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// SPDX-License-Identifier: LGPL-2.1+
/* Copyright (C) 2022 Kent Overstreet */
#ifdef __KERNEL__
#include <linux/export.h>
#include <linux/kernel.h>
#else
#define EXPORT_SYMBOL(x)
#endif
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/printbuf.h>
static inline size_t printbuf_linelen(struct printbuf *buf)
{
return buf->pos - buf->last_newline;
}
int printbuf_make_room(struct printbuf *out, unsigned extra)
{
unsigned new_size;
char *buf;
if (!out->heap_allocated)
return 0;
/* Reserved space for terminating nul: */
extra += 1;
if (out->pos + extra < out->size)
return 0;
new_size = roundup_pow_of_two(out->size + extra);
/*
* Note: output buffer must be freeable with kfree(), it's not required
* that the user use printbuf_exit().
*/
buf = krealloc(out->buf, new_size, !out->atomic ? GFP_KERNEL : GFP_NOWAIT);
if (!buf) {
out->allocation_failure = true;
return -ENOMEM;
}
out->buf = buf;
out->size = new_size;
return 0;
}
EXPORT_SYMBOL(printbuf_make_room);
/**
* printbuf_str - returns printbuf's buf as a C string, guaranteed to be null
* terminated
*/
const char *printbuf_str(const struct printbuf *buf)
{
/*
* If we've written to a printbuf then it's guaranteed to be a null
* terminated string - but if we haven't, then we might not have
* allocated a buffer at all:
*/
return buf->pos
? buf->buf
: "";
}
EXPORT_SYMBOL(printbuf_str);
/**
* printbuf_exit - exit a printbuf, freeing memory it owns and poisoning it
* against accidental use.
*/
void printbuf_exit(struct printbuf *buf)
{
if (buf->heap_allocated) {
kfree(buf->buf);
buf->buf = ERR_PTR(-EINTR); /* poison value */
}
}
EXPORT_SYMBOL(printbuf_exit);
void prt_newline(struct printbuf *buf)
{
unsigned i;
printbuf_make_room(buf, 1 + buf->indent);
__prt_char(buf, '\n');
buf->last_newline = buf->pos;
for (i = 0; i < buf->indent; i++)
__prt_char(buf, ' ');
printbuf_nul_terminate(buf);
buf->last_field = buf->pos;
buf->tabstop = 0;
}
EXPORT_SYMBOL(prt_newline);
/**
* printbuf_indent_add - add to the current indent level
*
* @buf: printbuf to control
* @spaces: number of spaces to add to the current indent level
*
* Subsequent lines, and the current line if the output position is at the start
* of the current line, will be indented by @spaces more spaces.
*/
void printbuf_indent_add(struct printbuf *buf, unsigned spaces)
{
if (WARN_ON_ONCE(buf->indent + spaces < buf->indent))
spaces = 0;
buf->indent += spaces;
while (spaces--)
prt_char(buf, ' ');
}
EXPORT_SYMBOL(printbuf_indent_add);
/**
* printbuf_indent_sub - subtract from the current indent level
*
* @buf: printbuf to control
* @spaces: number of spaces to subtract from the current indent level
*
* Subsequent lines, and the current line if the output position is at the start
* of the current line, will be indented by @spaces less spaces.
*/
void printbuf_indent_sub(struct printbuf *buf, unsigned spaces)
{
if (WARN_ON_ONCE(spaces > buf->indent))
spaces = buf->indent;
if (buf->last_newline + buf->indent == buf->pos) {
buf->pos -= spaces;
printbuf_nul_terminate(buf);
}
buf->indent -= spaces;
}
EXPORT_SYMBOL(printbuf_indent_sub);
/**
* prt_tab - Advance printbuf to the next tabstop
*
* @buf: printbuf to control
*
* Advance output to the next tabstop by printing spaces.
*/
void prt_tab(struct printbuf *out)
{
int spaces = max_t(int, 0, out->tabstops[out->tabstop] - printbuf_linelen(out));
BUG_ON(out->tabstop > ARRAY_SIZE(out->tabstops));
prt_chars(out, ' ', spaces);
out->last_field = out->pos;
out->tabstop++;
}
EXPORT_SYMBOL(prt_tab);
/**
* prt_tab_rjust - Advance printbuf to the next tabstop, right justifying
* previous output
*
* @buf: printbuf to control
*
* Advance output to the next tabstop by inserting spaces immediately after the
* previous tabstop, right justifying previously outputted text.
*/
void prt_tab_rjust(struct printbuf *buf)
{
BUG_ON(buf->tabstop > ARRAY_SIZE(buf->tabstops));
if (printbuf_linelen(buf) < buf->tabstops[buf->tabstop]) {
unsigned move = buf->pos - buf->last_field;
unsigned shift = buf->tabstops[buf->tabstop] -
printbuf_linelen(buf);
printbuf_make_room(buf, shift);
if (buf->last_field + shift < buf->size)
memmove(buf->buf + buf->last_field + shift,
buf->buf + buf->last_field,
min(move, buf->size - 1 - buf->last_field - shift));
if (buf->last_field < buf->size)
memset(buf->buf + buf->last_field, ' ',
min(shift, buf->size - buf->last_field));
buf->pos += shift;
printbuf_nul_terminate(buf);
}
buf->last_field = buf->pos;
buf->tabstop++;
}
EXPORT_SYMBOL(prt_tab_rjust);
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