summaryrefslogtreecommitdiffstats
path: root/lib/seq_buf.c
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--lib/seq_buf.c397
1 files changed, 397 insertions, 0 deletions
diff --git a/lib/seq_buf.c b/lib/seq_buf.c
new file mode 100644
index 000000000..0a68f7aa8
--- /dev/null
+++ b/lib/seq_buf.c
@@ -0,0 +1,397 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * 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 (s->len + len < s->size) {
+ 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;
+}
+EXPORT_SYMBOL_GPL(seq_buf_printf);
+
+#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 (s->len + ret < s->size) {
+ 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)
+{
+ size_t len = strlen(str);
+
+ WARN_ON(s->size == 0);
+
+ /* Add 1 to len for the trailing null byte which must be there */
+ len += 1;
+
+ if (seq_buf_can_fit(s, len)) {
+ memcpy(s->buffer + s->len, str, len);
+ /* Don't count the trailing null byte against the capacity */
+ s->len += len - 1;
+ 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);
+
+ BUILD_BUG_ON(MAX_MEMHEX_BYTES * 2 >= HEX_CHARS);
+
+ while (len) {
+ start_len = min(len, MAX_MEMHEX_BYTES);
+#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 */
+ hex[j++] = ' ';
+
+ seq_buf_putmem(s, hex, j);
+ if (seq_buf_has_overflowed(s))
+ return -1;
+
+ len -= start_len;
+ data += start_len;
+ }
+ 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 sequence 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;
+
+ len = seq_buf_used(s);
+
+ if (len <= s->readpos)
+ return -EBUSY;
+
+ len -= 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_hex_dump - print formatted hex dump into the sequence buffer
+ * @s: seq_buf descriptor
+ * @prefix_str: string to prefix each line with;
+ * caller supplies trailing spaces for alignment if desired
+ * @prefix_type: controls whether prefix of an offset, address, or none
+ * is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
+ * @rowsize: number of bytes to print per line; must be 16 or 32
+ * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
+ * @buf: data blob to dump
+ * @len: number of bytes in the @buf
+ * @ascii: include ASCII after the hex output
+ *
+ * Function is an analogue of print_hex_dump() and thus has similar interface.
+ *
+ * linebuf size is maximal length for one line.
+ * 32 * 3 - maximum bytes per line, each printed into 2 chars + 1 for
+ * separating space
+ * 2 - spaces separating hex dump and ascii representation
+ * 32 - ascii representation
+ * 1 - terminating '\0'
+ *
+ * Returns zero on success, -1 on overflow
+ */
+int seq_buf_hex_dump(struct seq_buf *s, const char *prefix_str, int prefix_type,
+ int rowsize, int groupsize,
+ const void *buf, size_t len, bool ascii)
+{
+ const u8 *ptr = buf;
+ int i, linelen, remaining = len;
+ unsigned char linebuf[32 * 3 + 2 + 32 + 1];
+ int ret;
+
+ if (rowsize != 16 && rowsize != 32)
+ rowsize = 16;
+
+ for (i = 0; i < len; i += rowsize) {
+ linelen = min(remaining, rowsize);
+ remaining -= rowsize;
+
+ hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
+ linebuf, sizeof(linebuf), ascii);
+
+ switch (prefix_type) {
+ case DUMP_PREFIX_ADDRESS:
+ ret = seq_buf_printf(s, "%s%p: %s\n",
+ prefix_str, ptr + i, linebuf);
+ break;
+ case DUMP_PREFIX_OFFSET:
+ ret = seq_buf_printf(s, "%s%.8x: %s\n",
+ prefix_str, i, linebuf);
+ break;
+ default:
+ ret = seq_buf_printf(s, "%s%s\n", prefix_str, linebuf);
+ break;
+ }
+ if (ret)
+ return ret;
+ }
+ return 0;
+}