X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fcommon%2Funix.c;h=0409750c3ff7ada10465c1d1ee92d878afb3309a;hp=11c30781ba02ea5fa81f84e7f7400e15bb4436ce;hb=5b86bd5e6c2e05f3a6296fd569d824f03d5e7857;hpb=7f8bf46706c381d1a340a07b728dfcebafa72afc

diff --git a/src/common/unix.c b/src/common/unix.c
index 11c30781b..0409750c3 100644
--- a/src/common/unix.c
+++ b/src/common/unix.c
@@ -1,19 +1,9 @@
 /*
- * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
- *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
+ * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License, version 2 only,
- * as published by the Free Software Foundation.
+ * SPDX-License-Identifier: GPL-2.0-only
  *
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
- * more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program; if not, write to the Free Software Foundation, Inc.,
- * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
 #define _LGPL_SOURCE
@@ -216,6 +206,58 @@ ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
 	return ret;
 }
 
+/*
+ * Receive data of size len in put that data into the buf param. Using recvmsg
+ * API. Only use with sockets set in non-blocking mode.
+ *
+ * NOTE: EPIPE errors are NOT reported. This call expects the socket to be in a
+ * poll set. The poll loop will handle the EPIPE original cause.
+ *
+ * Return the size of received data.
+ */
+LTTNG_HIDDEN
+ssize_t lttcomm_recv_unix_sock_non_block(int sock, void *buf, size_t len)
+{
+	struct msghdr msg;
+	struct iovec iov[1];
+	ssize_t ret;
+
+	memset(&msg, 0, sizeof(msg));
+
+	iov[0].iov_base = buf;
+	iov[0].iov_len = len;
+	msg.msg_iov = iov;
+	msg.msg_iovlen = 1;
+
+retry:
+	ret = lttng_recvmsg_nosigpipe(sock, &msg);
+	if (ret < 0) {
+		if (errno == EINTR) {
+			goto retry;
+		} else {
+			/*
+			 * We consider EPIPE and EAGAIN/EWOULDBLOCK as expected.
+			 */
+			if (errno == EAGAIN || errno == EWOULDBLOCK ||
+					errno == EPIPE) {
+				/*
+				 * Nothing was recv.
+				 */
+				ret = 0;
+				goto end;
+			}
+
+			/* Unexpected error */
+			PERROR("recvmsg");
+			ret = -1;
+			goto end;
+		}
+	}
+
+end:
+	return ret;
+}
+
 /*
  * Send buf data of size len. Using sendmsg API.
  *
@@ -226,7 +268,57 @@ ssize_t lttcomm_send_unix_sock(int sock, const void *buf, size_t len)
 {
 	struct msghdr msg;
 	struct iovec iov[1];
-	ssize_t ret = -1;
+	ssize_t ret;
+
+	memset(&msg, 0, sizeof(msg));
+
+	iov[0].iov_base = (void *) buf;
+	iov[0].iov_len = len;
+	msg.msg_iov = iov;
+	msg.msg_iovlen = 1;
+
+	while (iov[0].iov_len) {
+		ret = sendmsg(sock, &msg, 0);
+		if (ret < 0) {
+			if (errno == EINTR) {
+				continue;
+			} else {
+				/*
+				 * Only warn about EPIPE when quiet mode is
+				 * deactivated.
+				 * We consider EPIPE as expected.
+				 */
+				if (errno != EPIPE || !lttng_opt_quiet) {
+					PERROR("sendmsg");
+				}
+				goto end;
+			}
+		}
+		iov[0].iov_len -= ret;
+		iov[0].iov_base += ret;
+	}
+	ret = len;
+end:
+	return ret;
+}
+
+/*
+ * Send buf data of size len. Using sendmsg API.
+ * Only use with non-blocking sockets. The difference with the blocking version
+ * of the function is that this one does not retry to send on partial sends,
+ * except if the interruption was caused by a signal (EINTR).
+ *
+ * NOTE: EPIPE errors are NOT reported. This call expects the socket to be in a
+ * poll set. The poll loop will handle the EPIPE original cause.
+ *
+ * Return the size of sent data.
+ */
+LTTNG_HIDDEN
+ssize_t lttcomm_send_unix_sock_non_block(int sock, const void *buf, size_t len)
+{
+	struct msghdr msg;
+	struct iovec iov[1];
+	ssize_t ret;
 
 	memset(&msg, 0, sizeof(msg));
 
@@ -235,17 +327,32 @@ ssize_t lttcomm_send_unix_sock(int sock, const void *buf, size_t len)
 	msg.msg_iov = iov;
 	msg.msg_iovlen = 1;
 
