1 files changed, 244 insertions, 0 deletions
diff --git a/pseudo_ipc.c b/pseudo_ipc.c
new file mode 100644
index 0000000..cd18140
--- /dev/null
+++ b/pseudo_ipc.c
@@ -0,0 +1,244 @@
+/*
+ * pseudo_ipc.c, IPC code for pseudo client/server
+ *
+ * Copyright (c) 2008-2010 Wind River Systems, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the Lesser GNU General Public License version 2.1 as
+ * published by the Free Software Foundation.
+ *
+ * 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 Lesser GNU General Public License for more details.
+ *
+ * You should have received a copy of the Lesser GNU General Public License
+ * version 2.1 along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 
+ *
+ */
+#include <stddef.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <signal.h>
+#include <string.h>
+#include <unistd.h>
+#include <ctype.h>
+#include <errno.h>
+#include <sys/stat.h>
+
+#include "pseudo.h"
+#include "pseudo_ipc.h"
+
+/* Short reads or writes can cause a sigpipe, killing the program, so we
+ * trap it and report that something happened.
+ */
+static sig_atomic_t pipe_error = 0;
+static void (*old_handler)(int) = SIG_DFL;
+
+static void
+sigpipe_trap(int unused) {
+	pipe_error = 1;
+}
+
+static void
+ignore_sigpipe(void) {
+	pipe_error = 0;
+	old_handler = signal(SIGPIPE, sigpipe_trap);
+}
+
+static void
+allow_sigpipe(void) {
+	signal(SIGPIPE, old_handler);
+}
+
+#if 0
+/* useful only when debugging crazy stuff */
+static void
+display_msg_header(pseudo_msg_t *msg) {
+	pseudo_debug(4, "type: %d\n", msg->type);
+	pseudo_debug(4, "inode: %llu\n", (unsigned long long) msg->ino);
+	pseudo_debug(4, "uid: %d\n", msg->uid);
+	pseudo_debug(4, "pathlen: %d\n", (int) msg->pathlen);
+	if (msg->pathlen) {
+		pseudo_debug(4, "path: %s\n", msg->path);
+	}
+}
+#endif
+
+/*
+ * send message on fd
+ * return:
+ * 0 on success
+ * >0 on error
+ * <0 on error suggesting other end is dead
+ */
+int
+pseudo_msg_send(int fd, pseudo_msg_t *msg, size_t len, const char *path) {
+	int r;
+
+	if (!msg)
+		return 1;
+
+	if (fd < 0)
+		return -1;
+
+	if (path) {
+		pseudo_debug(4, "msg type %d (%s), external path %s, mode 0%o\n",
+			msg->type, pseudo_op_name(msg->op), path, (int) msg->mode);
+		if (len == -1)
+			len = strlen(path) + 1;
+		msg->pathlen = len;
+		ignore_sigpipe();
+		r = write(fd, msg, PSEUDO_HEADER_SIZE);
+		if (r == PSEUDO_HEADER_SIZE) {
+			r += write(fd, path, len);
+		}
+		allow_sigpipe();
+		pseudo_debug(5, "wrote %d bytes\n", r);
+		if (pipe_error || (r == -1 && errno == EBADF))
+			return -1;
+		return (r != PSEUDO_HEADER_SIZE + len);
+	} else {
+		pseudo_debug(4, "msg type %d (%s), result %d (%s), path %.*s, mode 0%o\n",
+			msg->type, pseudo_op_name(msg->op),
+			msg->result, pseudo_res_name(msg->result),
+			msg->pathlen, msg->path, (int) msg->mode);
+		// display_msg_header(msg);
+		ignore_sigpipe();
+		r = write(fd, msg, PSEUDO_HEADER_SIZE + msg->pathlen);
+		allow_sigpipe();
+		pseudo_debug(5, "wrote %d bytes\n", r);
+		if (pipe_error || (r == -1 && errno == EBADF))
+			return -1;
+		return (r != PSEUDO_HEADER_SIZE + msg->pathlen);
+	}
+}
+
+/* attempts to receive a message from fd
+ * return is allocated message if one is provided
+ */
+pseudo_msg_t *
