bpf/scripts: Raise an exception if the correct number of sycalls are not generated

Currently the syscalls rst and subsequently man page are auto-generated using function documentation present in bpf.h. If the documentation for the syscall is missing or doesn't follow a specific format, then that syscall is not dumped in the auto-generated rst. This patch checks the number of syscalls documented within the header file with those present as part of the enum bpf_cmd and raises an Exception if they don't match. It is not needed with the currently documented upstream syscalls, but can help in debugging when developing new syscalls when there might be missing or misformatted documentation. The function helper_number_check is moved to the Printer parent class and renamed to elem_number_check as all the most derived children classes are using this function now.

Usama Arif committed 4 years ago

Commit 0ba39291 parent f1f3f671 file · +59 −27Browse files

Unified · Split

scripts/bpf_doc.py+59−27

         self.commands = []
         self.desc_unique_helpers = set()
         self.define_unique_helpers = []
+        self.desc_syscalls = []
+        self.enum_syscalls = []
     def parse_element(self):
         proto    = self.parse_symbol()
         return Helper(proto=proto, desc=desc, ret=ret)
     def parse_symbol(self):
-        p = re.compile(' \* ?(.+)$')
+        p = re.compile(' \* ?(BPF\w+)$')
         capture = p.match(self.line)
         if not capture:
             raise NoSyscallCommandFound
             raise Exception("No return found for " + proto)
         return ret
-    def seek_to(self, target, help_message):
+    def seek_to(self, target, help_message, discard_lines = 1):
         self.reader.seek(0)
         offset = self.reader.read().find(target)
         if offset == -1:
             raise Exception(help_message)
         self.reader.seek(offset)
         self.reader.readline()
-        self.reader.readline()
+        for _ in range(discard_lines):
+            self.reader.readline()
         self.line = self.reader.readline()
-    def parse_syscall(self):
+    def parse_desc_syscall(self):
         self.seek_to('* DOC: eBPF Syscall Commands',
                      'Could not find start of eBPF syscall descriptions list')
         while True:
             try:
                 command = self.parse_element()
                 self.commands.append(command)
+                self.desc_syscalls.append(command.proto)
             except NoSyscallCommandFound:
                 break
+    def parse_enum_syscall(self):
+        self.seek_to('enum bpf_cmd {',
+                     'Could not find start of bpf_cmd enum', 0)
+        # Searches for either one or more BPF\w+ enums
+        bpf_p = re.compile('\s*(BPF\w+)+')
+        # Searches for an enum entry assigned to another entry,
+        # for e.g. BPF_PROG_RUN = BPF_PROG_TEST_RUN, which is
+        # not documented hence should be skipped in check to
+        # determine if the right number of syscalls are documented
+        assign_p = re.compile('\s*(BPF\w+)\s*=\s*(BPF\w+)')
+        bpf_cmd_str = ''
+        while True:
+            capture = assign_p.match(self.line)
+            if capture:
+                # Skip line if an enum entry is assigned to another entry
+                self.line = self.reader.readline()
+                continue
+            capture = bpf_p.match(self.line)
+            if capture:
+                bpf_cmd_str += self.line
+            else:
+                break
+            self.line = self.reader.readline()
+        # Find the number of occurences of BPF\w+
+        self.enum_syscalls = re.findall('(BPF\w+)+', bpf_cmd_str)
     def parse_desc_helpers(self):
         self.seek_to('* Start of BPF helper function descriptions:',
                      'Could not find start of eBPF helper descriptions list')
         self.define_unique_helpers = re.findall('FN\(\w+\)', fn_defines_str)
     def run(self):
-        self.parse_syscall()
+        self.parse_desc_syscall()
+        self.parse_enum_syscall()
         self.parse_desc_helpers()
         self.parse_define_helpers()
         self.reader.close()
             self.print_one(elem)
         self.print_footer()
+    def elem_number_check(self, desc_unique_elem, define_unique_elem, type, instance):
+        """
+        Checks the number of helpers/syscalls documented within the header file
+        description with those defined as part of enum/macro and raise an
+        Exception if they don't match.
+        """
+        nr_desc_unique_elem = len(desc_unique_elem)
+        nr_define_unique_elem = len(define_unique_elem)
+        if nr_desc_unique_elem != nr_define_unique_elem:
+            exception_msg = '''
+The number of unique %s in description (%d) doesn\'t match the number of unique %s defined in %s (%d)
+''' % (type, nr_desc_unique_elem, type, instance, nr_define_unique_elem)
+            if nr_desc_unique_elem < nr_define_unique_elem:
+                # Function description is parsed until no helper is found (which can be due to
+                # misformatting). Hence, only print the first missing/misformatted helper/enum.
+                exception_msg += '''
+The description for %s is not present or formatted correctly.
+''' % (define_unique_elem[nr_desc_unique_elem])
+            raise Exception(exception_msg)
 class PrinterRST(Printer):
     """
         print('')
-def helper_number_check(desc_unique_helpers, define_unique_helpers):
-    """
-    Checks the number of functions documented within the header file
-    with those present as part of #define __BPF_FUNC_MAPPER and raise an
-    Exception if they don't match.
-    """
-    nr_desc_unique_helpers = len(desc_unique_helpers)
-    nr_define_unique_helpers = len(define_unique_helpers)
-    if nr_desc_unique_helpers != nr_define_unique_helpers:
-        helper_exception = '''
-The number of unique helpers in description (%d) doesn\'t match the number of unique helpers defined in __BPF_FUNC_MAPPER (%d)
-''' % (nr_desc_unique_helpers, nr_define_unique_helpers)
-        if nr_desc_unique_helpers < nr_define_unique_helpers:
-            # Function description is parsed until no helper is found (which can be due to
-            # misformatting). Hence, only print the first missing/misformatted function.
-            helper_exception += '''
-The description for %s is not present or formatted correctly.
-''' % (define_unique_helpers[nr_desc_unique_helpers])
-        raise Exception(helper_exception)
 class PrinterHelpersRST(PrinterRST):
     """
     A printer for dumping collected information about helpers as a ReStructured
     """
     def __init__(self, parser):
         self.elements = parser.helpers
-        helper_number_check(parser.desc_unique_helpers, parser.define_unique_helpers)
+        self.elem_number_check(parser.desc_unique_helpers, parser.define_unique_helpers, 'helper', '__BPF_FUNC_MAPPER')
     def print_header(self):
         header = '''\
     """
     def __init__(self, parser):
         self.elements = parser.commands
+        self.elem_number_check(parser.desc_syscalls, parser.enum_syscalls, 'syscall', 'bpf_cmd')
     def print_header(self):
         header = '''\
     """
     def __init__(self, parser):
         self.elements = parser.helpers
-        helper_number_check(parser.desc_unique_helpers, parser.define_unique_helpers)
+        self.elem_number_check(parser.desc_unique_helpers, parser.define_unique_helpers, 'helper', '__BPF_FUNC_MAPPER')
     type_fwds = [
             'struct bpf_fib_lookup',