From 6e9d5164153ad6539edd31e7afb02a3e79124cad Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Sat, 21 Jan 2012 10:26:26 -0800 Subject: sysctl: Add support for register sysctl tables with a normal cstring path. Make __register_sysctl_table the core sysctl registration operation and make it take a char * string as path. Now that binary paths have been banished into the real of backwards compatibility in kernel/binary_sysctl.c where they can be safely ignored there is no longer a need to use struct ctl_path to represent path names when registering ctl_tables. Start the transition to using normal char * strings to represent pathnames when registering sysctl tables. Normal strings are easier to deal with both in the internal sysctl implementation and for programmers registering sysctl tables. __register_sysctl_paths is turned into a backwards compatibility wrapper that converts a ctl_path array into a normal char * string. Signed-off-by: Eric W. Biederman --- fs/proc/proc_sysctl.c | 94 ++++++++++++++++++++++++++++++++++++++++++++------ include/linux/sysctl.h | 3 ++ 2 files changed, 87 insertions(+), 10 deletions(-) diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index bcf60fb8dce..5704ff0e889 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_paths - register a sysctl hierarchy + * __register_sysctl_table - register a 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. @@ -934,21 +934,34 @@ static int sysctl_check_table(struct nsproxy *namespaces, struct ctl_table *tabl * This routine returns %NULL on a failure to register, and a pointer * to the table header on success. */ -struct ctl_table_header *__register_sysctl_paths( +struct ctl_table_header *__register_sysctl_table( struct ctl_table_root *root, struct nsproxy *namespaces, - const struct ctl_path *path, struct ctl_table *table) + const char *path, struct ctl_table *table) { struct ctl_table_header *header; struct ctl_table *new, **prevp; - unsigned int n, npath; + const char *name, *nextname; + unsigned int npath = 0; struct ctl_table_set *set; size_t path_bytes = 0; char *new_name; /* Count the path components */ - for (npath = 0; path[npath].procname; ++npath) - path_bytes += strlen(path[npath].procname) + 1; + for (name = path; name; name = nextname) { + int namelen; + nextname = strchr(name, '/'); + if (nextname) { + namelen = nextname - name; + nextname++; + } else { + namelen = strlen(name); + } + if (namelen == 0) + continue; + path_bytes += namelen + 1; + npath++; + } /* * For each path component, allocate a 2-element ctl_table array. @@ -968,9 +981,20 @@ struct ctl_table_header *__register_sysctl_paths( /* Now connect the dots */ prevp = &header->ctl_table; - for (n = 0; n < npath; ++n, ++path) { - /* Copy the procname */ - strcpy(new_name, path->procname); + for (name = path; name; name = nextname) { + int namelen; + nextname = strchr(name, '/'); + if (nextname) { + namelen = nextname - name; + nextname++; + } else { + namelen = strlen(name); + } + if (namelen == 0) + continue; + memcpy(new_name, name, namelen); + new_name[namelen] = '\0'; + new->procname = new_name; new->mode = 0555; @@ -978,7 +1002,7 @@ struct ctl_table_header *__register_sysctl_paths( prevp = &new->child; new += 2; - new_name += strlen(new_name) + 1; + new_name += namelen + 1; } *prevp = table; header->ctl_table_arg = table; @@ -1022,6 +1046,56 @@ struct ctl_table_header *__register_sysctl_paths( return header; } +static char *append_path(const char *path, char *pos, const char *name) +{ + int namelen; + namelen = strlen(name); + if (((pos - path) + namelen + 2) >= PATH_MAX) + return NULL; + memcpy(pos, name, namelen); + pos[namelen] = '/'; + pos[namelen + 1] = '\0'; + pos += namelen + 1; + return pos; +} + +/** + * __register_sysctl_paths - register a sysctl table hierarchy + * @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. + * @table: the top-level table structure + * + * Register a sysctl table hierarchy. @table should be a filled in ctl_table + * array. A completely 0 filled entry terminates the table. + * + * See __register_sysctl_table for more details. + */ +struct ctl_table_header *__register_sysctl_paths( + struct ctl_table_root *root, + struct nsproxy *namespaces, + const struct ctl_path *path, struct ctl_table *table) +{ + struct ctl_table_header *header = NULL; + const struct ctl_path *component; + char *new_path, *pos; + + pos = new_path = kmalloc(PATH_MAX, GFP_KERNEL); + if (!new_path) + return NULL; + + pos[0] = '\0'; + for (component = path; component->procname; component++) { + pos = append_path(new_path, pos, component->procname); + if (!pos) + goto out; + } + header = __register_sysctl_table(root, namespaces, new_path, table); +out: + kfree(new_path); + return header; +} + /** * register_sysctl_table_path - register a sysctl table hierarchy * @path: The path to the directory the sysctl table is in. diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index 43c36acdb62..a514e0f6056 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -1073,6 +1073,9 @@ extern void setup_sysctl_set(struct ctl_table_set *p, extern void retire_sysctl_set(struct ctl_table_set *set); void register_sysctl_root(struct ctl_table_root *root); +struct ctl_table_header *__register_sysctl_table( + struct ctl_table_root *root, struct nsproxy *namespaces, + const char *path, struct ctl_table *table); struct ctl_table_header *__register_sysctl_paths( struct ctl_table_root *root, struct nsproxy *namespaces, const struct ctl_path *path, struct ctl_table *table); -- cgit v1.2.3