diff options
Diffstat (limited to 'fs/seq_file.c')
| -rw-r--r-- | fs/seq_file.c | 113 |
1 files changed, 92 insertions, 21 deletions
diff --git a/fs/seq_file.c b/fs/seq_file.c index 853770274f2..3f54dbd6c49 100644 --- a/fs/seq_file.c +++ b/fs/seq_file.c @@ -25,6 +25,7 @@ * 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) { @@ -114,8 +115,10 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos) if (!p || IS_ERR(p)) break; err = m->op->show(m, p); - if (err) + if (err < 0) break; + if (unlikely(err)) + m->count = 0; if (m->count < m->size) goto Fill; m->op->stop(m, p); @@ -140,9 +143,10 @@ Fill: break; } err = m->op->show(m, p); - if (err || m->count == m->size) { + if (m->count == m->size || err) { m->count = offs; - break; + if (likely(err <= 0)) + break; } pos = next; } @@ -199,8 +203,12 @@ static int traverse(struct seq_file *m, loff_t offset) if (IS_ERR(p)) break; error = m->op->show(m, p); - if (error) + if (error < 0) break; + if (unlikely(error)) { + error = 0; + m->count = 0; + } if (m->count == m->size) goto Eoverflow; if (pos + m->count > offset) { @@ -239,7 +247,7 @@ Eoverflow: 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; + loff_t retval = -EINVAL; mutex_lock(&m->lock); m->version = file->f_version; @@ -342,28 +350,40 @@ int seq_printf(struct seq_file *m, const char *f, ...) } EXPORT_SYMBOL(seq_printf); +static char *mangle_path(char *s, char *p, 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; +} + +/* + * return the absolute path of 'dentry' residing in mount 'mnt'. + */ 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); - } + s = mangle_path(s, p, esc); + if (s) { + p = m->buf + m->count; + m->count = s - m->buf; + return s - p; } } } @@ -372,6 +392,57 @@ int seq_path(struct seq_file *m, struct path *path, char *esc) } 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 err = -ENAMETOOLONG; + if (m->count < m->size) { + char *s = m->buf + m->count; + char *p; + + spin_lock(&dcache_lock); + p = __d_path(path, root, s, m->size - m->count); + spin_unlock(&dcache_lock); + err = PTR_ERR(p); + if (!IS_ERR(p)) { + s = mangle_path(s, p, esc); + if (s) { + p = m->buf + m->count; + m->count = s - m->buf; + return 0; + } + } + } + m->count = m->size; + return err; +} + +/* + * returns the path of the 'dentry' from the root of its filesystem. + */ +int seq_dentry(struct seq_file *m, struct dentry *dentry, char *esc) +{ + if (m->count < m->size) { + char *s = m->buf + m->count; + char *p = dentry_path(dentry, s, m->size - m->count); + if (!IS_ERR(p)) { + s = mangle_path(s, p, esc); + if (s) { + p = m->buf + m->count; + m->count = s - m->buf; + return s - p; + } + } + } + m->count = m->size; + return -1; +} + static void *single_start(struct seq_file *p, loff_t *pos) { return NULL + (*pos == 0); |