aboutsummaryrefslogtreecommitdiffstats
path: root/fs/utimes.c
blob: 99cf2cb11fec4ad0090c9d2f12d966a7dadb1ef1 (plain) (blame) 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138

#include <linux/compiler.h>
#include <linux/fs.h>
#include <linux/linkage.h>
#include <linux/namei.h>
#include <linux/sched.h>
#include <linux/utime.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>

#ifdef __ARCH_WANT_SYS_UTIME

/*
 * sys_utime() can be implemented in user-level using sys_utimes().
 * Is this for backwards compatibility?  If so, why not move it
 * into the appropriate arch directory (for those architectures that
 * need it).
 */

/* If times==NULL, set access and modification to current time,
 * must be owner or have write permission.
 * Else, update from *times, must be owner or super user.
 */
asmlinkage long sys_utime(char __user * filename, struct utimbuf __user * times)
{
	int error;
	struct nameidata nd;
	struct inode * inode;
	struct iattr newattrs;

	error = user_path_walk(filename, &nd);
	if (error)
		goto out;
	inode = nd.dentry->d_inode;

	error = -EROFS;
	if (IS_RDONLY(inode))
		goto dput_and_out;

	/* Don't worry, the checks are done in inode_change_ok() */
	newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
	if (times) {
		error = -EPERM;
		if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
			goto dput_and_out;

		error = get_user(newattrs.ia_atime.tv_sec, &times->actime);
		newattrs.ia_atime.tv_nsec = 0;
		if (!error)
			error = get_user(newattrs.ia_mtime.tv_sec, &times->modtime);
		newattrs.ia_mtime.tv_nsec = 0;
		if (error)
			goto dput_and_out;

		newattrs.ia_valid |= ATTR_ATIME_SET | ATTR_MTIME_SET;
	} else {
                error = -EACCES;
                if (IS_IMMUTABLE(inode))
                        goto dput_and_out;

		if (current->fsuid != inode->i_uid &&
		    (error = vfs_permission(&nd, MAY_WRITE)) != 0)
			goto dput_and_out;
	}
	mutex_lock(&inode->i_mutex);
	error = notify_change(nd.dentry, &newattrs);
	mutex_unlock(&inode->i_mutex);
dput_and_out:
	path_release(&nd);
out:
	return error;
}

#endif

/* If times==NULL, set access and modification to current time,
 * must be owner or have write permission.
 * Else, update from *times, must be owner or super user.
 */
long do_utimes(int dfd, char __user *filename, struct timeval *times)
{
	int error;
	struct nameidata nd;
	struct inode * inode;
	struct iattr newattrs;

	error = __user_walk_fd(dfd, filename, LOOKUP_FOLLOW, &nd);

	if (error)
		goto out;
	inode = nd.dentry->d_inode;

	error = -EROFS;
	if (IS_RDONLY(inode))
		goto dput_and_out;

	/* Don't worry, the checks are done in inode_change_ok() */
	newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
	if (times) {
		error = -EPERM;
                if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
                        goto dput_and_out;

		newattrs.ia_atime.tv_sec = times[0].tv_sec;
		newattrs.ia_atime.tv_nsec = times[0].tv_usec * 1000;
		newattrs.ia_mtime.tv_sec = times[1].tv_sec;
		newattrs.ia_mtime.tv_nsec = times[1].tv_usec * 1000;
		newattrs.ia_valid |= ATTR_ATIME_SET | ATTR_MTIME_SET;
	} else {
		error = -EACCES;
                if (IS_IMMUTABLE(inode))
                        goto dput_and_out;

		if (current->fsuid != inode->i_uid &&
		    (error = vfs_permission(&nd, MAY_WRITE)) != 0)
			goto dput_and_out;
	}
	mutex_lock(&inode->i_mutex);
	error = notify_change(nd.dentry, &newattrs);
	mutex_unlock(&inode->i_mutex);
dput_and_out:
	path_release(&nd);
out:
	return error;
}

asmlinkage long sys_futimesat(int dfd, char __user *filename, struct timeval __user *utimes)
{
	struct timeval times[2];

	if (utimes && copy_from_user(&times, utimes, sizeof(times)))
		return -EFAULT;
	return do_utimes(dfd, filename, utimes ? times : NULL);
}

