {
+    int ret;
+    struct pollfd pfd[2];
+
+    pfd[0].fd = s->fd;
+    pfd[0].events = POLLIN;
+    pfd[0].revents = 0;
+    pfd[1].fd = s->abort_fd[0];
+    pfd[1].events = POLLIN;
+    pfd[1].revents = 0;
+
+    do {
+        ret = poll(pfd, 2, timeout);
+    } while (ret < 0 && errno == EINTR);
+
+    if (ret < 0)
+        return -1;
+    else if (ret == 0) {
+        /* timeout */
+        errno = ETIMEDOUT;
+        return -1;
+    }
+
+    if (pfd[1].revents) {
+        /* abort due to asocket_abort() */
+        errno = ECANCELED;
+        return -1;
+    }
+
+    if (pfd[0].revents) {
+        if (pfd[0].revents & POLLIN) {
+            /* ready to read() without blocking */
+            do {
+                ret = read(s->fd, buf, count);
+            } while (ret < 0 && errno == EINTR);
+        } else {
+            /* some error event on this fd */
+            errno = ECONNABORTED;
+            return -1;
+        }
+    }
+
+    return ret;
+}
+
+int asocket_write(struct asocket *s, const void *buf, size_t count,
+        int timeout) {
+    int ret;
+    struct pollfd pfd[2];
+
+    pfd[0].fd = s->fd;
+    pfd[0].events = POLLOUT;
+    pfd[0].revents = 0;
+    pfd[1].fd = s->abort_fd[0];
+    pfd[1].events = POLLIN;
+    pfd[1].revents = 0;
+
+    do {
+        ret = poll(pfd, 2, timeout);
+    } while (ret < 0 && errno == EINTR);
+
+    if (ret < 0)
+        return -1;
+    else if (ret == 0) {
+        /* timeout */
+        errno = ETIMEDOUT;
+        return -1;
+    }
+
+    if (pfd[1].revents) {
+        /* abort due to asocket_abort() */
+        errno = ECANCELED;
+        return -1;
+    }
+
+    if (pfd[0].revents) {
+        if (pfd[0].revents & POLLIN) {
+            /* ready to write() without blocking */
+            do {
+                ret = write(s->fd, buf, count);
+            } while (ret < 0 && errno == EINTR);
+        } else {
+            /* some error event on this fd */
+            errno = ECONNABORTED;
+            return -1;
+        }
+    }
+
+    return ret;
+}
+
+void asocket_abort(struct asocket *s) {
+    int ret;
+    char buf = 0;
+
+    /* Prevent further use of fd, without yet releasing the fd */
+    shutdown(s->fd, SHUT_RDWR);
+
+    /* wake up calls blocked at poll() */
+    do {
+        ret = write(s->abort_fd[1], &buf, 1);
+    } while (ret < 0 && errno == EINTR);
+}
+
+void asocket_destroy(struct asocket *s) {
+    struct asocket s_copy = *s;
+
+    /* Clients should *not* be using these fd's after calling
+       asocket_destroy(), but in case they do, set to -1 so they cannot use a
+       stale fd */
+    s->fd = -1;
+    s->abort_fd[0] = -1;
+    s->abort_fd[1] = -1;
+
+    /* Call asocket_abort() in case there are still threads blocked on this
+       socket. Clients should not rely on this behavior - it is racy because we
+       are about to close() these sockets - clients should instead make sure
+       all threads are done with the socket before calling asocket_destory().
+     */
+    asocket_abort(&s_copy);
+
+    /* enough safety checks, close and release memory */
+    close(s_copy.abort_fd[1]);
+    close(s_copy.abort_fd[0]);
+    close(s_copy.fd);
+
+    free(s);
+}