diff options
Diffstat (limited to 'communication.c')
| -rw-r--r-- | communication.c | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/communication.c b/communication.c new file mode 100644 index 0000000..13d5046 --- /dev/null +++ b/communication.c @@ -0,0 +1,159 @@ +/* See LICENSE file for copyright and license details. */ +#include "communication.h" +#include "state.h" +#include "servers-coopgamma.h" + +#include <sys/socket.h> +#include <errno.h> +#include <string.h> + + +/** + * Send a message + * + * @param conn The index of the connection + * @param buf The data to send + * @param n The size of `buf` + * @return Zero on success, -1 on error, 1 if disconncted + * EINTR, EAGAIN, EWOULDBLOCK, and ECONNRESET count + * as success (ECONNRESET cause 1 to be returned), + * and are handled appropriately. + */ +int +send_message(size_t conn, char *restrict buf, size_t n) +{ + struct ring *restrict ring = outbound + conn; + int fd = connections[conn]; + int saved_errno; + size_t ptr = 0; + ssize_t sent; + size_t chunksize = n; + size_t sendsize; + size_t old_n; + char *old_buf; + size_t old_ptr; + + while ((old_buf = ring_peek(ring, &old_n))) { + for (old_ptr = 0; old_ptr < n;) { + sendsize = old_n - old_ptr < chunksize ? old_n - old_ptr : chunksize; + sent = send(fd, old_buf + old_ptr, sendsize, MSG_NOSIGNAL); + if (sent < 0) { + if (errno == EPIPE) + errno = ECONNRESET; + if (errno != EMSGSIZE) + goto fail; + chunksize >>= 1; + if (!chunksize) + goto fail; + continue; + } + old_ptr += (size_t)sent; + ring_pop(ring, (size_t)sent); + } + } + + while (ptr < n) { + sendsize = n - ptr < chunksize ? n - ptr : chunksize; + sent = send(fd, buf + ptr, sendsize, MSG_NOSIGNAL); + if (sent < 0) { + if (errno == EPIPE) + errno = ECONNRESET; + if (errno != EMSGSIZE) + goto fail; + chunksize >>= 1; + if (!chunksize) + goto fail; + continue; + } + ptr += (size_t)sent; + } + + free(buf); + return 0; + +fail: + switch (errno) { + case EINTR: +#if defined(EAGAIN) + case EAGAIN: +#endif +#if defined(EWOULDBLOCK) && (!defined(EAGAIN) || EAGAIN != EWOULDBLOCK) + case EWOULDBLOCK: +#endif + if (ring_push(ring, buf + ptr, n - ptr) < 0) + goto proper_fail; + free(buf); + return 0; + + case ECONNRESET: + free(buf); + if (connection_closed(fd) < 0) + return -1; + return 1; + + default: + break; + } + +proper_fail: + saved_errno = errno; + free(buf); + errno = saved_errno; + return -1; +} + + +/** + * Send a custom error without an error number + * + * @param conn The index of the connection + * @param message_id The ID of the message to which this message is a response + * @param desc The error description to send + * @return 1: Client disconnected + * 0: Success (possibily delayed) + * -1: An error occurred + */ +int +(send_error)(size_t conn, const char *restrict message_id, const char *restrict desc) +{ + char *restrict buf; + size_t n; + + MAKE_MESSAGE(&buf, &n, 0, + "Command: error\n" + "In response to: %s\n" + "Error: custom\n" + "Length: %zu\n" + "\n" + "%s\n", + message_id, strlen(desc) + 1, desc); + + return send_message(conn, buf, n); +} + + +/** + * Send a standard error + * + * @param conn The index of the connection + * @param message_id The ID of the message to which this message is a response + * @param number The value of `errno`, 0 to indicate success + * @return 1: Client disconnected + * 0: Success (possibily delayed) + * -1: An error occurred + */ +int +(send_errno)(size_t conn, const char *restrict message_id, int number) +{ + char *restrict buf; + size_t n; + + MAKE_MESSAGE(&buf, &n, 0, + "Command: error\n" + "In response to: %s\n" + "Error: %i\n" + "\n", + message_id, number); + + return send_message(conn, buf, n); +} |