+retry:
 	ret = sendmsg(sock, &msg, 0);
 	if (ret < 0) {
-		/*
-		 * Only warn about EPIPE when quiet mode is deactivated.
-		 * We consider EPIPE as expected.
-		 */
-		if (errno != EPIPE || !lttng_opt_quiet) {
+		if (errno == EINTR) {
+			goto retry;
+		} else {
+			/*
+			 * We consider EPIPE and EAGAIN/EWOULDBLOCK as expected.
+			 */
+			if (errno == EAGAIN || errno == EWOULDBLOCK ||
+					errno == EPIPE) {
+				/*
+				 * This can happen in non blocking mode.
+				 * Nothing was sent.
+				 */
+				ret = 0;
+				goto end;
+			}
+
+			/* Unexpected error */
 			PERROR("sendmsg");
+			ret = -1;
+			goto end;
 		}
 	}
-
+end:
 	return ret;
 }
 
@@ -277,7 +384,7 @@ int lttcomm_close_unix_sock(int sock)
  * Returns the size of data sent, or negative error value.
  */
 LTTNG_HIDDEN
-ssize_t lttcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
+ssize_t lttcomm_send_fds_unix_sock(int sock, const int *fds, size_t nb_fd)
 {
 	struct msghdr msg;
 	struct cmsghdr *cmptr;
@@ -288,7 +395,7 @@ ssize_t lttcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 	char dummy = 0;
 
 	memset(&msg, 0, sizeof(msg));
-	memset(tmp, 0, CMSG_SPACE(sizeof_fds) * sizeof(char));
+	memset(tmp, 0, sizeof(tmp));
 
 	if (nb_fd > LTTCOMM_MAX_SEND_FDS)
 		return -EINVAL;
@@ -300,6 +407,7 @@ ssize_t lttcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 	if (!cmptr) {
 		return -1;
 	}
+
 	cmptr->cmsg_level = SOL_SOCKET;
 	cmptr->cmsg_type = SCM_RIGHTS;
 	cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
@@ -327,6 +435,85 @@ ssize_t lttcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 	return ret;
 }
 
+/*
+ * Send a message accompanied by fd(s) over a unix socket.
+ * Only use for non blocking socket.
+ *
+ * Returns the size of data sent, or negative error value.
+ */
+LTTNG_HIDDEN
+ssize_t lttcomm_send_fds_unix_sock_non_block(int sock, const int *fds, size_t nb_fd)
+{
+	struct msghdr msg;
+	struct cmsghdr *cmptr;
+	struct iovec iov[1];
+	ssize_t ret = -1;
+	unsigned int sizeof_fds = nb_fd * sizeof(int);
+	char tmp[CMSG_SPACE(sizeof_fds)];
+	char dummy = 0;
+
+	memset(&msg, 0, sizeof(msg));
+	memset(tmp, 0, sizeof(tmp));
+
+	if (nb_fd > LTTCOMM_MAX_SEND_FDS)
+		return -EINVAL;
+
+	msg.msg_control = (caddr_t)tmp;
+	msg.msg_controllen = CMSG_LEN(sizeof_fds);
+
+	cmptr = CMSG_FIRSTHDR(&msg);
+	if (!cmptr) {
+		return -1;
+	}
+
+	cmptr->cmsg_level = SOL_SOCKET;
+	cmptr->cmsg_type = SCM_RIGHTS;
+	cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
+	memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
+	/* Sum of the length of all control messages in the buffer: */
+	msg.msg_controllen = cmptr->cmsg_len;
+
+	iov[0].iov_base = &dummy;
+	iov[0].iov_len = 1;
+	msg.msg_iov = iov;
+	msg.msg_iovlen = 1;
+
+retry:
+	ret = sendmsg(sock, &msg, 0);
+	if (ret < 0) {
+		if (errno == EINTR) {
+			goto retry;
+		} else {
+			/*
+			 * We consider EPIPE and EAGAIN/EWOULDBLOCK as expected.
+			 */
+			if (errno == EAGAIN || errno == EWOULDBLOCK) {
+				/*
+				 * This can happen in non blocking mode.
+				 * Nothing was sent.
+				 */
+				ret = 0;
+				goto end;
+			}
+
+			if (errno == EPIPE) {
+				/* Expected error, pass error to caller */
+				DBG3("EPIPE on sendmsg");
+				ret = -1;
+				goto end;
+			}
+
+			/* Unexpected error */
+			PERROR("sendmsg");
+			ret = -1;
+			goto end;
+		}
+	}
+
+end:
+	return ret;
+}
+
 /*
  * Recv a message accompanied by fd(s) from a unix socket.
  *
@@ -342,7 +529,15 @@ ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 	ssize_t ret = 0;
 	struct cmsghdr *cmsg;
 	size_t sizeof_fds = nb_fd * sizeof(int);
-	char recv_fd[CMSG_SPACE(sizeof_fds)];
+
+#ifdef __linux__
+/* Account for the struct ucred cmsg in the buffer size */
+#define LTTNG_SOCK_RECV_FDS_BUF_SIZE CMSG_SPACE(sizeof_fds) + CMSG_SPACE(sizeof(struct ucred))
+#else
+#define LTTNG_SOCK_RECV_FDS_BUF_SIZE CMSG_SPACE(sizeof_fds)
+#endif /* __linux__ */
+
+	char recv_buf[LTTNG_SOCK_RECV_FDS_BUF_SIZE];
 	struct msghdr msg;
 	char dummy;
 
