Merge #13705: build: Add format string linter

bcd4b0f5cdde2a1b562a612c78ec1ef1fe47d3dd Add linting of WalletLogPrintf(...) format strings (practicalswift)
a3e455694901a887e0feef69bd63e3aa122ea44b build: Add format string linter (practicalswift)

Pull request description:

  Add format string linter.

  This linter checks that the number of arguments passed to each variadic format string function matches the number of format specifiers in the format string.

  Example output:

  ```
  $ test/lint/lint-format-strings.sh
  src/init.cpp: Expected 2 argument(s) after format string but found 1 argument(s):
    LogPrintf("We have a mismatch here: foo=%s bar=%d\n", foo)
  src/init.cpp: Expected 1 argument(s) after format string but found 2 argument(s):
    LogPrint(BCLog::RPC, "RPC stopped. This is a mismatch: %s\n", s1, s2)
  $ echo $?
  1
  ```

Tree-SHA512: 19ab844a63f04bf193d66682ca42745a1c7d6c454b30222491b9fe8dc047054c4a6d3ee7921ec0676fb9ca2e7f6f93bd6c97996fb09667269bd491cb875349f3

2 files changed, 295 insertions, 0 deletions

diff --git a/test/lint/lint-format-strings.py b/test/lint/lint-format-strings.py
new file mode 100755
index 0000000000..c07dfe317b
--- /dev/null
+++ b/test/lint/lint-format-strings.py
@@ -0,0 +1,254 @@
+#!/usr/bin/env python3
+#
+# Copyright (c) 2018 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+#
+# Lint format strings: This program checks that the number of arguments passed
+# to a variadic format string function matches the number of format specifiers
+# in the format string.
+
+import argparse
+import re
+import sys
+
+FALSE_POSITIVES = [
+    ("src/dbwrapper.cpp", "vsnprintf(p, limit - p, format, backup_ap)"),
+    ("src/index/base.cpp", "FatalError(const char* fmt, const Args&... args)"),
+    ("src/netbase.cpp", "LogConnectFailure(bool manual_connection, const char* fmt, const Args&... args)"),
+    ("src/util.cpp", "strprintf(_(COPYRIGHT_HOLDERS), _(COPYRIGHT_HOLDERS_SUBSTITUTION))"),
+    ("src/util.cpp", "strprintf(COPYRIGHT_HOLDERS, COPYRIGHT_HOLDERS_SUBSTITUTION)"),
+    ("src/wallet/wallet.h",  "WalletLogPrintf(std::string fmt, Params... parameters)"),
+    ("src/wallet/wallet.h", "LogPrintf((\"%s \" + fmt).c_str(), GetDisplayName(), parameters...)"),
+]
+
+
+def parse_function_calls(function_name, source_code):
+    """Return an array with all calls to function function_name in string source_code.
+    Preprocessor directives and C++ style comments ("//") in source_code are removed.
+
+    >>> len(parse_function_calls("foo", "foo();bar();foo();bar();"))
+    2
+    >>> parse_function_calls("foo", "foo(1);bar(1);foo(2);bar(2);")[0].startswith("foo(1);")
+    True
+    >>> parse_function_calls("foo", "foo(1);bar(1);foo(2);bar(2);")[1].startswith("foo(2);")
+    True
+    >>> len(parse_function_calls("foo", "foo();bar();// foo();bar();"))
+    1
+    >>> len(parse_function_calls("foo", "#define FOO foo();"))
+    0
+    """
+    assert(type(function_name) is str and type(source_code) is str and function_name)
+    lines = [re.sub("// .*", " ", line).strip()
+             for line in source_code.split("\n")
+             if not line.strip().startswith("#")]
+    return re.findall(r"[^a-zA-Z_](?=({}\(.*).*)".format(function_name), " " + " ".join(lines))
+
+
+def normalize(s):
+    """Return a normalized version of string s with newlines, tabs and C style comments ("/* ... */")
+    replaced with spaces. Multiple spaces are replaced with a single space.
+
+    >>> normalize("  /* nothing */   foo\tfoo  /* bar */  foo     ")
+    'foo foo foo'
+    """
+    assert(type(s) is str)
+    s = s.replace("\n", " ")
+    s = s.replace("\t", " ")
+    s = re.sub("/\*.*?\*/", " ", s)
+    s = re.sub(" {2,}", " ", s)
+    return s.strip()
+
+
+ESCAPE_MAP = {
+    r"\n": "[escaped-newline]",
+    r"\t": "[escaped-tab]",
+    r'\"': "[escaped-quote]",
+}
+
+
+def escape(s):
+    """Return the escaped version of string s with "\\\"", "\\n" and "\\t" escaped as
+    "[escaped-backslash]", "[escaped-newline]" and "[escaped-tab]".
+
+    >>> unescape(escape("foo")) == "foo"
+    True
+    >>> escape(r'foo \\t foo \\n foo \\\\ foo \\ foo \\"bar\\"')
