diff options
Diffstat (limited to 'scripts/bpf_doc.py')
| -rwxr-xr-x | scripts/bpf_doc.py | 229 |
1 files changed, 178 insertions, 51 deletions
diff --git a/scripts/bpf_doc.py b/scripts/bpf_doc.py index eaae2ce78381..15d113a1bc1d 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): @@ -59,9 +68,9 @@ class Helper(APIElement): Break down helper function protocol into smaller chunks: return type, name, distincts arguments. """ - arg_re = re.compile('((\w+ )*?(\w+|...))( (\**)(\w+))?$') + arg_re = re.compile(r'((\w+ )*?(\w+|...))( (\**)(\w+))?$') res = {} - proto_re = re.compile('(.+) (\**)(\w+)\(((([^,]+)(, )?){1,5})\)$') + proto_re = re.compile(r'(.+) (\**)(\w+)\(((([^,]+)(, )?){1,5})\)$') capture = proto_re.match(self.proto) res['ret_type'] = capture.group(1) @@ -80,6 +89,17 @@ class Helper(APIElement): return res + def to_dict(self): + d = super().to_dict() + d["attrs"] = self.attrs + d.update(self.proto_break_down()) + return d + + +ATTRS = { + '__bpf_fastcall': 'bpf_fastcall' +} + class HeaderParser(object): """ @@ -111,14 +131,15 @@ class HeaderParser(object): proto = self.parse_proto() desc = self.parse_desc(proto) ret = self.parse_ret(proto) - return Helper(proto=proto, desc=desc, ret=ret) + attrs = self.parse_attrs(proto) + return Helper(proto=proto, desc=desc, ret=ret, attrs=attrs) def parse_symbol(self): - p = re.compile(' \* ?(BPF\w+)$') + p = re.compile(r' \* ?(BPF\w+)$') capture = p.match(self.line) if not capture: raise NoSyscallCommandFound - end_re = re.compile(' \* ?NOTES$') + end_re = re.compile(r' \* ?NOTES$') end = end_re.match(self.line) if end: raise NoSyscallCommandFound @@ -133,7 +154,7 @@ class HeaderParser(object): # - Same as above, with "const" and/or "struct" in front of type # - "..." (undefined number of arguments, for bpf_trace_printk()) # There is at least one term ("void"), and at most five arguments. - p = re.compile(' \* ?((.+) \**\w+\((((const )?(struct )?(\w+|\.\.\.)( \**\w+)?)(, )?){1,5}\))$') + p = re.compile(r' \* ?((.+) \**\w+\((((const )?(struct )?(\w+|\.\.\.)( \**\w+)?)(, )?){1,5}\))$') capture = p.match(self.line) if not capture: raise NoHelperFound @@ -141,7 +162,7 @@ class HeaderParser(object): return capture.group(1) def parse_desc(self, proto): - p = re.compile(' \* ?(?:\t| {5,8})Description$') + p = re.compile(r' \* ?(?:\t| {5,8})Description$') capture = p.match(self.line) if not capture: raise Exception("No description section found for " + proto) @@ -154,7 +175,7 @@ class HeaderParser(object): if self.line == ' *\n': desc += '\n' else: - p = re.compile(' \* ?(?:\t| {5,8})(?:\t| {8})(.*)') + p = re.compile(r' \* ?(?:\t| {5,8})(?:\t| {8})(.*)') capture = p.match(self.line) if capture: desc_present = True @@ -167,7 +188,7 @@ class HeaderParser(object): return desc def parse_ret(self, proto): - p = re.compile(' \* ?(?:\t| {5,8})Return$') + p = re.compile(r' \* ?(?:\t| {5,8})Return$') capture = p.match(self.line) if not capture: raise Exception("No return section found for " + proto) @@ -180,7 +201,7 @@ class HeaderParser(object): if self.line == ' *\n': ret += '\n' else: - p = re.compile(' \* ?(?:\t| {5,8})(?:\t| {8})(.*)') + p = re.compile(r' \* ?(?:\t| {5,8})(?:\t| {8})(.*)') capture = p.match(self.line) if capture: ret_present = True @@ -192,6 +213,28 @@ class HeaderParser(object): raise Exception("No return found for " + proto) return ret + def parse_attrs(self, proto): + p = re.compile(r' \* ?