| /* |
| * linux/fs/seq_file.c |
| * |
| * helper functions for making synthetic files from sequences of records. |
| * initial implementation -- AV, Oct 2001. |
| */ |
| |
| #include <linux/fs.h> |
| #include <linux/module.h> |
| #include <linux/seq_file.h> |
| #include <linux/slab.h> |
| |
| #include <asm/uaccess.h> |
| #include <asm/page.h> |
| |
| /** |
| * seq_open - initialize sequential file |
| * @file: file we initialize |
| * @op: method table describing the sequence |
| * |
| * seq_open() sets @file, associating it with a sequence described |
| * by @op. @op->start() sets the iterator up and returns the first |
| * element of sequence. @op->stop() shuts it down. @op->next() |
| * returns the next element of sequence. @op->show() prints element |
| * into the buffer. In case of error ->start() and ->next() return |
| * ERR_PTR(error). In the end of sequence they return %NULL. ->show() |
| * returns 0 in case of success and negative number in case of error. |
| */ |
| int seq_open(struct file *file, const struct seq_operations *op) |
| { |
| struct seq_file *p = file->private_data; |
| |
| if (!p) { |
| p = kmalloc(sizeof(*p), GFP_KERNEL); |
| if (!p) |
| return -ENOMEM; |
| file->private_data = p; |
| } |
| memset(p, 0, sizeof(*p)); |
| mutex_init(&p->lock); |
| p->op = op; |
| |
| /* |
| * Wrappers around seq_open(e.g. swaps_open) need to be |
| * aware of this. If they set f_version themselves, they |
| * should call seq_open first and then set f_version. |
| */ |
| file->f_version = 0; |
| |
| /* SEQ files support lseek, but not pread/pwrite */ |
| file->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE); |
| return 0; |
| } |
| EXPORT_SYMBOL(seq_open); |
| |
| /** |
| * seq_read - ->read() method for sequential files. |
| * @file: the file to read from |
| * @buf: the buffer to read to |
| * @size: the maximum number of bytes to read |
| * @ppos: the current position in the file |
| * |
| * Ready-made ->f_op->read() |
| */ |
| ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos) |
| { |
| struct seq_file *m = (struct seq_file *)file->private_data; |
| size_t copied = 0; |
| loff_t pos; |
| size_t n; |
| void *p; |
| int err = 0; |
| |
| mutex_lock(&m->lock); |
| /* |
| * seq_file->op->..m_start/m_stop/m_next may do special actions |
| * or optimisations based on the file->f_version, so we want to |
| * pass the file->f_version to those methods. |
| * |
| * seq_file->version is just copy of f_version, and seq_file |
| * methods can treat it simply as file version. |
| * It is copied in first and copied out after all operations. |
| * It is convenient to have it as part of structure to avoid the |
| * need of passing another argument to all the seq_file methods. |
| */ |
| m->version = file->f_version; |
| /* grab buffer if we didn't have one */ |
| if (!m->buf) { |
| m->buf = kmalloc(m->size = PAGE_SIZE, GFP_KERNEL); |
| if (!m->buf) |
| goto Enomem; |
| } |
| /* if not empty - flush it first */ |
| if (m->count) { |
| n = min(m->count, size); |
| err = copy_to_user(buf, m->buf + m->from, n); |
| if (err) |
| goto Efault; |
| m->count -= n; |
| m->from += n; |
| size -= n; |
| buf += n; |
| copied += n; |
| if (!m->count) |
| m->index++; |
| if (!size) |
| goto Done; |
| } |
| /* we need at least one record in buffer */ |
| while (1) { |
| pos = m->index; |
| p = m->op->start(m, &pos); |
| err = PTR_ERR(p); |
| if (!p || IS_ERR(p)) |
| break; |
| err = m->op->show(m, p); |
| if (err) |
| break; |
| if (m->count < m->size) |
| goto Fill; |
| m->op->stop(m, p); |
| kfree(m->buf); |
| m->buf = kmalloc(m->size <<= 1, GFP_KERNEL); |
| if (!m->buf) |
| goto Enomem; |
| m->count = 0; |
| m->version = 0; |
| } |
| m->op->stop(m, p); |
| m->count = 0; |
| goto Done; |
| Fill: |
| /* they want more? let's try to get some more */ |
| while (m->count < size) { |
| size_t offs = m->count; |
| loff_t next = pos; |
| p = m->op->next(m, p, &next); |
| if (!p || IS_ERR(p)) { |
| err = PTR_ERR(p); |
| break; |
| } |
| err = m->op->show(m, p); |
| if (err || m->count == m->size) { |
| m->count = offs; |
| break; |
| } |
| pos = next; |
| } |
| m->op->stop(m, p); |
