diff options
Diffstat (limited to 'scripts/bpf_doc.py')
| -rwxr-xr-x | scripts/bpf_doc.py | 172 |
1 files changed, 149 insertions, 23 deletions
diff --git a/scripts/bpf_doc.py b/scripts/bpf_doc.py index 61b7dddedc46..c77dc40f7689 100755 --- a/scripts/bpf_doc.py +++ b/scripts/bpf_doc.py @@ -8,6 +8,7 @@ from __future__ import print_function import argparse +import json import re import sys, os import subprocess @@ -42,6 +43,13 @@ class APIElement(object): self.desc = desc self.ret = ret + def to_dict(self): + return { + 'proto': self.proto, + 'desc': self.desc, + 'ret': self.ret + } + class Helper(APIElement): """ @@ -50,8 +58,9 @@ class Helper(APIElement): @desc: textual description of the helper function @ret: description of the return value of the helper function """ - def __init__(self, *args, **kwargs): - super().__init__(*args, **kwargs) + def __init__(self, proto='', desc='', ret='', attrs=[]): + super().__init__(proto, desc, ret) + self.attrs = attrs self.enum_val = None def proto_break_down(self): @@ -80,6 +89,17 @@ class Helper(APIElement): return res + def to_dict(self): + d = super().to_dict() + d["attrs"] = self.attrs + d.update(self.proto_break_down()) + return d + + +ATTRS = { + '__bpf_fastcall': 'bpf_fastcall' +} + class HeaderParser(object): """ @@ -111,7 +131,8 @@ class HeaderParser(object): proto = self.parse_proto() desc = self.parse_desc(proto) ret = self.parse_ret(proto) - return Helper(proto=proto, desc=desc, ret=ret) + attrs = self.parse_attrs(proto) + return Helper(proto=proto, desc=desc, ret=ret, attrs=attrs) def parse_symbol(self): p = re.compile(r' \* ?(BPF\w+)$') @@ -192,6 +213,28 @@ class HeaderParser(object): raise Exception("No return found for " + proto) return ret + def parse_attrs(self, proto): + p = re.compile(r' \* ?(?:\t| {5,8})Attributes$') + capture = p.match(self.line) + if not capture: + return [] + # Expect a single line with mnemonics for attributes separated by spaces + self.line = self.reader.readline() + p = re.compile(r' \* ?(?:\t| {5,8})(?:\t| {8})(.*)') + capture = p.match(self.line) + if not capture: + raise Exception("Incomplete 'Attributes' section for " + proto) + attrs = capture.group(1).split(' ') + for attr in attrs: + if attr not in ATTRS: + raise Exception("Unexpected attribute '" + attr + "' specified for " + proto) + self.line = self.reader.readline() + if self.line != ' *\n': + raise Exception("Expecting empty line after 'Attributes' section for " + proto) + # Prepare a line for next self.parse_* to consume + self.line = self.reader.readline() + return attrs + def seek_to(self, target, help_message, discard_lines = 1): self.reader.seek(0) offset = self.reader.read().find(target) @@ -414,8 +457,8 @@ class PrinterRST(Printer): version = version.stdout.decode().rstrip() except: try: - version = subprocess.run(['make', 'kernelversion'], cwd=linuxRoot, - capture_output=True, check=True) + version = subprocess.run(['make', '-s', '--no-print-directory', 'kernelversion'], + cwd=linuxRoot, capture_output=True, check=True) version = version.stdout.decode().rstrip() except: return 'Linux' @@ -513,7 +556,7 @@ eBPF programs can have an associated license, passed along with the bytecode instructions to the kernel when the programs are loaded. The format for that string is identical to the one in use for kernel modules (Dual licenses, such as "Dual BSD/GPL", may be used). Some helper functions are only accessible to -programs that are compatible with the GNU Privacy License (GPL). +programs that are compatible with the GNU General Public License (GNU GPL). In order to use such helpers, the eBPF program must be loaded with the correct license string passed (via **attr**) to the **bpf**\\ () system call, and this @@ -646,7 +689,7 @@ COMMANDS self.print_elem(command) -class PrinterHelpers(Printer): +class PrinterHelpersHeader(Printer): """ A printer for dumping collected information about helpers as C header to be included from BPF program. @@ -789,6 +832,21 @@ class PrinterHelpers(Printer): print('%s;' % fwd) print('') + used_attrs = set() + for helper in self.elements: + for attr in helper.attrs: + used_attrs.add(attr) + for attr in sorted(used_attrs): + print('#ifndef %s' % attr) + print('#if __has_attribute(%s)' % ATTRS[attr]) + print('#define %s __attribute__((%s))' % (attr, ATTRS[attr])) + print('#else') + print('#define %s' % attr) + print('#endif') + print('#endif') + if used_attrs: + print('') + def print_footer(self): footer = '' print(footer) @@ -827,7 +885,10 @@ class PrinterHelpers(Printer): print(' *{}{}'.format(' \t' if line else '', line)) print(' */') - print('static %s %s(*%s)(' % (self.map_type(proto['ret_type']), + print('static ', end='') + if helper.attrs: + print('%s ' % (" ".join(helper.attrs)), end='') + print('%s %s(* const %s)(' % (self.map_type(proto['ret_type']), proto['ret_star'], proto['name']), end='') comma = '' for i, a in enumerate(proto['args']): @@ -849,6 +910,43 @@ class PrinterHelpers(Printer): print(') = (void *) %d;' % helper.enum_val) print('') + +class PrinterHelpersJSON(Printer): + """ + A printer for dumping collected information about helpers as a JSON file. + @parser: A HeaderParser with Helper objects + """ + + def __init__(self, parser): + self.elements = parser.helpers + self.elem_number_check( + parser.desc_unique_helpers, + parser.define_unique_helpers, + "helper", + "___BPF_FUNC_MAPPER", + ) + + def print_all(self): + helper_dicts = [helper.to_dict() for helper in self.elements] + out_dict = {'helpers': helper_dicts} + print(json.dumps(out_dict, indent=4)) + + +class PrinterSyscallJSON(Printer): + """ + A printer for dumping collected syscall information as a JSON file. + @parser: A HeaderParser with APIElement objects + """ + + def __init__(self, parser): + self.elements = parser.commands + self.elem_number_check(parser.desc_syscalls, parser.enum_syscalls, 'syscall', 'bpf_cmd') + + def print_all(self): + syscall_dicts = [syscall.to_dict() for syscall in self.elements] + out_dict = {'syscall': syscall_dicts} + print(json.dumps(out_dict, indent=4)) + ############################################################################### # If script is launched from scripts/ from kernel tree and can access @@ -858,9 +956,17 @@ script = os.path.abspath(sys.argv[0]) linuxRoot = os.path.dirname(os.path.dirname(script)) bpfh = os.path.join(linuxRoot, 'include/uapi/linux/bpf.h') +# target -> output format -> printer printers = { - 'helpers': PrinterHelpersRST, - 'syscall': PrinterSyscallRST, + 'helpers': { + 'rst': PrinterHelpersRST, + 'json': PrinterHelpersJSON, + 'header': PrinterHelpersHeader, + }, + 'syscall': { + 'rst': PrinterSyscallRST, + 'json': PrinterSyscallJSON + }, } argParser = argparse.ArgumentParser(description=""" @@ -870,6 +976,8 @@ rst2man utility. """) argParser.add_argument('--header', action='store_true', help='generate C header file') +argParser.add_argument('--json', action='store_true', + help='generate a JSON') if (os.path.isfile(bpfh)): argParser.add_argument('--filename', help='path to include/uapi/linux/bpf.h', default=bpfh) @@ -877,17 +985,35 @@ else: argParser.add_argument('--filename', help='path to include/uapi/linux/bpf.h') argParser.add_argument('target', nargs='?', default='helpers', choices=printers.keys(), help='eBPF API target') -args = argParser.parse_args() -# Parse file. -headerParser = HeaderParser(args.filename) -headerParser.run() - -# Print formatted output to standard output. -if args.header: - if args.target != 'helpers': - raise NotImplementedError('Only helpers header generation is supported') - printer = PrinterHelpers(headerParser) -else: - printer = printers[args.target](headerParser) -printer.print_all() +def error_die(message: str): + argParser.print_usage(file=sys.stderr) + print('Error: {}'.format(message), file=sys.stderr) + exit(1) + +def parse_and_dump(): + args = argParser.parse_args() + + # Parse file. + headerParser = HeaderParser(args.filename) + headerParser.run() + + if args.header and args.json: + error_die('Use either --header or --json, not both') + + output_format = 'rst' + if args.header: + output_format = 'header' + elif args.json: + output_format = 'json' + + try: + printer = printers[args.target][output_format](headerParser) + # Print formatted output to standard output. + printer.print_all() + except KeyError: + error_die('Unsupported target/format combination: "{}", "{}"' + .format(args.target, output_format)) + +if __name__ == "__main__": + parse_and_dump() |