Convert PS to PDF using gs as filter.

src/protocols/rdp/guac_rdpdr/rdpdr_printer.c

@@ -1,4 +1,6 @@
 
+#include <errno.h>
+
 #include <freerdp/utils/stream.h>
 #include <freerdp/utils/svc_plugin.h>
 
@@ -9,6 +11,127 @@
 #include "rdpdr_service.h"
 #include "client.h"
 
+/* Command to run GhostScript safely as a filter writing PDF */
+char* const guac_rdpdr_pdf_filter_command[] = {
+    "gs",
+    "-q",
+    "-dNOPAUSE",
+    "-dBATCH",
+    "-dSAFER",
+    "-dPARANOIDSAFER",
+    "-sDEVICE=pdfwrite",
+    "-sOutputFile=-",
+    "-c",
+    ".setpdfwrite",
+    "-f",
+    "-",
+    NULL
+};
+
+static void* guac_rdpdr_print_filter_output_thread(void* data) {
+
+    guac_rdpdrPlugin* rdpdr = (guac_rdpdrPlugin*) data;
+    rdp_guac_client_data* client_data = (rdp_guac_client_data*) rdpdr->client->data;
+
+    int length;
+    char buffer[8192];
+
+    /* Write all output as blobs */
+    while ((length = read(rdpdr->printer_output, buffer, sizeof(buffer))) > 0) {
+        pthread_mutex_lock(&(client_data->update_lock));
+        guac_protocol_send_blob(rdpdr->client->socket,
+                GUAC_RDPDR_PRINTER_BLOB, buffer, length);
+        pthread_mutex_unlock(&(client_data->update_lock));
+    }
+
+    /* Log any error */
+    if (length < 0)
+        guac_client_log_error(rdpdr->client, "Error reading from filter: %s", strerror(errno));
+
+    return NULL;
+
+}
+
+static int guac_rdpdr_create_print_process(guac_rdpdrPlugin* rdpdr) {
+
+    int child_pid;
+    int stdin_pipe[2];
+    int stdout_pipe[2];
+
+    /* Create STDIN pipe */
+    if (pipe(stdin_pipe)) {
+        guac_client_log_error(rdpdr->client, "Unable to create STDIN pipe for PDF filter process: %s", strerror(errno));
+        return 1;
+    }
+
+    /* Create STDOUT pipe */
+    if (pipe(stdout_pipe)) {
+        guac_client_log_error(rdpdr->client, "Unable to create STDIN pipe for PDF filter process: %s", strerror(errno));
+        close(stdin_pipe[0]);
+        close(stdin_pipe[1]);
+        return 1;
+    }
+
+    /* Store our side of stdin/stdout */
+    rdpdr->printer_input  = stdin_pipe[1];
+    rdpdr->printer_output = stdout_pipe[0];
+
+    /* Start output thread */
+    if (pthread_create(&(rdpdr->printer_output_thread), NULL, guac_rdpdr_print_filter_output_thread, rdpdr)) {
+        guac_client_log_error(rdpdr->client, "Unable to fork PDF filter process");
+        close(stdin_pipe[0]);
+        close(stdin_pipe[1]);
+        close(stdout_pipe[0]);
+        close(stdout_pipe[1]);
+        return 1;
+    }
+
+    /* Fork child process */
+    child_pid = fork();
+
+    /* Log fork errors */
+    if (child_pid == -1) {
+        guac_client_log_error(rdpdr->client, "Unable to fork PDF filter process: %s", strerror(errno));
+        close(stdin_pipe[0]);
+        close(stdin_pipe[1]);
+        close(stdout_pipe[0]);
+        close(stdout_pipe[1]);
+        return 1;
+    }
+
+    /* Child process */
+    if (child_pid == 0) {
+
+        /* Close unneeded ends of pipe */
+        close(stdin_pipe[1]);
+        close(stdout_pipe[0]);
+
+        /* Reassign file descriptors as STDIN/STDOUT */
+        dup2(stdin_pipe[0], STDIN_FILENO);
+        dup2(stdout_pipe[1], STDOUT_FILENO);
+
+        /* Run PDF filter */
+        guac_client_log_info(rdpdr->client, "Running %s", guac_rdpdr_pdf_filter_command[0]);
+        if (execvp(guac_rdpdr_pdf_filter_command[0], guac_rdpdr_pdf_filter_command) < 0)
+            guac_client_log_error(rdpdr->client, "Unable to execute PDF filter command: %s", strerror(errno));
+        else
+            guac_client_log_error(rdpdr->client, "Unable to execute PDF filter command, but no error given");
+
+        /* Terminate child process */
+        exit(1);
+
+    }
+
+    /* Log fork success */
+    guac_client_log_info(rdpdr->client, "Created PDF filter process PID=%i", child_pid);
+
+    /* Close unneeded ends of pipe */
+    close(stdin_pipe[0]);
+    close(stdout_pipe[1]);
+    return 0;
+
+}
+
 void guac_rdpdr_process_print_job_create(guac_rdpdrPlugin* rdpdr, STREAM* input_stream, int completion_id) {
 
