selftests/bpf: Convert glob_match() to bpf_arena Step 1: Copy paste lib/glob.c into bpf_arena_strsearch.h Copy paste lib/globtests.c into progs/arena_strsearch.c Step 2: Add __arean to pointers Add __arg_arena to global functions that accept arena pointers Add cond_break to loops Signed-off-by: Alexei Starovoitov <ast@kernel.org>
diff --git a/tools/testing/selftests/bpf/bpf_arena_strsearch.h b/tools/testing/selftests/bpf/bpf_arena_strsearch.h new file mode 100644 index 0000000..297c279 --- /dev/null +++ b/tools/testing/selftests/bpf/bpf_arena_strsearch.h
@@ -0,0 +1,128 @@ +/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */ +/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */ +#pragma once +#include "bpf_arena_common.h" + +__noinline int bpf_strlen(const char __arena *s __arg_arena) +{ + const char __arena *sc; + + for (sc = s; *sc != '\0'; ++sc) + cond_break; + return sc - s; +} + +/** + * glob_match - Shell-style pattern matching, like !fnmatch(pat, str, 0) + * @pat: Shell-style pattern to match, e.g. "*.[ch]". + * @str: String to match. The pattern must match the entire string. + * + * Perform shell-style glob matching, returning true (1) if the match + * succeeds, or false (0) if it fails. Equivalent to !fnmatch(@pat, @str, 0). + * + * Pattern metacharacters are ?, *, [ and \. + * (And, inside character classes, !, - and ].) + * + * This is small and simple implementation intended for device blacklists + * where a string is matched against a number of patterns. Thus, it + * does not preprocess the patterns. It is non-recursive, and run-time + * is at most quadratic: strlen(@str)*strlen(@pat). + * + * An example of the worst case is glob_match("*aaaaa", "aaaaaaaaaa"); + * it takes 6 passes over the pattern before matching the string. + * + * Like !fnmatch(@pat, @str, 0) and unlike the shell, this does NOT + * treat / or leading . specially; it isn't actually used for pathnames. + * + * Note that according to glob(7) (and unlike bash), character classes + * are complemented by a leading !; this does not support the regex-style + * [^a-z] syntax. + * + * An opening bracket without a matching close is matched literally. + */ +__noinline bool glob_match(char const __arena *pat __arg_arena, char const __arena *str __arg_arena) +{ + /* + * Backtrack to previous * on mismatch and retry starting one + * character later in the string. Because * matches all characters + * (no exception for /), it can be easily proved that there's + * never a need to backtrack multiple levels. + */ + char const __arena *back_pat = NULL, *back_str; + + /* + * Loop over each token (character or class) in pat, matching + * it against the remaining unmatched tail of str. Return false + * on mismatch, or true after matching the trailing nul bytes. + */ + for (;;) { + unsigned char c = *str++; + unsigned char d = *pat++; + + switch (d) { + case '?': /* Wildcard: anything but nul */ + if (c == '\0') + return false; + break; + case '*': /* Any-length wildcard */ + if (*pat == '\0') /* Optimize trailing * case */ + return true; + back_pat = pat; + back_str = --str; /* Allow zero-length match */ + break; + case '[': { /* Character class */ + bool match = false, inverted = (*pat == '!'); + char const __arena *class = pat + inverted; + unsigned char a = *class++; + + /* + * Iterate over each span in the character class. + * A span is either a single character a, or a + * range a-b. The first span may begin with ']'. + */ + do { + unsigned char b = a; + + if (a == '\0') /* Malformed */ + goto literal; + + if (class[0] == '-' && class[1] != ']') { + b = class[1]; + + if (b == '\0') + goto literal; + + class += 2; + /* Any special action if a > b? */ + } + match |= (a <= c && c <= b); + cond_break; + } while ((a = *class++) != ']'); + + if (match == inverted) + goto backtrack; + pat = class; + } + break; + case '\\': + d = *pat++; +// fallthrough; + default: /* Literal character */ +literal: + if (c == d) { + if (d == '\0') + return true; + break; + } +backtrack: + if (c == '\0' || !back_pat) + return false; /* No point continuing */ + /* Try again from last *, one character later in str. */ + pat = back_pat; + str = ++back_str; + break; + } + cond_break; + } + return false; +}
diff --git a/tools/testing/selftests/bpf/prog_tests/arena_strsearch.c b/tools/testing/selftests/bpf/prog_tests/arena_strsearch.c new file mode 100644 index 0000000..d2bad29 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/arena_strsearch.c
