niceSOFT/systemd: The systemd System and Service Manager

src/basic/hash-funcs.c
146 строк5 KB
Michael Vogt
basic: make check-pointer-deref clean
31 мар 2026, 19:30
31 мар 2026, 19:3018e70ee
/* SPDX-License-Identifier: LGPL-2.1-or-later */

#include <stdlib.h>
#include <string.h>
#include <sys/sysmacros.h>

#include "hash-funcs.h"
#include "path-util.h"
#include "siphash24.h"
#include "strv.h"

void string_hash_func(const char *p, struct siphash *state) {
        siphash24_compress(p, strlen(p) + 1, state);
}

DEFINE_HASH_OPS(string_hash_ops,
                char, string_hash_func, string_compare_func);
DEFINE_HASH_OPS_WITH_KEY_DESTRUCTOR(
                string_hash_ops_free,
                char, string_hash_func, string_compare_func, free);
DEFINE_HASH_OPS_WITH_VALUE_DESTRUCTOR(
                string_hash_ops_value_free,
                char, string_hash_func, string_compare_func,
                void, free);
DEFINE_HASH_OPS_FULL(
                string_hash_ops_free_free,
                char, string_hash_func, string_compare_func, free,
                void, free);
DEFINE_HASH_OPS_FULL(
                string_hash_ops_free_strv_free,
                char, string_hash_func, string_compare_func, free,
                char*, strv_free);

void path_hash_func(const char *p, struct siphash *state) {
        bool add_slash = false;

        assert(p);
        assert(state);

        /* Calculates a hash for a path in a way this duplicate inner slashes don't make a differences, and also
         * whether there's a trailing slash or not. This fits well with the semantics of path_compare(), which does
         * similar checks and also doesn't care for trailing slashes. Note that relative and absolute paths (i.e. those
         * which begin in a slash or not) will hash differently though. */

        /* if path is absolute, add one "/" to the hash. */
        if (path_is_absolute(p))
                siphash24_compress_byte('/', state);

        for (;;) {
                const char *e;
                int r;

                r = path_find_first_component(&p, true, &e);
                if (r == 0)
                        return;

                if (add_slash)
                        siphash24_compress_byte('/', state);

                if (r < 0) {
                        /* if a component is invalid, then add remaining part as a string. */
                        string_hash_func(p, state);
                        return;
                }

                /* Add this component to the hash. */
                siphash24_compress(e, r, state);

                add_slash = true;
        }
}

DEFINE_HASH_OPS(path_hash_ops,
                char, path_hash_func, path_compare);
DEFINE_HASH_OPS_WITH_KEY_DESTRUCTOR(
                path_hash_ops_free,
                char, path_hash_func, path_compare, free);
DEFINE_HASH_OPS_FULL(
                path_hash_ops_free_free,
                char, path_hash_func, path_compare, free,
                void, free);

void trivial_hash_func(const void *p, struct siphash *state) {
        siphash24_compress_typesafe(p, state);
}

int trivial_compare_func(const void *a, const void *b) {
        return CMP(a, b);
}

DEFINE_HASH_OPS(trivial_hash_ops,
                void, trivial_hash_func, trivial_compare_func);
DEFINE_HASH_OPS_WITH_KEY_DESTRUCTOR(
                trivial_hash_ops_free,
                void, trivial_hash_func, trivial_compare_func, free);
DEFINE_HASH_OPS_WITH_VALUE_DESTRUCTOR(
                trivial_hash_ops_value_free,
                void, trivial_hash_func, trivial_compare_func,
                void, free);
DEFINE_HASH_OPS_FULL(
                trivial_hash_ops_free_free,
                void, trivial_hash_func, trivial_compare_func, free,
                void, free);

void uint64_hash_func(const uint64_t *p, struct siphash *state) {
        assert(p);

        siphash24_compress_typesafe(*p, state);
}

int uint64_compare_func(const uint64_t *a, const uint64_t *b) {
        assert(a);
        assert(b);

        return CMP(*a, *b);
}

DEFINE_HASH_OPS(uint64_hash_ops,
                uint64_t, uint64_hash_func, uint64_compare_func);
DEFINE_HASH_OPS_WITH_VALUE_DESTRUCTOR(
                uint64_hash_ops_value_free,
                uint64_t, uint64_hash_func, uint64_compare_func,
                void, free);

#if SIZEOF_DEV_T != 8
void devt_hash_func(const dev_t *p, struct siphash *state) {
        assert(p);

        siphash24_compress_typesafe(*p, state);
}
#endif

int devt_compare_func(const dev_t *a, const dev_t *b) {
        int r;

        assert(a);
        assert(b);

        r = CMP(major(*a), major(*b));
        if (r != 0)
                return r;

        return CMP(minor(*a), minor(*b));
}

DEFINE_HASH_OPS(devt_hash_ops, dev_t, devt_hash_func, devt_compare_func);