GUAC-236: Add common functions for creating client-level session recordings (Guacamole protocol dumps).

src/common/Makefile.am

@@ -37,6 +37,7 @@ noinst_HEADERS =          \
     guac_json.h           \
     guac_list.h           \
     guac_pointer_cursor.h \
+    guac_recording.h      \
     guac_rect.h           \
     guac_string.h         \
     guac_surface.h
@@ -53,6 +54,7 @@ libguac_common_la_SOURCES = \
     guac_json.c             \
     guac_list.c             \
     guac_pointer_cursor.c   \
+    guac_recording.c        \
     guac_rect.c             \
     guac_string.c           \
     guac_surface.c

src/common/guac_recording.c

@@ -0,0 +1,143 @@
+/*
+ * Copyright (C) 2014 Glyptodon LLC
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "guac_recording.h"
+
+#include <guacamole/client.h>
+#include <guacamole/socket.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+/**
+ * Attempts to open a new recording within the given path and having the given
+ * name. If such a file already exists, sequential numeric suffixes (.1, .2,
+ * .3, etc.) are appended until a filename is found which does not exist (or
+ * until the maximum number of numeric suffixes has been tried). If the file
+ * absolutely cannot be opened due to an error, -1 is returned and errno is set
+ * appropriately.
+ *
+ * @param path
+ *     The full path to the directory in which the data file should be created.
+ *
+ * @param name
+ *     The name of the data file which should be crated within the given path.
+ *
+ * @param basename
+ *     A buffer in which the path, a path separator, the filename, any
+ *     necessary suffix, and a NULL terminator will be stored. If insufficient
+ *     space is available, -1 will be returned, and errno will be set to
+ *     ENAMETOOLONG.
+ *
+ * @param basename_size
+ *     The number of bytes available within the provided basename buffer.
+ *
+ * @return
+ *     The file descriptor of the open data file if open succeeded, or -1 on
+ *     failure.
+ */
+static int guac_common_recording_open(const char* path,
+        const char* name, char* basename, int basename_size) {
+
+    int i;
+
+    /* Concatenate path and name (separated by a single slash) */
+    int basename_length = snprintf(basename,
+            basename_size - GUAC_COMMON_RECORDING_MAX_SUFFIX_LENGTH,
+            "%s/%s", path, name);
+
+    /* Abort if maximum length reached */
+    if (basename_length ==
+            basename_size - GUAC_COMMON_RECORDING_MAX_SUFFIX_LENGTH) {
+        errno = ENAMETOOLONG;
+        return -1;
+    }
+
+    /* Attempt to open recording */
+    int fd = open(basename,
+            O_CREAT | O_EXCL | O_WRONLY,
+            S_IRUSR | S_IWUSR);
+
+    /* Continuously retry with alternate names on failure */
+    if (fd == -1) {
+
+        /* Prepare basename for additional suffix */
+        basename[basename_length] = '.';
+        char* suffix = &(basename[basename_length + 1]);
+
+        /* Continue retrying alternative suffixes if file already exists */
+        for (i = 1; fd == -1 && errno == EEXIST
+                && i <= GUAC_COMMON_RECORDING_MAX_SUFFIX; i++) {
+
+            /* Append new suffix */
+            sprintf(suffix, "%i", i);
+
+            /* Retry with newly-suffixed filename */
+            fd = open(basename,
+                    O_CREAT | O_EXCL | O_WRONLY,
+                    S_IRUSR | S_IWUSR);
+
+        }
+
+    } /* end if open succeeded */
+
+    return fd;
+
+}
+
+int guac_common_recording_create(guac_client* client, const char* path,
+        const char* name, int create_path) {
+
+    char filename[GUAC_COMMON_RECORDING_MAX_NAME_LENGTH];
+
+    /* Create path if it does not exist, fail if impossible */
+    if (create_path && mkdir(path, S_IRWXU) && errno != EEXIST) {
+        guac_client_log(client, GUAC_LOG_ERROR,
+                "Creation of recording failed: %s", strerror(errno));
+        return 1;
+    }
+
+    /* Attempt to open recording file */
+    int fd = guac_common_recording_open(path, name, filename, sizeof(filename));
+    if (fd == -1) {
+        guac_client_log(client, GUAC_LOG_ERROR,
+                "Creation of recording failed: %s", strerror(errno));
+        return 1;
+    }
+
+    /* Replace client socket with wrapped socket */
+    client->socket = guac_socket_tee(client->socket, guac_socket_open(fd));
+
+    /* Recording creation succeeded */
+    guac_client_log(client, GUAC_LOG_INFO,
+            "Recording of session will be saved to \"%s\".",
+            filename);
+
+    return 0;
+
+}
+

src/common/guac_recording.h

@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2016 Glyptodon LLC
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef GUAC_COMMON_RECORDING_H
+#define GUAC_COMMON_RECORDING_H
+
+#include <guacamole/client.h>
+
+/**
+ * The maximum numeric value allowed for the .1, .2, .3, etc. suffix appended
+ * to the end of the session recording filename if a recording having the
+ * requested name already exists.
+ */
+#define GUAC_COMMON_RECORDING_MAX_SUFFIX 255
+
+/**
+ * The maximum length of the string containing a sequential numeric suffix
+ * between 1 and GUAC_COMMON_RECORDING_MAX_SUFFIX inclusive, in bytes,
+ * including NULL terminator.
+ */
+#define GUAC_COMMON_RECORDING_MAX_SUFFIX_LENGTH 4
+
+/**
+ * The maximum overall length of the full path to the session recording file,
+ * including any additional suffix and NULL terminator, in bytes.
+ */
+#define GUAC_COMMON_RECORDING_MAX_NAME_LENGTH 2048
+
+/**
+ * Replaces the socket of the given client such that all further Guacamole
+ * protocol output will be copied into a file within the given path and having
+ * the given name. If the create_path flag is non-zero, the given path will be
+ * created if it does not yet exist. If creation of the recording file or path
+ * fails, error messages will automatically be logged, and no recording will be
+ * written. The recording will automatically be closed once the client is
+ * freed.
+ *
+ * @param client
+ *     The client whose output should be copied to a recording file.
+ *
+ * @param path
+ *     The full absolute path to a directory in which the recording file should
+ *     be created.
+ *
+ * @param name
+ *     The base name to use for the recording file created within the specified
+ *     path.
+ *
+ * @param create_path
+ *     Zero if the specified path MUST exist for the recording file to be
+ *     written, or non-zero if the path should be created if it does not yet
+ *     exist.
+ *
+ * @return
+ *     Zero if the recording file has been successfully created and a recording
+ *     will be written, non-zero otherwise.
+ */
+int guac_common_recording_create(guac_client* client, const char* path,
+        const char* name, int create_path);
+
+#endif
+