1 | // SPDX-License-Identifier: GPL-2.0 |
2 | #include "cache.h" |
3 | #include "debug.h" |
4 | #include "strbuf.h" |
5 | #include <linux/kernel.h> |
6 | #include <linux/string.h> |
7 | #include <linux/zalloc.h> |
8 | #include <errno.h> |
9 | #include <stdio.h> |
10 | #include <stdlib.h> |
11 | #include <unistd.h> |
12 | |
13 | /* |
14 | * Used as the default ->buf value, so that people can always assume |
15 | * buf is non NULL and ->buf is NUL terminated even for a freshly |
16 | * initialized strbuf. |
17 | */ |
18 | char strbuf_slopbuf[1]; |
19 | |
20 | int strbuf_init(struct strbuf *sb, ssize_t hint) |
21 | { |
22 | sb->alloc = sb->len = 0; |
23 | sb->buf = strbuf_slopbuf; |
24 | if (hint) |
25 | return strbuf_grow(buf: sb, hint); |
26 | return 0; |
27 | } |
28 | |
29 | void strbuf_release(struct strbuf *sb) |
30 | { |
31 | if (sb->alloc) { |
32 | zfree(&sb->buf); |
33 | strbuf_init(sb, hint: 0); |
34 | } |
35 | } |
36 | |
37 | char *strbuf_detach(struct strbuf *sb, size_t *sz) |
38 | { |
39 | char *res = sb->alloc ? sb->buf : NULL; |
40 | if (sz) |
41 | *sz = sb->len; |
42 | strbuf_init(sb, hint: 0); |
43 | return res; |
44 | } |
45 | |
46 | int strbuf_grow(struct strbuf *sb, size_t ) |
47 | { |
48 | char *buf; |
49 | size_t nr = sb->len + extra + 1; |
50 | |
51 | if (nr < sb->alloc) |
52 | return 0; |
53 | |
54 | if (nr <= sb->len) |
55 | return -E2BIG; |
56 | |
57 | if (alloc_nr(sb->alloc) > nr) |
58 | nr = alloc_nr(sb->alloc); |
59 | |
60 | /* |
61 | * Note that sb->buf == strbuf_slopbuf if sb->alloc == 0, and it is |
62 | * a static variable. Thus we have to avoid passing it to realloc. |
63 | */ |
64 | buf = realloc(sb->alloc ? sb->buf : NULL, nr * sizeof(*buf)); |
65 | if (!buf) |
66 | return -ENOMEM; |
67 | |
68 | sb->buf = buf; |
69 | sb->alloc = nr; |
70 | return 0; |
71 | } |
72 | |
73 | int strbuf_addch(struct strbuf *sb, int c) |
74 | { |
75 | int ret = strbuf_grow(sb, extra: 1); |
76 | if (ret) |
77 | return ret; |
78 | |
79 | sb->buf[sb->len++] = c; |
80 | sb->buf[sb->len] = '\0'; |
81 | return 0; |
82 | } |
83 | |
84 | int strbuf_add(struct strbuf *sb, const void *data, size_t len) |
85 | { |
86 | int ret = strbuf_grow(sb, extra: len); |
87 | if (ret) |
88 | return ret; |
89 | |
90 | memcpy(sb->buf + sb->len, data, len); |
91 | return strbuf_setlen(sb, len: sb->len + len); |
92 | } |
93 | |
94 | static int strbuf_addv(struct strbuf *sb, const char *fmt, va_list ap) |
95 | { |
96 | int len, ret; |
97 | va_list ap_saved; |
98 | |
99 | if (!strbuf_avail(sb)) { |
100 | ret = strbuf_grow(sb, extra: 64); |
101 | if (ret) |
102 | return ret; |
103 | } |
104 | |
105 | va_copy(ap_saved, ap); |
106 | len = vsnprintf(buf: sb->buf + sb->len, size: sb->alloc - sb->len, fmt, args: ap); |
107 | if (len < 0) { |
108 | va_end(ap_saved); |
109 | return len; |
110 | } |
111 | if (len > strbuf_avail(sb)) { |
112 | ret = strbuf_grow(sb, extra: len); |
113 | if (ret) { |
114 | va_end(ap_saved); |
115 | return ret; |
116 | } |
117 | len = vsnprintf(buf: sb->buf + sb->len, size: sb->alloc - sb->len, fmt, args: ap_saved); |
118 | if (len > strbuf_avail(sb)) { |
119 | pr_debug("this should not happen, your vsnprintf is broken" ); |
120 | va_end(ap_saved); |
121 | return -EINVAL; |
122 | } |
123 | } |
124 | va_end(ap_saved); |
125 | return strbuf_setlen(sb, len: sb->len + len); |
126 | } |
127 | |
128 | int strbuf_addf(struct strbuf *sb, const char *fmt, ...) |
129 | { |
130 | va_list ap; |
131 | int ret; |
132 | |
133 | va_start(ap, fmt); |
134 | ret = strbuf_addv(sb, fmt, ap); |
135 | va_end(ap); |
136 | return ret; |
137 | } |
138 | |
139 | ssize_t strbuf_read(struct strbuf *sb, int fd, ssize_t hint) |
140 | { |
141 | size_t oldlen = sb->len; |
142 | size_t oldalloc = sb->alloc; |
143 | int ret; |
144 | |
145 | ret = strbuf_grow(sb, extra: hint ? hint : 8192); |
146 | if (ret) |
147 | return ret; |
148 | |
149 | for (;;) { |
150 | ssize_t cnt; |
151 | |
152 | cnt = read(fd, sb->buf + sb->len, sb->alloc - sb->len - 1); |
153 | if (cnt < 0) { |
154 | if (oldalloc == 0) |
155 | strbuf_release(sb); |
156 | else |
157 | strbuf_setlen(sb, len: oldlen); |
158 | return cnt; |
159 | } |
160 | if (!cnt) |
161 | break; |
162 | sb->len += cnt; |
163 | ret = strbuf_grow(sb, extra: 8192); |
164 | if (ret) |
165 | return ret; |
166 | } |
167 | |
168 | sb->buf[sb->len] = '\0'; |
169 | return sb->len - oldlen; |
170 | } |
171 | |