/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_SEQ_FILE_H
#define _LINUX_SEQ_FILE_H

#include <linux/types.h>
#include <linux/string.h>
#include <linux/bug.h>
#include <linux/mutex.h>
#include <linux/cpumask.h>
#include <linux/nodemask.h>
#include <linux/fs.h>
#include <linux/cred.h>

struct seq_operations;

struct seq_file {
        char *buf;
        size_t size;
        size_t from;
        size_t count;
        size_t pad_until;
        loff_t index;
        loff_t read_pos;
        struct mutex lock;
        const struct seq_operations *op;
        int poll_event;
        const struct file *file;
        void *private;
};

struct seq_operations {
        void * (*start) (struct seq_file *m, loff_t *pos);
        void (*stop) (struct seq_file *m, void *v);
        void * (*next) (struct seq_file *m, void *v, loff_t *pos);
        int (*show) (struct seq_file *m, void *v);
};

#define SEQ_SKIP 1

/**
 * seq_has_overflowed - check if the buffer has overflowed
 * @m: the seq_file handle
 *
 * seq_files have a buffer which may overflow. When this happens a larger
 * buffer is reallocated and all the data will be printed again.
 * The overflow state is true when m->count == m->size.
 *
 * Returns true if the buffer received more than it can hold.
 */
static inline bool seq_has_overflowed(struct seq_file *m)
{
        return m->count == m->size;
}

/**
 * seq_get_buf - get buffer to write arbitrary data to
 * @m: the seq_file handle
 * @bufp: the beginning of the buffer is stored here
 *
 * Return the number of bytes available in the buffer, or zero if
 * there's no space.
 */
static inline size_t seq_get_buf(struct seq_file *m, char **bufp)
{
        BUG_ON(m->count > m->size);
        if (m->count < m->size)
                *bufp = m->buf + m->count;
        else
                *bufp = NULL;

        return m->size - m->count;
}

/**
 * seq_commit - commit data to the buffer
 * @m: the seq_file handle
 * @num: the number of bytes to commit
 *
 * Commit @num bytes of data written to a buffer previously acquired
 * by seq_buf_get.  To signal an error condition, or that the data
 * didn't fit in the available space, pass a negative @num value.
 */
static inline void seq_commit(struct seq_file *m, int num)
{
        if (num < 0) {
                m->count = m->size;
        } else {
                BUG_ON(m->count + num > m->size);
                m->count += num;
        }
}

/**
 * seq_setwidth - set padding width
 * @m: the seq_file handle
 * @size: the max number of bytes to pad.
 *
 * Call seq_setwidth() for setting max width, then call seq_printf() etc. and
 * finally call seq_pad() to pad the remaining bytes.
 */
static inline void seq_setwidth(struct seq_file *m, size_t size)
{
        m->pad_until = m->count + size;
}
void seq_pad(struct seq_file *m, char c);

char *mangle_path(char *s, const char *p, const char *esc);
int seq_open(struct file *, const struct seq_operations *);
ssize_t seq_read(struct file *, char __user *, size_t, loff_t *);
loff_t seq_lseek(struct file *, loff_t, int);
int seq_release(struct inode *, struct file *);
int seq_write(struct seq_file *seq, const void *data, size_t len);

__printf(2, 0)
void seq_vprintf(struct seq_file *m, const char *fmt, va_list args);
__printf(2, 3)
void seq_printf(struct seq_file *m, const char *fmt, ...);
void seq_putc(struct seq_file *m, char c);
void seq_puts(struct seq_file *m, const char *s);
void seq_put_decimal_ull_width(struct seq_file *m, const char *delimiter,
                               unsigned long long num, unsigned int width);
void seq_put_decimal_ull(struct seq_file *m, const char *delimiter,
                         unsigned long long num);
void seq_put_decimal_ll(struct seq_file *m, const char *delimiter, long long num);
void seq_put_hex_ll(struct seq_file *m, const char *delimiter,
                    unsigned long long v, unsigned int width);

void seq_escape(struct seq_file *m, const char *s, const char *esc);
void seq_escape_mem_ascii(struct seq_file *m, const char *src, size_t isz);

void seq_hex_dump(struct seq_file *m, const char *prefix_str, int prefix_type,
                  int rowsize, int groupsize, const void *buf, size_t len,
                  bool ascii);

int seq_path(struct seq_file *, const struct path *, const char *);
int seq_file_path(struct seq_file *, struct file *, const char *);
int seq_dentry(struct seq_file *, struct dentry *, const char *);
int seq_path_root(struct seq_file *m, const struct path *path,
                  const struct path *root, const char *esc);

int single_open(struct file *, int (*)(struct seq_file *, void *), void *);
int single_open_size(struct file *, int (*)(struct seq_file *, void *), void *, size_t);
int single_release(struct inode *, struct file *);
void *__seq_open_private(struct file *, const struct seq_operations *, int);
int seq_open_private(struct file *, const struct seq_operations *, int);
int seq_release_private(struct inode *, struct file *);

