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 kunit_kfree(test, frag);
28 return ERR_PTR(-ENOMEM);
29 }
30
31 return frag;
32 }
33
string_stream_fragment_destroy(struct kunit * test,struct string_stream_fragment * frag)34 static void string_stream_fragment_destroy(struct kunit *test,
35 struct string_stream_fragment *frag)
36 {
37 list_del(&frag->node);
38 kunit_kfree(test, frag->fragment);
39 kunit_kfree(test, frag);
40 }
41
string_stream_vadd(struct string_stream * stream,const char * fmt,va_list args)42 int string_stream_vadd(struct string_stream *stream,
43 const char *fmt,
44 va_list args)
45 {
46 struct string_stream_fragment *frag_container;
47 int len;
48 va_list args_for_counting;
49
50 /* Make a copy because `vsnprintf` could change it */
51 va_copy(args_for_counting, args);
52
53 /* Need space for null byte. */
54 len = vsnprintf(NULL, 0, fmt, args_for_counting) + 1;
55
56 va_end(args_for_counting);
57
58 frag_container = alloc_string_stream_fragment(stream->test,
59 len,
60 stream->gfp);
61 if (IS_ERR(frag_container))
62 return PTR_ERR(frag_container);
63
64 len = vsnprintf(frag_container->fragment, len, fmt, args);
65 spin_lock(&stream->lock);
66 stream->length += len;
67 list_add_tail(&frag_container->node, &stream->fragments);
68 spin_unlock(&stream->lock);
69
70 return 0;
71 }
72
string_stream_add(struct string_stream * stream,const char * fmt,...)73 int string_stream_add(struct string_stream *stream, const char *fmt, ...)
74 {
75 va_list args;
76 int result;
77
78 va_start(args, fmt);
79 result = string_stream_vadd(stream, fmt, args);
80 va_end(args);
81
82 return result;
83 }
84
string_stream_clear(struct string_stream * stream)85 static void string_stream_clear(struct string_stream *stream)
86 {
87 struct string_stream_fragment *frag_container, *frag_container_safe;
88
89 spin_lock(&stream->lock);
90 list_for_each_entry_safe(frag_container,
91 frag_container_safe,
92 &stream->fragments,
93 node) {
94 string_stream_fragment_destroy(stream->test, frag_container);
95 }
96 stream->length = 0;
97 spin_unlock(&stream->lock);
98 }
99
string_stream_get_string(struct string_stream * stream)100 char *string_stream_get_string(struct string_stream *stream)
101 {
102 struct string_stream_fragment *frag_container;
103 size_t buf_len = stream->length + 1; /* +1 for null byte. */
104 char *buf;
105
106 buf = kunit_kzalloc(stream->test, buf_len, stream->gfp);
107 if (!buf)
108 return NULL;
109
110 spin_lock(&stream->lock);
111 list_for_each_entry(frag_container, &stream->fragments, node)
112 strlcat(buf, frag_container->fragment, buf_len);
113 spin_unlock(&stream->lock);
114
115 return buf;
116 }
117
string_stream_append(struct string_stream * stream,struct string_stream * other)118 int string_stream_append(struct string_stream *stream,
119 struct string_stream *other)
120 {
121 const char *other_content;
122
123 other_content = string_stream_get_string(other);
124
125 if (!other_content)
126 return -ENOMEM;
127
128 return string_stream_add(stream, other_content);
129 }
130
string_stream_is_empty(struct string_stream * stream)131 bool string_stream_is_empty(struct string_stream *stream)
132 {
133 return list_empty(&stream->fragments);
134 }
135
136 struct string_stream_alloc_context {
137 struct kunit *test;
138 gfp_t gfp;
139 };
140
alloc_string_stream(struct kunit * test,gfp_t gfp)141 struct string_stream *alloc_string_stream(struct kunit *test, gfp_t gfp)
142 {
143 struct string_stream *stream;
144
145 stream = kunit_kzalloc(test, sizeof(*stream), gfp);
146 if (!stream)
147 return ERR_PTR(-ENOMEM);
148
149 stream->gfp = gfp;
150 stream->test = test;
151 INIT_LIST_HEAD(&stream->fragments);
152 spin_lock_init(&stream->lock);
153
154 return stream;
155 }
156
string_stream_destroy(struct string_stream * stream)157 void string_stream_destroy(struct string_stream *stream)
158 {
159 string_stream_clear(stream);
160 }
161