From 034dd340b08be1f2f0477ad16131d609f9dbd53c Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 30 Aug 2026 09:22:00 -0700 Subject: Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Fix error output of boot instance creation failure Currently if a boot instance creation fails, instead of printing out the name of the instance that failed, it prints "(null)". That is because it prints "cur_str" that had already been processed by strsep(). Print the saved name instead. While at it, print the error code of the failure. - Fix use-after-free for same named historgrams Histograms can be named so that they can be used in multiple events. But if the named histogram has a variable attached, the second event that uses the named histogram which duplicates it and needs to free the original after duplication leaves the old variable in place and still visible. If another histogram uses than variable, it will use the stale one which will try to reference the freed duplicate histogram and crash the kernel. Free the duplicate variables along with the duplicated histogram data. - Check return value of kthread_run() in event self test The events self tests uses a kthread for testing but does not check if it succeeded in creating a kthread. If the kthread creation were to fail, the code will still try to call kthread_stop() on the error returned. - Fix race between reading trace_pipe and updating subbuffer size If a user is reading the trace_pipe file at the same time they update the ring buffer sub-buffer size, can cause the trace_pipe read to read stale data. Add trace_access_lock() around updating the ring buffer sub-buffer size. - Fix eventfs_inode on failure path in creation of the events directory In the creation of the "events" directory, if after allocating the eventfs_inode a failure is detected, it calls cleanup_ei() which calls free_ei(). The free_ei() will test if eventfs_inode being freed has no children. It is a bug if it does. But on the failure case of the creation of the "events" directory, the children lists have not yet been initialized and the free will trigger a warning because list_empty() on an uninitialized list returns false. Move the initialization into init_ei() where it makes more sense and makes sure that a created eventfs_inode has its lists initialized upon creation. - Check return value of kthread_run() in ftrace direct sample code The sample code that shows how to use the ftrace direct calls does not test the return of kthread_run() to see if it succeeds. Return a failure if the kthread_run() doesn't succeed. - Clear user events state on fork in case of alloc failure On fork, the child gets a pointer to the parent's user events state. It makes a copy of it then updates the child's pointer to it. But if the allocation fails, the duplication function leaves the child with a pointer to its parent's descriptor. When the child cleans up its data, it will free the parent's descriptor while the parent is still using it. In the duplication function, set the child's user_event_mm to NULL before testing if the allocation succeeded, and when it exits it will not free the parent's descriptor. - Fix retry exhaustion in simple ring buffer reader swap simple_ring_buffer_swap_reader_page() starts with retry set to 8 and post-decrements it only after a failed link replacement. On the final attempt, a successful replacement leaves retry at zero, while a failed replacement leaves it at -1. But the check for success expects the retry value to be non-zero and exits with an error on zero. This is the opposite result. Fix it. - Fail nicely when the remote swap_reader_page() returns an error Currently, if the swap_reader_page() of a remote buffer fails, it triggers a WARN_ON_ONCE() and continues normally. Instead, have it exit with an error and a pr_warn() print instead of a full