#define DEFINE_SHOW_ATTRIBUTE(__name)                                   \
static int __name ## _open(struct inode *inode, struct file *file)      \
{                                                                       \
        return single_open(file, __name ## _show, inode->i_private);    \
}                                                                       \
                                                                        \
static const struct file_operations __name ## _fops = {                 \
        .owner          = THIS_MODULE,                                  \
        .open           = __name ## _open,                              \
        .read           = seq_read,                                     \
        .llseek         = seq_lseek,                                    \
        .release        = single_release,                               \
}

#define DEFINE_PROC_SHOW_ATTRIBUTE(__name)                              \
static int __name ## _open(struct inode *inode, struct file *file)      \
{                                                                       \
        return single_open(file, __name ## _show, inode->i_private);    \
}                                                                       \
                                                                        \
static const struct proc_ops __name ## _proc_ops = {                    \
        .proc_open      = __name ## _open,                              \
        .proc_read      = seq_read,                                     \
        .proc_lseek     = seq_lseek,                                    \
        .proc_release   = single_release,                               \
}

static inline struct user_namespace *seq_user_ns(struct seq_file *seq)
{
#ifdef CONFIG_USER_NS
        return seq->file->f_cred->user_ns;
#else
        extern struct user_namespace init_user_ns;
        return &init_user_ns;
#endif
}

/**
 * seq_show_options - display mount options with appropriate escapes.
 * @m: the seq_file handle
 * @name: the mount option name
 * @value: the mount option name's value, can be NULL
 */
static inline void seq_show_option(struct seq_file *m, const char *name,
                                   const char *value)
{
        seq_putc(m, ',');
        seq_escape(m, name, ",= \t\n\\");
        if (value) {
                seq_putc(m, '=');
                seq_escape(m, value, ", \t\n\\");
        }
}

/**
 * seq_show_option_n - display mount options with appropriate escapes
 *                     where @value must be a specific length.
 * @m: the seq_file handle
 * @name: the mount option name
 * @value: the mount option name's value, cannot be NULL
 * @length: the length of @value to display
 *
 * This is a macro since this uses "length" to define the size of the
 * stack buffer.
 */
#define seq_show_option_n(m, name, value, length) {     \
        char val_buf[length + 1];                       \
        strncpy(val_buf, value, length);                \
        val_buf[length] = '\0';                         \
        seq_show_option(m, name, val_buf);              \
}

#define SEQ_START_TOKEN ((void *)1)
/*
 * Helpers for iteration over list_head-s in seq_files
 */

extern struct list_head *seq_list_start(struct list_head *head,
                loff_t pos);
extern struct list_head *seq_list_start_head(struct list_head *head,
                loff_t pos);
extern struct list_head *seq_list_next(void *v, struct list_head *head,
                loff_t *ppos);

/*
 * Helpers for iteration over hlist_head-s in seq_files
 */

extern struct hlist_node *seq_hlist_start(struct hlist_head *head,
                                          loff_t pos);
extern struct hlist_node *seq_hlist_start_head(struct hlist_head *head,
                                               loff_t pos);
extern struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head,
                                         loff_t *ppos);

extern struct hlist_node *seq_hlist_start_rcu(struct hlist_head *head,
                                              loff_t pos);
extern struct hlist_node *seq_hlist_start_head_rcu(struct hlist_head *head,
                                                   loff_t pos);
extern struct hlist_node *seq_hlist_next_rcu(void *v,
                                                   struct hlist_head *head,
                                                   loff_t *ppos);

/* Helpers for iterating over per-cpu hlist_head-s in seq_files */
extern struct hlist_node *seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos);

extern struct hlist_node *seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head, int *cpu, loff_t *pos);

void seq_file_init(void);
#endif