/* * 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/export.h>#include <linux/seq_file.h>#include <linux/slab.h>#include <linux/cred.h> #include <asm/uaccess.h>#include <asm/page.h> /* * seq_files have a buffer which can 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. */static bool seq_overflow(struct seq_file *m){ return m->count == m->size;} static void seq_set_overflow(struct seq_file *m){ m->count = m->size;} /** * 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. * Returning SEQ_SKIP means "discard this element and move on". */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;#ifdef CONFIG_USER_NS p->user_ns = file->f_cred->user_ns;#endif /* * 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() and pread(). They do not implement * write() at all, but we clear FMODE_PWRITE here for historical * reasons. * * If a client of seq_files a) implements file.write() and b) wishes to * support pwrite() then that client will need to implement its own * file.open() which calls seq_open() and then sets FMODE_PWRITE. */ file->f_mode &= ~FMODE_PWRITE; return 0;}EXPORT_SYMBOL(seq_open); 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 < 0) break; if (unlikely(error)) { error = 0; m->count = 0; } if (seq_overflow(m)) 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); m->index = index; return error; Eoverflow: m->op->stop(m, p); kfree(m->buf); m->count = 0; m->buf = kmalloc(m->size <<= 1, GFP_KERNEL); return !m->buf ? -ENOMEM : -EAGAIN;} /** * 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 = 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; /* Don't assume *ppos is where we left it */ if (unlikely(*ppos != m->read_pos)) { while ((err = traverse(m, *ppos)) == -EAGAIN) ; if (err) { /* With prejudice... */ m->read_pos = 0; m->version = 0; m->index = 0; m->count = 0; goto Done; } else { m->read_pos = *ppos; } } /* 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 */ pos = m->index; p = m->op->start(m, &pos); while (1) { err = PTR_ERR(p); if (!p || IS_ERR(p)) break; err = m->op->show(m, p); if (err < 0) break; if (unlikely(err)) m->count = 0; if (unlikely(!m->count)) { p = m->op->next(m, p, &pos); m->index = pos; continue; } if (m->count < m->size) goto Fill; m->op->stop(m, p); kfree(m->buf); m->count = 0; m->buf = kmalloc(m->size <<= 1, GFP_KERNEL); if (!m->buf) goto Enomem; m->version = 0; pos = m->index; p = m->op->start(m, &pos); } 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 (seq_overflow(m) || err) { m->count = offs; if (likely(err <= 0)) 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; m->read_pos += 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); /** * seq_lseek - ->llseek() method for sequential files. * @file: the file in question * @offset: new position * @whence: 0 for absolute, 1 for relative position * * Ready-made ->f_op->llseek() */loff_t seq_lseek(struct file *file, loff_t offset, int whence){ struct seq_file *m = file->private_data; loff_t retval = -EINVAL; mutex_lock(&m->lock); m->version = file->f_version; switch (whence) { case SEEK_CUR: offset += file->f_pos; case SEEK_SET: if (offset < 0) break; retval = offset; if (offset != m->read_pos) { while ((retval = traverse(m, offset)) == -EAGAIN) ; if (retval) { /* with extreme prejudice... */ file->f_pos = 0; m->read_pos = 0; m->version = 0; m->index = 0; m->count = 0; } else { m->read_pos = offset; retval = file->f_pos = offset; } } else { 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: its 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 = 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; } seq_set_overflow(m); return -1; } m->count = p - m->buf; return 0;}EXPORT_SYMBOL(seq_escape); int seq_vprintf(struct seq_file *m, const char *f, va_list args){ int len; if (m->count < m->size) { len = vsnprintf(m->buf + m->count, m->size - m->count, f, args); if (m->count + len < m->size) { m->count += len; return 0; } } seq_set_overflow(m); return -1;}EXPORT_SYMBOL(seq_vprintf); int seq_printf(struct seq_file *m, const char *f, ...){ int ret; va_list args; va_start(args, f); ret = seq_vprintf(m, f, args); va_end(args); return ret;}EXPORT_SYMBOL(seq_printf); /** * mangle_path - mangle and copy path to buffer beginning * @s: buffer start * @p: beginning of path in above buffer * @esc: set of characters that need escaping * * Copy the path from @p to @s, replacing each occurrence of character from * @esc with usual octal escape. * Returns pointer past last written character in @s, or NULL in case of * failure. */char *mangle_path(char *s, const char *p, const char *esc){ while (s <= p) { char c = *p++; if (!c) { return s; } 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); } } return NULL;}EXPORT_SYMBOL(mangle_path); /** * seq_path - seq_file interface to print a pathname * @m: the seq_file handle * @path: the struct path to print * @esc: set of characters to escape in the output * * return the absolute path of 'path', as represented by the * dentry / mnt pair in the path parameter. */int seq_path(struct seq_file *m, const struct path *path, const char *esc){ char *buf; size_t size = seq_get_buf(m, &buf); int res = -1; 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_commit(m, res); return res;}EXPORT_SYMBOL(seq_path); /* * Same as seq_path, but relative to supplied root. */int seq_path_root(struct seq_file *m, const struct path *path, const struct path *root, const char *esc){ char *buf; size_t size = seq_get_buf(m, &buf); int res = -ENAMETOOLONG; if (size) { char *p; p = __d_path(path, root, buf, size); if (!p) return SEQ_SKIP;Lines 1–500 of 995. 