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