+pseudo_msg_receive(int fd) {
+	static pseudo_msg_t *incoming;
+	static size_t incoming_pathlen;
+	pseudo_msg_t *newmsg, header;
+	int r;
+
+	if (fd < 0)
+		return 0;
+	errno = 0;
+	r = read(fd, &header, PSEUDO_HEADER_SIZE);
+	if (r == -1) {
+		pseudo_debug(2, "read failed: %s\n", strerror(errno));
+		return 0;
+	}
+	if (r < (int) PSEUDO_HEADER_SIZE) {
+		pseudo_debug(2, "got only %d bytes (%s)\n", r, strerror(errno));
+		return 0;
+	}
+	pseudo_debug(4, "got header, type %d, pathlen %d\n", header.type, (int) header.pathlen);
+	// display_msg_header(&header);
+	if (!incoming || header.pathlen >= incoming_pathlen) {
+		newmsg = pseudo_msg_new(header.pathlen + 128, 0);
+		if (!newmsg) {
+			pseudo_diag("Couldn't allocate header for path of %d bytes.\n",
+				(int) header.pathlen);
+			return 0;
+		}
+		free(incoming);
+		incoming = newmsg;
+		incoming_pathlen = header.pathlen + 128;
+	}
+	*incoming = header;
+	if (incoming->pathlen) {
+		r = read(fd, incoming->path, incoming->pathlen);
+		if (r < incoming->pathlen) {
+			pseudo_debug(2, "short read on path, expecting %d, got %d\n",
+				(int) incoming->pathlen, r);
+			return 0;
+		}
+		/* ensure null termination */
+		incoming->path[r] = '\0';
+	}
+	// display_msg_header(incoming);
+	return incoming;
+}
+
+/* duplicate a message -- currently totally unused */
+pseudo_msg_t *
+pseudo_msg_dup(pseudo_msg_t *old) {
+	pseudo_msg_t *newmsg;
+	if (!old)
+		return NULL;
+	newmsg = malloc(sizeof(pseudo_msg_t) + old->pathlen);
+	if (!newmsg)
+		return NULL;
+	memcpy(newmsg, old, sizeof(pseudo_msg_t) + old->pathlen);
+	return newmsg;
+}
+
+/* allocate a message either with pathlen chars of storage or with enough
+ * storage for path
+ */
+pseudo_msg_t *
+pseudo_msg_new(size_t pathlen, const char *path) {
+	pseudo_msg_t *newmsg;
+	if (pathlen) {
+		newmsg = malloc(sizeof(pseudo_msg_t) + pathlen);
+		if (newmsg) {
+			newmsg->pathlen = pathlen;
+			if (path)
+				memcpy(newmsg->path, path, pathlen);
+			newmsg->path[pathlen - 1] = '\0';
+		}
+		return newmsg;
+	} else {
+		if (!path) {
+			/* no pathlen, no path == purely informational */
+			newmsg = malloc(sizeof(pseudo_msg_t));
+			if (newmsg) {
+				newmsg->pathlen = 0;
+			}
+			return newmsg;
+		} else {
+			pathlen = strlen(path) + 1;
+			newmsg = malloc(sizeof(pseudo_msg_t) + pathlen);
+			if (newmsg) {
+				memcpy(newmsg->path, path, pathlen);
+				newmsg->pathlen = pathlen;
+			}
+			return newmsg;
+		}
+	}
+}
+
+/* The following functions populate messages from statbufs and vice versa.
+ * It is intentional that copying a message into a stat doesn't touch nlink;
+ * the nlink value was not stored in the database (it is in the message at
+ * all only so the server can do sanity checks).
+ */
+
+void
+pseudo_msg_stat(pseudo_msg_t *msg, const struct stat64 *buf) {
+	if (!msg || !buf)
+		return;
+	msg->uid = buf->st_uid;
+	msg->gid = buf->st_gid;
+	msg->dev = buf->st_dev;
+	msg->ino = buf->st_ino;
+	msg->mode = buf->st_mode;
+	msg->rdev = buf->st_rdev;
+	msg->nlink = buf->st_nlink;
+}
+
+void
+pseudo_stat_msg(struct stat64 *buf, const pseudo_msg_t *msg) {
+	if (!msg || !buf)
+		return;
+	buf->st_uid = msg->uid;
+	buf->st_gid = msg->gid;
+	buf->st_mode = msg->mode;
+	buf->st_rdev = msg->rdev;
+}
+