From a9fc08b035fb917c7bad870f0aa199499325f437 Mon Sep 17 00:00:00 2001
From: Konstantin Osipov <kostja@tarantool.org>
Date: Mon, 10 Dec 2018 20:40:39 +0300
Subject: [PATCH] sio: prepare for conversion to plain C.
Describe in module comments the principles of API construction
for sio.c. Add necessary comments. Add a helper function
which makes the code a little simpler.
In scope of gh-3234.
---
src/sio.cc | 70 ++++++++----------------------------------
src/sio.h | 89 ++++++++++++++++++++++++++++++++++++++++++++++++++++--
2 files changed, 100 insertions(+), 59 deletions(-)
diff --git a/src/sio.cc b/src/sio.cc
index f2e1034607..5dcf9fdd19 100644
--- a/src/sio.cc
+++ b/src/sio.cc
@@ -32,7 +32,6 @@
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/uio.h>
-#include <errno.h>
#include <stdio.h>
#include <limits.h>
#include <netinet/in.h> /* TCP_NODELAY */
@@ -41,7 +40,6 @@
#include "trivia/util.h"
#include "exception.h"
-/** Pretty print socket name and peer (for exceptions) */
const char *
sio_socketname(int fd)
{
@@ -120,7 +118,6 @@ sio_listen_backlog()
return SOMAXCONN;
}
-/** Create a TCP socket. */
int
sio_socket(int domain, int type, int protocol)
{
@@ -133,7 +130,6 @@ sio_socket(int domain, int type, int protocol)
return fd;
}
-/** Get socket flags, raise an exception if error. */
int
sio_getfl(int fd)
{
@@ -144,7 +140,6 @@ sio_getfl(int fd)
return flags;
}
-/** Set socket flags, raise an exception if error. */
int
sio_setfl(int fd, int flag, int on)
{
@@ -158,9 +153,6 @@ sio_setfl(int fd, int flag, int on)
return flags;
}
-/** Set an option on a socket.
- * @retval -1 on error
- * */
int
sio_setsockopt(int fd, int level, int optname,
const void *optval, socklen_t optlen)
@@ -173,7 +165,6 @@ sio_setsockopt(int fd, int level, int optname,
return rc;
}
-/** Get a socket option value. */
int
sio_getsockopt(int fd, int level, int optname,
void *optval, socklen_t *optlen)
@@ -186,7 +177,6 @@ sio_getsockopt(int fd, int level, int optname,
return rc;
}
-/** Connect a client socket to a server. */
int
sio_connect(int fd, struct sockaddr *addr, socklen_t addrlen)
{
@@ -199,7 +189,6 @@ sio_connect(int fd, struct sockaddr *addr, socklen_t addrlen)
return rc;
}
-/** Bind a socket to the given address. */
int
sio_bind(int fd, struct sockaddr *addr, socklen_t addrlen)
{
@@ -209,7 +198,6 @@ sio_bind(int fd, struct sockaddr *addr, socklen_t addrlen)
return rc;
}
-/** Mark a socket as accepting connections. */
int
sio_listen(int fd)
{
@@ -219,41 +207,31 @@ sio_listen(int fd)
return rc;
}
-/** Accept a client connection on a server socket. */
int
sio_accept(int fd, struct sockaddr *addr, socklen_t *addrlen)
{
/* Accept a connection. */
int newfd = accept(fd, addr, addrlen);
- if (newfd < 0 &&
- (errno != EAGAIN && errno != EWOULDBLOCK && errno != EINTR))
+ if (newfd < 0 && !sio_wouldblock(errno))
tnt_raise(SocketError, sio_socketname(fd), "accept");
return newfd;
}
-/** Read up to 'count' bytes from a socket. */
ssize_t
sio_read(int fd, void *buf, size_t count)
{
ssize_t n = read(fd, buf, count);
- if (n < 0) {
- if (errno == EWOULDBLOCK)
- errno = EINTR;
- switch (errno) {
- case EAGAIN:
- case EINTR:
- break;
+ if (n < 0 && !sio_wouldblock(errno)) {
/*
* Happens typically when the client closes
* socket on timeout without reading the previous
* query's response completely. Treat the same as
* EOF.
