diff options
Diffstat (limited to 'src/common/compat_threads.c')
| -rw-r--r-- | src/common/compat_threads.c | 128 |
1 files changed, 98 insertions, 30 deletions
diff --git a/src/common/compat_threads.c b/src/common/compat_threads.c index f4809060d6..208d3138d9 100644 --- a/src/common/compat_threads.c +++ b/src/common/compat_threads.c @@ -1,6 +1,6 @@ /* Copyright (c) 2003-2004, Roger Dingledine * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. - * Copyright (c) 2007-2016, The Tor Project, Inc. */ + * Copyright (c) 2007-2017, The Tor Project, Inc. */ /* See LICENSE for licensing information */ /** @@ -94,51 +94,73 @@ in_main_thread(void) } #if defined(HAVE_EVENTFD) || defined(HAVE_PIPE) -/* As write(), but retry on EINTR */ +/* As write(), but retry on EINTR, and return the negative error code on + * error. */ static int write_ni(int fd, const void *buf, size_t n) { int r; again: r = (int) write(fd, buf, n); - if (r < 0 && errno == EINTR) - goto again; + if (r < 0) { + if (errno == EINTR) + goto again; + else + return -errno; + } return r; } -/* As read(), but retry on EINTR */ +/* As read(), but retry on EINTR, and return the negative error code on error. + */ static int read_ni(int fd, void *buf, size_t n) { int r; again: r = (int) read(fd, buf, n); - if (r < 0 && errno == EINTR) - goto again; + if (r < 0) { + if (errno == EINTR) + goto again; + else + return -errno; + } return r; } -#endif +#endif /* defined(HAVE_EVENTFD) || defined(HAVE_PIPE) */ -/** As send(), but retry on EINTR. */ +/** As send(), but retry on EINTR, and return the negative error code on + * error. */ static int send_ni(int fd, const void *buf, size_t n, int flags) { int r; again: r = (int) send(fd, buf, n, flags); - if (r < 0 && ERRNO_IS_EINTR(tor_socket_errno(fd))) - goto again; + if (r < 0) { + int error = tor_socket_errno(fd); + if (ERRNO_IS_EINTR(error)) + goto again; + else + return -error; + } return r; } -/** As recv(), but retry on EINTR. */ +/** As recv(), but retry on EINTR, and return the negative error code on + * error. */ static int recv_ni(int fd, void *buf, size_t n, int flags) { int r; again: r = (int) recv(fd, buf, n, flags); - if (r < 0 && ERRNO_IS_EINTR(tor_socket_errno(fd))) - goto again; + if (r < 0) { + int error = tor_socket_errno(fd); + if (ERRNO_IS_EINTR(error)) + goto again; + else + return -error; + } return r; } @@ -149,7 +171,7 @@ eventfd_alert(int fd) { uint64_t u = 1; int r = write_ni(fd, (void*)&u, sizeof(u)); - if (r < 0 && errno != EAGAIN) + if (r < 0 && -r != EAGAIN) return -1; return 0; } @@ -160,11 +182,11 @@ eventfd_drain(int fd) { uint64_t u = 0; int r = read_ni(fd, (void*)&u, sizeof(u)); - if (r < 0 && errno != EAGAIN) - return -1; + if (r < 0 && -r != EAGAIN) + return r; return 0; } -#endif +#endif /* defined(HAVE_EVENTFD) */ #ifdef HAVE_PIPE /** Send a byte over a pipe. Return 0 on success or EAGAIN; -1 on error */ @@ -172,8 +194,8 @@ static int pipe_alert(int fd) { ssize_t r = write_ni(fd, "x", 1); - if (r < 0 && errno != EAGAIN) - return -1; + if (r < 0 && -r != EAGAIN) + return (int)r; return 0; } @@ -188,11 +210,11 @@ pipe_drain(int fd) r = read_ni(fd, buf, sizeof(buf)); } while (r > 0); if (r < 0 && errno != EAGAIN) - return -1; + return -errno; /* A value of r = 0 means EOF on the fd so successfully drained. */ return 0; } -#endif +#endif /* defined(HAVE_PIPE) */ /** Send a byte on socket <b>fd</b>t. Return 0 on success or EAGAIN, * -1 on error. */ @@ -200,13 +222,13 @@ static int sock_alert(tor_socket_t fd) { ssize_t r = send_ni(fd, "x", 1, 0); - if (r < 0 && !ERRNO_IS_EAGAIN(tor_socket_errno(fd))) - return -1; + if (r < 0 && !ERRNO_IS_EAGAIN(-r)) + return (int)r; return 0; } /** Drain all the input from a socket <b>fd</b>, and ignore it. Return 0 on - * success, -1 on error. */ + * success, -errno on error. */ static int sock_drain(tor_socket_t fd) { @@ -215,8 +237,8 @@ sock_drain(tor_socket_t fd) do { r = recv_ni(fd, buf, sizeof(buf), 0); } while (r > 0); - if (r < 0 && !ERRNO_IS_EAGAIN(tor_socket_errno(fd))) - return -1; + if (r < 0 && !ERRNO_IS_EAGAIN(-r)) + return (int)r; /* A value of r = 0 means EOF on the fd so successfully drained. */ return 0; } @@ -254,7 +276,7 @@ alert_sockets_create(alert_sockets_t *socks_out, uint32_t flags) socks_out->drain_fn = eventfd_drain; return 0; } -#endif +#endif /* defined(HAVE_EVENTFD) */ #ifdef HAVE_PIPE2 /* Now we're going to try pipes. First type the pipe2() syscall, if we @@ -267,7 +289,7 @@ alert_sockets_create(alert_sockets_t *socks_out, uint32_t flags) socks_out->drain_fn = pipe_drain; return 0; } -#endif +#endif /* defined(HAVE_PIPE2) */ #ifdef HAVE_PIPE /* Now try the regular pipe() syscall. Pipes have a bit lower overhead than @@ -291,7 +313,7 @@ alert_sockets_create(alert_sockets_t *socks_out, uint32_t flags) socks_out->drain_fn = pipe_drain; return 0; } -#endif +#endif /* defined(HAVE_PIPE) */ /* If nothing else worked, fall back on socketpair(). */ if (!(flags & ASOCKS_NOSOCKETPAIR) && @@ -330,3 +352,49 @@ alert_sockets_close(alert_sockets_t *socks) socks->read_fd = socks->write_fd = -1; } +/* + * XXXX We might be smart to move to compiler intrinsics or real atomic + * XXXX operations at some point. But not yet. + * + */ + +/** Initialize a new atomic counter with the value 0 */ +void +atomic_counter_init(atomic_counter_t *counter) +{ + memset(counter, 0, sizeof(*counter)); + tor_mutex_init_nonrecursive(&counter->mutex); +} +/** Clean up all resources held by an atomic counter. */ +void +atomic_counter_destroy(atomic_counter_t *counter) +{ + tor_mutex_uninit(&counter->mutex); + memset(counter, 0, sizeof(*counter)); +} +/** Add a value to an atomic counter. */ +void +atomic_counter_add(atomic_counter_t *counter, size_t add) +{ + tor_mutex_acquire(&counter->mutex); + counter->val += add; + tor_mutex_release(&counter->mutex); +} +/** Subtract a value from an atomic counter. */ +void +atomic_counter_sub(atomic_counter_t *counter, size_t sub) +{ + // this relies on unsigned overflow, but that's fine. + atomic_counter_add(counter, -sub); +} +/** Return the current value of an atomic counter */ +size_t +atomic_counter_get(atomic_counter_t *counter) +{ + size_t val; + tor_mutex_acquire(&counter->mutex); + val = counter->val; + tor_mutex_release(&counter->mutex); + return val; +} + |