WARNING. * tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: ring-buffer: Stop remote reader update when page swap fails tracing: Fix retry exhaustion in simple ring buffer reader swap tracing/user_events: Clear copied tracing state before fork duplication samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify eventfs: Initialize ei->children and ei->list in init_ei() tracing: Fix use-after-free in trace_pipe read on sub-buffer order change tracing: Fix crash passing ERR_PTR to kthread_stop() tracing: Fix use-after-free with same-name named triggers tracing: Fix logged instance name on creation failure --- fs/seq_file.c | 1143 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 1143 insertions(+) create mode 100644 fs/seq_file.c (limited to 'fs/seq_file.c') diff --git a/fs/seq_file.c b/fs/seq_file.c new file mode 100644 index 000000000..456c78719 --- /dev/null +++ b/fs/seq_file.c @@ -0,0 +1,1143 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * linux/fs/seq_file.c + * + * helper functions for making synthetic files from sequences of records. + * initial implementation -- AV, Oct 2001. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +static struct kmem_cache *seq_file_cache __ro_after_init; + +static void seq_set_overflow(struct seq_file *m) +{ + m->count = m->size; +} + +static void *seq_buf_alloc(unsigned long size) +{ + if (unlikely(size > MAX_RW_COUNT)) + return NULL; + + return kvmalloc(size, GFP_KERNEL_ACCOUNT); +} + +/** + * 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". + * Note: seq_open() will allocate a struct seq_file and store its + * pointer in @file->private_data. This pointer should not be modified. + */ +int seq_open(struct file *file, const struct seq_operations *op) +{ + struct seq_file *p; + + WARN_ON(file->private_data); + + p = kmem_cache_zalloc(seq_file_cache, GFP_KERNEL); + if (!p) + return -ENOMEM; + + file->private_data = p; + + mutex_init(&p->lock); + p->op = op; + + // No refcounting: the lifetime of 'p' is constrained + // to the lifetime of the file. + p->file = file; + + /* + * 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; + int error = 0; + void *p; + + m->index = 0; + m->count = m->from = 0; + if (!offset) + return 0; + + if (!m->buf) { + m->buf = seq_buf_alloc(m->size = PAGE_SIZE); + 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 < 0) + break; + if (unlikely(error)) { + error = 0; + m->count = 0; + } + if (seq_has_overflowed(m)) + goto Eoverflow; + p = m->op->next(m, p, &m->index); + if (pos + m->count > offset) { + m->from = offset - pos; + m->count -= m->from; + break; + } + pos += m->count; + m->count = 0; + if (pos == offset) + break; + } + m->op->stop(m, p); + return error; + +Eoverflow: + m->op->stop(m, p); + kvfree(m->buf); + m->count = 0; + m->buf = seq_buf_alloc(m->size <<= 1); + 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 iovec iov = { .iov_base = buf, .iov_len = size}; + struct kiocb kiocb; + struct iov_iter iter; + ssize_t ret; + + init_sync_kiocb(&kiocb, file); + iov_iter_init(&iter, ITER_DEST, &iov, 1, size); + + kiocb.ki_pos = *ppos; + ret = seq_read_iter(&kiocb, &iter); + *ppos = kiocb.ki_pos; + return ret; +} +EXPORT_SYMBOL(seq_read); + +/* + * Ready-made ->f_op->read_iter() + */ +ssize_t seq_read_iter(struct kiocb *iocb, struct iov_iter *iter) +{ + struct seq_file *m = iocb->ki_filp->private_data; + size_t copied = 0; + size_t n; + void *p; + int err = 0; + + if (!iov_iter_count(iter)) + return 0; + + mutex_lock(&m->lock); + + /* + * if request is to read from zero offset, reset iterator to first + * record as it might have been already advanced by previous requests + */ + if (iocb->ki_pos == 0) { + m->index = 0; + m->count = 0; + } + + /* Don't assume ki_pos is where we left it */ + if (unlikely(iocb->ki_pos != m->read_pos)) { + while ((err = traverse(m, iocb->ki_pos)) == -EAGAIN) + ; + if (err) { + /* With prejudice... */ + m->read_pos = 0; + m->index = 0; + m->count = 0; + goto Done; + } else { + m->read_pos = iocb->ki_pos; + } + } + + /* grab buffer if we didn't have one */ + if (!m->buf) { + m->buf = seq_buf_alloc(m->size = PAGE_SIZE); + if (!m->buf) + goto Enomem; + } + // something left in the buffer - copy it out first + if (m->count) { + n = copy_to_iter(m->buf + m->from, m->count, iter); + m->count -= n; + m->from += n; + copied += n; + if (m->count) // hadn't managed to copy everything + goto Done; + } + // get a non-empty record in the buffer + m->from = 0; + p = m->op->start(m, &m->index); + while (1) { + err = PTR_ERR(p); + if (!p || IS_ERR(p)) // EOF or an error + break; + err = m->op->show(m, p); + if (err < 0) // hard error + break; + if (unlikely(err)) // ->show() says "skip it" + m->count = 0; + if (unlikely(!m->count)) { // empty record + p = m->op->next(m, p, &m->index); + continue; + } + if (!seq_has_overflowed(m)) // got it + goto Fill; + // need a bigger buffer + m->op->stop(m, p); + kvfree(m->buf); + m->count = 0; + m->buf = seq_buf_alloc(m->size <<= 1); + if (!m->buf) + goto Enomem; + p = m->op->start(m, &m->index); + } + // EOF or an error + m->op->stop(m, p); + m->count = 0; + goto Done; +Fill: + // one non-empty record is in the buffer; if they want more, + // try to fit more in, but in any case we need to advance + // the iterator once for every record shown. + while (1) { + size_t offs = m->count; + loff_t pos = m->index; + + p = m->op->next(m, p, &m->index); + if (pos == m->index) { + pr_info_ratelimited("buggy .next function %ps did not update position index\n", + m->op->next); + m->index++; + } + if (!p || IS_ERR(p)) // no next record for us + break; + if (m->count >= iov_iter_count(iter)) + break; + err = m->op->show(m, p); + if (err > 0) { // ->show() says "skip it" + m->count = offs; + } else if (err || seq_has_overflowed(m)) { + m->count = offs; + break; + } + } + m->op->stop(m, p); + n = copy_to_iter(m->buf, m->count, iter); + copied += n; + m->count -= n; + m->from = n; +Done: + if (unlikely(!copied)) { + copied = m->count ? -EFAULT : err; + } else { + iocb->ki_pos += copied; + m->read_pos += copied; + } + mutex_unlock(&m->lock); + return copied; +Enomem: + err = -ENOMEM; + goto Done; +} +EXPORT_SYMBOL(seq_read_iter); + +/** + * 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); + switch (whence) { + case SEEK_CUR: + offset += file->f_pos; + fallthrough; + 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->index = 0; + m->count = 0; + } else { + m->read_pos = offset; + retval = file->f_pos = offset; + } + } else { + file->f_pos = offset; + } + } + mutex_unlock(&m->lock); + return retval; +} +EXPORT_SYMBOL(seq_lseek); + +/** + * seq_release - free the structures associated with sequential file. + * @inode: its inode + * @file: file in question + * + * 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; + kvfree(m->buf); + kmem_cache_free(seq_file_cache, m); + return 0; +} +EXPORT_SYMBOL(seq_release); + +/** + * seq_escape_mem - print data into buffer, escaping some characters + * @m: target buffer + * @src: source buffer + * @len: size of source buffer + * @flags: flags to pass to string_escape_mem() + * @esc: set of characters that need escaping + * + * Puts data into buffer, replacing each occurrence of character from + * given class (defined by @flags and @esc) with printable escaped sequence. + * + * Use seq_has_overflowed() to check for errors. + */ +void seq_escape_mem(struct seq_file *m, const char *src, size_t len, + unsigned int flags, const char *esc) +{ + char *buf; + size_t size = seq_get_buf(m, &buf); + int ret; + + ret = string_escape_mem(src, len, buf, size, flags, esc); + seq_commit(m, ret < size ? ret : -1); +} +EXPORT_SYMBOL(seq_escape_mem); + +void 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; + } + } + seq_set_overflow(m); +} +EXPORT_SYMBOL(seq_vprintf); + +void seq_printf(struct seq_file *m, const char *f, ...) +{ + va_list args; + + va_start(args, f); + seq_vprintf(m, f, args); + va_end(args); +} +EXPORT_SYMBOL(seq_printf); + +#ifdef CONFIG_BINARY_PRINTF +void seq_bprintf(struct seq_file *m, const char *f, const u32 *binary) +{ + int len; + + if (m->count < m->size) { + len = bstr_printf(m->buf + m->count, m->size - m->count, f, + binary); + if (m->count + len < m->size) { + m->count += len; + return; + } + } + seq_set_overflow(m); +} +EXPORT_SYMBOL(seq_bprintf); +#endif /* CONFIG_BINARY_PRINTF */ + +/** + * seq_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 *seq_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; +} + +/** + * 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 = seq_mangle_path(buf, p, esc); + if (end) + res = end - buf; + } + } + seq_commit(m, res); + + return res; +} +EXPORT_SYMBOL(seq_path); + +/** + * seq_file_path - seq_file interface to print a pathname of a file + * @m: the seq_file handle + * @file: the struct file to print + * @esc: set of characters to escape in the output + * + * return the absolute path to the file. + */ +int seq_file_path(struct seq_file *m, struct file *file, const char *esc) +{ + return seq_path(m, &file->f_path, esc); +} +EXPORT_SYMBOL(seq_file_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; + res = PTR_ERR(p); + if (!IS_ERR(p)) { + char *end = seq_mangle_path(buf, p, esc); + if (end) + res = end - buf; + else + res = -ENAMETOOLONG; + } + } + seq_commit(m, res); + + 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, const char *esc) +{ + char *buf; + size_t size = seq_get_buf(m, &buf); + int res = -1; + + if (size) { + char *p = dentry_path(dentry, buf, size); + if (!IS_ERR(p)) { + char *end = seq_mangle_path(buf, p, esc); + if (end) + res = end - buf; + } + } + seq_commit(m, res); + + return res; +} +EXPORT_SYMBOL(seq_dentry); + +void *single_start(struct seq_file *p, loff_t *pos) +{ + return *pos ? NULL : SEQ_START_TOKEN; +} + +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_obj(*op, GFP_KERNEL_ACCOUNT); + 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_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; + 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_ACCOUNT); + 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); + +void seq_putc(struct seq_file *m, char c) +{ + if (m->count >= m->size) + return; + + m->buf[m->count++] = c; +} +EXPORT_SYMBOL(seq_putc); + +void __seq_puts(struct seq_file *m, const char *s) +{ + seq_write(m, s, strlen(s)); +} +EXPORT_SYMBOL(__seq_puts); + +/** + * seq_put_decimal_ull_width - A helper routine for putting decimal numbers + * without rich format of printf(). + * only 'unsigned long long' is supported. + * @m: seq_file identifying the buffer to which data should be written + * @delimiter: a string which is printed before the number + * @num: the number + * @width: a minimum field width + * + * This routine will put strlen(delimiter) + number into seq_filed. + * 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. + */ +void seq_put_decimal_ull_width(struct seq_file *m, const char *delimiter, + unsigned long long num, unsigned int width) +{ + int len; + + if (m->count + 2 >= m->size) /* we'll write 2 bytes at least */ + goto overflow; + + if (delimiter && delimiter[0]) { + if (delimiter[1] == 0) + seq_putc(m, delimiter[0]); + else + seq_puts(m, delimiter); + } + + if (!width) + width = 1; + + if (m->count + width >= m->size) + goto overflow; + + len = num_to_str(m->buf + m->count, m->size - m->count, num, width); + if (!len) + goto overflow; + + m->count += len; + return; + +overflow: + seq_set_overflow(m); +} + +void seq_put_decimal_ull(struct seq_file *m, const char *delimiter, + unsigned long