/* * seq_buf.c * * Copyright (C) 2014 Red Hat Inc, Steven Rostedt <srostedt@redhat.com> * * The seq_buf is a handy tool that allows you to pass a descriptor around * to a buffer that other functions can write to. It is similar to the * seq_file functionality but has some differences. * * To use it, the seq_buf must be initialized with seq_buf_init(). * This will set up the counters within the descriptor. You can call * seq_buf_init() more than once to reset the seq_buf to start * from scratch. */#include <linux/uaccess.h>#include <linux/seq_file.h>#include <linux/seq_buf.h> /** * seq_buf_can_fit - can the new data fit in the current buffer? * @s: the seq_buf descriptor * @len: The length to see if it can fit in the current buffer * * Returns true if there's enough unused space in the seq_buf buffer * to fit the amount of new data according to @len. */static bool seq_buf_can_fit(struct seq_buf *s, size_t len){ return s->len + len <= s->size;} /** * seq_buf_print_seq - move the contents of seq_buf into a seq_file * @m: the seq_file descriptor that is the destination * @s: the seq_buf descriptor that is the source. * * Returns zero on success, non zero otherwise */int seq_buf_print_seq(struct seq_file *m, struct seq_buf *s){ unsigned int len = seq_buf_used(s); return seq_write(m, s->buffer, len);} /** * seq_buf_vprintf - sequence printing of information. * @s: seq_buf descriptor * @fmt: printf format string * @args: va_list of arguments from a printf() type function * * Writes a vnprintf() format into the sequencce buffer. * * Returns zero on success, -1 on overflow. */int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args){ int len; WARN_ON(s->size == 0); if (s->len < s->size) { len = vsnprintf(s->buffer + s->len, s->size - s->len, fmt, args); if (seq_buf_can_fit(s, len)) { s->len += len; return 0; } } seq_buf_set_overflow(s); return -1;} /** * seq_buf_printf - sequence printing of information * @s: seq_buf descriptor * @fmt: printf format string * * Writes a printf() format into the sequence buffer. * * Returns zero on success, -1 on overflow. */int seq_buf_printf(struct seq_buf *s, const char *fmt, ...){ va_list ap; int ret; va_start(ap, fmt); ret = seq_buf_vprintf(s, fmt, ap); va_end(ap); return ret;} /** * seq_buf_bitmask - write a bitmask array in its ASCII representation * @s: seq_buf descriptor * @maskp: points to an array of unsigned longs that represent a bitmask * @nmaskbits: The number of bits that are valid in @maskp * * Writes a ASCII representation of a bitmask string into @s. * * Returns zero on success, -1 on overflow. */int seq_buf_bitmask(struct seq_buf *s, const unsigned long *maskp, int nmaskbits){ unsigned int len = seq_buf_buffer_left(s); int ret; WARN_ON(s->size == 0); /* * Note, because bitmap_scnprintf() only returns the number of bytes * written and not the number that would be written, we use the last * byte of the buffer to let us know if we overflowed. There's a small * chance that the bitmap could have fit exactly inside the buffer, but * it's not that critical if that does happen. */ if (len > 1) { ret = bitmap_scnprintf(s->buffer + s->len, len, maskp, nmaskbits); if (ret < len) { s->len += ret; return 0; } } seq_buf_set_overflow(s); return -1;} #ifdef CONFIG_BINARY_PRINTF/** * seq_buf_bprintf - Write the printf string from binary arguments * @s: seq_buf descriptor * @fmt: The format string for the @binary arguments * @binary: The binary arguments for @fmt. * * When recording in a fast path, a printf may be recorded with just * saving the format and the arguments as they were passed to the * function, instead of wasting cycles converting the arguments into * ASCII characters. Instead, the arguments are saved in a 32 bit * word array that is defined by the format string constraints. * * This function will take the format and the binary array and finish * the conversion into the ASCII string within the buffer. * * Returns zero on success, -1 on overflow. */int seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary){ unsigned int len = seq_buf_buffer_left(s); int ret; WARN_ON(s->size == 0); if (s->len < s->size) { ret = bstr_printf(s->buffer + s->len, len, fmt, binary); if (seq_buf_can_fit(s, ret)) { s->len += ret; return 0; } } seq_buf_set_overflow(s); return -1;}#endif /* CONFIG_BINARY_PRINTF */ /** * seq_buf_puts - sequence printing of simple string * @s: seq_buf descriptor * @str: simple string to record * * Copy a simple string into the sequence