sane-project-website/old-archive/1999-05/0239.html

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<!-- name="Nick Lamb" -->
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<!-- subject="find-scanner &amp; SCSI generic test [patch]" -->
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<title>sane-devel: find-scanner &amp; SCSI generic test [patch]</title>
<h1>find-scanner &amp; SCSI generic test [patch]</h1>
<b>Nick Lamb</b> (<a href="mailto:njl98r@ecs.soton.ac.uk"><i>njl98r@ecs.soton.ac.uk</i></a>)<br>
<i>Sat, 22 May 1999 04:28:21 +0100 (GMT)</i>
<p>
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After I sent my original patch to the list a week or so ago, I was asked<br>
to alter it so that future kernel changes were less likely to disrupt<br>
operation on any Linux or Linux-like system. Here's the new version of<br>
the patch (you'll have to back the old one out if you've applied it)<br>
<p>
For those who missed this the first time -<br>
Not all SANE first-timers realise that they need SCSI drivers, and in<br>
particular SCSI generic drivers, before SANE can talk to their scanner.<br>
This patch checks (on Linux only so far) for SCSI Generic support in<br>
the OS kernel. If NOT present it tells the user they may need SG drivers<br>
<p>
Nick.<br>
<p>
--- find-scanner.c.old	Tue May 11 15:30:07 1999<br>
+++ find-scanner.c	Sat May 22 04:14:46 1999<br>
@@ -74,6 +74,38 @@<br>
     fprintf (stderr, "\t%s\n", msg);<br>
 }<br>
 <br>
+/* if SCSI generic is optional on your OS, and there is a software test<br>
+   which will determine if it is included, add it here. If you are sure<br>
+   that SCSI generic was found, return 1. If SCSI generic is always<br>
+   available in your OS, return 1 */<br>
+<br>
+int<br>
+check_sg (void)<br>
+{<br>
+#if defined(__linux__)<br>
+  /* Assumption: /proc/devices lines are shorter than 256 characters */<br>
+  char line[256], driver[256]= "";<br>
+  FILE *stream;<br>
+<br>
+  stream= fopen("/proc/devices", "r");<br>
+  /* Likely reason for failure, no /proc =&gt; probably no SG either */<br>
+  if (stream == NULL) return 0;<br>
+  <br>
+  while (fgets(line, 255, stream)) {<br>
+    if (sscanf(line, " %*d %s\n", driver) &gt; 0 &amp;&amp; !strcmp(driver, "sg"))<br>
+      break;<br>
+  }<br>
+  fclose(stream);<br>
+<br>
+  if (strcmp(driver, "sg")) {<br>
+    return 0;<br>
+  } else {<br>
+    return 1;<br>
+  }<br>
+#endif<br>
+  return 1; /* Give up, and assume yes to avoid false negatives */<br>
+}<br>
+<br>
 void <br>
 scanner_do_inquiry (unsigned char *buffer, int sfd)<br>
 {<br>
@@ -408,6 +440,13 @@<br>
 	  sanei_scsi_close (sfd);<br>
 	}<br>
     }<br>
+  if (!check_sg()) {<br>
+    printf (<br>
+     "# If your scanner uses SCSI, you must have a driver for your SCSI\n"<br>
+     "# adaptor and support for SCSI Generic (sg) in your Operating System\n"<br>
+     "# in order for the scanner to be used with SANE. If your scanner is\n"<br>
+     "# NOT listed above, check that you have installed the drivers.\n\n");<br>
+  }<br>
   if (verbose)<br>
     printf ("%s: done\n", prog_name);<br>
   return 0;<br>
<p>
<p>
<pre>
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</pre>
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<p>
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<li> <b>Next message:</b> <a href="0240.html">Oliver Rauch: "New UMAX-backend available"</a>
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