| n = min(m->count, size); |
| err = copy_to_user(buf, m->buf, n); |
| if (err) |
| goto Efault; |
| copied += n; |
| m->count -= n; |
| if (m->count) |
| m->from = n; |
| else |
| pos++; |
| m->index = pos; |
| Done: |
| if (!copied) |
| copied = err; |
| else |
| *ppos += copied; |
| file->f_version = m->version; |
| mutex_unlock(&m->lock); |
| return copied; |
| Enomem: |
| err = -ENOMEM; |
| goto Done; |
| Efault: |
| err = -EFAULT; |
| goto Done; |
| } |
| EXPORT_SYMBOL(seq_read); |
| |
| static int traverse(struct seq_file *m, loff_t offset) |
| { |
| loff_t pos = 0, index; |
| int error = 0; |
| void *p; |
| |
| m->version = 0; |
| index = 0; |
| m->count = m->from = 0; |
| if (!offset) { |
| m->index = index; |
| return 0; |
| } |
| if (!m->buf) { |
| m->buf = kmalloc(m->size = PAGE_SIZE, GFP_KERNEL); |
| if (!m->buf) |
| return -ENOMEM; |
| } |
| p = m->op->start(m, &index); |
| while (p) { |
| error = PTR_ERR(p); |
| if (IS_ERR(p)) |
| break; |
| error = m->op->show(m, p); |
| if (error) |
| break; |
| if (m->count == m->size) |
| goto Eoverflow; |
| if (pos + m->count > offset) { |
| m->from = offset - pos; |
| m->count -= m->from; |
| m->index = index; |
| break; |
| } |
| pos += m->count; |
| m->count = 0; |
| if (pos == offset) { |
| index++; |
| m->index = index; |
| break; |
| } |
| p = m->op->next(m, p, &index); |
| } |
| m->op->stop(m, p); |
| return error; |
| |
| Eoverflow: |
| m->op->stop(m, p); |
| kfree(m->buf); |
| m->buf = kmalloc(m->size <<= 1, GFP_KERNEL); |
| return !m->buf ? -ENOMEM : -EAGAIN; |
| } |
| |
| /** |
| * seq_lseek - ->llseek() method for sequential files. |
| * @file: the file in question |
| * @offset: new position |
| * @origin: 0 for absolute, 1 for relative position |
| * |
| * Ready-made ->f_op->llseek() |
| */ |
| loff_t seq_lseek(struct file *file, loff_t offset, int origin) |
| { |
| struct seq_file *m = (struct seq_file *)file->private_data; |
| loff_t retval = -EINVAL; |
| |
| mutex_lock(&m->lock); |
| m->version = file->f_version; |
| switch (origin) { |
| case 1: |
| offset += file->f_pos; |
| case 0: |
| if (offset < 0) |
| break; |
| retval = offset; |
| if (offset != file->f_pos) { |
| while ((retval=traverse(m, offset)) == -EAGAIN) |
| ; |
| if (retval) { |
| /* with extreme prejudice... */ |
| file->f_pos = 0; |
| m->version = 0; |
| m->index = 0; |
| m->count = 0; |
| } else { |
| retval = file->f_pos = offset; |
| } |
| } |
| } |
| file->f_version = m->version; |
| mutex_unlock(&m->lock); |
| return retval; |
| } |
| EXPORT_SYMBOL(seq_lseek); |
| |
| /** |
| * seq_release - free the structures associated with sequential file. |
| * @file: file in question |
| * @inode: file->f_path.dentry->d_inode |
| * |
| * Frees the structures associated with sequential file; can be used |
| * as ->f_op->release() if you don't have private data to destroy. |
| */ |
| int seq_release(struct inode *inode, struct file *file) |
| { |
| struct seq_file *m = (struct seq_file *)file->private_data; |
| kfree(m->buf); |
| kfree(m); |
| return 0; |
| } |
| EXPORT_SYMBOL(seq_release); |
| |
| /** |
| * seq_escape - print string into buffer, escaping some characters |
| * @m: target buffer |
| * @s: string |
| * @esc: set of characters that need escaping |
| * |
| * Puts string into buffer, replacing each occurrence of character from |
| * @esc with usual octal escape. Returns 0 in case of success, -1 - in |
| * case of overflow. |
| */ |
| int seq_escape(struct seq_file *m, const char *s, const char *esc) |
| { |
| char *end = m->buf + m->size; |
| char *p; |
| char c; |
| |
| for (p = m->buf + m->count; (c = *s) != '\0' && p < end; s++) { |
| if (!strchr(esc, c)) { |
| *p++ = c; |
| continue; |
| } |
| if (p + 3 < end) { |
| *p++ = '\\'; |
| *p++ = '0' + ((c & 0300) >> 6); |
| *p++ = '0' + ((c & 070) >> 3); |
| *p++ = '0' + (c & 07); |
| continue; |
| } |
| m->count = m->size; |
| return -1; |
| } |
| m->count = p - m->buf; |
| return 0; |
| } |
| EXPORT_SYMBOL(seq_escape); |
| |
| int seq_printf(struct seq_file *m, const char *f, ...) |
| { |
| va_list args; |
| int len; |
| |
| if (m->count < m->size) { |
