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