1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * C++ stream style string builder used in KUnit for building messages. 4 * 5 * Copyright (C) 2019, Google LLC. 6 * Author: Brendan Higgins <brendanhiggins@google.com> 7 */ 8 9 #include <kunit/test.h> 10 #include <linux/list.h> 11 #include <linux/slab.h> 12 13 #include "string-stream.h" 14 15 struct string_stream_fragment_alloc_context { 16 struct kunit *test; 17 int len; 18 gfp_t gfp; 19 }; 20 21 static int string_stream_fragment_init(struct kunit_resource *res, 22 void *context) 23 { 24 struct string_stream_fragment_alloc_context *ctx = context; 25 struct string_stream_fragment *frag; 26 27 frag = kunit_kzalloc(ctx->test, sizeof(*frag), ctx->gfp); 28 if (!frag) 29 return -ENOMEM; 30 31 frag->test = ctx->test; 32 frag->fragment = kunit_kmalloc(ctx->test, ctx->len, ctx->gfp); 33 if (!frag->fragment) 34 return -ENOMEM; 35 36 res->allocation = frag; 37 38 return 0; 39 } 40 41 static void string_stream_fragment_free(struct kunit_resource *res) 42 { 43 struct string_stream_fragment *frag = res->allocation; 44 45 list_del(&frag->node); 46 kunit_kfree(frag->test, frag->fragment); 47 kunit_kfree(frag->test, frag); 48 } 49 50 static struct string_stream_fragment *alloc_string_stream_fragment( 51 struct kunit *test, int len, gfp_t gfp) 52 { 53 struct string_stream_fragment_alloc_context context = { 54 .test = test, 55 .len = len, 56 .gfp = gfp 57 }; 58 59 return kunit_alloc_resource(test, 60 string_stream_fragment_init, 61 string_stream_fragment_free, 62 gfp, 63 &context); 64 } 65 66 static int string_stream_fragment_destroy(struct string_stream_fragment *frag) 67 { 68 return kunit_resource_destroy(frag->test, 69 kunit_resource_instance_match, 70 string_stream_fragment_free, 71 frag); 72 } 73 74 int string_stream_vadd(struct string_stream *stream, 75 const char *fmt, 76 va_list args) 77 { 78 struct string_stream_fragment *frag_container; 79 int len; 80 va_list args_for_counting; 81 82 /* Make a copy because `vsnprintf` could change it */ 83 va_copy(args_for_counting, args); 84 85 /* Need space for null byte. */ 86 len = vsnprintf(NULL, 0, fmt, args_for_counting) + 1; 87 88 va_end(args_for_counting); 89 90 frag_container = alloc_string_stream_fragment(stream->test, 91 len, 92 stream->gfp); 93 if (!frag_container) 94 return -ENOMEM; 95 96 len = vsnprintf(frag_container->fragment, len, fmt, args); 97 spin_lock(&stream->lock); 98 stream->length += len; 99 list_add_tail(&frag_container->node, &stream->fragments); 100 spin_unlock(&stream->lock); 101 102 return 0; 103 } 104 105 int string_stream_add(struct string_stream *stream, const char *fmt, ...) 106 { 107 va_list args; 108 int result; 109 110 va_start(args, fmt); 111 result = string_stream_vadd(stream, fmt, args); 112 va_end(args); 113 114 return result; 115 } 116 117 static void string_stream_clear(struct string_stream *stream) 118 { 119 struct string_stream_fragment *frag_container, *frag_container_safe; 120 121 spin_lock(&stream->lock); 122 list_for_each_entry_safe(frag_container, 123 frag_container_safe, 124 &stream->fragments, 125 node) { 126 string_stream_fragment_destroy(frag_container); 127 } 128 stream->length = 0; 129 spin_unlock(&stream->lock); 130 } 131 132 char *string_stream_get_string(struct string_stream *stream) 133 { 134 struct string_stream_fragment *frag_container; 135 size_t buf_len = stream->length + 1; /* +1 for null byte. */ 136 char *buf; 137 138 buf = kunit_kzalloc(stream->test, buf_len, stream->gfp); 139 if (!buf) 140 return NULL; 141 142 spin_lock(&stream->lock); 143 list_for_each_entry(frag_container, &stream->fragments, node) 144 strlcat(buf, frag_container->fragment, buf_len); 145 spin_unlock(&stream->lock); 146 147 return buf; 148 } 149 150 int string_stream_append(struct string_stream *stream, 151 struct string_stream *other) 152 { 153 const char *other_content; 154 155 other_content = string_stream_get_string(other); 156 157 if (!other_content) 158 return -ENOMEM; 159 160 return string_stream_add(stream, other_content); 161 } 162 163 bool string_stream_is_empty(struct string_stream *stream) 164 { 165 return list_empty(&stream->fragments); 166 } 167 168 struct string_stream_alloc_context { 169 struct kunit *test; 170 gfp_t gfp; 171 }; 172 173 static int string_stream_init(struct kunit_resource *res, void *context) 174 { 175 struct string_stream *stream; 176 struct string_stream_alloc_context *ctx = context; 177 178 stream = kunit_kzalloc(ctx->test, sizeof(*stream), ctx->gfp); 179 if (!stream) 180 return -ENOMEM; 181 182 res->allocation = stream; 183 stream->gfp = ctx->gfp; 184 stream->test = ctx->test; 185 INIT_LIST_HEAD(&stream->fragments); 186 spin_lock_init(&stream->lock); 187 188 return 0; 189 } 190 191 static void string_stream_free(struct kunit_resource *res) 192 { 193 struct string_stream *stream = res->allocation; 194 195 string_stream_clear(stream); 196 } 197 198 struct string_stream *alloc_string_stream(struct kunit *test, gfp_t gfp) 199 { 200 struct string_stream_alloc_context context = { 201 .test = test, 202 .gfp = gfp 203 }; 204 205 return kunit_alloc_resource(test, 206 string_stream_init, 207 string_stream_free, 208 gfp, 209 &context); 210 } 211 212 int string_stream_destroy(struct string_stream *stream) 213 { 214 return kunit_resource_destroy(stream->test, 215 kunit_resource_instance_match, 216 string_stream_free, 217 stream); 218 } 219