diff options
| -rw-r--r-- | Documentation/filesystems/afs.txt | 28 | ||||
| -rw-r--r-- | fs/afs/dir.c | 63 | ||||
| -rw-r--r-- | fs/afs/internal.h | 16 | ||||
| -rw-r--r-- | fs/afs/main.c | 44 | ||||
| -rw-r--r-- | fs/afs/proc.c | 231 |
5 files changed, 380 insertions, 2 deletions
diff --git a/Documentation/filesystems/afs.txt b/Documentation/filesystems/afs.txt index c5254f6d234d..8c6ea7b41048 100644 --- a/Documentation/filesystems/afs.txt +++ b/Documentation/filesystems/afs.txt @@ -11,7 +11,7 @@ Contents: - Proc filesystem. - The cell database. - Security. - - Examples. + - The @sys substitution. ======== @@ -230,3 +230,29 @@ If a file is opened with a particular key and then the file descriptor is passed to a process that doesn't have that key (perhaps over an AF_UNIX socket), then the operations on the file will be made with key that was used to open the file. + + +===================== +THE @SYS SUBSTITUTION +===================== + +The list of up to 16 @sys substitutions for the current network namespace can +be configured by writing a list to /proc/fs/afs/sysname: + + [root@andromeda ~]# echo foo amd64_linux_26 >/proc/fs/afs/sysname + +or cleared entirely by writing an empty list: + + [root@andromeda ~]# echo >/proc/fs/afs/sysname + +The current list for current network namespace can be retrieved by: + + [root@andromeda ~]# cat /proc/fs/afs/sysname + foo + amd64_linux_26 + +When @sys is being substituted for, each element of the list is tried in the +order given. + +By default, the list will contain one item that conforms to the pattern +"<arch>_linux_26", amd64 being the name for x86_64. diff --git a/fs/afs/dir.c b/fs/afs/dir.c index 27c5231e89e7..3ebd741b74d0 100644 --- a/fs/afs/dir.c +++ b/fs/afs/dir.c @@ -767,6 +767,62 @@ out: } /* + * Look up an entry in a directory with @sys substitution. + */ +static struct dentry *afs_lookup_atsys(struct inode *dir, struct dentry *dentry, + struct key *key) +{ + struct afs_sysnames *subs; + struct afs_net *net = afs_i2net(dir); + struct dentry *ret; + char *buf, *p, *name; + int len, i; + + _enter(""); + + ret = ERR_PTR(-ENOMEM); + p = buf = kmalloc(AFSNAMEMAX, GFP_KERNEL); + if (!buf) + goto out_p; + if (dentry->d_name.len > 4) { + memcpy(p, dentry->d_name.name, dentry->d_name.len - 4); + p += dentry->d_name.len - 4; + } + + /* There is an ordered list of substitutes that we have to try. */ + read_lock(&net->sysnames_lock); + subs = net->sysnames; + refcount_inc(&subs->usage); + read_unlock(&net->sysnames_lock); + + for (i = 0; i < subs->nr; i++) { + name = subs->subs[i]; + len = dentry->d_name.len - 4 + strlen(name); + if (len >= AFSNAMEMAX) { + ret = ERR_PTR(-ENAMETOOLONG); + goto out_s; + } + + strcpy(p, name); + ret = lookup_one_len(buf, dentry->d_parent, len); + if (IS_ERR(ret) || d_is_positive(ret)) + goto out_s; + dput(ret); + } + + /* We don't want to d_add() the @sys dentry here as we don't want to + * the cached dentry to hide changes to the sysnames list. + */ + ret = NULL; +out_s: + afs_put_sysnames(subs); + kfree(buf); +out_p: + key_put(key); + return ret; +} + +/* * look up an entry in a directory */ static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry, @@ -805,6 +861,13 @@ static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry, return ERR_PTR(ret); } + if (dentry->d_name.len >= 4 && + dentry->d_name.name[dentry->d_name.len - 4] == '@' && + dentry->d_name.name[dentry->d_name.len - 3] == 