asmlinkage long sys_utimes(char __user *filename, struct timeval __user *utimes)
{
	return sys_futimesat(AT_FDCWD, filename, utimes);
}
generated by cgit v1.2.2 (git 2.25.0) at 2025-09-20 11:09:04 -0400
void __poison_element(void *element, size_t size) { u8 *obj = element; memset(obj, POISON_FREE, size - 1); obj[size - 1] = POISON_END; } static void poison_element(mempool_t *pool, void *element) { /* Mempools backed by slab allocator */ if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc) __poison_element(element, ksize(element)); /* Mempools backed by page allocator */ if (pool->alloc == mempool_alloc_pages) { int order = (int)(long)pool->pool_data; void *addr = kmap_atomic((struct page *)element); __poison_element(addr, 1UL << (PAGE_SHIFT + order)); kunmap_atomic(addr); } } #else /* CONFIG_DEBUG_SLAB || CONFIG_SLUB_DEBUG_ON */ static inline void check_element(mempool_t *pool, void *element) { } static inline void poison_element(mempool_t *pool, void *element) { } #endif /* CONFIG_DEBUG_SLAB || CONFIG_SLUB_DEBUG_ON */ static void kasan_poison_element(mempool_t *pool, void *element) { if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc) kasan_poison_kfree(element); if (pool->alloc == mempool_alloc_pages) kasan_free_pages(element, (unsigned long)pool->pool_data); } static void kasan_unpoison_element(mempool_t *pool, void *element, gfp_t flags) { if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc) kasan_unpoison_slab(element); if (pool->alloc == mempool_alloc_pages) kasan_alloc_pages(element, (unsigned long)pool->pool_data); } static void add_element(mempool_t *pool, void *element) { BUG_ON(pool->curr_nr >= pool->min_nr); poison_element(pool, element); kasan_poison_element(pool, element); pool->elements[pool->curr_nr++] = element; } static void *remove_element(mempool_t *pool, gfp_t flags) { void *element = pool->elements[--pool->curr_nr]; BUG_ON(pool->curr_nr < 0); kasan_unpoison_element(pool, element, flags); check_element(pool, element); return element; } /** * mempool_destroy - deallocate a memory pool * @pool: pointer to the memory pool which was allocated via * mempool_create(). * * Free all reserved elements in @pool and @pool itself. This function * only sleeps if the free_fn() function sleeps. */ void mempool_destroy(mempool_t *pool) { if (unlikely(!pool)) return; while (pool->curr_nr) { void *element = remove_element(pool, GFP_KERNEL); pool->free(element, pool->pool_data); } kfree(pool->elements); kfree(pool); } EXPORT_SYMBOL(mempool_destroy); /** * mempool_create - create a memory pool * @min_nr: the minimum number of elements guaranteed to be * allocated for this pool. * @alloc_fn: user-defined element-allocation function. * @free_fn: user-defined element-freeing function. * @pool_data: optional private data available to the user-defined functions. * * this function creates and allocates a guaranteed size, preallocated * memory pool. The pool can be used from the mempool_alloc() and mempool_free() * functions. This function might sleep. Both the alloc_fn() and the free_fn() * functions might sleep - as long as the mempool_alloc() function is not called * from IRQ contexts. */ mempool_t *mempool_create(int min_nr, mempool_alloc_t *alloc_fn, mempool_free_t *free_fn, void *pool_data) { return mempool_create_node(min_nr,alloc_fn,free_fn, pool_data, GFP_KERNEL, NUMA_NO_NODE); } EXPORT_SYMBOL(mempool_create); mempool_t *mempool_create_node(int min_nr, mempool_alloc_t *alloc_fn, mempool_free_t *free_fn, void *pool_data, gfp_t gfp_mask, int node_id) { mempool_t *pool; pool = kzalloc_node(sizeof(*pool), gfp_mask, node_id); if (!pool) return NULL; pool->elements = kmalloc_node(min_nr * sizeof(void *), gfp_mask, node_id); if (!pool->elements) { kfree(pool); return NULL; } spin_lock_init(&pool->lock); pool->min_nr = min_nr; pool->pool_data = pool_data; init_waitqueue_head(&pool->wait); pool->alloc = alloc_fn; pool->free = free_fn; /* * First