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