@@ -353,45 +548,219 @@ ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 	iov[0].iov_len = 1;
 	msg.msg_iov = iov;
 	msg.msg_iovlen = 1;
-	msg.msg_control = recv_fd;
-	msg.msg_controllen = sizeof(recv_fd);
 
-	do {
-		ret = recvmsg(sock, &msg, 0);
-	} while (ret < 0 && errno == EINTR);
+	cmsg = (struct cmsghdr *) recv_buf;
+	cmsg->cmsg_len = CMSG_LEN(sizeof_fds);
+	cmsg->cmsg_level = SOL_SOCKET;
+	cmsg->cmsg_type = SCM_RIGHTS;
+
+	msg.msg_control = cmsg;
+	msg.msg_controllen = CMSG_LEN(sizeof(recv_buf));
+	msg.msg_flags = 0;
+
+retry:
+	ret = lttng_recvmsg_nosigpipe(sock, &msg);
 	if (ret < 0) {
-		PERROR("recvmsg fds");
-		goto end;
+		if (errno == EINTR) {
+			goto retry;
+		} else {
+			/* We consider EPIPE and EAGAIN as expected. */
+			if (!lttng_opt_quiet &&
+					(errno != EPIPE && errno != EAGAIN)) {
+				PERROR("recvmsg");
+			}
+			goto end;
+		}
 	}
+
 	if (ret != 1) {
 		fprintf(stderr, "Error: Received %zd bytes, expected %d\n",
 				ret, 1);
 		goto end;
 	}
+
 	if (msg.msg_flags & MSG_CTRUNC) {
 		fprintf(stderr, "Error: Control message truncated.\n");
 		ret = -1;
 		goto end;
 	}
-	cmsg = CMSG_FIRSTHDR(&msg);
-	if (!cmsg) {
-		fprintf(stderr, "Error: Invalid control message header\n");
-		ret = -1;
-		goto end;
+
+	/*
+	 * If the socket was configured with SO_PASSCRED, the kernel will add a
+	 * control message (cmsg) to the ancillary data of the unix socket. We
+	 * need to expect a cmsg of the SCM_CREDENTIALS as the first control
+	 * message.
+	 */
+	for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
+		if (cmsg->cmsg_level != SOL_SOCKET) {
+			fprintf(stderr, "Error: The socket needs to be of type SOL_SOCKET\n");
+			ret = -1;
+			goto end;
+		}
+		if (cmsg->cmsg_type == SCM_RIGHTS) {
+			/*
+			 * We found the controle message for file descriptors,
+			 * now copy the fds to the fds ptr and return success.
+			 */
+			if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
+				fprintf(stderr, "Error: Received %zu bytes of"
+					"ancillary data for FDs, expected %zu\n",
+					(size_t) cmsg->cmsg_len,
+					(size_t) CMSG_LEN(sizeof_fds));
+				ret = -1;
+				goto end;
+			}
+			memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
+			ret = sizeof_fds;
+			goto end;
+		}
+#ifdef __linux__
+		if (cmsg->cmsg_type == SCM_CREDENTIALS) {
+			/*
+			 * Expect credentials to be sent when expecting fds even
+			 * if no credential were include in the send(). The
+			 * kernel adds them...
+			 */
+			ret = -1;
+		}
+#endif /* __linux__ */
 	}
-	if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
-		fprintf(stderr, "Didn't received any fd\n");
-		ret = -1;
+end:
+	return ret;
+}
+
+/*
+ * Recv a message accompanied by fd(s) from a non-blocking unix socket.
+ * Only use with non-blocking sockets.
+ *
+ * Returns the size of received data, or negative error value.
+ *
+ * Expect at most "nb_fd" file descriptors.
+ *
+ * Note that based on our comprehension, partial reception of fds is not
+ * possible since the FDs are actually in the control message. It is all or
+ * nothing, still the sender side can send the wrong number of fds.
+ */
+LTTNG_HIDDEN
+ssize_t lttcomm_recv_fds_unix_sock_non_block(int sock, int *fds, size_t nb_fd)
+{
+	struct iovec iov[1];