pre-allocate the guaranteed number of buffers. */ while (pool->curr_nr < pool->min_nr) { void *element; element = pool->alloc(gfp_mask, pool->pool_data); if (unlikely(!element)) { mempool_destroy(pool); return NULL; } add_element(pool, element); } return pool; } EXPORT_SYMBOL(mempool_create_node); /** * mempool_resize - resize an existing memory pool * @pool: pointer to the memory pool which was allocated via * mempool_create(). * @new_min_nr: the new minimum number of elements guaranteed to be * allocated for this pool. * * This function shrinks/grows the pool. In the case of growing, * it cannot be guaranteed that the pool will be grown to the new * size immediately, but new mempool_free() calls will refill it. * This function may sleep. * * Note, the caller must guarantee that no mempool_destroy is called * while this function is running. mempool_alloc() & mempool_free() * might be called (eg. from IRQ contexts) while this function executes. */ int mempool_resize(mempool_t *pool, int new_min_nr) { void *element; void **new_elements; unsigned long flags; BUG_ON(new_min_nr <= 0); might_sleep(); spin_lock_irqsave(&pool->lock, flags); if (new_min_nr <= pool->min_nr) { while (new_min_nr < pool->curr_nr) { element = remove_element(pool, GFP_KERNEL); spin_unlock_irqrestore(&pool->lock, flags); pool->free(element, pool->pool_data); spin_lock_irqsave(&pool->lock, flags); } pool->min_nr = new_min_nr; goto out_unlock; } spin_unlock_irqrestore(&pool->lock, flags); /* Grow the pool */ new_elements = kmalloc_array(new_min_nr, sizeof(*new_elements), GFP_KERNEL); if (!new_elements) return -ENOMEM; spin_lock_irqsave(&pool->lock, flags); if (unlikely(new_min_nr <= pool->min_nr)) { /* Raced, other resize will do our work */ spin_unlock_irqrestore(&pool->lock, flags); kfree(new_elements); goto out; } memcpy(new_elements, pool->elements, pool->curr_nr * sizeof(*new_elements)); kfree(pool->elements); pool->elements = new_elements; pool->min_nr = new_min_nr; while (pool->curr_nr < pool->min_nr) { spin_unlock_irqrestore(&pool->lock, flags); element = pool->alloc(GFP_KERNEL, pool->pool_data); if (!element) goto out; spin_lock_irqsave(&pool->lock, flags); if (pool->curr_nr < pool->min_nr) { add_element(pool, element); } else { spin_unlock_irqrestore(&pool->lock, flags); pool->free(element, pool->pool_data); /* Raced */ goto out; } } out_unlock: spin_unlock_irqrestore(&pool->lock, flags); out: return 0; } EXPORT_SYMBOL(mempool_resize); /** * mempool_alloc - allocate an element from a specific memory pool * @pool: pointer to the memory pool which was allocated via * mempool_create(). * @gfp_mask: the usual allocation bitmask. * * this function only sleeps if the alloc_fn() function sleeps or * returns NULL. Note that due to preallocation, this function * *never* fails when called from process contexts. (it might * fail if called from an IRQ context.) * Note: using __GFP_ZERO is not supported. */ void *mempool_alloc(mempool_t *pool, gfp_t gfp_mask) { void *element; unsigned long flags; wait_queue_t wait; gfp_t gfp_temp; VM_WARN_ON_ONCE(gfp_mask & __GFP_ZERO); might_sleep_if(gfp_mask & __GFP_DIRECT_RECLAIM); gfp_mask |= __GFP_NOMEMALLOC; /* don't allocate emergency reserves */ gfp_mask |= __GFP_NORETRY; /* don't loop in __alloc_pages */ gfp_mask |= __GFP_NOWARN; /* failures are OK */ gfp_temp = gfp_mask & ~(__GFP_DIRECT_RECLAIM|__GFP_IO); repeat_alloc: element = pool->alloc(gfp_temp, pool->pool_data); if (likely(element != NULL)) return element; spin_lock_irqsave(&pool->lock, flags); if (likely(pool->curr_nr)) { element = remove_element(pool, gfp_temp); spin_unlock_irqrestore(&pool->lock, flags); /* paired with rmb in mempool_free(), read comment there */ smp_wmb(); /* * Update the allocation stack trace as this is more useful * for debugging. */ kmemleak_update_trace(element); return element; } /* * We use gfp mask w/o direct reclaim or IO for the first round. If * alloc failed with that and @pool was empty, retry immediately. */ if (gfp_temp != gfp_mask) { spin_unlock_irqrestore(&pool->lock, flags); gfp_temp = gfp_mask; goto repeat_alloc; } /* We must not sleep if !