@@ -0,0 +1,38 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */ +#include <test_progs.h> +#include <sys/mman.h> +#include <network_helpers.h> + +#define PAGE_SIZE 4096 + +//#include "bpf_arena_strsearch.h" +#include "arena_strsearch.skel.h" + +static void test_arena_str(int cnt) +{ + LIBBPF_OPTS(bpf_test_run_opts, opts); + struct arena_strsearch *skel; + int ret; + + skel = arena_strsearch__open_and_load(); + if (!ASSERT_OK_PTR(skel, "arena_strsearch__open_and_load")) + return; + + ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.arena_strsearch), &opts); + ASSERT_OK(ret, "ret_add"); + ASSERT_OK(opts.retval, "retval"); + if (skel->bss->skip) { + printf("%s:SKIP:compiler doesn't support arena_cast\n", __func__); + test__skip(); + goto out; + } +out: + arena_strsearch__destroy(skel); +} + +void test_arena_strsearch(void) +{ + if (test__start_subtest("arena_strsearch")) + test_arena_str(1); +}
diff --git a/tools/testing/selftests/bpf/progs/arena_strsearch.c b/tools/testing/selftests/bpf/progs/arena_strsearch.c new file mode 100644 index 0000000..91233ac --- /dev/null +++ b/tools/testing/selftests/bpf/progs/arena_strsearch.c
@@ -0,0 +1,160 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */ +#include <vmlinux.h> +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h> +#include <bpf/bpf_core_read.h> +#include "bpf_experimental.h" + +struct { + __uint(type, BPF_MAP_TYPE_ARENA); + __uint(map_flags, BPF_F_MMAPABLE); + __uint(max_entries, 100); /* number of pages */ +} arena SEC(".maps"); + +#include "bpf_arena_strsearch.h" + +bool skip = false; + +#if defined(__BPF_FEATURE_ARENA_CAST) + +struct glob_test { + char const __arena *pat, *str; + bool expected; +}; + +static bool test(char const __arena *pat, char const __arena *str, bool expected) +{ + bool match = glob_match(pat, str); + bool success = match == expected; + + bpf_printk("glob_match %s %s res %d ok %d", pat, str, match, success); + return success; +} + +/* + * The tests are all jammed together in one array to make it simpler + * to place that array in the .init.rodata section. The obvious + * "array of structures containing char *" has no way to force the + * pointed-to strings to be in a particular section. + * + * Anyway, a test consists of: + * 1. Expected glob_match result: '1' or '0'. + * 2. Pattern to match: null-terminated string + * 3. String to match against: null-terminated string + * + * The list of tests is terminated with a final '\0' instead of + * a glob_match result character. + */ +static char const __arena glob_tests[] = + /* Some basic tests */ + "1" "a\0" "a\0" + "0" "a\0" "b\0" + "0" "a\0" "aa\0" + "0" "a\0" "\0" + "1" "\0" "\0" + "0" "\0" "a\0" + /* Simple character class tests */ + "1" "[a]\0" "a\0" + "0" "[a]\0" "b\0" + "0" "[!a]\0" "a\0" + "1" "[!a]\0" "b\0" + "1" "[ab]\0" "a\0" + "1" "[ab]\0" "b\0" + "0" "[ab]\0" "c\0" + "1" "[!ab]\0" "c\0" + "1" "[a-c]\0" "b\0" + "0" "[a-c]\0" "d\0" + /* Corner cases in character class parsing */ + "1" "[a-c-e-g]\0" "-\0" + "0" "[a-c-e-g]\0" "d\0" + "1" "[a-c-e-g]\0" "f\0" + "1" "[]a-ceg-ik[]\0" "a\0" + "1" "[]a-ceg-ik[]\0" "]\0" + "1" "[]a-ceg-ik[]\0" "[\0" + "1" "[]a-ceg-ik[]\0" "h\0" + "0" "[]a-ceg-ik[]\0" "f\0" + "0" "[!]a-ceg-ik[]\0" "h\0" + "0" "[!]a-ceg-ik[]\0" "]\0" + "1" "[!]a-ceg-ik[]\0" "f\0" + /* Simple wild cards */ + "1" "?\0" "a\0" + "0" "?\0" "aa\0" + "0" "??\0" "a\0" + "1" "?x?\0" "axb\0" + "0" "?x?\0" "abx\0" + "0" "?x?\0" "xab\0" + /* Asterisk wild cards (backtracking) */ + "0" "*??\0" "a\0" + "1" "*??\0" "ab\0" + "1" "*??\0" "abc\0" + "1" "*??\0" "abcd\0" + "0" "??*\0" "a\0" + "1" "??*\0" "ab\0" + "1" "??*\0" "abc\0" + "1" "??*\0" "abcd\0" + "0" "?*?\0" "a\0" + "1" "?*?\0" "ab\0" + "1" "?*?\0" "abc\0" + "1" "?*?\0" "abcd\0" + "1" "*b\0" "b\0" + "1" "*b\0" "ab\0" + "0" "*b\0" "ba\0" + "1" "*b\0" "bb\0" + "1" "*b\0" "abb\0" + "1" "*b\0" "bab\0" + "1" "*bc\0" "abbc\0" + "1" "*bc\0" "bc\0" + "1" "*bc\0" "bbc\0" + "1" "*bc\0" "bcbc\0" + /* Multiple asterisks (complex backtracking) */ + "1" "*ac*\0" "abacadaeafag\0" + "1" "*ac*ae*ag*\0" "abacadaeafag\0" + "1" "*a*b*[bc]*[ef]*g*\0" "abacadaeafag\0" + "0" "*a*b*[ef]*[cd]*g*\0" "abacadaeafag\0" + "1" "*abcd*\0" "abcabcabcabcdefg\0" + "1" "*ab*cd*\0" "abcabcabcabcdefg\0" + "1" "*abcd*abcdef*\0" "abcabcdabcdeabcdefg\0" + "0" "*abcd*\0" "abcabcabcabcefg\0" + "0" "*ab*cd*\0" "abcabcabcabcefg\0"; + +SEC("syscall") +int arena_strsearch(void *ctx) +{ + unsigned successes = 0; + unsigned n = 0; + char const __arena *p = glob_tests; + + /* + * Tests are jammed together in a string. The first byte is '1' + * or '0' to indicate the expected outcome, or '\0' to indicate the + * end of the tests. Then come two null-terminated strings: the + * pattern and the string to match it against. + */ + while (*p) { + bool expected = *p++ & 1; + char const __arena *pat = p; + + cond_break; + p += bpf_strlen(p) + 1; + successes += test(pat, p, expected); + p += bpf_strlen(p) + 1; + n++; + } + + n -= successes; + bpf_printk("glob: %u self-tests passed, %u failed\n", successes, n); + + /* What's the errno for "kernel bug detected"? Guess... */ + return n ? -1 : 0; +} +#else +SEC("syscall") +int arena_strsearch(void *ctx) +{ + skip = true; + return 0; +} +#endif + +char _license[] SEC("license") = "GPL";