On 18/01/2022 16:04, Quentin Monnet wrote:
2022-01-18 11:56 UTC+0000 ~ Usama Arif <usama.arif@xxxxxxxxxxxxx>
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.
Signed-off-by: Usama Arif <usama.arif@xxxxxxxxxxxxx>
Thanks for the follow-up, looks good and seems to work well. Please find
just a few nitpicks below.
---
scripts/bpf_doc.py | 88 ++++++++++++++++++++++++++++++++--------------
1 file changed, 61 insertions(+), 27 deletions(-)
diff --git a/scripts/bpf_doc.py b/scripts/bpf_doc.py
index 20441e5d2..11304427e 100755
--- a/scripts/bpf_doc.py
+++ b/scripts/bpf_doc.py
@@ -89,6 +89,8 @@ class HeaderParser(object):
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()
@@ -103,7 +105,7 @@ class HeaderParser(object):
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
@@ -181,26 +183,55 @@ class HeaderParser(object):
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
Sounds good. If you respin, would you mind taking this opportunity to
add, at the end of BPF_PROG_TEST_RUN's description in
{tools/,}include/uapi/linux/bpf.h, that BPF_PROG_RUN is an alias to this
command? It may be useful for users looking for BPF_PROG_RUN in the
generated man page.
Thanks for the reviews! Added in v2.
+ 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')
@@ -234,7 +265,8 @@ class HeaderParser(object):
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()
@@ -266,6 +298,27 @@ class Printer(object):
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)
Nit: I think you didn't mean to indent the two lines above?
Thanks, removed indent here and below in v2.
+ 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])
Same thing for the indent
+ print(define_unique_elem)
+ print(desc_unique_elem)
These two objects should accompany the error message from the Exception.
Did you consider adding them to exception_msg? If not convenient, should
we at least send them to stderr instead of stdout?
They were debug prints that i was using while writing the patch. I
should have removed them before sending to the mailing list! Removed in
v2, Thanks!
+ raise Exception(exception_msg)
