libppd: When parsing *.drv files for PPD collections, eliminate stderr

When generating PPD lists for PPD collections or extracting a PPD file
from a collection, *.drv files (CUPS has them in /usr/share/cups/drv)
can be parsed with the CUPS PPD compiler functions which got adopted
into libppd.

These functions are originally created for command line utilities to
handle *.drv files and PPD files and therefore they were rather
verbose on stderr in case there was an error in a file. As the PPD
collection handling functionality (ppd/pdd-collection.cxx) only
retro-fits existing *.drv files and does not serve for creating or
developing them, we simply re-direct stderr to /dev/null while
executing these functions to avoid any messages leaking into syslog or
the journal while running Printer Applications. This is much easier as
and less error-prone than introducing support for logging functions
into the obsolete and retro-fit-only *.drv handling function.

diff --git a/ppd/ppd-collection.cxx b/ppd/ppd-collection.cxx
index 5646c74aa5e1915729f994b7e1ceb64b2a83b3a8..8cc4d99c91e784c880530bbf803abb66a59dcbc4 100644 (file)
--- a/ppd/ppd-collection.cxx
+++ b/ppd/ppd-collection.cxx
@@ -948,7 +948,8 @@ cat_drv(const char *filename,               /* I - *.drv file name */
   char         tempname[1024];         // Name for the temporary file
   ppdcSource   *src;                   // PPD source file data
   ppdcDriver   *d;                     // Current driver
-  cups_file_t  *out;                   // PPD output to temp file
+  cups_file_t  *out = NULL;            // PPD output to temp file
+  int           fd1, fd2;
 
   if ((fp = cupsFileOpen(filename, "r")) == NULL)
   {
@@ -959,6 +960,13 @@ cat_drv(const char *filename,              /* I - *.drv file name */
     return (NULL);
   }
 
+  /* Eliminate any output to stderr, to get rid of the error messages of
+     the *.drv file parser */
+  fd1 = dup(2);
+  fd2 = open("/dev/null", O_WRONLY);
+  dup2(fd2, 2);
+  close(fd2);
+
   src = new ppdcSource(filename, fp);
 
   for (d = (ppdcDriver *)src->drivers->first();
@@ -974,43 +982,40 @@ cat_drv(const char *filename,             /* I - *.drv file name */
     ppdcCatalog        *catalog;               // Message catalog in .drv file
 
 
-    if (log) log(ld, FILTER_LOGLEVEL_DEBUG,
-                "libppd: [PPD Collections] %u locales defined in \"%s\"...\n",
-                (unsigned)src->po_files->count, filename);
-
-    locales = new ppdcArray();
-    for (catalog = (ppdcCatalog *)src->po_files->first();
-         catalog;
-        catalog = (ppdcCatalog *)src->po_files->next())
-    {
-      if (log) log(ld, FILTER_LOGLEVEL_DEBUG,
-                  "libppd: [PPD Collections] Adding locale \"%s\"...\n",
-                  catalog->locale->value);
-      catalog->locale->retain();
-      locales->add(catalog->locale);
-    }
-
     if ((fd = cupsTempFd(tempname, sizeof(tempname))) < 0)
     {
       if (log) log(ld, FILTER_LOGLEVEL_ERROR,
                   "libppd: [PPD Collections] Unable to copy PPD to temp "
                   "file: %s",
                   strerror(errno));
-      return (NULL);
     }
-    out = cupsFileOpenFd(fd, "w");
-    d->write_ppd_file(out, NULL, locales, src, PPDC_LFONLY);
-    cupsFileClose(out);
-    close(fd);
-    locales->release();
-    src->release();
-    cupsFileClose(fp);
+    else
+    {
+      if (log) log(ld, FILTER_LOGLEVEL_DEBUG,
+                  "libppd: [PPD Collections] %u locales defined in \"%s\"...\n",
+                  (unsigned)src->po_files->count, filename);
 
-    out = cupsFileOpen(tempname, "r");
-    unlink(tempname);
+      locales = new ppdcArray();
+      for (catalog = (ppdcCatalog *)src->po_files->first();
+          catalog;
+          catalog = (ppdcCatalog *)src->po_files->next())
+      {
+       if (log) log(ld, FILTER_LOGLEVEL_DEBUG,
+                    "libppd: [PPD Collections] Adding locale \"%s\"...\n",
+                    catalog->locale->value);
+       catalog->locale->retain();
+       locales->add(catalog->locale);
+      }
 
-    return(out);
+      out = cupsFileOpenFd(fd, "w");
+      d->write_ppd_file(out, NULL, locales, src, PPDC_LFONLY);
+      cupsFileClose(out);
+      close(fd);
+      locales->release();
 
+      out = cupsFileOpen(tempname, "r");
+      unlink(tempname);
+    }
   }
   else
     if (log) log(ld, FILTER_LOGLEVEL_ERROR,
@@ -1019,7 +1024,11 @@ cat_drv(const char *filename,            /* I - *.drv file name */
   src->release();
   cupsFileClose(fp);
 
-  return (NULL);
+  /* Re-activate stderr output */
+  dup2(fd1, 2);
+  close(fd1);
+
+  return (out);
 }
 
 
@@ -1463,7 +1472,18 @@ load_drv(const char  *filename,          /* I - Actual filename */
   char         uri[2048],              // Driver URI
                make_model[1024];       // Make and model
   int          type;                   // Driver type
+  int           fd1, fd2;
+
 
+ /*
+  * Eliminate any output to stderr, to get rid of the error messages of
+  * the *.drv file parser
+  */
+
+  fd1 = dup(2);
+  fd2 = open("/dev/null", O_WRONLY);
+  dup2(fd2, 2);
+  close(fd2);
 
  /*
   * Load the driver info file...
@@ -1477,6 +1497,9 @@ load_drv(const char  *filename,           /* I - Actual filename */
                 "libppd: [PPD Collections] Bad driver information file \"%s\"!\n",
                 filename);
     src->release();
+    /* Re-activate stderr output */
+    dup2(fd1, 2);
+    close(fd1);
     return (0);
   }
 
@@ -1565,6 +1588,13 @@ load_drv(const char  *filename,          /* I - Actual filename */
 
   src->release();
 
+ /*
+  * Re-activate stderr output
+  */
+
+  dup2(fd1, 2);
+  close(fd1);
+
   return (1);
 }