Clean up device fact gathering

Remove lots of re use that really shouldn't have been re in the first
place. Initialize pcidata even if lspci is unavailable, and check for
its usability before trying to use it.

Fixes #2060.

setup

@@ -380,6 +380,8 @@ class LinuxHardware(Hardware):
         lspci = module.get_bin_path('lspci')
         if lspci:
             rc, pcidata, err = module.run_command(lspci)
+        else:
+            pcidata = None
 
         try:
             block_devs = os.listdir("/sys/block")
@@ -397,19 +399,18 @@ class LinuxHardware(Hardware):
                     sysfs_no_links = 1
                 else:
                     continue
-            if re.search("virtual", path):
+            if "virtual" in path:
                 continue
             sysdir = os.path.join("/sys/block", path)
             if sysfs_no_links == 1:
                 for folder in os.listdir(sysdir):
-                    if re.search("device", folder):
+                    if "device" in folder:
                         virtual = 0
                         break
                 if virtual:
                     continue
             d = {}
-            m = re.match(".*/(.+)$", sysdir)
-            diskname = m.group(1)
+            diskname = os.path.basename(sysdir)
             for key in ['vendor', 'model']:
                 d[key] = get_file_content(sysdir + "/device/" + key)
 
@@ -448,8 +449,8 @@ class LinuxHardware(Hardware):
             d['size'] = module.pretty_bytes(float(d['sectors']) * float(d['sectorsize']))
 
             d['host'] = ""
-            m = re.match(".+/\d+:(\w+:\w+\.\w)/host\d+/\s*", sysdir)
-            if m:
+            m = re.match(".+/[a-f0-9]+:([a-f0-9]+:[a-f0-9]+\.[a-f0-9]+)/host\d+/", sysdir)
+            if m and pcidata:
                 pciid = m.group(1)
                 did = re.escape(pciid)
                 m = re.search("^" + did + "\s(.*)$", pcidata, re.MULTILINE)
@@ -457,8 +458,9 @@ class LinuxHardware(Hardware):
 
             d['holders'] = []
             for folder in os.listdir(sysdir + "/holders"):
-                if re.search("^dm-.*", folder):
-                    name = get_file_content(sysdir + "/holders/" + folder + "/dm/name")
+                if not folder.startswith("dm-"):
+                    continue
+                name = get_file_content(sysdir + "/holders/" + folder + "/dm/name")
                 if name:
                     d['holders'].append(name)
                 else: