From 9fe2a7015393dc0203ac39242ae9c89038994f3c Mon Sep 17 00:00:00 2001 From: Srivatsa Vaddagiri Date: Fri, 23 Mar 2012 13:36:28 +0530 Subject: debugfs: Add support to print u32 array in debugfs Move the code from Xen to debugfs to make the code common for other users as well. Accked-by: Greg Kroah-Hartman Signed-off-by: Srivatsa Vaddagiri Signed-off-by: Suzuki Poulose [v1: Fixed rebase issues] [v2: Fixed PPC compile issues] Signed-off-by: Raghavendra K T Signed-off-by: Konrad Rzeszutek Wilk --- fs/debugfs/file.c | 128 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 128 insertions(+) (limited to 'fs/debugfs') diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c index 5dfafdd1dbd..2340f6978d6 100644 --- a/fs/debugfs/file.c +++ b/fs/debugfs/file.c @@ -20,6 +20,7 @@ #include #include #include +#include static ssize_t default_read_file(struct file *file, char __user *buf, size_t count, loff_t *ppos) @@ -520,6 +521,133 @@ struct dentry *debugfs_create_blob(const char *name, umode_t mode, } EXPORT_SYMBOL_GPL(debugfs_create_blob); +struct array_data { + void *array; + u32 elements; +}; + +static int u32_array_open(struct inode *inode, struct file *file) +{ + file->private_data = NULL; + return nonseekable_open(inode, file); +} + +static size_t format_array(char *buf, size_t bufsize, const char *fmt, + u32 *array, u32 array_size) +{ + size_t ret = 0; + u32 i; + + for (i = 0; i < array_size; i++) { + size_t len; + + len = snprintf(buf, bufsize, fmt, array[i]); + len++; /* ' ' or '\n' */ + ret += len; + + if (buf) { + buf += len; + bufsize -= len; + buf[-1] = (i == array_size-1) ? '\n' : ' '; + } + } + + ret++; /* \0 */ + if (buf) + *buf = '\0'; + + return ret; +} + +static char *format_array_alloc(const char *fmt, u32 *array, + u32 array_size) +{ + size_t len = format_array(NULL, 0, fmt, array, array_size); + char *ret; + + ret = kmalloc(len, GFP_KERNEL); + if (ret == NULL) + return NULL; + + format_array(ret, len, fmt, array, array_size); + return ret; +} + +static ssize_t u32_array_read(struct file *file, char __user *buf, size_t len, + loff_t *ppos) +{ + struct inode *inode = file->f_path.dentry->d_inode; + struct array_data *data = inode->i_private; + size_t size; + + if (*ppos == 0) { + if (file->private_data) { + kfree(file->private_data); + file->private_data = NULL; + } + + file->private_data = format_array_alloc("%u", data->array, + data->elements); + } + + size = 0; + if (file->private_data) + size = strlen(file->private_data); + + return simple_read_from_buffer(buf, len, ppos, + file->private_data, size); +} + +static int u32_array_release(struct inode *inode, struct file *file) +{ + kfree(file->private_data); + + return 0; +} + +static const struct file_operations u32_array_fops = { + .owner = THIS_MODULE, + .open = u32_array_open, + .release = u32_array_release, + .read = u32_array_read, + .llseek = no_llseek, +}; + +/** + * debugfs_create_u32_array - create a debugfs file that is used to read u32 + * array. + * @name: a pointer to a string containing the name of the file to create. + * @mode: the permission that the file should have. + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this parameter is %NULL, then the + * file will be created in the root of the debugfs filesystem. + * @array: u32 array that provides data. + * @elements: total number of elements in the array. + * + * This function creates a file in debugfs with the given name that exports + * @array as data. If the @mode variable is so set it can be read from. + * Writing is not supported. Seek within the file is also not supported. + * Once array is created its size can not be changed. + * + * The function returns a pointer to dentry on success. If debugfs is not + * enabled in the kernel, the value -%ENODEV will be returned. + */ +struct dentry *debugfs_create_u32_array(const char *name, umode_t mode, + struct dentry *parent, + u32 *array, u32 elements) +{ + struct array_data *data = kmalloc(sizeof(*data), GFP_KERNEL); + + if (data == NULL) + return NULL; + + data->array = array; + data->elements = elements; + + return debugfs_create_file(name, mode, parent, data, &u32_array_fops); +} +EXPORT_SYMBOL_GPL(debugfs_create_u32_array); + #ifdef CONFIG_HAS_IOMEM /* -- cgit v1.2.3