's' && + dentry->d_name.name[dentry->d_name.len - 2] == 'y' && + dentry->d_name.name[dentry->d_name.len - 1] == 's') + return afs_lookup_atsys(dir, dentry, key); + inode = afs_do_lookup(dir, dentry, key); if (IS_ERR(inode)) { ret = PTR_ERR(inode); diff --git a/fs/afs/internal.h b/fs/afs/internal.h index 55b07e818400..27150bbc50d8 100644 --- a/fs/afs/internal.h +++ b/fs/afs/internal.h @@ -199,6 +199,18 @@ static inline struct afs_super_info *AFS_FS_S(struct super_block *sb) extern struct file_system_type afs_fs_type; /* + * Set of substitutes for @sys. + */ +struct afs_sysnames { +#define AFS_NR_SYSNAME 16 + char *subs[AFS_NR_SYSNAME]; + refcount_t usage; + unsigned short nr; + short error; + char blank[1]; +}; + +/* * AFS network namespace record. */ struct afs_net { @@ -246,8 +258,11 @@ struct afs_net { /* Misc */ struct proc_dir_entry *proc_afs; /* /proc/net/afs directory */ + struct afs_sysnames *sysnames; + rwlock_t sysnames_lock; }; +extern const char afs_init_sysname[]; extern struct afs_net __afs_net;// Dummy AFS network namespace; TODO: replace with real netns enum afs_cell_state { @@ -789,6 +804,7 @@ extern int __net_init afs_proc_init(struct afs_net *); extern void __net_exit afs_proc_cleanup(struct afs_net *); extern int afs_proc_cell_setup(struct afs_net *, struct afs_cell *); extern void afs_proc_cell_remove(struct afs_net *, struct afs_cell *); +extern void afs_put_sysnames(struct afs_sysnames *); /* * rotate.c diff --git a/fs/afs/main.c b/fs/afs/main.c index 15a02a05ff40..d7560168b3bf 100644 --- a/fs/afs/main.c +++ b/fs/afs/main.c @@ -34,11 +34,42 @@ MODULE_PARM_DESC(rootcell, "root AFS cell name and VL server IP addr list"); struct workqueue_struct *afs_wq; struct afs_net __afs_net; +#if defined(CONFIG_ALPHA) +const char afs_init_sysname[] = "alpha_linux26"; +#elif defined(CONFIG_X86_64) +const char afs_init_sysname[] = "amd64_linux26"; +#elif defined(CONFIG_ARM) +const char afs_init_sysname[] = "arm_linux26"; +#elif defined(CONFIG_ARM64) +const char afs_init_sysname[] = "aarch64_linux26"; +#elif defined(CONFIG_X86_32) +const char afs_init_sysname[] = "i386_linux26"; +#elif defined(CONFIG_IA64) +const char afs_init_sysname[] = "ia64_linux26"; +#elif defined(CONFIG_PPC64) +const char afs_init_sysname[] = "ppc64_linux26"; +#elif defined(CONFIG_PPC32) +const char afs_init_sysname[] = "ppc_linux26"; +#elif defined(CONFIG_S390) +#ifdef CONFIG_64BIT +const char afs_init_sysname[] = "s390x_linux26"; +#else +const char afs_init_sysname[] = "s390_linux26"; +#endif +#elif defined(CONFIG_SPARC64) +const char afs_init_sysname[] = "sparc64_linux26"; +#elif defined(CONFIG_SPARC32) +const char afs_init_sysname[] = "sparc_linux26"; +#else +const char afs_init_sysname[] = "unknown_linux26"; +#endif + /* * Initialise an AFS network namespace record. */ static int __net_init afs_net_init(struct afs_net *net) { + struct afs_sysnames *sysnames; int ret; net->live = true; @@ -67,6 +98,16 @@ static int __net_init afs_net_init(struct afs_net *net) INIT_WORK(&net->fs_manager, afs_manage_servers); timer_setup(&net->fs_timer, afs_servers_timer, 0); + ret = -ENOMEM; + sysnames = kzalloc(sizeof(*sysnames), GFP_KERNEL); + if (!sysnames) + goto error_sysnames; + sysnames->subs[0] = (char *)&afs_init_sysname; + sysnames->nr = 1; + refcount_set(&sysnames->usage, 1); + net->sysnames = sysnames; + rwlock_init(&net->sysnames_lock); + /* Register the /proc stuff */ ret = afs_proc_init(net); if (ret < 0) @@ -92,6 +133,8 @@ error_cell_init: net->live = false; afs_proc_cleanup(net); error_proc: + afs_put_sysnames(net->sysnames); +error_sysnames: net->live = false; return ret; } @@ -106,6 +149,7 @@ static void __net_exit afs_net_exit(struct afs_net *net) afs_purge_servers(net); afs_close_socket(net); afs_proc_cleanup(net); + afs_put_sysnames(net->sysnames); } /* diff --git a/fs/afs/proc.c b/fs/afs/proc.c index 2f04d37eeef0..15650cd59404 100644 --- a/fs/afs/proc.c +++ b/fs/afs/proc.c @@ -126,6 +126,32 @@ static const struct file_operations afs_proc_servers_fops = { .release = seq_release, }; +static int afs_proc_sysname_open(struct inode *inode, struct file *file); +static int afs_proc_sysname_release(struct inode *inode, struct file *file); +static void *afs_proc_sysname_start(struct seq_file *p, loff_t *pos); +static void *afs_proc_sysname_next(struct seq_file *p, void *v, + loff_t *pos); +static void afs_proc_sysname_stop(struct seq_file *p, void *v); +static int afs_proc_sysname_show(struct seq_file *m, void *v); +static ssize_t afs_proc_sysname_write(struct file *file, + const char __user *buf, + size_t size, loff_t *_pos); + +static const struct seq_operations afs_proc_sysname_ops = { + .start = afs_proc_sysname_start, + .next = afs_proc_sysname_next, + .stop = afs_proc_sysname_stop, + .show = afs_proc_sysname_show, +}; + +static const struct file_operations afs_proc_sysname_fops = { + .open = afs_proc_sysname_open, + .read = seq_read, + .llseek = seq_lseek, + .release = afs_proc_sysname_release, + .write = afs_proc_sysname_write, +}; + /* * initialise the /proc/fs/afs/ directory */ @@ -139,7 +165,8 @@ int afs_proc_init(struct afs_net *net) if (!proc_create("cells", 0644, net->proc_afs, &afs_proc_cells_fops) || !proc_create("rootcell", 0644, net->proc_afs, &afs_proc_rootcell_fops) || - !proc_create("servers", 0644, net->proc_afs, &afs_proc_servers_fops)) + !proc_create("servers", 0644, net->proc_afs, &afs_proc_servers_fops) || + !proc_create("sysname", 0644, net->proc_afs, &afs_proc_sysname_fops)) goto error_tree; _leave(" = 0"); @@ -330,6 +357,12 @@ static ssize_t afs_proc_rootcell_write(struct file *file, if (IS_ERR(kbuf)) return PTR_ERR(kbuf); + ret = -EINVAL; + if (kbuf[0] == '.') + goto out; + if (memchr(kbuf, '/', size)) + goto out; + /* trim to first NL */ s = memchr(kbuf, '\n', size); if (s) @@ -342,6 +375,7 @@ static ssize_t afs_proc_rootcell_write(struct file *file, if (ret >= 0) ret = size; /* consume everything, always */ +out: kfree(kbuf); _leave(" = %d", ret); return ret; @@ -635,3 +669,198 @@ static int afs_proc_servers_show(struct seq_file *m, void *v) &alist->addrs[alist->index].transport); return 0; } + +void afs_put_sysnames(struct afs_sysnames *sysnames) +{ + int i; + + if (sysnames && refcount_dec_and_test(&sysnames->usage)) { + for (i = 0; i < sysnames->nr; i++) + if (sysnames->subs[i] != afs_init_sysname && + sysnames->subs[i] != sysnames->blank) + kfree(sysnames->subs[i]); + } +} + +/* + * Handle opening of /proc/fs/afs/sysname. If it is opened for writing, we + * assume the caller wants to change the substitution list and we allocate a + * buffer to hold the list. + */ +static int afs_proc_sysname_open(struct inode *inode, struct file *file) +{ + struct afs_sysnames *sysnames; + struct seq_file *m; + int ret; + + ret = seq_open(file, &afs_proc_sysname_ops); + if (ret < 0) + return ret; + + if (file->f_mode & FMODE_WRITE) { + sysnames = kzalloc(sizeof(*sysnames), GFP_KERNEL); + if (!sysnames) { + seq_release(inode, file); + return -ENOMEM; + } + + refcount_set(&sysnames->usage, 1); + m = file->private_data; + m->private = sysnames; + } + + return 0; +} + +/* + * Handle writes to /proc/fs/afs/sysname to set the @sys substitution. + */ +static ssize_t afs_proc_sysname_write(struct file *file, + const char __user *buf, + size_t size, loff_t *_pos) +{ + struct afs_sysnames *sysnames; + struct seq_file *m = file->private_data; + char *kbuf = NULL, *s, *p, *sub; + int ret, len; + + sysnames = m->private; + if (!sysnames) + return -EINVAL; + if (sysnames->error) + return sysnames->error; + + if (size >= PAGE_SIZE - 1) { + sysnames->error = -EINVAL; + return -EINVAL; + } + if (size == 0) + return 0; + + kbuf = memdup_user_nul(buf, size); + if (IS_ERR(kbuf)) + return PTR_ERR(kbuf); + + inode_lock(file_inode(file)); + + p = kbuf; + while ((s = strsep(&p, " \t\n"))) { + len = strlen(s); + if (len == 0) + continue; + ret = -ENAMETOOLONG; + if (len >= AFSNAMEMAX) + goto error; + + if (len >= 4 && + s[len - 4] == '@' && + s[len - 3] == 's' && + s[len - 2] == 'y' && + s[len - 1] == 's') + /* Protect against recursion */ + goto invalid; + + if (s[0] == '.' && + (len < 2 || (len == 2 && s[1] == '.'))) + goto invalid; + + if (memchr(s, '/', len)) + goto invalid; + + ret = -EFBIG; + if (sysnames->nr >= AFS_NR_SYSNAME) + goto out; + + if (strcmp(s, afs_init_sysname) == 0) { + sub = (char *)afs_init_sysname; + } else { + ret = -ENOMEM; + sub = kmemdup(s, len + 1, GFP_KERNEL); + if (!sub) + goto out; + } + + sysnames->subs[sysnames->nr] = sub; + sysnames->nr++; + } + + ret = size; /* consume everything, always */ +out: + inode_unlock(file_inode(file)); + kfree(kbuf); + return ret; + +invalid: + ret = -EINVAL; +error: + sysnames->error = ret; + goto out; +} + +static int afs_proc_sysname_release(struct inode *inode, struct file *file) +{ + struct afs_sysnames *sysnames, *kill = NULL; + struct seq_file *m = file->private_data; + struct afs_net *net = afs_seq2net(m); + + sysnames = m->private; + if (sysnames) { + if (!sysnames->error) { + kill = sysnames; + if (sysnames->nr == 0) { + sysnames->subs[0] = sysnames->blank; + sysnames->nr++; + } + write_lock(&net->sysnames_lock); + kill = net->sysnames; + net->sysnames = sysnames; + write_unlock(&net->sysnames_lock); + } + afs_put_sysnames(kill); + } + + return seq_release(inode, file); +} + +static void *afs_proc_sysname_start(struct seq_file *m, loff_t *pos) + __acquires(&net->sysnames_lock) +{ + struct afs_net *net = afs_seq2net(m); + struct afs_sysnames *names = net->sysnames; + + read_lock(&net->sysnames_lock); + + if (*pos >= names->nr) + return NULL; + return (void *)(unsigned long)(*pos + 1); +} + +static void *afs_proc_sysname_next(struct seq_file *m, void *v, loff_t *pos) +{ + struct afs_net *net = afs_seq2net(m); + struct afs_sysnames *names = net->sysnames; + + *pos += 1; + if (*pos >= names->nr) + return NULL; + return (void *)(unsigned long)(*pos + 1); +} + +static void afs_proc_sysname_stop(struct seq_file *m, void *v) + __releases(&net->sysnames_lock) +{ + struct afs_net *net = afs_seq2net(m); + + read_unlock(&net->sysnames_lock); +} + +static int afs_proc_sysname_show(struct seq_file *m, void *v) +{ + struct afs_net *net = afs_seq2net(m); + struct afs_sysnames *sysnames = net->sysnames; + unsigned int i = (unsigned long)v - 1; + + if (i < sysnames->nr) + seq_printf(m, "%s\n", sysnames->subs[i]); + return 0; +} |