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170 lines
3.1 KiB
170 lines
3.1 KiB
// SPDX-License-Identifier: GPL-2.0 |
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#include "cache.h" |
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#include "debug.h" |
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#include "strbuf.h" |
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#include <linux/kernel.h> |
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#include <linux/string.h> |
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#include <linux/zalloc.h> |
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#include <errno.h> |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <unistd.h> |
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/* |
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* Used as the default ->buf value, so that people can always assume |
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* buf is non NULL and ->buf is NUL terminated even for a freshly |
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* initialized strbuf. |
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*/ |
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char strbuf_slopbuf[1]; |
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int strbuf_init(struct strbuf *sb, ssize_t hint) |
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{ |
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sb->alloc = sb->len = 0; |
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sb->buf = strbuf_slopbuf; |
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if (hint) |
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return strbuf_grow(sb, hint); |
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return 0; |
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} |
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void strbuf_release(struct strbuf *sb) |
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{ |
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if (sb->alloc) { |
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zfree(&sb->buf); |
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strbuf_init(sb, 0); |
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} |
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} |
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char *strbuf_detach(struct strbuf *sb, size_t *sz) |
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{ |
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char *res = sb->alloc ? sb->buf : NULL; |
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if (sz) |
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*sz = sb->len; |
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strbuf_init(sb, 0); |
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return res; |
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} |
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int strbuf_grow(struct strbuf *sb, size_t extra) |
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{ |
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char *buf; |
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size_t nr = sb->len + extra + 1; |
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if (nr < sb->alloc) |
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return 0; |
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if (nr <= sb->len) |
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return -E2BIG; |
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if (alloc_nr(sb->alloc) > nr) |
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nr = alloc_nr(sb->alloc); |
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/* |
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* Note that sb->buf == strbuf_slopbuf if sb->alloc == 0, and it is |
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* a static variable. Thus we have to avoid passing it to realloc. |
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*/ |
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buf = realloc(sb->alloc ? sb->buf : NULL, nr * sizeof(*buf)); |
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if (!buf) |
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return -ENOMEM; |
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sb->buf = buf; |
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sb->alloc = nr; |
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return 0; |
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} |
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int strbuf_addch(struct strbuf *sb, int c) |
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{ |
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int ret = strbuf_grow(sb, 1); |
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if (ret) |
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return ret; |
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sb->buf[sb->len++] = c; |
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sb->buf[sb->len] = '\0'; |
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return 0; |
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} |
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int strbuf_add(struct strbuf *sb, const void *data, size_t len) |
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{ |
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int ret = strbuf_grow(sb, len); |
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if (ret) |
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return ret; |
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memcpy(sb->buf + sb->len, data, len); |
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return strbuf_setlen(sb, sb->len + len); |
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} |
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static int strbuf_addv(struct strbuf *sb, const char *fmt, va_list ap) |
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{ |
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int len, ret; |
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va_list ap_saved; |
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if (!strbuf_avail(sb)) { |
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ret = strbuf_grow(sb, 64); |
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if (ret) |
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return ret; |
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} |
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va_copy(ap_saved, ap); |
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len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap); |
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if (len < 0) { |
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va_end(ap_saved); |
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return len; |
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} |
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if (len > strbuf_avail(sb)) { |
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ret = strbuf_grow(sb, len); |
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if (ret) { |
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va_end(ap_saved); |
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return ret; |
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} |
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len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap_saved); |
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if (len > strbuf_avail(sb)) { |
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pr_debug("this should not happen, your vsnprintf is broken"); |
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va_end(ap_saved); |
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return -EINVAL; |
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} |
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} |
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va_end(ap_saved); |
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return strbuf_setlen(sb, sb->len + len); |
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} |
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int strbuf_addf(struct strbuf *sb, const char *fmt, ...) |
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{ |
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va_list ap; |
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int ret; |
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va_start(ap, fmt); |
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ret = strbuf_addv(sb, fmt, ap); |
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va_end(ap); |
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return ret; |
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} |
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ssize_t strbuf_read(struct strbuf *sb, int fd, ssize_t hint) |
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{ |
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size_t oldlen = sb->len; |
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size_t oldalloc = sb->alloc; |
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int ret; |
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ret = strbuf_grow(sb, hint ? hint : 8192); |
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if (ret) |
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return ret; |
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for (;;) { |
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ssize_t cnt; |
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cnt = read(fd, sb->buf + sb->len, sb->alloc - sb->len - 1); |
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if (cnt < 0) { |
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if (oldalloc == 0) |
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strbuf_release(sb); |
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else |
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strbuf_setlen(sb, oldlen); |
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return cnt; |
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} |
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if (!cnt) |
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break; |
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sb->len += cnt; |
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ret = strbuf_grow(sb, 8192); |
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if (ret) |
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return ret; |
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} |
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sb->buf[sb->len] = '\0'; |
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return sb->len - oldlen; |
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}
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