// SPDX-License-Identifier: GPL-2.0 /* * seq_buf.c * * Copyright (C) 2014 Red Hat Inc, Steven Rostedt <[email protected]> * * 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/bug.h> #include <linux/err.h> #include <linux/export.h> #include <linux/hex.h> #include <linux/minmax.h> #include <linux/printk.h> #include <linux/seq_buf.h> #include <linux/seq_file.h> #include <linux/sprintf.h> #include <linux/string.h> #include <linux/types.h> #include <linux/uaccess.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) { … } /** * 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) { … } /** * 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 sequence buffer. * * Returns: zero on success, -1 on overflow. */ int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args) { … } /** * 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, ...) { … } EXPORT_SYMBOL_GPL(…); /** * seq_buf_do_printk - printk() seq_buf line by line * @s: seq_buf descriptor * @lvl: printk level * * printk()-s a multi-line sequential buffer line by line. The function * makes sure that the buffer in @s is NUL-terminated and safe to read * as a string. */ void seq_buf_do_printk(struct seq_buf *s, const char *lvl) { … } EXPORT_SYMBOL_GPL(…); #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) { … } #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) { … } EXPORT_SYMBOL_GPL(…); /** * 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) { … } EXPORT_SYMBOL_GPL(…); /** * seq_buf_putmem - write raw data into the sequence 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) { … } #define MAX_MEMHEX_BYTES … #define HEX_CHARS … /** * 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) { … } /** * 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) { … } /** * seq_buf_to_user - copy the sequence buffer to user space * @s: seq_buf descriptor * @ubuf: The userspace memory location to copy to * @start: The first byte in the buffer to copy * @cnt: The amount to copy * * Copies the sequence buffer into the userspace memory pointed to * by @ubuf. It starts from @start and writes up to @cnt characters * or until it reaches the end of the content in the buffer (@s->len), * whichever comes first. * * Returns: * 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 == @start). * * Returns -EFAULT if the copy to userspace fails. */ int seq_buf_to_user(struct seq_buf *s, char __user *ubuf, size_t start, int 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) { … }
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