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
alloc_string_stream_fragment(struct kunit * test,int len,gfp_t gfp)16 static struct string_stream_fragment *alloc_string_stream_fragment(
17 struct kunit *test, int len, gfp_t gfp)
18 {
19 struct string_stream_fragment *frag;
20
21 frag = kunit_kzalloc(test, sizeof(*frag), gfp);
22 if (!frag)
23 return ERR_PTR(-ENOMEM);
24
25 frag->fragment = kunit_kmalloc(test, len, gfp);
26 if (!frag->fragment)
27 return ERR_PTR(-ENOMEM);
28
29 return frag;
30 }
31
string_stream_fragment_destroy(struct kunit * test,struct string_stream_fragment * frag)32 static void string_stream_fragment_destroy(struct kunit *test,
33 struct string_stream_fragment *frag)
34 {
35 list_del(&frag->node);
36 kunit_kfree(test, frag->fragment);
37 kunit_kfree(test, frag);
38 }
39
string_stream_vadd(struct string_stream * stream,const char * fmt,va_list args)40 int string_stream_vadd(struct string_stream *stream,
41 const char *fmt,
42 va_list args)
43 {
44 struct string_stream_fragment *frag_container;
45 int len;
46 va_list args_for_counting;
47
48 /* Make a copy because `vsnprintf` could change it */
49 va_copy(args_for_counting, args);
50
51 /* Need space for null byte. */
52 len = vsnprintf(NULL, 0, fmt, args_for_counting) + 1;
53
54 va_end(args_for_counting);
55
56 frag_container = alloc_string_stream_fragment(stream->test,
57 len,
58 stream->gfp);
59 if (IS_ERR(frag_container))
60 return PTR_ERR(frag_container);
61
62 len = vsnprintf(frag_container->fragment, len, fmt, args);
63 spin_lock(&stream->lock);
64 stream->length += len;
65 list_add_tail(&frag_container->node, &stream->fragments);
66 spin_unlock(&stream->lock);
67
68 return 0;
69 }
70
string_stream_add(struct string_stream * stream,const char * fmt,...)71 int string_stream_add(struct string_stream *stream, const char *fmt, ...)
72 {
73 va_list args;
74 int result;
75
76 va_start(args, fmt);
77 result = string_stream_vadd(stream, fmt, args);
78 va_end(args);
79
80 return result;
81 }
82
string_stream_clear(struct string_stream * stream)83 static void string_stream_clear(struct string_stream *stream)
84 {
85 struct string_stream_fragment *frag_container, *frag_container_safe;
86
87 spin_lock(&stream->lock);
88 list_for_each_entry_safe(frag_container,
89 frag_container_safe,
90 &stream->fragments,
91 node) {
92 string_stream_fragment_destroy(stream->test, frag_container);
93 }
94 stream->length = 0;
95 spin_unlock(&stream->lock);
96 }
97
string_stream_get_string(struct string_stream * stream)98 char *string_stream_get_string(struct string_stream *stream)
99 {
100 struct string_stream_fragment *frag_container;
101 size_t buf_len = stream->length + 1; /* +1 for null byte. */
102 char *buf;
103
104 buf = kunit_kzalloc(stream->test, buf_len, stream->gfp);
105 if (!buf)
106 return NULL;
107
108 spin_lock(&stream->lock);
109 list_for_each_entry(frag_container, &stream->fragments, node)
110 strlcat(buf, frag_container->fragment, buf_len);
111 spin_unlock(&stream->lock);
112
113 return buf;
114 }
115
string_stream_append(struct string_stream * stream,struct string_stream * other)116 int string_stream_append(struct string_stream *stream,
117 struct string_stream *other)
118 {
119 const char *other_content;
120
121 other_content = string_stream_get_string(other);
122
123 if (!other_content)
124 return -ENOMEM;
125
126 return string_stream_add(stream, other_content);
127 }
128
string_stream_is_empty(struct string_stream * stream)129 bool string_stream_is_empty(struct string_stream *stream)
130 {
131 return list_empty(&stream->fragments);
132 }
133
134 struct string_stream_alloc_context {
135 struct kunit *test;
136 gfp_t gfp;
137 };
138
alloc_string_stream(struct kunit * test,gfp_t gfp)139 struct string_stream *alloc_string_stream(struct kunit *test, gfp_t gfp)
140 {
141 struct string_stream *stream;
142
143 stream = kunit_kzalloc(test, sizeof(*stream), gfp);
144 if (!stream)
145 return ERR_PTR(-ENOMEM);
146
147 stream->gfp = gfp;
148 stream->test = test;
149 INIT_LIST_HEAD(&stream->fragments);
150 spin_lock_init(&stream->lock);
151
152 return stream;
153 }
154
string_stream_destroy(struct string_stream * stream)155 void string_stream_destroy(struct string_stream *stream)
156 {
157 string_stream_clear(stream);
158 }
159
