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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /fs/seq_file.c | |
download | kernel_samsung_aries-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.zip kernel_samsung_aries-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz kernel_samsung_aries-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.bz2 |
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'fs/seq_file.c')
-rw-r--r-- | fs/seq_file.c | 440 |
1 files changed, 440 insertions, 0 deletions
diff --git a/fs/seq_file.c b/fs/seq_file.c new file mode 100644 index 0000000..650c43b --- /dev/null +++ b/fs/seq_file.c @@ -0,0 +1,440 @@ +/* + * 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, struct seq_operations *op) +{ + struct seq_file *p = kmalloc(sizeof(*p), GFP_KERNEL); + if (!p) + return -ENOMEM; + memset(p, 0, sizeof(*p)); + sema_init(&p->sem, 1); + p->op = op; + file->private_data = p; + + /* + * 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, @buf, @size, @ppos: see file_operations method + * + * 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; + + down(&m->sem); + /* + * 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; + up(&m->sem); + 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; + int error = 0; + void *p; + + m->version = 0; + m->index = 0; + m->count = m->from = 0; + if (!offset) + return 0; + if (!m->buf) { + m->buf = kmalloc(m->size = PAGE_SIZE, GFP_KERNEL); + if (!m->buf) + return -ENOMEM; + } + p = m->op->start(m, &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; + break; + } + pos += m->count; + m->count = 0; + if (pos == offset) { + m->index++; + break; + } + p = m->op->next(m, p, &m->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, @offset, @origin: see file_operations method + * + * 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; + long long retval = -EINVAL; + + down(&m->sem); + 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; + } + } + } + up(&m->sem); + file->f_version = m->version; + return retval; +} +EXPORT_SYMBOL(seq_lseek); + +/** + * seq_release - free the structures associated with sequential file. + * @file: file in question + * @inode: file->f_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 vfsmount *mnt, struct dentry *dentry, + char *esc) +{ + if (m->count < m->size) { + char *s = m->buf + m->count; + char *p = d_path(dentry, mnt, 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) +{ + 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); + +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); |