tools/syz-declextract: extract file_operations descriptions

Extend the clang tool to locate file_operations variables and arrays
and dump open/read/write/mmap/ioctl callbacks for each.
It also tries to extract set of ioctl commands and argument types
for them in a simple best-effort way (for now). It just locates switch
in the ioctl callback and extracts each case as a command.

1 files changed, 118 insertions, 0 deletions

diff --git a/tools/syz-declextract/testdata/file_operations.c.json b/tools/syz-declextract/testdata/file_operations.c.json
new file mode 100644
index 000000000..e5ddad2b2
--- /dev/null
+++ b/tools/syz-declextract/testdata/file_operations.c.json
@@ -0,0 +1,118 @@
+{
+	"includes": [
+		"include/uapi/file_operations.h"
+	],
+	"structs": [
+		{
+			"name": "foo_ioctl_arg",
+			"byte_size": 8,
+			"fields": [
+				{
+					"name": "a",
+					"counted_by": -1,
+					"type": {
+						"int": {
+							"byte_size": 4,
+							"name": "int",
+							"base": "int"
+						}
+					}
+				},
+				{
+					"name": "b",
+					"counted_by": -1,
+					"type": {
+						"int": {
+							"byte_size": 4,
+							"name": "int",
+							"base": "int"
+						}
+					}
+				}
+			]
+		}
+	],
+	"file_ops": [
+		{
+			"name": "foo_file_operations",
+			"open": "foo_open",
+			"read": "foo_read",
+			"write": "foo_write",
+			"mmap": "foo_mmap",
+			"ioctl": "foo_ioctl",
+			"ioctl_cmds": [
+				{
+					"name": "FOO_IOCTL5",
+					"type": {
+						"ptr": {
+							"elem": {
+								"struct": "foo_ioctl_arg"
+							}
+						}
+					}
+				},
+				{
+					"name": "FOO_IOCTL4",
+					"type": {
+						"ptr": {
+							"elem": {
+								"struct": "foo_ioctl_arg"
+							}
+						}
+					}
+				},
+				{
+					"name": "FOO_IOCTL3",
+					"type": {
+						"ptr": {
+							"elem": {
+								"struct": "foo_ioctl_arg"
+							},
+							"is_const": true
+						}
+					}
+				},
+				{
+					"name": "FOO_IOCTL2",
+					"type": {
+						"ptr": {
+							"elem": {
+								"int": {
+									"byte_size": 4,
+									"name": "int",
+									"base": "int"
+								}
+							},
+							"is_const": true
+						}
+					}
+				},
+				{
+					"name": "FOO_IOCTL1",
+					"type": {
+						"int": {
+							"byte_size": 1,
+							"is_const": true
+						}
+					}
+				}
+			],
+			"source_file": "file_operations.c"
+		},
+		{
+			"name": "proc_ops_file_operations",
+			"open": "proc_open",
+			"read": "proc_read",
+			"write": "proc_write",
+			"mmap": "proc_open",
+			"source_file": "file_operations.c"
+		},
+		{
+			"name": "proc_ops_file_operations1",
+			"open": "proc_open",
+			"mmap": "proc_open",
+			"ioctl": "proc_ioctl",
+			"source_file": "file_operations.c"
+		}
+	]
+}
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