| va_start(args, f); |
| len = vsnprintf(m->buf + m->count, m->size - m->count, f, args); |
| va_end(args); |
| if (m->count + len < m->size) { |
| m->count += len; |
| return 0; |
| } |
| } |
| m->count = m->size; |
| return -1; |
| } |
| EXPORT_SYMBOL(seq_printf); |
| |
| int seq_path(struct seq_file *m, struct path *path, char *esc) |
| { |
| if (m->count < m->size) { |
| char *s = m->buf + m->count; |
| char *p = d_path(path, s, m->size - m->count); |
| if (!IS_ERR(p)) { |
| while (s <= p) { |
| char c = *p++; |
| if (!c) { |
| p = m->buf + m->count; |
| m->count = s - m->buf; |
| return s - p; |
| } else if (!strchr(esc, c)) { |
| *s++ = c; |
| } else if (s + 4 > p) { |
| break; |
| } else { |
| *s++ = '\\'; |
| *s++ = '0' + ((c & 0300) >> 6); |
| *s++ = '0' + ((c & 070) >> 3); |
| *s++ = '0' + (c & 07); |
| } |
| } |
| } |
| } |
| m->count = m->size; |
| return -1; |
| } |
| EXPORT_SYMBOL(seq_path); |
| |
| static void *single_start(struct seq_file *p, loff_t *pos) |
| { |
| return NULL + (*pos == 0); |
| } |
| |
| static void *single_next(struct seq_file *p, void *v, loff_t *pos) |
| { |
| ++*pos; |
| return NULL; |
| } |
| |
| static void single_stop(struct seq_file *p, void *v) |
| { |
| } |
| |
| int single_open(struct file *file, int (*show)(struct seq_file *, void *), |
| void *data) |
| { |
| struct seq_operations *op = kmalloc(sizeof(*op), GFP_KERNEL); |
| int res = -ENOMEM; |
| |
| if (op) { |
| op->start = single_start; |
| op->next = single_next; |
| op->stop = single_stop; |
| op->show = show; |
| res = seq_open(file, op); |
| if (!res) |
| ((struct seq_file *)file->private_data)->private = data; |
| else |
| kfree(op); |
| } |
| return res; |
| } |
| EXPORT_SYMBOL(single_open); |
| |
| int single_release(struct inode *inode, struct file *file) |
| { |
| const struct seq_operations *op = ((struct seq_file *)file->private_data)->op; |
| int res = seq_release(inode, file); |
| kfree(op); |
| return res; |
| } |
| EXPORT_SYMBOL(single_release); |
| |
| int seq_release_private(struct inode *inode, struct file *file) |
| { |
| struct seq_file *seq = file->private_data; |
| |
| kfree(seq->private); |
| seq->private = NULL; |
| return seq_release(inode, file); |
| } |
| EXPORT_SYMBOL(seq_release_private); |
| |
| void *__seq_open_private(struct file *f, const struct seq_operations *ops, |
| int psize) |
| { |
| int rc; |
| void *private; |
| struct seq_file *seq; |
| |
| private = kzalloc(psize, GFP_KERNEL); |
| if (private == NULL) |
| goto out; |
| |
| rc = seq_open(f, ops); |
| if (rc < 0) |
| goto out_free; |
| |
| seq = f->private_data; |
| seq->private = private; |
| return private; |
| |
| out_free: |
| kfree(private); |
| out: |
| return NULL; |
| } |
| EXPORT_SYMBOL(__seq_open_private); |
| |
| int seq_open_private(struct file *filp, const struct seq_operations *ops, |
| int psize) |
| { |
| return __seq_open_private(filp, ops, psize) ? 0 : -ENOMEM; |
| } |
| EXPORT_SYMBOL(seq_open_private); |
| |
| int seq_putc(struct seq_file *m, char c) |
| { |
| if (m->count < m->size) { |
| m->buf[m->count++] = c; |
| return 0; |
| } |
| return -1; |
| } |
| EXPORT_SYMBOL(seq_putc); |
| |
| int seq_puts(struct seq_file *m, const char *s) |
| { |
| int len = strlen(s); |
| if (m->count + len < m->size) { |
| memcpy(m->buf + m->count, s, len); |
| m->count += len; |
| return 0; |
| } |
| m->count = m->size; |
| return -1; |
| } |
| EXPORT_SYMBOL(seq_puts); |
| |
| struct list_head *seq_list_start(struct list_head *head, loff_t pos) |
| { |
| struct list_head *lh; |
| |
| list_for_each(lh, head) |
| if (pos-- == 0) |
| return lh; |
| |
| return NULL; |
| } |
| |
| EXPORT_SYMBOL(seq_list_start); |
| |
| struct list_head *seq_list_start_head(struct list_head *head, loff_t pos) |
| { |
| if (!pos) |
| return head; |
| |
| return seq_list_start(head, pos - 1); |
| } |
| |
| EXPORT_SYMBOL(seq_list_start_head); |
| |
| struct list_head *seq_list_next(void *v, struct list_head *head, loff_t *ppos) |
| { |
| struct list_head *lh; |
| |
| lh = ((struct list_head *)v)->next; |
| ++*ppos; |
| return lh == head ? NULL : lh; |
| } |
| |
| EXPORT_SYMBOL(seq_list_next); |