long num) +{ + return seq_put_decimal_ull_width(m, delimiter, num, 0); +} +EXPORT_SYMBOL(seq_put_decimal_ull); + +/** + * seq_put_hex_ll - put a number in hexadecimal notation + * @m: seq_file identifying the buffer to which data should be written + * @delimiter: a string which is printed before the number + * @v: the number + * @width: a minimum field width + * + * seq_put_hex_ll(m, "", v, 8) is equal to seq_printf(m, "%08llx", v) + * + * 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. + */ +void seq_put_hex_ll(struct seq_file *m, const char *delimiter, + unsigned long long v, unsigned int width) +{ + unsigned int len; + int i; + + if (delimiter && delimiter[0]) { + if (delimiter[1] == 0) + seq_putc(m, delimiter[0]); + else + seq_puts(m, delimiter); + } + + /* If x is 0, the result of __builtin_clzll is undefined */ + if (v == 0) + len = 1; + else + len = (sizeof(v) * 8 - __builtin_clzll(v) + 3) / 4; + + if (len < width) + len = width; + + if (m->count + len > m->size) { + seq_set_overflow(m); + return; + } + + for (i = len - 1; i >= 0; i--) { + m->buf[m->count + i] = hex_asc[0xf & v]; + v = v >> 4; + } + m->count += len; +} + +void seq_put_decimal_ll(struct seq_file *m, const char *delimiter, long long num) +{ + int len; + + if (m->count + 3 >= m->size) /* we'll write 2 bytes at least */ + goto overflow; + + if (delimiter && delimiter[0]) { + if (delimiter[1] == 0) + seq_putc(m, delimiter[0]); + else + seq_puts(m, delimiter); + } + + if (m->count + 2 >= m->size) + goto overflow; + + if (num < 0) { + m->buf[m->count++] = '-'; + num = -num; + } + + if (num < 10) { + m->buf[m->count++] = num + '0'; + return; + } + + len = num_to_str(m->buf + m->count, m->size - m->count, num, 0); + if (!len) + goto overflow; + + m->count += len; + return; + +overflow: + seq_set_overflow(m); +} +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 + * @data: data address + * @len: number of bytes + * + * Return 0 on success, non-zero otherwise. + */ +int seq_write(struct seq_file *seq, const void *data, size_t len) +{ + if (seq->count + len < seq->size) { + memcpy(seq->buf + seq->count, data, len); + seq->count += len; + return 0; + } + 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) { + if (size + m->count > m->size) { + seq_set_overflow(m); + return; + } + memset(m->buf + m->count, ' ', size); + m->count += size; + } + if (c) + seq_putc(m, c); +} +EXPORT_SYMBOL(seq_pad); + +/* A complete analogue of print_hex_dump() */ +void seq_hex_dump(struct seq_file *m, const char *prefix_str, int prefix_type, + int rowsize, int groupsize, const void *buf, size_t len, + bool ascii) +{ + const u8 *ptr = buf; + int i, linelen, remaining = len; + char *buffer; + size_t size; + int ret; + + if (rowsize != 16 && rowsize != 32) + rowsize = 16; + + for (i = 0; i < len && !seq_has_overflowed(m); i += rowsize) { + linelen = min(remaining, rowsize); + remaining -= rowsize; + + switch (prefix_type) { + case DUMP_PREFIX_ADDRESS: + seq_printf(m, "%s%p: ", prefix_str, ptr + i); + break; + case DUMP_PREFIX_OFFSET: + seq_printf(m, "%s%.8x: ", prefix_str, i); + break; + default: + seq_printf(m, "%s", prefix_str); + break; + } + + size = seq_get_buf(m, &buffer); + ret = hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize, + buffer, size, ascii); + seq_commit(m, ret < size ? ret : -1); + + seq_putc(m, '\n'); + } +} +EXPORT_SYMBOL(seq_hex_dump); + +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); + +struct list_head *seq_list_start_rcu(struct list_head *head, loff_t pos) +{ + struct list_head *lh; + + list_for_each_rcu(lh, head) + if (pos-- == 0) + return lh; + + return NULL; +} +EXPORT_SYMBOL(seq_list_start_rcu); + +struct list_head *seq_list_start_head_rcu(struct list_head *head, loff_t pos) +{ + if (!pos) + return head; + + return seq_list_start_rcu(head, pos - 1); +} +EXPORT_SYMBOL(seq_list_start_head_rcu); + +struct