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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-23 13:28:57 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-23 13:28:57 -0700 |
| commit | 4352b8aee98005853aa63f57d6377282de17a33f (patch) | |
| tree | 27614d7a9ef05c32d089004e104364ce42324837 /fs/cachefiles/daemon.c | |
| download | linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.tar.gz linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.zip | |
Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted
Pull I3C updates from Alexandre Belloni:
"A new driver this cycle, for the AMD AXI I3C controller.
There are also new features such as IBI wakeup support, SETAASA device
discovery and ACPI support for the the DAA methods, meaning we can now
communicate with the SPD devices on DDR5 modules.
New driver:
- AMD AXI I3C master controller
Subsystem:
- I3C Common Command Code (CCC) handling improvements, especially
around GET CCCs
- SETAASA device discovery support
- ACPI support for all existing DAA methods like SETDASA, SETNEWDA as
well as I2C devices on I3C bus
- IBI-based wakeup support
Drivers:
- dw: SETAASA support
- mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C
controller support, PIO queue management support for HCI v1.2
- renesas: improve suspend to RAM support, add runtime PM support"
* tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits)
i3c: dw: reduce do_daa time if there's no client
i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller
i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2
i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode
i3c: dw: rename "pclk" to "apb" to match dt-binding
i3c: dw: make struct dw_i3c_cmd smaller
i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding
i3c: renesas: Don't register devices when ENTDAA times out
i3c: master: dw-i3c-master: fix OD timing for first broadcast
i3c: mipi-i3c-hci: Advertise IBI wakeup capability
i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev()
i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI
i3c: master: Reject IBI requests from non-IBI-capable devices
i3c: master: Add helper to query bus wakeup requirements
i3c: master: Report wakeup events for IBIs
i3c: master: Support IBI-based wakeup capability
i3c: master: Fix potential UAF in i3c_device_match()
i3c: master: Fix potential UAF in i3c_device_uevent()
i3c: Make dev->desc locking assumptions explicit
i3c: master: Fix use-after-free of master->this
...
Diffstat (limited to 'fs/cachefiles/daemon.c')
| -rw-r--r-- | fs/cachefiles/daemon.c | 745 |
1 files changed, 745 insertions, 0 deletions
diff --git a/fs/cachefiles/daemon.c b/fs/cachefiles/daemon.c new file mode 100644 index 000000000..1a66e0af2 --- /dev/null +++ b/fs/cachefiles/daemon.c @@ -0,0 +1,745 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* Daemon interface + * + * Copyright (C) 2007, 2021 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/sched.h> +#include <linux/completion.h> +#include <linux/slab.h> +#include <linux/fs.h> +#include <linux/file.h> +#include <linux/namei.h> +#include <linux/poll.h> +#include <linux/mount.h> +#include <linux/security.h> +#include <linux/statfs.h> +#include <linux/ctype.h> +#include <linux/string.h> +#include <linux/fs_struct.h> +#include "internal.h" + +static int cachefiles_daemon_open(struct inode *, struct file *); +static int cachefiles_daemon_release(struct inode *, struct file *); +static ssize_t cachefiles_daemon_read(struct file *, char __user *, size_t, + loff_t *); +static ssize_t cachefiles_daemon_write(struct file *, const char __user *, + size_t, loff_t *); +static __poll_t cachefiles_daemon_poll(struct file *, + struct poll_table_struct *); +static int cachefiles_daemon_frun(struct cachefiles_cache *, char *); +static int cachefiles_daemon_fcull(struct cachefiles_cache *, char *); +static int cachefiles_daemon_fstop(struct cachefiles_cache *, char *); +static int cachefiles_daemon_brun(struct cachefiles_cache *, char *); +static int cachefiles_daemon_bcull(struct cachefiles_cache *, char *); +static int cachefiles_daemon_bstop(struct cachefiles_cache *, char *); +static int cachefiles_daemon_cull(struct cachefiles_cache *, char *); +static int cachefiles_daemon_debug(struct cachefiles_cache *, char *); +static int cachefiles_daemon_dir(struct cachefiles_cache *, char *); +static int cachefiles_daemon_inuse(struct cachefiles_cache *, char *); +static int cachefiles_daemon_secctx(struct cachefiles_cache *, char *); +static int cachefiles_daemon_tag(struct cachefiles_cache *, char *); +static int cachefiles_daemon_bind(struct cachefiles_cache *, char *); +static void cachefiles_daemon_unbind(struct cachefiles_cache *); + +static unsigned long cachefiles_open; + +const struct file_operations cachefiles_daemon_fops = { + .owner = THIS_MODULE, + .open = cachefiles_daemon_open, + .release = cachefiles_daemon_release, + .read = cachefiles_daemon_read, + .write = cachefiles_daemon_write, + .poll = cachefiles_daemon_poll, + .llseek = noop_llseek, +}; + +struct cachefiles_daemon_cmd { + char name[8]; + int (*handler)(struct cachefiles_cache *cache, char *args); +}; + +static const struct cachefiles_daemon_cmd cachefiles_daemon_cmds[] = { + { "bind", cachefiles_daemon_bind }, + { "brun", cachefiles_daemon_brun }, + { "bcull", cachefiles_daemon_bcull }, + { "bstop", cachefiles_daemon_bstop }, + { "cull", cachefiles_daemon_cull }, + { "debug", cachefiles_daemon_debug }, + { "dir", cachefiles_daemon_dir }, + { "frun", cachefiles_daemon_frun }, + { "fcull", cachefiles_daemon_fcull }, + { "fstop", cachefiles_daemon_fstop }, + { "inuse", cachefiles_daemon_inuse }, + { "secctx", cachefiles_daemon_secctx }, + { "tag", cachefiles_daemon_tag }, + { "", NULL } +}; + + +/* + * Prepare a cache for caching. + */ +static int cachefiles_daemon_open(struct inode *inode, struct file *file) +{ + struct cachefiles_cache *cache; + + _enter(""); + + /* only the superuser may do this */ + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + /* the cachefiles device may only be open once at a time */ + if (xchg(&cachefiles_open, 1) == 1) + return -EBUSY; + + /* allocate a cache record */ + cache = kzalloc_obj(struct cachefiles_cache); + if (!cache) { + cachefiles_open = 0; + return -ENOMEM; + } + + mutex_init(&cache->daemon_mutex); + init_waitqueue_head(&cache->daemon_pollwq); + INIT_LIST_HEAD(&cache->volumes); + INIT_LIST_HEAD(&cache->object_list); + spin_lock_init(&cache->object_list_lock); + + /* set default caching limits + * - limit at 1% free space and/or free files + * - cull below 5% free space and/or free files + * - cease culling above 7% free space and/or free files + */ + cache->frun_percent = 7; + cache->fcull_percent = 5; + cache->fstop_percent = 1; + cache->brun_percent = 7; + cache->bcull_percent = 5; + cache->bstop_percent = 1; + + file->private_data = cache; + cache->cachefilesd = file; + return 0; +} + +/* + * Release a cache. + */ +static int cachefiles_daemon_release(struct inode *inode, struct file *file) +{ + struct cachefiles_cache *cache = file->private_data; + + _enter(""); + + ASSERT(cache); + + set_bit(CACHEFILES_DEAD, &cache->flags); + cachefiles_daemon_unbind(cache); + + /* clean up the control file interface */ + cache->cachefilesd = NULL; + file->private_data = NULL; + cachefiles_open = 0; + + kfree(cache); + _leave(""); + return 0; +} + +static ssize_t cachefiles_do_daemon_read(struct cachefiles_cache *cache, + char __user *_buffer, size_t buflen) +{ + unsigned long long b_released; + unsigned f_released; + char buffer[256]; + int n; + + /* check how much space the cache has */ + cachefiles_has_space(cache, 0, 0, cachefiles_has_space_check); + + /* summarise */ + f_released = atomic_xchg(&cache->f_released, 0); + b_released = atomic_long_xchg(&cache->b_released, 0); + clear_bit(CACHEFILES_STATE_CHANGED, &cache->flags); + + n = snprintf(buffer, sizeof(buffer), + "cull=%c" + " frun=%llx" + " fcull=%llx" + " fstop=%llx" + " brun=%llx" + " bcull=%llx" + " bstop=%llx" + " freleased=%x" + " breleased=%llx", + test_bit(CACHEFILES_CULLING, &cache->flags) ? '1' : '0', + (unsigned long long) cache->frun, + (unsigned long long) cache->fcull, + (unsigned long long) cache->fstop, + (unsigned long long) cache->brun, + (unsigned long long) cache->bcull, + (unsigned long long) cache->bstop, + f_released, + b_released); + + if (n > buflen) + return -EMSGSIZE; + + if (copy_to_user(_buffer, buffer, n) != 0) + return -EFAULT; + + return n; +} + +/* + * Read the cache state. + */ +static ssize_t cachefiles_daemon_read(struct file *file, char __user *_buffer, + size_t buflen, loff_t *pos) +{ + struct cachefiles_cache *cache = file->private_data; + + //_enter(",,%zu,", buflen); + + if (!test_bit(CACHEFILES_READY, &cache->flags)) + return 0; + + return cachefiles_do_daemon_read(cache, _buffer, buflen); +} + +/* + * Take a command from cachefilesd, parse it and act on it. + */ +static ssize_t cachefiles_daemon_write(struct file *file, + const char __user *_data, + size_t datalen, + loff_t *pos) +{ + const struct cachefiles_daemon_cmd *cmd; + struct cachefiles_cache *cache = file->private_data; + ssize_t ret; + char *data, *args, *cp; + + //_enter(",,%zu,", datalen); + + ASSERT(cache); + + if (test_bit(CACHEFILES_DEAD, &cache->flags)) + return -EIO; + + if (datalen > PAGE_SIZE - 1) + return -EOPNOTSUPP; + + /* drag the command string into the kernel so we can parse it */ + data = memdup_user_nul(_data, datalen); + if (IS_ERR(data)) + return PTR_ERR(data); + + ret = -EINVAL; + if (memchr(data, '\0', datalen)) + goto error; + + /* strip any newline */ + cp = memchr(data, '\n', datalen); + if (cp) { + if (cp == data) + goto error; + + *cp = '\0'; + } + + /* parse the command */ + ret = -EOPNOTSUPP; + + for (args = data; *args; args++) + if (isspace(*args)) + break; + if (*args) { + if (args == data) + goto error; + *args = '\0'; + args = skip_spaces(++args); + } + + /* run the appropriate command handler */ + for (cmd = cachefiles_daemon_cmds; cmd->name[0]; cmd++) + if (strcmp(cmd->name, data) == 0) + goto found_command; + +error: + kfree(data); + //_leave(" = %zd", ret); + return ret; + +found_command: + mutex_lock(&cache->daemon_mutex); + + ret = -EIO; + if (!test_bit(CACHEFILES_DEAD, &cache->flags)) + ret = cmd->handler(cache, args); + + mutex_unlock(&cache->daemon_mutex); + + if (ret == 0) + ret = datalen; + goto error; +} + +/* + * Poll for culling state + * - use EPOLLOUT to indicate culling state + */ +static __poll_t cachefiles_daemon_poll(struct file *file, + struct poll_table_struct *poll) +{ + struct cachefiles_cache *cache = file->private_data; + __poll_t mask; + + poll_wait(file, &cache->daemon_pollwq, poll); + mask = 0; + + if (test_bit(CACHEFILES_STATE_CHANGED, &cache->flags)) + mask |= EPOLLIN; + + if (test_bit(CACHEFILES_CULLING, &cache->flags)) + mask |= EPOLLOUT; + + return mask; +} + +/* + * Give a range error for cache space constraints + * - can be tail-called + */ +static int cachefiles_daemon_range_error(struct cachefiles_cache *cache, + char *args) +{ + pr_err("Free space limits must be in range 0%%<=stop<cull<run<100%%\n"); + + return -EINVAL; +} + +/* + * Set the percentage of files at which to stop culling + * - command: "frun <N>%" + */ +static int cachefiles_daemon_frun(struct cachefiles_cache *cache, char *args) +{ + unsigned long frun; + + _enter(",%s", args); + + if (!*args) + return -EINVAL; + + frun = simple_strtoul(args, &args, 10); + if (args[0] != '%' || args[1] != '\0') + return -EINVAL; + + if (frun <= cache->fcull_percent || frun >= 100) + return cachefiles_daemon_range_error(cache, args); + + cache->frun_percent = frun; + return 0; +} + +/* + * Set the percentage of files at which to start culling + * - command: "fcull <N>%" + */ +static int cachefiles_daemon_fcull(struct cachefiles_cache *cache, char *args) +{ + unsigned long fcull; + + _enter(",%s", args); + + if (!