buffer. * * Returns zero on success, -1 on overflow */int seq_buf_puts(struct seq_buf *s, const char *str){ unsigned int len = strlen(str); WARN_ON(s->size == 0); if (seq_buf_can_fit(s, len)) { memcpy(s->buffer + s->len, str, len); s->len += len; return 0; } seq_buf_set_overflow(s); return -1;} /** * seq_buf_putc - sequence printing of simple character * @s: seq_buf descriptor * @c: simple character to record * * Copy a single character into the sequence buffer. * * Returns zero on success, -1 on overflow */int seq_buf_putc(struct seq_buf *s, unsigned char c){ WARN_ON(s->size == 0); if (seq_buf_can_fit(s, 1)) { s->buffer[s->len++] = c; return 0; } seq_buf_set_overflow(s); return -1;} /** * seq_buf_putmem - write raw data into the sequenc buffer * @s: seq_buf descriptor * @mem: The raw memory to copy into the buffer * @len: The length of the raw memory to copy (in bytes) * * There may be cases where raw memory needs to be written into the * buffer and a strcpy() would not work. Using this function allows * for such cases. * * Returns zero on success, -1 on overflow */int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len){ WARN_ON(s->size == 0); if (seq_buf_can_fit(s, len)) { memcpy(s->buffer + s->len, mem, len); s->len += len; return 0; } seq_buf_set_overflow(s); return -1;} #define MAX_MEMHEX_BYTES 8U#define HEX_CHARS (MAX_MEMHEX_BYTES*2 + 1) /** * seq_buf_putmem_hex - write raw memory into the buffer in ASCII hex * @s: seq_buf descriptor * @mem: The raw memory to write its hex ASCII representation of * @len: The length of the raw memory to copy (in bytes) * * This is similar to seq_buf_putmem() except instead of just copying the * raw memory into the buffer it writes its ASCII representation of it * in hex characters. * * Returns zero on success, -1 on overflow */int seq_buf_putmem_hex(struct seq_buf *s, const void *mem, unsigned int len){ unsigned char hex[HEX_CHARS]; const unsigned char *data = mem; unsigned int start_len; int i, j; WARN_ON(s->size == 0); while (len) { start_len = min(len, HEX_CHARS - 1);#ifdef __BIG_ENDIAN for (i = 0, j = 0; i < start_len; i++) {#else for (i = start_len-1, j = 0; i >= 0; i--) {#endif hex[j++] = hex_asc_hi(data[i]); hex[j++] = hex_asc_lo(data[i]); } if (WARN_ON_ONCE(j == 0 || j/2 > len)) break; /* j increments twice per loop */ len -= j / 2; hex[j++] = ' '; seq_buf_putmem(s, hex, j); if (seq_buf_has_overflowed(s)) return -1; } return 0;} /** * seq_buf_path - copy a path into the sequence buffer * @s: seq_buf descriptor * @path: path to write into the sequence buffer. * @esc: set of characters to escape in the output * * Write a path name into the sequence buffer. * * Returns the number of written bytes on success, -1 on overflow */int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc){ char *buf; size_t size = seq_buf_get_buf(s, &buf); int res = -1; WARN_ON(s->size == 0); if (size) { char *p = d_path(path, buf, size); if (!IS_ERR(p)) { char *end = mangle_path(buf, p, esc); if (end) res = end - buf; } } seq_buf_commit(s, res); return res;} /** * seq_buf_to_user - copy the squence buffer to user space * @s: seq_buf descriptor * @ubuf: The userspace memory location to copy to * @cnt: The amount to copy * * Copies the sequence buffer into the userspace memory pointed to * by @ubuf. It starts from the last read position (@s->readpos) * and writes up to @cnt characters or till it reaches the end of * the content in the buffer (@s->len), which ever comes first. * * On success, it returns a positive number of the number of bytes * it copied. * * On failure it returns -EBUSY if all of the content in the * sequence has been already read, which includes nothing in the * sequence (@s->len == @s->readpos). * * Returns -EFAULT if the copy to userspace fails. */int seq_buf_to_user(struct seq_buf *s, char __user *ubuf, int cnt){ int len; int ret; if (!cnt) return 0; if (s->len <= s->readpos) return -EBUSY; len = seq_buf_used(s) - s->readpos; if (cnt > len) cnt = len; ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt); if (ret == cnt) return -EFAULT; cnt -= ret; s->readpos += cnt; return cnt;}
/*
* seq_buf.c
*
* Copyright (C) 2014 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
*
* The seq_buf is a handy tool that allows you to pass a descriptor around
* to a buffer that other functions can write to. It is similar to the
* seq_file functionality but has some differences.
*
* To use it, the seq_buf must be initialized with seq_buf_init().