(?:\t| {5,8})Attributes$') + 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) @@ -219,12 +262,12 @@ class HeaderParser(object): 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+)+') + bpf_p = re.compile(r'\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+)') + assign_p = re.compile(r'\s*(BPF\w+)\s*=\s*(BPF\w+)') bpf_cmd_str = '' while True: capture = assign_p.match(self.line) @@ -239,7 +282,7 @@ class HeaderParser(object): break self.line = self.reader.readline() # Find the number of occurences of BPF\w+ - self.enum_syscalls = re.findall('(BPF\w+)+', bpf_cmd_str) + self.enum_syscalls = re.findall(r'(BPF\w+)+', bpf_cmd_str) def parse_desc_helpers(self): self.seek_to(helpersDocStart, @@ -263,7 +306,7 @@ class HeaderParser(object): self.seek_to('#define ___BPF_FUNC_MAPPER(FN, ctx...)', 'Could not find start of eBPF helper definition list') # Searches for one FN(\w+) define or a backslash for newline - p = re.compile('\s*FN\((\w+), (\d+), ##ctx\)|\\\\') + p = re.compile(r'\s*FN\((\w+), (\d+), ##ctx\)|\\\\') fn_defines_str = '' i = 0 while True: @@ -278,7 +321,7 @@ class HeaderParser(object): break self.line = self.reader.readline() # Find the number of occurences of FN(\w+) - self.define_unique_helpers = re.findall('FN\(\w+, \d+, ##ctx\)', fn_defines_str) + self.define_unique_helpers = re.findall(r'FN\(\w+, \d+, ##ctx\)', fn_defines_str) def validate_helpers(self): last_helper = '' @@ -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' @@ -425,7 +468,7 @@ class PrinterRST(Printer): try: cmd = ['git', 'log', '-1', '--pretty=format:%cs', '--no-patch', '-L', - '/{}/,/\*\//:include/uapi/linux/bpf.h'.format(delimiter)] + '/{}/,/\\*\\//:include/uapi/linux/bpf.h'.format(delimiter)] date = subprocess.run(cmd, cwd=linuxRoot, capture_output=True, check=True) return date.stdout.decode().rstrip() @@ -513,10 +556,10 @@ 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 +license string passed (via **attr**) to the **bpf**\\ () system call, and this generally translates into the C source code of the program containing a line similar to the following: @@ -550,7 +593,7 @@ may be interested in: * The bpftool utility can be used to probe the availability of helper functions on the system (as well as supported program and map types, and a number of other parameters). To do so, run **bpftool feature probe** (see - **bpftool-feature**\ (8) for details). Add the **unprivileged** keyword to + **bpftool-feature**\\ (8) for details). Add the **unprivileged** keyword to list features available to unprivileged users. Compatibility between helper functions and program types can generally be found @@ -562,23 +605,23 @@ other functions, themselves allowing access to additional helpers. The requirement for GPL license is also in those **struct bpf_func_proto**. Compatibility between helper functions and map types can be found in the -**check_map_func_compatibility**\ () function in file *kernel/bpf/verifier.c*. +**check_map_func_compatibility**\\ () function in file *kernel/bpf/verifier.c*. Helper functions that invalidate the checks on **data** and **data_end** pointers for network processing are listed in function -**bpf_helper_changes_pkt_data**\ () in file *net/core/filter.c*. +**bpf_helper_changes_pkt_data**\\ () in file *net/core/filter.c*. SEE ALSO ======== -**bpf**\ (2), -**bpftool**\ (8), -**cgroups**\ (7), -**ip**\ (8), -**perf_event_open**\ (2), -**sendmsg**\ (2), -**socket**\ (7), -**tc-bpf**\ (8)''' +**bpf**\\ (2), +**bpftool**\\ (8), +**cgroups**\\ (7), +**ip**\\ (8), +**perf_event_open**\\ (2), +**sendmsg**\\ (2), +**socket**\\ (7), +**tc-bpf**\\ (8)''' print(footer) def print_proto(self, helper): @@ -598,7 +641,7 @@ SEE ALSO one_arg = '{}{}'.format(comma, a['type']) if a['name']: if a['star']: - one_arg += ' {}**\ '.format(a['star'].replace('*', '\\*')) + one_arg += ' {}**\\ '.format(a['star'].replace('*', '\\*')) else: one_arg += '** ' one_arg += '*{}*\\ **'.format(a['name']) @@ -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. @@ -745,6 +788,7 @@ class PrinterHelpers(Printer): 'struct task_struct', 'struct cgroup', 'struct path', + 'const struct path', 'struct btf_ptr', 'struct inode', 'struct socket', @@ -789,6 +833,21 @@ 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 +886,10 @@ 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 +911,43 @@ 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 +957,17 @@ 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 +977,8 @@ 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 +986,35 @@ 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() |