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author | David Howells <dhowells@redhat.com> | 2018-05-18 11:46:15 +0100 |
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committer | David Howells <dhowells@redhat.com> | 2018-05-18 11:46:15 +0100 |
commit | 564def71765caf65040f926c0783b9c27cc6c087 (patch) | |
tree | bf7b7051f76e961a082819f5eb126384495d0a89 /fs/proc/proc_net.c | |
parent | 5d9de25d934b9a6e3c9efdce782b0d23d0f1fa2a (diff) | |
download | linux-564def71765caf65040f926c0783b9c27cc6c087.tar.bz2 |
proc: Add a way to make network proc files writable
Provide two extra functions, proc_create_net_data_write() and
proc_create_net_single_write() that act like their non-write versions but
also set a write method in the proc_dir_entry struct.
An internal simple write function is provided that will copy its buffer and
hand it to the pde->write() method if available (or give an error if not).
The buffer may be modified by the write method.
Signed-off-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'fs/proc/proc_net.c')
-rw-r--r-- | fs/proc/proc_net.c | 92 |
1 files changed, 92 insertions, 0 deletions
diff --git a/fs/proc/proc_net.c b/fs/proc/proc_net.c index 7d94fa005b0d..d5e0fcb3439e 100644 --- a/fs/proc/proc_net.c +++ b/fs/proc/proc_net.c @@ -46,6 +46,9 @@ static int seq_open_net(struct inode *inode, struct file *file) WARN_ON_ONCE(state_size < sizeof(*p)); + if (file->f_mode & FMODE_WRITE && !PDE(inode)->write) + return -EACCES; + net = get_proc_net(inode); if (!net) return -ENXIO; @@ -73,6 +76,7 @@ static int seq_release_net(struct inode *ino, struct file *f) static const struct file_operations proc_net_seq_fops = { .open = seq_open_net, .read = seq_read, + .write = proc_simple_write, .llseek = seq_lseek, .release = seq_release_net, }; @@ -93,6 +97,50 @@ struct proc_dir_entry *proc_create_net_data(const char *name, umode_t mode, } EXPORT_SYMBOL_GPL(proc_create_net_data); +/** + * proc_create_net_data_write - Create a writable net_ns-specific proc file + * @name: The name of the file. + * @mode: The file's access mode. + * @parent: The parent directory in which to create. + * @ops: The seq_file ops with which to read the file. + * @write: The write method which which to 'modify' the file. + * @data: Data for retrieval by PDE_DATA(). + * + * Create a network namespaced proc file in the @parent directory with the + * specified @name and @mode that allows reading of a file that displays a + * series of elements and also provides for the file accepting writes that have + * some arbitrary effect. + * + * The functions in the @ops table are used to iterate over items to be + * presented and extract the readable content using the seq_file interface. + * + * The @write function is called with the data copied into a kernel space + * scratch buffer and has a NUL appended for convenience. The buffer may be + * modified by the @write function. @write should return 0 on success. + * + * The @data value is accessible from the @show and @write functions by calling + * PDE_DATA() on the file inode. The network namespace must be accessed by + * calling seq_file_net() on the seq_file struct. + */ +struct proc_dir_entry *proc_create_net_data_write(const char *name, umode_t mode, + struct proc_dir_entry *parent, + const struct seq_operations *ops, + proc_write_t write, + unsigned int state_size, void *data) +{ + struct proc_dir_entry *p; + + p = proc_create_reg(name, mode, &parent, data); + if (!p) + return NULL; + p->proc_fops = &proc_net_seq_fops; + p->seq_ops = ops; + p->state_size = state_size; + p->write = write; + return proc_register(parent, p); +} +EXPORT_SYMBOL_GPL(proc_create_net_data_write); + static int single_open_net(struct inode *inode, struct file *file) { struct proc_dir_entry *de = PDE(inode); @@ -119,6 +167,7 @@ static int single_release_net(struct inode *ino, struct file *f) static const struct file_operations proc_net_single_fops = { .open = single_open_net, .read = seq_read, + .write = proc_simple_write, .llseek = seq_lseek, .release = single_release_net, }; @@ -138,6 +187,49 @@ struct proc_dir_entry *proc_create_net_single(const char *name, umode_t mode, } EXPORT_SYMBOL_GPL(proc_create_net_single); +/** + * proc_create_net_single_write - Create a writable net_ns-specific proc file + * @name: The name of the file. + * @mode: The file's access mode. + * @parent: The parent directory in which to create. + * @show: The seqfile show method with which to read the file. + * @write: The write method which which to 'modify' the file. + * @data: Data for retrieval by PDE_DATA(). + * + * Create a network-namespaced proc file in the @parent directory with the + * specified @name and @mode that allows reading of a file that displays a + * single element rather than a series and also provides for the file accepting + * writes that have some arbitrary effect. + * + * The @show function is called to extract the readable content via the + * seq_file interface. + * + * The @write function is called with the data copied into a kernel space + * scratch buffer and has a NUL appended for convenience. The buffer may be + * modified by the @write function. @write should return 0 on success. + * + * The @data value is accessible from the @show and @write functions by calling + * PDE_DATA() on the file inode. The network namespace must be accessed by + * calling seq_file_single_net() on the seq_file struct. + */ +struct proc_dir_entry *proc_create_net_single_write(const char *name, umode_t mode, + struct proc_dir_entry *parent, + int (*show)(struct seq_file *, void *), + proc_write_t write, + void *data) +{ + struct proc_dir_entry *p; + + p = proc_create_reg(name, mode, &parent, data); + if (!p) + return NULL; + p->proc_fops = &proc_net_single_fops; + p->single_show = show; + p->write = write; + return proc_register(parent, p); +} +EXPORT_SYMBOL_GPL(proc_create_net_single_write); + static struct net *get_proc_task_net(struct inode *dir) { struct task_struct *task; |