diff options
Diffstat (limited to 'fs/seq_file.c')
| -rw-r--r-- | fs/seq_file.c | 318 |
1 files changed, 252 insertions, 66 deletions
diff --git a/fs/seq_file.c b/fs/seq_file.c index 05d6b0e78c9..3857b720cb1 100644 --- a/fs/seq_file.c +++ b/fs/seq_file.c @@ -6,13 +6,42 @@ */ #include <linux/fs.h> -#include <linux/module.h> +#include <linux/export.h> #include <linux/seq_file.h> +#include <linux/vmalloc.h> #include <linux/slab.h> +#include <linux/cred.h> +#include <linux/mm.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; +} + +static void *seq_buf_alloc(unsigned long size) +{ + void *buf; + + buf = kmalloc(size, GFP_KERNEL | __GFP_NOWARN); + if (!buf && size > PAGE_SIZE) + buf = vmalloc(size); + return buf; +} + /** * seq_open - initialize sequential file * @file: file we initialize @@ -40,6 +69,9 @@ int seq_open(struct file *file, const struct seq_operations *op) 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 @@ -76,7 +108,7 @@ static int traverse(struct seq_file *m, loff_t offset) return 0; } if (!m->buf) { - m->buf = kmalloc(m->size = PAGE_SIZE, GFP_KERNEL); + m->buf = seq_buf_alloc(m->size = PAGE_SIZE); if (!m->buf) return -ENOMEM; } @@ -92,7 +124,7 @@ static int traverse(struct seq_file *m, loff_t offset) error = 0; m->count = 0; } - if (m->count == m->size) + if (seq_overflow(m)) goto Eoverflow; if (pos + m->count > offset) { m->from = offset - pos; @@ -115,8 +147,9 @@ static int traverse(struct seq_file *m, loff_t offset) Eoverflow: m->op->stop(m, p); - kfree(m->buf); - m->buf = kmalloc(m->size <<= 1, GFP_KERNEL); + kvfree(m->buf); + m->count = 0; + m->buf = seq_buf_alloc(m->size <<= 1); return !m->buf ? -ENOMEM : -EAGAIN; } @@ -140,9 +173,21 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos) 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)) { - m->read_pos = *ppos; while ((err = traverse(m, *ppos)) == -EAGAIN) ; if (err) { @@ -152,24 +197,14 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos) m->index = 0; m->count = 0; goto Done; + } else { + m->read_pos = *ppos; } } - /* - * 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); + m->buf = seq_buf_alloc(m->size = PAGE_SIZE); if (!m->buf) goto Enomem; } @@ -209,11 +244,11 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos) if (m->count < m->size) goto Fill; m->op->stop(m, p); - kfree(m->buf); - m->buf = kmalloc(m->size <<= 1, GFP_KERNEL); + kvfree(m->buf); + m->count = 0; + m->buf = seq_buf_alloc(m->size <<= 1); if (!m->buf) goto Enomem; - m->count = 0; m->version = 0; pos = m->index; p = m->op->start(m, &pos); @@ -232,7 +267,7 @@ Fill: break; } err = m->op->show(m, p); - if (m->count == m->size || err) { + if (seq_overflow(m) || err) { m->count = offs; if (likely(err <= 0)) break; @@ -274,39 +309,41 @@ EXPORT_SYMBOL(seq_read); * seq_lseek - ->llseek() method for sequential files. * @file: the file in question * @offset: new position - * @origin: 0 for absolute, 1 for relative 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 origin) +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 (origin) { - case 1: - offset += file->f_pos; - case 0: - 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; - } + 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); @@ -317,7 +354,7 @@ EXPORT_SYMBOL(seq_lseek); /** * seq_release - free the structures associated with sequential file. * @file: file in question - * @inode: file->f_path.dentry->d_inode + * @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. @@ -325,7 +362,7 @@ EXPORT_SYMBOL(seq_lseek); int seq_release(struct