+	ssize_t ret = 0;
+	struct cmsghdr *cmsg;
+	size_t sizeof_fds = nb_fd * sizeof(int);
+
+#ifdef __linux__
+/* Account for the struct ucred cmsg in the buffer size */
+#define LTTNG_SOCK_RECV_FDS_BUF_SIZE CMSG_SPACE(sizeof_fds) + CMSG_SPACE(sizeof(struct ucred))
+#else
+#define LTTNG_SOCK_RECV_FDS_BUF_SIZE CMSG_SPACE(sizeof_fds)
+#endif /* __linux__ */
+
+	char recv_buf[LTTNG_SOCK_RECV_FDS_BUF_SIZE];
+	struct msghdr msg;
+	char dummy;
+
+	memset(&msg, 0, sizeof(msg));
+
+	/* Prepare to receive the structures */
+	iov[0].iov_base = &dummy;
+	iov[0].iov_len = 1;
+	msg.msg_iov = iov;
+	msg.msg_iovlen = 1;
+
+	cmsg = (struct cmsghdr *) recv_buf;
+	cmsg->cmsg_len = CMSG_LEN(sizeof_fds);
+	cmsg->cmsg_level = SOL_SOCKET;
+	cmsg->cmsg_type = SCM_RIGHTS;
+
+	msg.msg_control = cmsg;
+	msg.msg_controllen = CMSG_LEN(sizeof(recv_buf));
+	msg.msg_flags = 0;
+
+retry:
+	ret = lttng_recvmsg_nosigpipe(sock, &msg);
+	if (ret < 0) {
+		if (errno == EINTR) {
+			goto retry;
+		} else {
+			/*
+			 * We consider EPIPE and EAGAIN/EWOULDBLOCK as expected.
+			 */
+			if (errno == EAGAIN || errno == EWOULDBLOCK) {
+				/*
+				 * This can happen in non blocking mode.
+				 * Nothing was recv.
+				 */
+				ret = 0;
+				goto end;
+			}
+
+			if (errno == EPIPE) {
+				/* Expected error, pass error to caller */
+				DBG3("EPIPE on recvmsg");
+				ret = -1;
+				goto end;
+			}
+
+			/* Unexpected error */
+			PERROR("recvmsg");
+			ret = -1;
+			goto end;
+		}
+	}
+
+	if (ret != 1) {
+		fprintf(stderr, "Error: Received %zd bytes, expected %d\n",
+				ret, 1);
 		goto end;
 	}
-	if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
-		fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
-				(size_t) cmsg->cmsg_len, (size_t) CMSG_LEN(sizeof_fds));
+
+	if (msg.msg_flags & MSG_CTRUNC) {
+		fprintf(stderr, "Error: Control message truncated.\n");
 		ret = -1;
 		goto end;
 	}
-	memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
-	ret = sizeof_fds;
+
+	/*
+	 * If the socket was configured with SO_PASSCRED, the kernel will add a
+	 * control message (cmsg) to the ancillary data of the unix socket. We
+	 * need to expect a cmsg of the SCM_CREDENTIALS as the first control
+	 * message.
+	 */
+	for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
+		if (cmsg->cmsg_level != SOL_SOCKET) {
+			fprintf(stderr, "Error: The socket needs to be of type SOL_SOCKET\n");
+			ret = -1;
+			goto end;
+		}
+		if (cmsg->cmsg_type == SCM_RIGHTS) {
+			/*
+			 * We found the controle message for file descriptors,
+			 * now copy the fds to the fds ptr and return success.
+			 */
+			if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
+				fprintf(stderr, "Error: Received %zu bytes of"
+					"ancillary data for FDs, expected %zu\n",
+					(size_t) cmsg->cmsg_len,
+					(size_t) CMSG_LEN(sizeof_fds));
+				ret = -1;
+				goto end;
+			}
+			memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
+			ret = sizeof_fds;
+			goto end;
+		}
+#ifdef __linux__
+		if (cmsg->cmsg_type == SCM_CREDENTIALS) {
+			/*
+			 * Expect credentials to be sent when expecting fds even
+			 * if no credential were include in the send(). The
+			 * kernel adds them...
+			 */
+			ret = -1;
+		}
+#endif /* __linux__ */
+	}
 end:
 	return ret;
 }