     STREAM* output_stream = stream_new(24);
@@ -23,7 +146,7 @@ void guac_rdpdr_process_print_job_create(guac_rdpdrPlugin* rdpdr, STREAM* input_
     /* Write content */
     stream_write_uint32(output_stream, GUAC_PRINTER_DEVICE_ID);
     stream_write_uint32(output_stream, completion_id);
-    stream_write_uint32(output_stream, 0); /* NTSTATUS - success */
+    stream_write_uint32(output_stream, 0); /* Success */
     stream_write_uint32(output_stream, 0); /* fileId */
 
     svc_plugin_send((rdpSvcPlugin*) rdpdr, output_stream);
@@ -32,7 +155,7 @@ void guac_rdpdr_process_print_job_create(guac_rdpdrPlugin* rdpdr, STREAM* input_
 
 void guac_rdpdr_process_print_job_write(guac_rdpdrPlugin* rdpdr, STREAM* input_stream, int completion_id) {
 
-    int length;
+    int status=0, length;
     unsigned char* buffer;
 
     rdp_guac_client_data* client_data = (rdp_guac_client_data*) rdpdr->client->data;
@@ -49,7 +172,7 @@ void guac_rdpdr_process_print_job_write(guac_rdpdrPlugin* rdpdr, STREAM* input_s
     /* Create print job, if not yet created */
     if (rdpdr->bytes_received == 0) {
 
-        char filename[1024] = "guacamole-print.ps";
+        char filename[1024] = "guacamole-print.pdf";
         unsigned char* search = buffer;
         int i;
 
@@ -64,7 +187,7 @@ void guac_rdpdr_process_print_job_write(guac_rdpdrPlugin* rdpdr, STREAM* input_s
 
                 /* Copy as much of title as reasonable */
                 int j;
-                for (j=0; j<sizeof(filename) - 4 /* sizeof(".ps") + 1 */ && i<length; i++, j++) {
+                for (j=0; j<sizeof(filename) - 5 /* extension + 1 */ && i<length; i++, j++) {
 
                     /* Get character, stop at EOL */
                     char c = *(search++);
@@ -77,7 +200,7 @@ void guac_rdpdr_process_print_job_write(guac_rdpdrPlugin* rdpdr, STREAM* input_s
                 }
 
                 /* Append filename with extension */
-                strcpy(&(filename[j]), ".ps");
+                strcpy(&(filename[j]), ".pdf");
                 break;
             }
 
@@ -86,18 +209,36 @@ void guac_rdpdr_process_print_job_write(guac_rdpdrPlugin* rdpdr, STREAM* input_s
 
         }
 
+        /* Begin file */
         guac_client_log_info(rdpdr->client, "Print job created");
         guac_protocol_send_file(rdpdr->client->socket,
-                GUAC_RDPDR_PRINTER_BLOB, "application/postscript", filename);
+                GUAC_RDPDR_PRINTER_BLOB, "application/pdf", filename);
+
+        /* Start print process */
+        if (guac_rdpdr_create_print_process(rdpdr) != 0) {
+            status = 0x80000010;
+            length = 0;
+        }
 