*args) + return -EINVAL; + + fcull = simple_strtoul(args, &args, 10); + if (args[0] != '%' || args[1] != '\0') + return -EINVAL; + + if (fcull <= cache->fstop_percent || fcull >= cache->frun_percent) + return cachefiles_daemon_range_error(cache, args); + + cache->fcull_percent = fcull; + return 0; +} + +/* + * Set the percentage of files at which to stop allocating + * - command: "fstop <N>%" + */ +static int cachefiles_daemon_fstop(struct cachefiles_cache *cache, char *args) +{ + unsigned long fstop; + + _enter(",%s", args); + + if (!*args) + return -EINVAL; + + fstop = simple_strtoul(args, &args, 10); + if (args[0] != '%' || args[1] != '\0') + return -EINVAL; + + if (fstop >= cache->fcull_percent) + return cachefiles_daemon_range_error(cache, args); + + cache->fstop_percent = fstop; + return 0; +} + +/* + * Set the percentage of blocks at which to stop culling + * - command: "brun <N>%" + */ +static int cachefiles_daemon_brun(struct cachefiles_cache *cache, char *args) +{ + unsigned long brun; + + _enter(",%s", args); + + if (!*args) + return -EINVAL; + + brun = simple_strtoul(args, &args, 10); + if (args[0] != '%' || args[1] != '\0') + return -EINVAL; + + if (brun <= cache->bcull_percent || brun >= 100) + return cachefiles_daemon_range_error(cache, args); + + cache->brun_percent = brun; + return 0; +} + +/* + * Set the percentage of blocks at which to start culling + * - command: "bcull <N>%" + */ +static int cachefiles_daemon_bcull(struct cachefiles_cache *cache, char *args) +{ + unsigned long bcull; + + _enter(",%s", args); + + if (!*args) + return -EINVAL; + + bcull = simple_strtoul(args, &args, 10); + if (args[0] != '%' || args[1] != '\0') + return -EINVAL; + + if (bcull <= cache->bstop_percent || bcull >= cache->brun_percent) + return cachefiles_daemon_range_error(cache, args); + + cache->bcull_percent = bcull; + return 0; +} + +/* + * Set the percentage of blocks at which to stop allocating + * - command: "bstop <N>%" + */ +static int cachefiles_daemon_bstop(struct cachefiles_cache *cache, char *args) +{ + unsigned long bstop; + + _enter(",%s", args); + + if (!*args) + return -EINVAL; + + bstop = simple_strtoul(args, &args, 10); + if (args[0] != '%' || args[1] != '\0') + return -EINVAL; + + if (bstop >= cache->bcull_percent) + return cachefiles_daemon_range_error(cache, args); + + cache->bstop_percent = bstop; + return 0; +} + +/* + * Set the cache directory + * - command: "dir <name>" + */ +static int cachefiles_daemon_dir(struct cachefiles_cache *cache, char *args) +{ + char *dir; + + _enter(",%s", args); + + if (!*args) { + pr_err("Empty directory specified\n"); + return -EINVAL; + } + + if (cache->rootdirname) { + pr_err("Second cache directory specified\n"); + return -EEXIST; + } + + dir = kstrdup(args, GFP_KERNEL); + if (!dir) + return -ENOMEM; + + cache->rootdirname = dir; + return 0; +} + +/* + * Set the cache security context + * - command: "secctx <ctx>" + */ +static int cachefiles_daemon_secctx(struct cachefiles_cache *cache, char *args) +{ + int err; + + _enter(",%s", args); + + if (!*args) { + pr_err("Empty security context specified\n"); + return -EINVAL; + } + + if (cache->have_secid) { + pr_err("Second security context specified\n"); + return -EINVAL; + } + + err = security_secctx_to_secid(args, strlen(args), &cache->secid); + if (err) + return err; + + cache->have_secid = true; + return 0; +} + +/* + * Set the cache tag + * - command: "tag <name>" + */ +static int cachefiles_daemon_tag(struct cachefiles_cache *cache, char *args) +{ + char *tag; + + _enter(",%s", args); + + if (!