* This will set up the counters within the descriptor. You can call
* seq_buf_init() more than once to reset the seq_buf to start
* from scratch.
*/
#include <linux/uaccess.h>
#include <linux/seq_file.h>
#include <linux/seq_buf.h>
/**
* seq_buf_can_fit - can the new data fit in the current buffer?
* @s: the seq_buf descriptor
* @len: The length to see if it can fit in the current buffer
*
* Returns true if there's enough unused space in the seq_buf buffer
* to fit the amount of new data according to @len.
*/
static bool seq_buf_can_fit(struct seq_buf *s, size_t len)
{
return s->len + len <= s->size;
}
/**
* seq_buf_print_seq - move the contents of seq_buf into a seq_file
* @m: the seq_file descriptor that is the destination
* @s: the seq_buf descriptor that is the source.
*
* Returns zero on success, non zero otherwise
*/
int seq_buf_print_seq(struct seq_file *m, struct seq_buf *s)
{
unsigned int len = seq_buf_used(s);
return seq_write(m, s->buffer, len);
}
/**
* seq_buf_vprintf - sequence printing of information.
* @s: seq_buf descriptor
* @fmt: printf format string
* @args: va_list of arguments from a printf() type function
*
* Writes a vnprintf() format into the sequencce buffer.
*
* Returns zero on success, -1 on overflow.
*/
int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args)
{
int len;
WARN_ON(s->size == 0);
if (s->len < s->size) {
len = vsnprintf(s->buffer + s->len, s->size - s->len, fmt, args);
if (seq_buf_can_fit(s, len)) {
s->len += len;
return 0;
}
}
seq_buf_set_overflow(s);
return -1;
}
/**
* seq_buf_printf - sequence printing of information
* @s: seq_buf descriptor
* @fmt: printf format string
*
* Writes a printf() format into the sequence buffer.
*
* Returns zero on success, -1 on overflow.
*/
int seq_buf_printf(struct seq_buf *s, const char *fmt, ...)
{
va_list ap;
int ret;
va_start(ap, fmt);
ret = seq_buf_vprintf(s, fmt, ap);
va_end(ap);
return ret;
}
/**
* seq_buf_bitmask - write a bitmask array in its ASCII representation
* @s: seq_buf descriptor
* @maskp: points to an array of unsigned longs that represent a bitmask
* @nmaskbits: The number of bits that are valid in @maskp
*
* Writes a ASCII representation of a bitmask string into @s.
*
* Returns zero on success, -1 on overflow.
*/
int seq_buf_bitmask(struct seq_buf *s, const unsigned long *maskp,
int nmaskbits)
{
unsigned int len = seq_buf_buffer_left(s);
int ret;
WARN_ON(s->size == 0);
/*
* Note, because bitmap_scnprintf() only returns the number of bytes
* written and not the number that would be written, we use the last
* byte of the buffer to let us know if we overflowed. There's a small
* chance that the bitmap could have fit exactly inside the buffer, but
* it's not that critical if that does happen.
*/
if (len > 1) {
ret = bitmap_scnprintf(s->buffer + s->len, len, maskp, nmaskbits);
if (ret < len) {
s->len += ret;
return 0;
}
}
seq_buf_set_overflow(s);
return -1;
}
#ifdef CONFIG_BINARY_PRINTF
/**
* seq_buf_bprintf - Write the printf string from binary arguments
* @s: seq_buf descriptor
* @fmt: The format string for the @binary arguments
* @binary: The binary arguments for @fmt.
*
* When recording in a fast path, a printf may be recorded with just
* saving the format and the arguments as they were passed to the
* function, instead of wasting cycles converting the arguments into
* ASCII characters. Instead, the arguments are saved in a 32 bit
* word array that is defined by the format string constraints.
*
* This function will take the format and the binary array and finish
* the conversion into the ASCII string within the buffer.
*
* Returns zero on success, -1 on overflow.
*/
int seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary)
{
unsigned int len = seq_buf_buffer_left(s);
int ret;
WARN_ON(s->size == 0);
if (s->len < s->size) {
ret = bstr_printf(s->buffer + s->len, len, fmt, binary);
if (seq_buf_can_fit(s, ret)) {
s->len += ret;
return 0;
}
}
seq_buf_set_overflow(s);
return -1;
}
#endif /* CONFIG_BINARY_PRINTF */
/**
* seq_buf_puts - sequence printing of simple string
* @s: seq_buf descriptor
* @str: simple string to record
*
* Copy a simple string into the sequence buffer.