     }
 
     rdpdr->bytes_received += length;
 
-    guac_protocol_send_blob(rdpdr->client->socket,
-            GUAC_RDPDR_PRINTER_BLOB, buffer, length);
     pthread_mutex_unlock(&(client_data->update_lock));
 
+    /* If not yet failed, write received data */
+    if (status == 0) {
+
+        /* Write data to printer, translate output for RDP */
+        length = write(rdpdr->printer_input, buffer, length);
+        if (length == -1) {
+            guac_client_log_error(rdpdr->client, "Error writing to printer: %s", strerror(errno));
+            status = 0x80000010;
+            length = 0;
+        }
+
+    }
+
     /* Write header */
     stream_write_uint16(output_stream, RDPDR_CTYP_CORE);
     stream_write_uint16(output_stream, PAKID_CORE_DEVICE_IOCOMPLETION);
@@ -105,7 +246,7 @@ void guac_rdpdr_process_print_job_write(guac_rdpdrPlugin* rdpdr, STREAM* input_s
     /* Write content */
     stream_write_uint32(output_stream, GUAC_PRINTER_DEVICE_ID);
     stream_write_uint32(output_stream, completion_id);
-    stream_write_uint32(output_stream, 0); /* NTSTATUS - success */
+    stream_write_uint32(output_stream, status);
     stream_write_uint32(output_stream, length);
     stream_write_uint8(output_stream, 0); /* padding (stated as optional in spec, but requests fail without) */
 
@@ -118,6 +259,13 @@ void guac_rdpdr_process_print_job_close(guac_rdpdrPlugin* rdpdr, STREAM* input_s
     rdp_guac_client_data* client_data = (rdp_guac_client_data*) rdpdr->client->data;
     STREAM* output_stream = stream_new(24);
 
+    /* Close input and wait for output thread to finish */
+    close(rdpdr->printer_input);
+    pthread_join(rdpdr->printer_output_thread, NULL);
+
+    /* Close file descriptors */
+    close(rdpdr->printer_output);
+
     /* Close file */
     guac_client_log_info(rdpdr->client, "Print job closed");
     pthread_mutex_lock(&(client_data->update_lock));

src/protocols/rdp/guac_rdpdr/rdpdr_printer.h

@@ -54,5 +54,12 @@ void guac_rdpdr_process_print_job_create(guac_rdpdrPlugin* rdpdr, STREAM* input_
 void guac_rdpdr_process_print_job_write(guac_rdpdrPlugin* rdpdr, STREAM* input_stream, int completion_id);
 void guac_rdpdr_process_print_job_close(guac_rdpdrPlugin* rdpdr, STREAM* input_stream, int completion_id);
 
+/**
+ * The command to run when filtering postscript to produce PDF. This must be
+ * a NULL-terminated array of arguments, where the first argument is the name
+ * of the file to run.
+ */
+extern char* const guac_rdpdr_pdf_filter_command[];
+
 #endif
 

src/protocols/rdp/guac_rdpdr/rdpdr_service.h

@@ -38,6 +38,8 @@
 #ifndef __GUAC_RDPDR_SERVICE_H
 #define __GUAC_RDPDR_SERVICE_H
 
+#include <pthread.h>
+
 #include <guacamole/client.h>
 
 /**
@@ -58,6 +60,23 @@ typedef struct guac_rdpdrPlugin {
      */
     guac_client* client;
 
+    /**
+     * File descriptor that should be written to when sending documents to the
+     * printer.
+     */
+    int printer_input;
+
+    /**
+     * File descriptor that should be read from when receiving output from the
+     * printer.
+     */
+    int printer_output;
+
+    /**
+     * Thread which transfers data from the printer to the Guacamole client.
+     */
+    pthread_t printer_output_thread;
+
     /**
      * The number of bytes received in the current print job.
      */