tools: Fix regex syntax warnings with Python 3.12

Since Python 3.12, invalid escape sequences generate SyntaxWarning.  In the
future, these invalid sequences will raise a SyntaxError, so changed to using
raw string notation.

Link: https://docs.python.org/3/whatsnew/3.12.html#other-language-changes
Fixes: d8f3a67bf9 ("pygrub: further improve grub2 support")
Fixes: dd03048708 ("xen/pygrub: grub2/grub.cfg from RHEL 7 has new commands in menuentry")
Fixes: d1b93ea261 ("tools/pygrub: Make pygrub understand default entry in string format")
Fixes: 622e368758 ("Add ZFS libfsimage support patch")
Fixes: 02b26c02c7 ("xen/scripts: add cppcheck tool to the xen-analysis.py script")
Fixes: 56c0063f4e ("xen/misra: xen-analysis.py: Improve the cppcheck version check")
Signed-off-by: Ariel Otilibili <Ariel.Otilibili-Anieli@eurecom.fr>
Reviewed-by: Luca Fancellu <luca.fancellu@arm.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

tools/pygrub/src/GrubConf.py

@@ -320,7 +320,7 @@ class GrubConfigFile(_GrubConfigFile):
 def grub2_handle_set(arg):
     (com,arg) = grub_split(arg,2)
     com="set:" + com
-    m = re.match("([\"\'])(.*)\\1", arg)
+    m = re.match(r"([\"\'])(.*)\1", arg)
     if m is not None:
         arg=m.group(2)
     return (com,arg)
@@ -402,7 +402,7 @@ class Grub2ConfigFile(_GrubConfigFile):
                 continue
 
             # new image
-            title_match = re.match('^menuentry ["\'](.*?)["\'] (.*){', l)
+            title_match = re.match(r'^menuentry ["\'](.*?)["\'] (.*){', l)
             if title_match:
                 if img is not None:
                     raise RuntimeError("syntax error: cannot nest menuentry (%d %s)" % (len(img),img))

tools/pygrub/src/pygrub

@@ -614,7 +614,7 @@ class Grub:
             title = self.cf.default
             while 1:
                 try:
-                    title = re.search('(\S)>(\S.+$)',title).group(2)
+                    title = re.search(r'(\S)>(\S.+$)',title).group(2)
                 except AttributeError:
                     break
 
@@ -1039,7 +1039,7 @@ if __name__ == "__main__":
 
     # if boot filesystem is set then pass to fsimage.open
     bootfsargs = '"%s"' % incfg["args"]
-    bootfsgroup = re.findall('zfs-bootfs=(.*?)[\s\,\"]', bootfsargs)
+    bootfsgroup = re.findall(r'zfs-bootfs=(.*?)[\s\,\"]', bootfsargs)
     if bootfsgroup:
         bootfsoptions = bootfsgroup[0]
     else:
@@ -1104,7 +1104,7 @@ if __name__ == "__main__":
     if chosencfg["args"]:
         zfsinfo = xenfsimage.getbootstring(fs)
         if zfsinfo is not None:
-            e = re.compile("zfs-bootfs=[\w\-\.\:@/]+" )
+            e = re.compile(r"zfs-bootfs=[\w\-.:@/]+" )
             (chosencfg["args"],count) = e.subn(zfsinfo, chosencfg["args"])
             if count == 0:
                chosencfg["args"] += " -B %s" % zfsinfo

xen/scripts/xen_analysis/cppcheck_analysis.py

@@ -93,7 +93,7 @@ def __generate_suppression_list(out_file):
                         # start of a comment '/*'
                         comment_line_starts = re.match('^[ \t]*/\*.*$', line)
                         # Matches a line with text and the end of a comment '*/'
-                        comment_line_stops = re.match('^.*\*/$', line)
+                        comment_line_stops = re.match(r'^.*\*/$', line)
                         if (not comment_section) and comment_line_starts:
                             comment_section = True
                         if (len(line.strip()) != 0) and (not comment_section):
@@ -157,7 +157,7 @@ def generate_cppcheck_deps():
             "Error occured retrieving cppcheck version:\n{}\n\n{}"
         )
 
-    version_regex = re.search('^Cppcheck (\d+)\.(\d+)(?:\.\d+)?$',
+    version_regex = re.search(r'^Cppcheck (\d+)\.(\d+)(?:\.\d+)?$',
                               invoke_cppcheck, flags=re.M)
     # Currently, only cppcheck version >= 2.7 is supported, but version 2.8 is
     # known to be broken, please refer to docs/misra/cppcheck.txt