171 lines
3.1 KiB
C
171 lines
3.1 KiB
C
// 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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