*/
- case ECONNRESET:
+ if (errno == ECONNRESET) {
errno = 0;
n = 0;
- break;
- default:
+ } else {
tnt_raise(SocketError, sio_socketname(fd),
"read(%zd)", count);
}
@@ -261,61 +239,47 @@ sio_read(int fd, void *buf, size_t count)
return n;
}
-/** Write up to 'count' bytes to a socket. */
ssize_t
sio_write(int fd, const void *buf, size_t count)
{
ssize_t n = write(fd, buf, count);
- if (n < 0 && errno != EAGAIN &&
- errno != EWOULDBLOCK && errno != EINTR)
- tnt_raise(SocketError, sio_socketname(fd),
- "write(%zd)", count);
+ if (n < 0 && !sio_wouldblock(errno))
+ tnt_raise(SocketError, sio_socketname(fd), "write(%zd)", count);
return n;
}
-/** Write to a socket with iovec. */
ssize_t
sio_writev(int fd, const struct iovec *iov, int iovcnt)
{
int cnt = iovcnt < IOV_MAX ? iovcnt : IOV_MAX;
ssize_t n = writev(fd, iov, cnt);
- if (n < 0 && errno != EAGAIN && errno != EWOULDBLOCK &&
- errno != EINTR) {
- tnt_raise(SocketError, sio_socketname(fd),
- "writev(%d)", iovcnt);
- }
+ if (n < 0 && !sio_wouldblock(errno))
+ tnt_raise(SocketError, sio_socketname(fd), "writev(%d)", iovcnt);
return n;
}
-/** Send a message on a socket. */
ssize_t
sio_sendto(int fd, const void *buf, size_t len, int flags,
const struct sockaddr *dest_addr, socklen_t addrlen)
{
ssize_t n = sendto(fd, buf, len, flags, (struct sockaddr*)dest_addr,
addrlen);
- if (n < 0 && errno != EAGAIN &&
- errno != EWOULDBLOCK && errno != EINTR)
- tnt_raise(SocketError, sio_socketname(fd),
- "sendto(%zd)", len);
+ if (n < 0 && !sio_wouldblock(errno))
+ tnt_raise(SocketError, sio_socketname(fd), "sendto(%zd)", len);
return n;
}
-/** Receive a message on a socket. */
ssize_t
sio_recvfrom(int fd, void *buf, size_t len, int flags,
struct sockaddr *src_addr, socklen_t *addrlen)
{
ssize_t n = recvfrom(fd, buf, len, flags, (struct sockaddr*)src_addr,
addrlen);
- if (n < 0 && errno != EAGAIN &&
- errno != EWOULDBLOCK && errno != EINTR)
- tnt_raise(SocketError, sio_socketname(fd),
- "recvfrom(%zd)", len);
+ if (n < 0 && !sio_wouldblock(errno))
+ tnt_raise(SocketError, sio_socketname(fd), "recvfrom(%zd)", len);
return n;
}
-/** Get socket peer name. */
int
sio_getpeername(int fd, struct sockaddr *addr, socklen_t *addrlen)
{
@@ -323,22 +287,14 @@ sio_getpeername(int fd, struct sockaddr *addr, socklen_t *addrlen)
say_syserror("getpeername");
return -1;
}
- /* XXX: I've no idea where this is copy-pasted from. */
- /*
- if (addr->sin_addr.s_addr == 0) {
- say_syserror("getpeername: empty peer");
- return -1;
- }
- */
return 0;
}
-/** Pretty print a peer address. */
const char *
sio_strfaddr(struct sockaddr *addr, socklen_t addrlen)
{
static __thread char name[NI_MAXHOST + _POSIX_PATH_MAX + 2];
- switch(addr->sa_family) {
+ switch (addr->sa_family) {
case AF_UNIX:
if (addrlen >= sizeof(sockaddr_un)) {
snprintf(name, sizeof(name), "unix/:%s",
diff --git a/src/sio.h b/src/sio.h
index 2843c0c453..5bbe345b90 100644
--- a/src/sio.h
+++ b/src/sio.h
@@ -31,8 +31,13 @@
* SUCH DAMAGE.
*/
/**
- * Exception-aware wrappers around BSD sockets.
- * Provide better error logging and I/O statistics.
+ * A thin wrapper around BSD sockets. Sets the diagnostics
+ * area with a nicely formatted message for most errors (some
+ * intermittent errors such as EWOULDBLOCK, EINTR, EINPROGRESS,
+ * EAGAIN are an exception to this). The API is following
+ * suite of BSD socket API: most functinos -1 on error, 0 or a
+ * valid file descriptor on success. Exceptions to this rule, once
+ * again, are marked explicitly.