+    'foo [escaped-tab] foo [escaped-newline] foo \\\\\\\\ foo \\\\ foo [escaped-quote]bar[escaped-quote]'
+    """
+    assert(type(s) is str)
+    for raw_value, escaped_value in ESCAPE_MAP.items():
+        s = s.replace(raw_value, escaped_value)
+    return s
+
+
+def unescape(s):
+    """Return the unescaped version of escaped string s.
+    Reverses the replacements made in function escape(s).
+
+    >>> unescape(escape("bar"))
+    'bar'
+    >>> unescape("foo [escaped-tab] foo [escaped-newline] foo \\\\\\\\ foo \\\\ foo [escaped-quote]bar[escaped-quote]")
+    'foo \\\\t foo \\\\n foo \\\\\\\\ foo \\\\ foo \\\\"bar\\\\"'
+    """
+    assert(type(s) is str)
+    for raw_value, escaped_value in ESCAPE_MAP.items():
+        s = s.replace(escaped_value, raw_value)
+    return s
+
+
+def parse_function_call_and_arguments(function_name, function_call):
+    """Split string function_call into an array of strings consisting of:
+    * the string function_call followed by "("
+    * the function call argument #1
+    * ...
+    * the function call argument #n
+    * a trailing ");"
+
+    The strings returned are in escaped form. See escape(...).
+
+    >>> parse_function_call_and_arguments("foo", 'foo("%s", "foo");')
+    ['foo(', '"%s",', ' "foo"', ')']
+    >>> parse_function_call_and_arguments("foo", 'foo("%s", "foo");')
+    ['foo(', '"%s",', ' "foo"', ')']
+    >>> parse_function_call_and_arguments("foo", 'foo("%s %s", "foo", "bar");')
+    ['foo(', '"%s %s",', ' "foo",', ' "bar"', ')']
+    >>> parse_function_call_and_arguments("fooprintf", 'fooprintf("%050d", i);')
+    ['fooprintf(', '"%050d",', ' i', ')']
+    >>> parse_function_call_and_arguments("foo", 'foo(bar(foobar(barfoo("foo"))), foobar); barfoo')
+    ['foo(', 'bar(foobar(barfoo("foo"))),', ' foobar', ')']
+    >>> parse_function_call_and_arguments("foo", "foo()")
+    ['foo(', '', ')']
+    >>> parse_function_call_and_arguments("foo", "foo(123)")
+    ['foo(', '123', ')']
+    >>> parse_function_call_and_arguments("foo", 'foo("foo")')
+    ['foo(', '"foo"', ')']
+    """
+    assert(type(function_name) is str and type(function_call) is str and function_name)
+    remaining = normalize(escape(function_call))
+    expected_function_call = "{}(".format(function_name)
+    assert(remaining.startswith(expected_function_call))
+    parts = [expected_function_call]
+    remaining = remaining[len(expected_function_call):]
+    open_parentheses = 1
+    in_string = False
+    parts.append("")
+    for char in remaining:
+        parts.append(parts.pop() + char)
+        if char == "\"":
+            in_string = not in_string
+            continue
+        if in_string:
+            continue
+        if char == "(":
+            open_parentheses += 1
+            continue
+        if char == ")":
+            open_parentheses -= 1
+        if open_parentheses > 1:
+            continue
+        if open_parentheses == 0:
+            parts.append(parts.pop()[:-1])
+            parts.append(char)
+            break
+        if char == ",":
+            parts.append("")
+    return parts
+
+
+def parse_string_content(argument):
+    """Return the text within quotes in string argument.
+
+    >>> parse_string_content('1 "foo %d bar" 2')
+    'foo %d bar'
+    >>> parse_string_content('1 foobar 2')
+    ''
+    >>> parse_string_content('1 "bar" 2')
+    'bar'
+    >>> parse_string_content('1 "foo" 2 "bar" 3')
+    'foobar'
+    >>> parse_string_content('1 "foo" 2 " " "bar" 3')
+    'foo bar'
+    >>> parse_string_content('""')
+    ''
+    >>> parse_string_content('')
+    ''
+    >>> parse_string_content('1 2 3')
+    ''
+    """
+    assert(type(argument) is str)
+    string_content = ""
+    in_string = False
+    for char in normalize(escape(argument)):
+        if char == "\"":
+            in_string = not in_string
+        elif in_string:
+            string_content += char
+    return string_content
+
+
+def count_format_specifiers(format_string):
+    """Return the number of format specifiers in string format_string.
+
+    >>> count_format_specifiers("foo bar foo")
+    0
+    >>> count_format_specifiers("foo %d bar foo")