*args) { + pr_err("Empty tag specified\n"); + return -EINVAL; + } + + if (cache->tag) + return -EEXIST; + + tag = kstrdup(args, GFP_KERNEL); + if (!tag) + return -ENOMEM; + + cache->tag = tag; + return 0; +} + +/* + * Request a node in the cache be culled from the current working directory + * - command: "cull <name>" + */ +static int cachefiles_daemon_cull(struct cachefiles_cache *cache, char *args) +{ + struct path path; + const struct cred *saved_cred; + int ret; + + _enter(",%s", args); + + if (strchr(args, '/')) + goto inval; + + if (!test_bit(CACHEFILES_READY, &cache->flags)) { + pr_err("cull applied to unready cache\n"); + return -EIO; + } + + if (test_bit(CACHEFILES_DEAD, &cache->flags)) { + pr_err("cull applied to dead cache\n"); + return -EIO; + } + + get_fs_pwd(current->fs, &path); + + if (!d_can_lookup(path.dentry)) + goto notdir; + + cachefiles_begin_secure(cache, &saved_cred); + ret = cachefiles_cull(cache, path.dentry, args); + cachefiles_end_secure(cache, saved_cred); + + path_put(&path); + _leave(" = %d", ret); + return ret; + +notdir: + path_put(&path); + pr_err("cull command requires dirfd to be a directory\n"); + return -ENOTDIR; + +inval: + pr_err("cull command requires dirfd and filename\n"); + return -EINVAL; +} + +/* + * Set debugging mode + * - command: "debug <mask>" + */ +static int cachefiles_daemon_debug(struct cachefiles_cache *cache, char *args) +{ + unsigned long mask; + + _enter(",%s", args); + + mask = simple_strtoul(args, &args, 0); + if (args[0] != '\0') + goto inval; + + cachefiles_debug = mask; + _leave(" = 0"); + return 0; + +inval: + pr_err("debug command requires mask\n"); + return -EINVAL; +} + +/* + * Find out whether an object in the current working directory is in use or not + * - command: "inuse <name>" + */ +static int cachefiles_daemon_inuse(struct cachefiles_cache *cache, char *args) +{ + struct path path; + const struct cred *saved_cred; + int ret; + + //_enter(",%s", args); + + if (strchr(args, '/')) + goto inval; + + if (!test_bit(CACHEFILES_READY, &cache->flags)) { + pr_err("inuse applied to unready cache\n"); + return -EIO; + } + + if (test_bit(CACHEFILES_DEAD, &cache->flags)) { + pr_err("inuse applied to dead cache\n"); + return -EIO; + } + + get_fs_pwd(current->fs, &path); + + if (!d_can_lookup(path.dentry)) + goto notdir; + + cachefiles_begin_secure(cache, &saved_cred); + ret = cachefiles_check_in_use(cache, path.dentry, args); + cachefiles_end_secure(cache, saved_cred); + + path_put(&path); + //_leave(" = %d", ret); + return ret; + +notdir: + path_put(&path); + pr_err("inuse command requires dirfd to be a directory\n"); + return -ENOTDIR; + +inval: + pr_err("inuse command requires dirfd and filename\n"); + return -EINVAL; +} + +/* + * Bind a directory as a cache + */ +static int cachefiles_daemon_bind(struct cachefiles_cache *cache, char *args) +{ + _enter("{%u,%u,%u,%u,%u,%u},%s", + cache->frun_percent, + cache->fcull_percent, + cache->fstop_percent, + cache->brun_percent, + cache->bcull_percent, + cache->bstop_percent, + args); + + if (cache->fstop_percent >= cache->fcull_percent || + cache->fcull_percent >= cache->frun_percent || + cache->frun_percent >= 100) + return -ERANGE; + + if (cache->bstop_percent >= cache->bcull_percent || + cache->bcull_percent >= cache->brun_percent || + cache->brun_percent >= 100) + return -ERANGE; + + if (!cache->rootdirname) { + pr_err("No cache directory specified\n"); + return -EINVAL; + } + + /* Don't permit already bound caches to be re-bound */ + if (test_bit(CACHEFILES_READY, &cache->flags)) { + pr_err("Cache already bound\n"); + return -EBUSY; + } + + if (*args) { + pr_err("'bind' command doesn't take an argument\n"); + return -EINVAL; + } + + /* Make sure we have copies of the tag string */ + if (!cache->tag) { + /* + * The tag string is released by the fops->release() + * function, so we don't release it on error here + */ + cache->tag = kstrdup("CacheFiles", GFP_KERNEL); + if (!cache->tag) + return -ENOMEM; + } + + return cachefiles_add_cache(cache); +} + +/* + * Unbind a cache. + */ +static void cachefiles_daemon_unbind(struct cachefiles_cache *cache) +{ + _enter(""); + + if (test_bit(CACHEFILES_READY, &cache->flags)) + cachefiles_withdraw_cache(cache); + + cachefiles_put_directory(cache->graveyard); + cachefiles_put_directory(cache->store); + mntput(cache->mnt); + put_cred(cache->cache_cred); + + kfree(cache->rootdirname); + kfree(cache->tag); + + _leave(""); +} |
