| // SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) |
| /* Copyright (c) 2021 Facebook */ |
| #include <stdint.h> |
| #include <stdlib.h> |
| #include <stdio.h> |
| #include <errno.h> |
| #include <linux/err.h> |
| #include "hashmap.h" |
| #include "libbpf_internal.h" |
| #include "strset.h" |
| |
| struct strset { |
| void *strs_data; |
| size_t strs_data_len; |
| size_t strs_data_cap; |
| size_t strs_data_max_len; |
| |
| /* lookup index for each unique string in strings set */ |
| struct hashmap *strs_hash; |
| }; |
| |
| static size_t strset_hash_fn(const void *key, void *ctx) |
| { |
| const struct strset *s = ctx; |
| const char *str = s->strs_data + (long)key; |
| |
| return str_hash(str); |
| } |
| |
| static bool strset_equal_fn(const void *key1, const void *key2, void *ctx) |
| { |
| const struct strset *s = ctx; |
| const char *str1 = s->strs_data + (long)key1; |
| const char *str2 = s->strs_data + (long)key2; |
| |
| return strcmp(str1, str2) == 0; |
| } |
| |
| struct strset *strset__new(size_t max_data_sz, const char *init_data, size_t init_data_sz) |
| { |
| struct strset *set = calloc(1, sizeof(*set)); |
| struct hashmap *hash; |
| int err = -ENOMEM; |
| |
| if (!set) |
| return ERR_PTR(-ENOMEM); |
| |
| hash = hashmap__new(strset_hash_fn, strset_equal_fn, set); |
| if (IS_ERR(hash)) |
| goto err_out; |
| |
| set->strs_data_max_len = max_data_sz; |
| set->strs_hash = hash; |
| |
| if (init_data) { |
| long off; |
| |
| set->strs_data = malloc(init_data_sz); |
| if (!set->strs_data) |
| goto err_out; |
| |
| memcpy(set->strs_data, init_data, init_data_sz); |
| set->strs_data_len = init_data_sz; |
| set->strs_data_cap = init_data_sz; |
| |
| for (off = 0; off < set->strs_data_len; off += strlen(set->strs_data + off) + 1) { |
| /* hashmap__add() returns EEXIST if string with the same |
| * content already is in the hash map |
| */ |
| err = hashmap__add(hash, (void *)off, (void *)off); |
| if (err == -EEXIST) |
| continue; /* duplicate */ |
| if (err) |
| goto err_out; |
| } |
| } |
| |
| return set; |
| err_out: |
| strset__free(set); |
| return ERR_PTR(err); |
| } |
| |
| void strset__free(struct strset *set) |
| { |
| if (IS_ERR_OR_NULL(set)) |
| return; |
| |
| hashmap__free(set->strs_hash); |
| free(set->strs_data); |
| } |
| |
| size_t strset__data_size(const struct strset *set) |
| { |
| return set->strs_data_len; |
| } |
| |
| const char *strset__data(const struct strset *set) |
| { |
| return set->strs_data; |
| } |
| |
| static void *strset_add_str_mem(struct strset *set, size_t add_sz) |
| { |
| return libbpf_add_mem(&set->strs_data, &set->strs_data_cap, 1, |
| set->strs_data_len, set->strs_data_max_len, add_sz); |
| } |
| |
| /* Find string offset that corresponds to a given string *s*. |
| * Returns: |
| * - >0 offset into string data, if string is found; |
| * - -ENOENT, if string is not in the string data; |
| * - <0, on any other error. |
| */ |
| int strset__find_str(struct strset *set, const char *s) |
| { |
| long old_off, new_off, len; |
| void *p; |
| |
| /* see strset__add_str() for why we do this */ |
| len = strlen(s) + 1; |
| p = strset_add_str_mem(set, len); |
| if (!p) |
| return -ENOMEM; |
| |
| new_off = set->strs_data_len; |
| memcpy(p, s, len); |
| |
| if (hashmap__find(set->strs_hash, (void *)new_off, (void **)&old_off)) |
| return old_off; |
| |
| return -ENOENT; |
| } |
| |
| /* Add a string s to the string data. If the string already exists, return its |
| * offset within string data. |
| * Returns: |
| * - > 0 offset into string data, on success; |
| * - < 0, on error. |
| */ |
| int strset__add_str(struct strset *set, const char *s) |
| { |
| long old_off, new_off, len; |
| void *p; |
| int err; |
| |
| /* Hashmap keys are always offsets within set->strs_data, so to even |
| * look up some string from the "outside", we need to first append it |
| * at the end, so that it can be addressed with an offset. Luckily, |
| * until set->strs_data_len is incremented, that string is just a piece |
| * of garbage for the rest of the code, so no harm, no foul. On the |
| * other hand, if the string is unique, it's already appended and |
| * ready to be used, only a simple set->strs_data_len increment away. |
| */ |
| len = strlen(s) + 1; |
| p = strset_add_str_mem(set, len); |
| if (!p) |
| return -ENOMEM; |
| |
| new_off = set->strs_data_len; |
| memcpy(p, s, len); |
| |
| /* Now attempt to add the string, but only if the string with the same |
| * contents doesn't exist already (HASHMAP_ADD strategy). If such |
| * string exists, we'll get its offset in old_off (that's old_key). |
| */ |
| err = hashmap__insert(set->strs_hash, (void *)new_off, (void *)new_off, |
| HASHMAP_ADD, (const void **)&old_off, NULL); |
| if (err == -EEXIST) |
| return old_off; /* duplicated string, return existing offset */ |
| if (err) |
| return err; |
| |
| set->strs_data_len += len; /* new unique string, adjust data length */ |
| return new_off; |
| } |