Lots of changes: Two binaries (selection/pw auth), qmake -> cmake, gitignore, more error handling

1. We now have two binaries: One pops up when the print job comes in so you can
select the printer, duplex, copies, etc... The other one pops up when used as
a backend and handles authentication by asking for username and password (WORK
IN PROGRESS!). This is to better handle things like smb printing

2. We use cmake everywhere, and now that we want two binaries it made sense to
switch.

3. Gitignore, well, what to say

4. Show an error message when calling ghostscript for grayscale conversion failed,
insted of just doing nothing and not even closing the GUI.

5. Keep the printergui open for a few seconds after printing, but hide the
window. Later we want to check in the password gui if the printergui is
open to make sure we really should run, and maybe even exchange some information.

1 files changed, 135 insertions, 0 deletions

diff --git a/src/pwgui/main.cpp b/src/pwgui/main.cpp
new file mode 100644
index 0000000..d75f280
--- /dev/null
+++ b/src/pwgui/main.cpp
@@ -0,0 +1,135 @@
+#include "pwgui.h"
+#include "config.h"
+#include <QApplication>
+#include <cups/backend.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <time.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#define NAMELEN 400
+#define BUFLEN 1000
+
+static int run_backend(char *backend, char *uri, char *jobid, char *user, char *title, char *copies, char *options, char *file, char *password);
+
+int main(int argc, char *argv[])
+{
+  char tmpfile[NAMELEN];
+  char device[NAMELEN];
+  char backend[NAMELEN];
+  int spoolres;
+
+  // Pretty much what smbspool does, but in a generalized way
+  if (argc > 2 && strstr(argv[0], ":/") == NULL && strstr(argv[1], ":/") != NULL) {
+    argv++;
+    argc--;
+   }
+
+  // First check parameter count
+  if (argc != 6 && argc != 7) {
+    fputs("ERROR: Invalid number of arguments passed.\n", stderr);
+    return CUPS_BACKEND_FAILED;
+  }
+
+  if (argc == 6) {
+    // Data comes from stdin, save...
+    snprintf(tmpfile, NAMELEN, "/tmp/print-%s-%d-%s-%d", argv[1], (int)time(NULL), argv[2], (int)getpid());
+    int fh = open(tmpfile, O_CREAT | O_WRONLY | O_TRUNC, 0600);
+    if (fh < 0) {
+      fprintf(stderr, "ERROR: Could not open %s for writing..\n", tmpfile);
+      return CUPS_BACKEND_FAILED;
+    }
+    char buffer[BUFLEN];
+    size_t bytes, ret;
+    while (!feof(stdin)) {
+      bytes = fread(buffer, BUFLEN, 1, stdin);
+      if (bytes == 0) break;
+      if ((ret = write(fh, buffer, bytes)) != bytes) {
+        fprintf(stderr, "ERROR: Could not write %d bytes to %s (wrote %d)\n", (int)bytes, tmpfile, (int)ret);
+        remove(tmpfile);
+        return CUPS_BACKEND_FAILED;
+      }
+    }
+    close(fh);
+    //
+  } else {
+    // File given, check if file exists
+    snprintf(tmpfile, NAMELEN, "%s", argv[6]);
+    int fh = open(tmpfile, O_RDONLY);
+    if (fh < 0) {
+      fprintf(stderr, "ERROR: Could not open %s for reading..\n", tmpfile);
+      return CUPS_BACKEND_FAILED;
+    }
+    close(fh);
+    //
+  }
+
+  // Determine device uri
+  char *env = getenv("DEVICE_URI");
+  if (env != NULL && strchr(env, ':') != NULL) {
+    snprintf(device, NAMELEN, "%s", env);
+  } else if (strstr(argv[0], ":/") != NULL)  {
+    snprintf(device, NAMELEN, "%s", argv[0]);
+  } else {
+    fputs("ERROR: No device URI given.\n", stderr);
+    return CUPS_BACKEND_FAILED;
+  }
+
+  // Get backend from uri
+  char *colon = strchr(device, ':');
+  *colon = '\0';
+  snprintf(backend, NAMELEN, "%s/%s", BACKEND_PATH, device);
+  *colon = ':';
+  // Is valid?
+  if (access(backend, X_OK | R_OK) != 0) {
+    fprintf(stderr, "ERROR: Backend %s is not executable.\n", backend);
+    return CUPS_BACKEND_FAILED;
+  }
+
+  // Try right away with what we got
+  spoolres = run_backend(backend, device, argv[1], argv[2], argv[3], argv[4], argv[5], tmpfile, NULL);
+  if (spoolres == CUPS_BACKEND_OK) return spoolres; // Yay
+
+  // Dialog - TODO: Drop privileges here!
+  QApplication a(argc, argv);
+  PwGui w(NULL);
+  w.show();
+  return a.exec();
+  // TODO .....
+}
+
+static int run_backend(char *backend, char *uri, char *jobid, char *user, char *title, char *copies, char *options, char *file, char *password)
+{
+  pid_t pid = fork();
+  if (pid == 0) {
+    // Child
+    if (user != NULL) setenv("AUTH_USERNAME", user, 1);
+    if (password != NULL) setenv("AUTH_PASSWORD", password, 1);
+    char *args[8];
+    args[0] = uri;
+    args[1] = jobid;
+    args[2] = user;
+    args[3] = title;
+    args[4] = copies;
+    args[5] = options;
+    args[6] = file;
+    args[7] = NULL;
+    execv(backend, args);
+    exit(127);
+    return 127;
+  }
+
+  // Main - wait for it...
+  int status;
+  waitpid(pid, &status, 0);
+  if (!WIFEXITED(status)) {
+    fprintf(stderr, "ERROR: Running backend %s failed!\n", backend);
+    return CUPS_BACKEND_FAILED;
+  }
+  return WEXITSTATUS(status);
+}
+