[PATCH 5.4 67/84] scripts/bpf: teach bpf_helpers_doc.py to dump BPF helper definitions

Greg Kroah-Hartman
2024-02-27T14:24:38Z

From: Andrii Nakryiko <andriin@fb.com>

[ Upstream commit 7a387bed47f7e80e257d966cd64a3e92a63e26a1 ]

Enhance scripts/bpf_helpers_doc.py to emit C header with BPF helper
definitions (to be included from libbpf's bpf_helpers.h).

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Stable-dep-of: e37243b65d52 ("bpf, scripts: Correct GPL license name")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
scripts/bpf_helpers_doc.py | 155 ++++++++++++++++++++++++++++++++++++-
1 file changed, 154 insertions(+), 1 deletion(-)

diff --git a/scripts/bpf_helpers_doc.py b/scripts/bpf_helpers_doc.py
index 894cc58c1a034..15d3d83d6297c 100755
--- a/scripts/bpf_helpers_doc.py
+++ b/scripts/bpf_helpers_doc.py
@@ -391,6 +391,154 @@ SEE ALSO

print('')

+class PrinterHelpers(Printer):
+ """
+ A printer for dumping collected information about helpers as C header to
+ be included from BPF program.
+ @helpers: array of Helper objects to print to standard output
+ """
+
+ type_fwds = [
+ 'struct bpf_fib_lookup',
+ 'struct bpf_perf_event_data',
+ 'struct bpf_perf_event_value',
+ 'struct bpf_sock',
+ 'struct bpf_sock_addr',
+ 'struct bpf_sock_ops',
+ 'struct bpf_sock_tuple',
+ 'struct bpf_spin_lock',
+ 'struct bpf_sysctl',
+ 'struct bpf_tcp_sock',
+ 'struct bpf_tunnel_key',
+ 'struct bpf_xfrm_state',
+ 'struct pt_regs',
+ 'struct sk_reuseport_md',
+ 'struct sockaddr',
+ 'struct tcphdr',
+
+ 'struct __sk_buff',
+ 'struct sk_msg_md',
+ 'struct xpd_md',
+ ]
+ known_types = {
+ '...',
+ 'void',
+ 'const void',
+ 'char',
+ 'const char',
+ 'int',
+ 'long',
+ 'unsigned long',
+
+ '__be16',
+ '__be32',
+ '__wsum',
+
+ 'struct bpf_fib_lookup',
+ 'struct bpf_perf_event_data',
+ 'struct bpf_perf_event_value',
+ 'struct bpf_sock',
+ 'struct bpf_sock_addr',
+ 'struct bpf_sock_ops',
+ 'struct bpf_sock_tuple',
+ 'struct bpf_spin_lock',
+ 'struct bpf_sysctl',
+ 'struct bpf_tcp_sock',
+ 'struct bpf_tunnel_key',
+ 'struct bpf_xfrm_state',
+ 'struct pt_regs',
+ 'struct sk_reuseport_md',
+ 'struct sockaddr',
+ 'struct tcphdr',
+ }
+ mapped_types = {
+ 'u8': '__u8',
+ 'u16': '__u16',
+ 'u32': '__u32',
+ 'u64': '__u64',
+ 's8': '__s8',
+ 's16': '__s16',
+ 's32': '__s32',
+ 's64': '__s64',
+ 'size_t': 'unsigned long',
+ 'struct bpf_map': 'void',
+ 'struct sk_buff': 'struct __sk_buff',
+ 'const struct sk_buff': 'const struct __sk_buff',
+ 'struct sk_msg_buff': 'struct sk_msg_md',
+ 'struct xdp_buff': 'struct xdp_md',
+ }
+
+ def print_header(self):
+ header = '''\
+/* This is auto-generated file. See bpf_helpers_doc.py for details. */
+
+/* Forward declarations of BPF structs */'''
+
+ print(header)
+ for fwd in self.type_fwds:
+ print('%s;' % fwd)
+ print('')
+
+ def print_footer(self):
+ footer = ''
+ print(footer)
+
+ def map_type(self, t):
+ if t in self.known_types:
+ return t
+ if t in self.mapped_types:
+ return self.mapped_types[t]
+ print("")
+ print("Unrecognized type '%s', please add it to known types!" % t)
+ sys.exit(1)
+
+ seen_helpers = set()
+
+ def print_one(self, helper):
+ proto = helper.proto_break_down()
+
+ if proto['name'] in self.seen_helpers:
+ return
+ self.seen_helpers.add(proto['name'])
+
+ print('/*')
+ print(" * %s" % proto['name'])
+ print(" *")
+ if (helper.desc):
+ # Do not strip all newline characters: formatted code at the end of
+ # a section must be followed by a blank line.
+ for line in re.sub('\n$', '', helper.desc, count=1).split('\n'):
+ print(' *{}{}'.format(' \t' if line else '', line))
+
+ if (helper.ret):
+ print(' *')
+ print(' * Returns')
+ for line in helper.ret.rstrip().split('\n'):
+ print(' *{}{}'.format(' \t' if line else '', line))
+
+ print(' */')
+ print('static %s %s(*%s)(' % (self.map_type(proto['ret_type']),
+ proto['ret_star'], proto['name']), end='')
+ comma = ''
+ for i, a in enumerate(proto['args']):
+ t = a['type']
+ n = a['name']
+ if proto['name'] == 'bpf_get_socket_cookie' and i == 0:
+ t = 'void'
+ n = 'ctx'
+ one_arg = '{}{}'.format(comma, self.map_type(t))
+ if n:
+ if a['star']:
+ one_arg += ' {}'.format(a['star'])
+ else:
+ one_arg += ' '
+ one_arg += '{}'.format(n)
+ comma = ', '
+ print(one_arg, end='')
+
+ print(') = (void *) %d;' % len(self.seen_helpers))
+ print('')
+
###############################################################################

# If script is launched from scripts/ from kernel tree and can access
@@ -405,6 +553,8 @@ Parse eBPF header file and generate documentation for eBPF helper functions.
The RST-formatted output produced can be turned into a manual page with the
rst2man utility.
""")
+argParser.add_argument('--header', action='store_true',
+ help='generate C header file')
if (os.path.isfile(bpfh)):
argParser.add_argument('--filename', help='path to include/uapi/linux/bpf.h',
default=bpfh)
@@ -417,5 +567,8 @@ headerParser = HeaderParser(args.filename)
headerParser.run()

# Print formatted output to standard output.
-printer = PrinterRST(headerParser.helpers)
+if args.header:
+ printer = PrinterHelpers(headerParser.helpers)
+else:
+ printer = PrinterRST(headerParser.helpers)
printer.print_all()
--
2.43.0