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/* * 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/export.h> #include <linux/seq_file.h> #include <linux/slab.h> #include <linux/cred.h> #include <asm/uaccess.h> #include <asm/page.h> /* * seq_files have a buffer which can 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. */ static bool seq_overflow(struct seq_file *m) { return m->count == m->size; } static void seq_set_overflow(struct seq_file *m) { m->count = m->size; } /** * 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. * Returning SEQ_SKIP means "discard this element and move on". */ 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; #ifdef CONFIG_USER_NS p->user_ns = file->f_cred->user_ns; #endif /* * 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() and pread(). They do not implement * write() at all, but we clear FMODE_PWRITE here for historical * reasons. * * If a client of seq_files a) implements file.write() and b) wishes to * support pwrite() then that client will need to implement its own * file.open() which calls seq_open() and then sets FMODE_PWRITE. */ file->f_mode &= ~FMODE_PWRITE; return 0; } EXPORT_SYMBOL(seq_open); 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 < 0) break; if (unlikely(error)) { error = 0; m->count = 0; } if (seq_overflow(m)) 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); m->index = index; return error; Eoverflow: m->op->stop(m, p); kfree(m->buf); m->count = 0; m->buf = kmalloc(m->size <<= 1, GFP_KERNEL); return !m->buf ? -ENOMEM : -EAGAIN; } /** * 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 = 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; /* Don't assume *ppos is where we left it */ if (unlikely(*ppos != m->read_pos)) { while ((err = traverse(m, *ppos)) == -EAGAIN) ; if (err) { /* With prejudice... */ m->read_pos = 0; m->version = 0; m->index = 0; m->count = 0; goto Done; } else { m->read_pos = *ppos; } } /* 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 */ pos = m->index; p = m->op->start(m, &pos); while (1) { err = PTR_ERR(p); if (!p || IS_ERR(p)) break; err = m->op->show(m, p); if (err < 0) break; if (unlikely(err)) m->count = 0; if (unlikely(!m->count)) { p = m->op->next(m, p, &pos); m->index = pos; continue; } if (m->count < m->size) goto Fill; m->op->stop(m, p); kfree(m->buf); m->count = 0; m->buf = kmalloc(m->size <<= 1, GFP_KERNEL); if (!m->buf) goto Enomem; m->version = 0; pos = m->index; p = m->op->start(m, &pos); } 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 (seq_overflow(m) || err) { m->count = offs; if (likely(err <= 0)) 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; m->read_pos += 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); /** * seq_lseek - ->llseek() method for sequential files. * @file: the file in question * @offset: new position * @whence: 0 for absolute, 1 for relative position * * Ready-made ->f_op->llseek() */ loff_t seq_lseek(struct file *file, loff_t offset, int whence) { struct seq_file *m = file->private_data; loff_t retval = -EINVAL; mutex_lock(&m->lock); m->version = file->f_version; switch (whence) { case SEEK_CUR: offset += file->f_pos; case SEEK_SET: if (offset < 0) break; retval = offset; if (offset != m->read_pos) { while ((retval = traverse(m, offset)) == -EAGAIN) ; if (retval) { /* with extreme prejudice... */ file->f_pos = 0; m->read_pos = 0; m->version = 0; m->index = 0; m->count = 0; } else { m->read_pos = offset; retval = file->f_pos = offset; } } else { 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: its 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 = 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; } seq_set_overflow(m); return -1; } m->count = p - m->buf; return 0; } EXPORT_SYMBOL(seq_escape); int seq_vprintf(struct seq_file *m, const char *f, va_list args) { int len; if (m->count < m->size) { len = vsnprintf(m->buf + m->count, m->size - m->count, f, args); if (m->count + len < m->size) { m->count += len; return 0; } } seq_set_overflow(m); return -1; } EXPORT_SYMBOL(seq_vprintf); int seq_printf(struct seq_file *m, const char *f, ...) { int ret; va_list args; va_start(args, f); ret = seq_vprintf(m, f, args); va_end(args); return ret; } EXPORT_SYMBOL(seq_printf); /** * mangle_path - mangle and copy path to buffer beginning * @s: buffer start * @p: beginning of path in above buffer * @esc: set of characters that need escaping * * Copy the path from @p to @s, replacing each occurrence of character from * @esc with usual octal escape. * Returns pointer past last written character in @s, or NULL in case of * failure. */ char *mangle_path(char *s, const char *p, const char *esc) { while (s <= p) { char c = *p++; if (!c) { return s; } 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); } } return NULL; } EXPORT_SYMBOL(mangle_path); /** * seq_path - seq_file interface to print a pathname * @m: the seq_file handle * @path: the struct path to print * @esc: set of characters to escape in the output * * return the absolute path of 'path', as represented by the * dentry / mnt pair in the path parameter. */ int seq_path(struct seq_file *m, const struct path *path, const char *esc) { char *buf; size_t size = seq_get_buf(m, &buf); int res = -1; 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_commit(m, res); return res; } EXPORT_SYMBOL(seq_path); /* * Same as seq_path, but relative to supplied root. */ int seq_path_root(struct seq_file *m, const struct path *path, const struct path *root, const char *esc) { char *buf; size_t size = seq_get_buf(m, &buf); int res = -ENAMETOOLONG; if (size) { char *p; p = __d_path(path, root, buf, size); if (!p) return SEQ_SKIP;