diff options
| -rw-r--r-- | fs/proc/proc_sysctl.c | 165 | ||||
| -rw-r--r-- | include/linux/sysctl.h | 2 |
2 files changed, 148 insertions, 19 deletions
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index 9b91deeeb56c..6bab2ae9e395 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -882,7 +882,7 @@ static int sysctl_check_table(struct nsproxy *namespaces, struct ctl_table *tabl #endif /* CONFIG_SYSCTL_SYSCALL_CHECK */ /** - * __register_sysctl_table - register a sysctl table + * __register_sysctl_table - register a leaf sysctl table * @root: List of sysctl headers to register on * @namespaces: Data to compute which lists of sysctl entries are visible * @path: The path to the directory the sysctl table is in. @@ -900,29 +900,19 @@ static int sysctl_check_table(struct nsproxy *namespaces, struct ctl_table *tabl * * maxlen - the maximum size in bytes of the data * - * mode - the file permissions for the /proc/sys file, and for sysctl(2) + * mode - the file permissions for the /proc/sys file * - * child - a pointer to the child sysctl table if this entry is a directory, or - * %NULL. + * child - must be %NULL. * * proc_handler - the text handler routine (described below) * - * de - for internal use by the sysctl routines - * * extra1, extra2 - extra pointers usable by the proc handler routines * * Leaf nodes in the sysctl tree will be represented by a single file * under /proc; non-leaf nodes will be represented by directories. * - * sysctl(2) can automatically manage read and write requests through - * the sysctl table. The data and maxlen fields of the ctl_table - * struct enable minimal validation of the values being written to be - * performed, and the mode field allows minimal authentication. - * - * There must be a proc_handler routine for any terminal nodes - * mirrored under /proc/sys (non-terminals are handled by a built-in - * directory handler). Several default handlers are available to - * cover common cases - + * There must be a proc_handler routine for any terminal nodes. + * Several default handlers are available to cover common cases - * * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(), * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(), @@ -1059,6 +1049,100 @@ static char *append_path(const char *path, char *pos, const char *name) return pos; } +static int count_subheaders(struct ctl_table *table) +{ + int has_files = 0; + int nr_subheaders = 0; + struct ctl_table *entry; + + /* special case: no directory and empty directory */ + if (!table || !table->procname) + return 1; + + for (entry = table; entry->procname; entry++) { + if (entry->child) + nr_subheaders += count_subheaders(entry->child); + else + has_files = 1; + } + return nr_subheaders + has_files; +} + +static int register_leaf_sysctl_tables(const char *path, char *pos, + struct ctl_table_header ***subheader, + struct ctl_table_root *root, struct nsproxy *namespaces, + struct ctl_table *table) +{ + struct ctl_table *ctl_table_arg = NULL; + struct ctl_table *entry, *files; + int nr_files = 0; + int nr_dirs = 0; + int err = -ENOMEM; + + for (entry = table; entry->procname; entry++) { + if (entry->child) + nr_dirs++; + else + nr_files++; + } + + files = table; + /* If there are mixed files and directories we need a new table */ + if (nr_dirs && nr_files) { + struct ctl_table *new; + files = kzalloc(sizeof(struct ctl_table) * (nr_files + 1), + GFP_KERNEL); + if (!files) + goto out; + + ctl_table_arg = files; + for (new = files, entry = table; entry->procname; entry++) { + if (entry->child) + continue; + *new = *entry; + new++; + } + } + + /* Register everything except a directory full of subdirectories */ + if (nr_files || !nr_dirs) { + struct ctl_table_header *header; + header = __register_sysctl_table(root, namespaces, path, files); + if (!header) { + kfree(ctl_table_arg); + goto out; + } + + /* Remember if we need to free the file table */ + header->ctl_table_arg = ctl_table_arg; + **subheader = header; + (*subheader)++; + } + + /* Recurse into the subdirectories. */ + for (entry = table; entry->procname; entry++) { + char *child_pos; + + if (!entry->child) + continue; + + err = -ENAMETOOLONG; + child_pos = append_path(path, pos, entry->procname); + if (!child_pos) + goto out; + + err = register_leaf_sysctl_tables(path, child_pos, subheader, + root, namespaces, entry->child); + pos[0] = '\0'; + if (err) + goto out; + } + err = 0; +out: + /* On failure our caller will unregister all registered subheaders */ + return err; +} + /** * __register_sysctl_paths - register a sysctl table hierarchy * @root: List of sysctl headers to register on @@ -1077,7 +1161,8 @@ struct ctl_table_header *__register_sysctl_paths( const struct ctl_path *path, struct ctl_table *table) { struct ctl_table *ctl_table_arg = table; - struct ctl_table_header *header = NULL; + int nr_subheaders = count_subheaders(table); + struct ctl_table_header *header = NULL, **subheaders, **subheader; const struct ctl_path *component; char *new_path, *pos; @@ -1097,12 +1182,39 @@ struct ctl_table_header *__register_sysctl_paths( goto out; table = table->child; } - header = __register_sysctl_table(root, namespaces, new_path, table); - if (header) + if (nr_subheaders == 1) { + header = __register_sysctl_table(root, namespaces, new_path, table); + if (header) + header->ctl_table_arg = ctl_table_arg; + } else { + header = kzalloc(sizeof(*header) + + sizeof(*subheaders)*nr_subheaders, GFP_KERNEL); + if (!header) + goto out; + + subheaders = (struct ctl_table_header **) (header + 1); + subheader = subheaders; header->ctl_table_arg = ctl_table_arg; + + if (register_leaf_sysctl_tables(new_path, pos, &subheader, + root, namespaces, table)) + goto err_register_leaves; + } + out: kfree(new_path); return header; + +err_register_leaves: + while (subheader > subheaders) { + struct ctl_table_header *subh = *(--subheader); + struct ctl_table *table = subh->ctl_table_arg; + unregister_sysctl_table(subh); + kfree(table); + } + kfree(header); + header = NULL; + goto out; } /** @@ -1149,11 +1261,28 @@ EXPORT_SYMBOL(register_sysctl_table); */ void unregister_sysctl_table(struct ctl_table_header * header) { + int nr_subheaders; might_sleep(); if (header == NULL) return; + nr_subheaders = count_subheaders(header->ctl_table_arg); + if (unlikely(nr_subheaders > 1)) { + struct ctl_table_header **subheaders; + int i; + + subheaders = (struct ctl_table_header **)(header + 1); + for (i = nr_subheaders -1; i >= 0; i--) { + struct ctl_table_header *subh = subheaders[i]; + struct ctl_table *table = subh->ctl_table_arg; + unregister_sysctl_table(subh); + kfree(table); + } + kfree(header); + return; + } + spin_lock(&sysctl_lock); start_unregistering(header); if (!--header->parent->count) { diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index a514e0f6056d..25c7dfe1a7ec 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -1015,7 +1015,7 @@ struct ctl_table void *data; int maxlen; umode_t mode; - struct ctl_table *child; + struct ctl_table *child; /* Deprecated */ struct ctl_table *parent; /* Automatically set */ proc_handler *proc_handler; /* Callback for text formatting */ struct ctl_table_poll *poll; |