*
* Returns zero on success, -1 on overflow
*/
int seq_buf_puts(struct seq_buf *s, const char *str)
{
unsigned int len = strlen(str);
WARN_ON(s->size == 0);
if (seq_buf_can_fit(s, len)) {
memcpy(s->buffer + s->len, str, len);
s->len += len;
return 0;
}
seq_buf_set_overflow(s);
return -1;
}
/**
* seq_buf_putc - sequence printing of simple character
* @s: seq_buf descriptor
* @c: simple character to record
*
* Copy a single character into the sequence buffer.
*
* Returns zero on success, -1 on overflow
*/
int seq_buf_putc(struct seq_buf *s, unsigned char c)
{
WARN_ON(s->size == 0);
if (seq_buf_can_fit(s, 1)) {
s->buffer[s->len++] = c;
return 0;
}
seq_buf_set_overflow(s);
return -1;
}
/**
* seq_buf_putmem - write raw data into the sequenc buffer
* @s: seq_buf descriptor
* @mem: The raw memory to copy into the buffer
* @len: The length of the raw memory to copy (in bytes)
*
* There may be cases where raw memory needs to be written into the
* buffer and a strcpy() would not work. Using this function allows
* for such cases.
*
* Returns zero on success, -1 on overflow
*/
int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len)
{
WARN_ON(s->size == 0);
if (seq_buf_can_fit(s, len)) {
memcpy(s->buffer + s->len, mem, len);
s->len += len;
return 0;
}
seq_buf_set_overflow(s);
return -1;
}
#define MAX_MEMHEX_BYTES 8U
#define HEX_CHARS (MAX_MEMHEX_BYTES*2 + 1)
/**
* seq_buf_putmem_hex - write raw memory into the buffer in ASCII hex
* @s: seq_buf descriptor
* @mem: The raw memory to write its hex ASCII representation of
* @len: The length of the raw memory to copy (in bytes)
*
* This is similar to seq_buf_putmem() except instead of just copying the
* raw memory into the buffer it writes its ASCII representation of it
* in hex characters.
*
* Returns zero on success, -1 on overflow
*/
int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
unsigned int len)
{
unsigned char hex[HEX_CHARS];
const unsigned char *data = mem;
unsigned int start_len;
int i, j;
WARN_ON(s->size == 0);
while (len) {
start_len = min(len, HEX_CHARS - 1);
#ifdef __BIG_ENDIAN
for (i = 0, j = 0; i < start_len; i++) {
#else
for (i = start_len-1, j = 0; i >= 0; i--) {
#endif
hex[j++] = hex_asc_hi(data[i]);
hex[j++] = hex_asc_lo(data[i]);
}
if (WARN_ON_ONCE(j == 0 || j/2 > len))
break;
/* j increments twice per loop */
len -= j / 2;
hex[j++] = ' ';
seq_buf_putmem(s, hex, j);
if (seq_buf_has_overflowed(s))
return -1;
}
return 0;
}
/**
* seq_buf_path - copy a path into the sequence buffer
* @s: seq_buf descriptor
* @path: path to write into the sequence buffer.
* @esc: set of characters to escape in the output
*
* Write a path name into the sequence buffer.
*
* Returns the number of written bytes on success, -1 on overflow
*/
int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc)
{
char *buf;
size_t size = seq_buf_get_buf(s, &buf);
int res = -1;
WARN_ON(s->size == 0);
if (size) {
char *p = d_path(path, buf, size);
if (!IS_ERR(p)) {
char *end = mangle_path(buf, p, esc);
if (end)
res = end - buf;
}
}
seq_buf_commit(s, res);
return res;
}
/**
* seq_buf_to_user - copy the squence buffer to user space
* @s: seq_buf descriptor
* @ubuf: The userspace memory location to copy to
* @cnt: The amount to copy
*
* Copies the sequence buffer into the userspace memory pointed to
* by @ubuf. It starts from the last read position (@s->readpos)
* and writes up to @cnt characters or till it reaches the end of
* the content in the buffer (@s->len), which ever comes first.
*
* On success, it returns a positive number of the number of bytes
* it copied.
*
* On failure it returns -EBUSY if all of the content in the
* sequence has been already read, which includes nothing in the
* sequence (@s->len == @s->readpos).
*
* Returns -EFAULT if the copy to userspace fails.
*/
int seq_buf_to_user(struct seq_buf *s, char __user *ubuf, int cnt)
{
int len;
int ret;
if (!cnt)
return 0;
if (s->len <= s->readpos)
return -EBUSY;
len = seq_buf_used(s) - s->readpos;
if (cnt > len)
cnt = len;
ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
if (ret == cnt)
return -EFAULT;
cnt -= ret;
s->readpos += cnt;
return cnt;
}