*/
#include <stdbool.h>
#include <sys/types.h>
@@ -41,6 +46,7 @@
#include <netdb.h>
#include <fcntl.h>
#include <tarantool_ev.h>
+#include <errno.h>
#if defined(__cplusplus)
extern "C" {
@@ -48,9 +54,35 @@ extern "C" {
enum { SERVICE_NAME_MAXLEN = 32 };
+/**
+ * Check if an errno, returned from a sio function, means a
+ * non-critical error: EAGAIN, EWOULDBLOCK, EINTR.
+ */
+static inline bool
+sio_wouldblock(int err)
+{
+ return err == EAGAIN || err == EWOULDBLOCK || err == EINTR;
+}
+
+
+/**
+ * Format the address provided in struct sockaddr *addr.
+ * Returns result in a static thread-local buffer.
+ * May garble errno. Used for error reporting.
+ */
const char *
sio_strfaddr(struct sockaddr *addr, socklen_t addrlen);
+/**
+ * Return a filled in struct sockaddr provided the file
+ * descriptor. May garble the errno.
+ *
+ * @param[in] fd a file descriptor; safe to hold any value,
+ * but don't expect meaningful results for -1
+ *
+ * @param[out] addr output buffer
+ * @param[out] addrlen buffer length
+ */
int
sio_getpeername(int fd, struct sockaddr *addr, socklen_t *addrlen);
@@ -92,32 +124,85 @@ sio_add_to_iov(struct iovec *iov, size_t size)
#if defined(__cplusplus)
} /* extern "C" */
+/**
+ * Pretty print socket name and peer (for exceptions).
+ * Preserves the errno. Returns a thread-local buffer.
+ */
const char *sio_socketname(int fd);
+
+/** Create a TCP or AF_UNIX socket. */
int sio_socket(int domain, int type, int protocol);
+/** Get socket flags. */
int sio_getfl(int fd);
+
+/** Set socket flags. */
int sio_setfl(int fd, int flag, int on);
+/** Set an option on a socket. */
int
sio_setsockopt(int fd, int level, int optname,
const void *optval, socklen_t optlen);
+
+/** Get a socket option value. */
int
sio_getsockopt(int fd, int level, int optname,
void *optval, socklen_t *optlen);
+/**
+ * Connect a client socket to a server.
+ * The diagnostics is not set in case of EINPROGRESS.
+ */
int sio_connect(int fd, struct sockaddr *addr, socklen_t addrlen);
+
+/**
+ * Bind a socket to the given address. The diagnostics is not set
+ * in case of EADDRINUSE.
+ */
int sio_bind(int fd, struct sockaddr *addr, socklen_t addrlen);
+
+/**
+ * Mark a socket as accepting connections. The diagnostics is not
+ * set in case of EADDRINUSE.
+ */
int sio_listen(int fd);
+
+/**
+ * Accept a client connection on a server socket. The
+ * diagnostics is not set for inprogress errors (@sa
+ * sio_wouldblock())
+ */
int sio_accept(int fd, struct sockaddr *addr, socklen_t *addrlen);
+/**
+ * Read *up to* 'count' bytes from a socket.
+ * The diagnostics is not set for sio_wouldblock() errors.
+ */
ssize_t sio_read(int fd, void *buf, size_t count);
+/**
+ * Write up to 'count' bytes to a socket.
+ * The diagnostics is not set in case of sio_wouldblock() errors.
+ */
ssize_t sio_write(int fd, const void *buf, size_t count);
+
+/**
+ * Write to a socket with iovec.
+ * The diagnostics is not set in case of sio_wouldblock() errors.
+ */
ssize_t sio_writev(int fd, const struct iovec *iov, int iovcnt);
+/**
+ * Send a message on a socket.
+ * The diagnostics is not set for sio_wouldblock() errors.
+ */
ssize_t sio_sendto(int fd, const void *buf, size_t len, int flags,
const struct sockaddr *dest_addr, socklen_t addrlen);
+/**
+ * Receive a message on a socket.
+ * The diagnostics is not set for sio_wouldblock() errors.
+ */
ssize_t sio_recvfrom(int fd, void *buf, size_t len, int flags,
struct sockaddr *src_addr, socklen_t *addrlen);
--
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