list_head *seq_list_next_rcu(void *v, struct list_head *head, + loff_t *ppos) +{ + struct list_head *lh; + + lh = list_next_rcu((struct list_head *)v); + ++*ppos; + return lh == head ? NULL : lh; +} +EXPORT_SYMBOL(seq_list_next_rcu); + +/** + * seq_hlist_start - start an iteration of a hlist + * @head: the head of the hlist + * @pos: the start position of the sequence + * + * Called at seq_file->op->start(). + */ +struct hlist_node *seq_hlist_start(struct hlist_head *head, loff_t pos) +{ + struct hlist_node *node; + + hlist_for_each(node, head) + if (pos-- == 0) + return node; + return NULL; +} +EXPORT_SYMBOL(seq_hlist_start); + +/** + * seq_hlist_start_head - start an iteration of a hlist + * @head: the head of the hlist + * @pos: the start position of the sequence + * + * Called at seq_file->op->start(). Call this function if you want to + * print a header at the top of the output. + */ +struct hlist_node *seq_hlist_start_head(struct hlist_head *head, loff_t pos) +{ + if (!pos) + return SEQ_START_TOKEN; + + return seq_hlist_start(head, pos - 1); +} +EXPORT_SYMBOL(seq_hlist_start_head); + +/** + * seq_hlist_next - move to the next position of the hlist + * @v: the current iterator + * @head: the head of the hlist + * @ppos: the current position + * + * Called at seq_file->op->next(). + */ +struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head, + loff_t *ppos) +{ + struct hlist_node *node = v; + + ++*ppos; + if (v == SEQ_START_TOKEN) + return head->first; + else + return node->next; +} +EXPORT_SYMBOL(seq_hlist_next); + +/** + * seq_hlist_start_rcu - start an iteration of a hlist protected by RCU + * @head: the head of the hlist + * @pos: the start position of the sequence + * + * Called at seq_file->op->start(). + * + * This list-traversal primitive may safely run concurrently with + * the _rcu list-mutation primitives such as hlist_add_head_rcu() + * as long as the traversal is guarded by rcu_read_lock(). + */ +struct hlist_node *seq_hlist_start_rcu(struct hlist_head *head, + loff_t pos) +{ + struct hlist_node *node; + + __hlist_for_each_rcu(node, head) + if (pos-- == 0) + return node; + return NULL; +} +EXPORT_SYMBOL(seq_hlist_start_rcu); + +/** + * seq_hlist_start_head_rcu - start an iteration of a hlist protected by RCU + * @head: the head of the hlist + * @pos: the start position of the sequence + * + * Called at seq_file->op->start(). Call this function if you want to + * print a header at the top of the output. + * + * This list-traversal primitive may safely run concurrently with + * the _rcu list-mutation primitives such as hlist_add_head_rcu() + * as long as the traversal is guarded by rcu_read_lock(). + */ +struct hlist_node *seq_hlist_start_head_rcu(struct hlist_head *head, + loff_t pos) +{ + if (!pos) + return SEQ_START_TOKEN; + + return seq_hlist_start_rcu(head, pos - 1); +} +EXPORT_SYMBOL(seq_hlist_start_head_rcu); + +/** + * seq_hlist_next_rcu - move to the next position of the hlist protected by RCU + * @v: the current iterator + * @head: the head of the hlist + * @ppos: the current position + * + * Called at seq_file->op->next(). + * + * This list-traversal primitive may safely run concurrently with + * the _rcu list-mutation primitives such as hlist_add_head_rcu() + * as long as the traversal is guarded by rcu_read_lock(). + */ +struct hlist_node *seq_hlist_next_rcu(void *v, + struct hlist_head *head, + loff_t *ppos) +{ + struct hlist_node *node = v; + + ++*ppos; + if (v == SEQ_START_TOKEN) + return rcu_dereference(head->first); + else + return rcu_dereference(node->next); +} +EXPORT_SYMBOL(seq_hlist_next_rcu); + +/** + * seq_hlist_start_percpu - 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); + +void __init seq_file_init(void) +{ + seq_file_cache = KMEM_CACHE(seq_file, SLAB_ACCOUNT|SLAB_PANIC); +} -- cgit v1.3.1