+    1
+    >>> count_format_specifiers("foo %d bar %i foo")
+    2
+    >>> count_format_specifiers("foo %d bar %i foo %% foo")
+    2
+    >>> count_format_specifiers("foo %d bar %i foo %% foo %d foo")
+    3
+    >>> count_format_specifiers("foo %d bar %i foo %% foo %*d foo")
+    4
+    """
+    assert(type(format_string) is str)
+    n = 0
+    in_specifier = False
+    for i, char in enumerate(format_string):
+        if format_string[i - 1:i + 1] == "%%" or format_string[i:i + 2] == "%%":
+            pass
+        elif char == "%":
+            in_specifier = True
+            n += 1
+        elif char in "aAcdeEfFgGinopsuxX":
+            in_specifier = False
+        elif in_specifier and char == "*":
+            n += 1
+    return n
+
+
+def main():
+    parser = argparse.ArgumentParser(description="This program checks that the number of arguments passed "
+                                     "to a variadic format string function matches the number of format "
+                                     "specifiers in the format string.")
+    parser.add_argument("--skip-arguments", type=int, help="number of arguments before the format string "
+                        "argument (e.g. 1 in the case of fprintf)", default=0)
+    parser.add_argument("function_name", help="function name (e.g. fprintf)", default=None)
+    parser.add_argument("file", type=argparse.FileType("r", encoding="utf-8"), nargs="*", help="C++ source code file (e.g. foo.cpp)")
+    args = parser.parse_args()
+
+    exit_code = 0
+    for f in args.file:
+        for function_call_str in parse_function_calls(args.function_name, f.read()):
+            parts = parse_function_call_and_arguments(args.function_name, function_call_str)
+            relevant_function_call_str = unescape("".join(parts))[:512]
+            if (f.name, relevant_function_call_str) in FALSE_POSITIVES:
+                continue
+            if len(parts) < 3 + args.skip_arguments:
+                exit_code = 1
+                print("{}: Could not parse function call string \"{}(...)\": {}".format(f.name, args.function_name, relevant_function_call_str))
+                continue
+            argument_count = len(parts) - 3 - args.skip_arguments
+            format_str = parse_string_content(parts[1 + args.skip_arguments])
+            format_specifier_count = count_format_specifiers(format_str)
+            if format_specifier_count != argument_count:
+                exit_code = 1
+                print("{}: Expected {} argument(s) after format string but found {} argument(s): {}".format(f.name, format_specifier_count, argument_count, relevant_function_call_str))
+                continue
+    sys.exit(exit_code)
+
+
+if __name__ == "__main__":
+    main()
diff --git a/test/lint/lint-format-strings.sh b/test/lint/lint-format-strings.sh
new file mode 100755
index 0000000000..17f846d29b
--- /dev/null
+++ b/test/lint/lint-format-strings.sh
@@ -0,0 +1,41 @@
+#!/usr/bin/env bash
+#
+# Copyright (c) 2018 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+#
+# Lint format strings: This program checks that the number of arguments passed
+# to a variadic format string function matches the number of format specifiers
+# in the format string.
+
+export LC_ALL=C
+
+FUNCTION_NAMES_AND_NUMBER_OF_LEADING_ARGUMENTS=(
+    FatalError,0
+    fprintf,1
+    LogConnectFailure,1
+    LogPrint,1
+    LogPrintf,0
+    printf,0
+    snprintf,2
+    sprintf,1
+    strprintf,0
+    vfprintf,1
+    vprintf,1
+    vsnprintf,1
+    vsprintf,1
+    WalletLogPrintf,0
+)
+
+EXIT_CODE=0
+if ! python3 -m doctest test/lint/lint-format-strings.py; then
+    EXIT_CODE=1
+fi
+for S in "${FUNCTION_NAMES_AND_NUMBER_OF_LEADING_ARGUMENTS[@]}"; do
+    IFS="," read -r FUNCTION_NAME SKIP_ARGUMENTS <<< "${S}"
+    mapfile -t MATCHING_FILES < <(git grep --full-name -l "${FUNCTION_NAME}" -- "*.c" "*.cpp" "*.h" | sort | grep -vE "^src/(leveldb|secp256k1|tinyformat|univalue)")
+    if ! test/lint/lint-format-strings.py --skip-arguments "${SKIP_ARGUMENTS}" "${FUNCTION_NAME}" "${MATCHING_FILES[@]}"; then
+        EXIT_CODE=1
+    fi
+done
+exit ${EXIT_CODE}