inode *inode, struct file *file) { struct seq_file *m = file->private_data; - kfree(m->buf); + kvfree(m->buf); kfree(m); return 0; } @@ -359,7 +396,7 @@ int seq_escape(struct seq_file *m, const char *s, const char *esc) *p++ = '0' + (c & 07); continue; } - m->count = m->size; + seq_set_overflow(m); return -1; } m->count = p - m->buf; @@ -367,23 +404,33 @@ int seq_escape(struct seq_file *m, const char *s, const char *esc) } EXPORT_SYMBOL(seq_escape); -int seq_printf(struct seq_file *m, const char *f, ...) +int seq_vprintf(struct seq_file *m, const char *f, va_list args) { - 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; + 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); /** @@ -397,7 +444,7 @@ EXPORT_SYMBOL(seq_printf); * Returns pointer past last written character in @s, or NULL in case of * failure. */ -char *mangle_path(char *s, char *p, char *esc) +char *mangle_path(char *s, const char *p, const char *esc) { while (s <= p) { char c = *p++; @@ -427,7 +474,7 @@ EXPORT_SYMBOL(mangle_path); * return the absolute path of 'path', as represented by the * dentry / mnt pair in the path parameter. */ -int seq_path(struct seq_file *m, struct path *path, char *esc) +int seq_path(struct seq_file *m, const struct path *path, const char *esc) { char *buf; size_t size = seq_get_buf(m, &buf); @@ -449,11 +496,9 @@ EXPORT_SYMBOL(seq_path); /* * Same as seq_path, but relative to supplied root. - * - * root may be changed, see __d_path(). */ -int seq_path_root(struct seq_file *m, struct path *path, struct path *root, - char *esc) +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); @@ -463,6 +508,8 @@ int seq_path_root(struct seq_file *m, struct path *path, struct path *root, char *p; p = __d_path(path, root, buf, size); + if (!p) + return SEQ_SKIP; res = PTR_ERR(p); if (!IS_ERR(p)) { char *end = mangle_path(buf, p, esc); @@ -474,13 +521,13 @@ int seq_path_root(struct seq_file *m, struct path *path, struct path *root, } seq_commit(m, res); - return res < 0 ? res : 0; + return res < 0 && res != -ENAMETOOLONG ? res : 0; } /* * returns the path of the 'dentry' from the root of its filesystem. */ -int seq_dentry(struct seq_file *m, struct dentry *dentry, char *esc) +int seq_dentry(struct seq_file *m, struct dentry *dentry, const char *esc) { char *buf; size_t size = seq_get_buf(m, &buf); @@ -510,7 +557,7 @@ int seq_bitmap(struct seq_file *m, const unsigned long *bits, return 0; } } - m->count = m->size; + seq_set_overflow(m); return -1; } EXPORT_SYMBOL(seq_bitmap); @@ -526,7 +573,7 @@ int seq_bitmap_list(struct seq_file *m, const unsigned long *bits, return 0; } } - m->count = m->size; + seq_set_overflow(m); return -1; } EXPORT_SYMBOL(seq_bitmap_list); @@ -567,6 +614,24 @@ int single_open(struct file *file, int (*show)(struct seq_file *, void *), } EXPORT_SYMBOL(single_open); +int single_open_size(struct file *file, int (*show)(struct seq_file *, void *), + void *data, size_t size) +{ + char *buf = seq_buf_alloc(size); + int ret; + if (!buf) + return -ENOMEM; + ret = single_open(file, show, data); + if (ret) { + kvfree(buf); + return ret; + } + ((struct seq_file *)file->private_data)->buf = buf; + ((struct seq_file *)file->private_data)->size = size; + return 0; +} +EXPORT_SYMBOL(single_open_size); + int single_release(struct inode *inode, struct file *file) { const struct seq_operations *op = ((struct seq_file *)file->private_data)->op; @@ -637,11 +702,63 @@ int seq_puts(struct seq_file *m, const char *s) m->count += len; return 0; } - m->count = m->size; + seq_set_overflow(m); return -1; } EXPORT_SYMBOL(seq_puts); +/* + * A helper routine for putting decimal numbers without rich format of printf(). + * only 'unsigned long long' is supported. + * This routine will put one byte delimiter + number into seq_file. + * This routine is very quick when you show lots of numbers. + * In usual cases, it will be better to use seq_printf(). It's easier to read. + */ +int seq_put_decimal_ull(struct seq_file *m, char delimiter, + unsigned long long num) +{ + int len; + + if (m->count + 2 >= m->size) /* we'll write 2 bytes at least */ + goto overflow; + + if (delimiter) + m->buf[m->count++] = delimiter; + + if (num < 10) { + m->buf[m->count++] = num + '0'; + return 0; + } + + len = num_to_str(m->buf + m->count, m->size - m->count, num); + if (!len) + goto overflow; + m->count += len; + return 0; +overflow: + seq_set_overflow(m); + return -1; +} +EXPORT_SYMBOL(seq_put_decimal_ull); + +int seq_put_decimal_ll(struct seq_file *m, char delimiter, + long long num) +{ + if (num < 0) { + if (m->count + 3 >= m->size) { + seq_set_overflow(m); + return -1; + } + if (delimiter) + m->buf[m->count++] = delimiter; + num = -num; + delimiter = '-'; + } + return seq_put_decimal_ull(m, delimiter, num); + +} +EXPORT_SYMBOL(seq_put_decimal_ll); + /** * seq_write - write arbitrary data to buffer * @seq: seq_file identifying the buffer to which data should be written @@ -657,11 +774,26 @@ int seq_write(struct seq_file *seq, const void *data, size_t len) seq->count += len; return 0; } - seq->count = seq->size; + seq_set_overflow(seq); return -1; } EXPORT_SYMBOL(seq_write); +/** + * seq_pad - write padding spaces to buffer + * @m: seq_file identifying the buffer to which data should be written + * @c: the byte to append after padding if non-zero + */ +void seq_pad(struct seq_file *m, char c) +{ + int size = m->pad_until - m->count; + if (size > 0) + seq_printf(m, "%*s", size, ""); + if (c) + seq_putc(m, c); +} +EXPORT_SYMBOL(seq_pad); + struct list_head *seq_list_start(struct list_head *head, loff_t pos) { struct list_head *lh; @@ -819,3 +951,57 @@ struct hlist_node *seq_hlist_next_rcu(void *v, return rcu_dereference(node->next); } EXPORT_SYMBOL(seq_hlist_next_rcu); + +/** + * seq_hlist_start_precpu - start an iteration of a percpu hlist array + * @head: pointer to percpu array of struct hlist_heads + * @cpu: pointer to cpu "cursor" + * @pos: start position of sequence + * + * Called at seq_file->op->start(). + */ +struct hlist_node * +seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos) +{ + struct hlist_node *node; + + for_each_possible_cpu(*cpu) { + hlist_for_each(node, per_cpu_ptr(head, *cpu)) { + if (pos-- == 0) + return node; + } + } + return NULL; +} +EXPORT_SYMBOL(seq_hlist_start_percpu); + +/** + * seq_hlist_next_percpu - move to the next position of the percpu hlist array + * @v: pointer to current hlist_node + * @head: pointer to percpu array of struct hlist_heads + * @cpu: pointer to cpu "cursor" + * @pos: start position of sequence + * + * Called at seq_file->op->next(). + */ +struct hlist_node * +seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head, + int *cpu, loff_t *pos) +{ + struct hlist_node *node = v; + + ++*pos; + + if (node->next) + return node->next; + + for (*cpu = cpumask_next(*cpu, cpu_possible_mask); *cpu < nr_cpu_ids; + *cpu = cpumask_next(*cpu, cpu_possible_mask)) { + struct hlist_head *bucket = per_cpu_ptr(head, *cpu); + + if (!hlist_empty(bucket)) + return bucket->first; + } + return NULL; +} +EXPORT_SYMBOL(seq_hlist_next_percpu); |