__GFP_DIRECT_RECLAIM */ if (!(gfp_mask & __GFP_DIRECT_RECLAIM)) { spin_unlock_irqrestore(&pool->lock, flags); return NULL; } /* Let's wait for someone else to return an element to @pool */ init_wait(&wait); prepare_to_wait(&pool->wait, &wait, TASK_UNINTERRUPTIBLE); spin_unlock_irqrestore(&pool->lock, flags); /* * FIXME: this should be io_schedule(). The timeout is there as a * workaround for some DM problems in 2.6.18. */ io_schedule_timeout(5*HZ); finish_wait(&pool->wait, &wait); goto repeat_alloc; } EXPORT_SYMBOL(mempool_alloc); /** * mempool_free - return an element to the pool. * @element: pool element pointer. * @pool: pointer to the memory pool which was allocated via * mempool_create(). * * this function only sleeps if the free_fn() function sleeps. */ void mempool_free(void *element, mempool_t *pool) { unsigned long flags; if (unlikely(element == NULL)) return; /* * Paired with the wmb in mempool_alloc(). The preceding read is * for @element and the following @pool->curr_nr. This ensures * that the visible value of @pool->curr_nr is from after the * allocation of @element. This is necessary for fringe cases * where @element was passed to this task without going through * barriers. * * For example, assume @p is %NULL at the beginning and one task * performs "p = mempool_alloc(...);" while another task is doing * "while (!p) cpu_relax(); mempool_free(p, ...);". This function * may end up using curr_nr value which is from before allocation * of @p without the following rmb. */ smp_rmb(); /* * For correctness, we need a test which is guaranteed to trigger * if curr_nr + #allocated == min_nr. Testing curr_nr < min_nr * without locking achieves that and refilling as soon as possible * is desirable. * * Because curr_nr visible here is always a value after the * allocation of @element, any task which decremented curr_nr below * min_nr is guaranteed to see curr_nr < min_nr unless curr_nr gets * incremented to min_nr afterwards. If curr_nr gets incremented * to min_nr after the allocation of @element, the elements * allocated after that are subject to the same guarantee. * * Waiters happen iff curr_nr is 0 and the above guarantee also * ensures that there will be frees which return elements to the * pool waking up the waiters. */ if (unlikely(pool->curr_nr < pool->min_nr)) { spin_lock_irqsave(&pool->lock, flags); if (likely(pool->curr_nr < pool->min_nr)) { add_element(pool, element); spin_unlock_irqrestore(&pool->lock, flags); wake_up(&pool->wait); return; } spin_unlock_irqrestore(&pool->lock, flags); } pool->free(element, pool->pool_data); } EXPORT_SYMBOL(mempool_free); /* * A commonly used alloc and free fn. */ void *mempool_alloc_slab(gfp_t gfp_mask, void *pool_data) { struct kmem_cache *mem = pool_data; VM_BUG_ON(mem->ctor); return kmem_cache_alloc(mem, gfp_mask); } EXPORT_SYMBOL(mempool_alloc_slab); void mempool_free_slab(void *element, void *pool_data) { struct kmem_cache *mem = pool_data; kmem_cache_free(mem, element); } EXPORT_SYMBOL(mempool_free_slab); /* * A commonly used alloc and free fn that kmalloc/kfrees the amount of memory * specified by pool_data */ void *mempool_kmalloc(gfp_t gfp_mask, void *pool_data) { size_t size = (size_t)pool_data; return kmalloc(size, gfp_mask); } EXPORT_SYMBOL(mempool_kmalloc); void mempool_kfree(void *element, void *pool_data) { kfree(element); } EXPORT_SYMBOL(mempool_kfree); /* * A simple mempool-backed page allocator that allocates pages * of the order specified by pool_data. */ void *mempool_alloc_pages(gfp_t gfp_mask, void *pool_data) { int order = (int)(long)pool_data; return alloc_pages(gfp_mask, order); } EXPORT_SYMBOL(mempool_alloc_pages); void mempool_free_pages(void *element, void *pool_data) { int order = (int)(long)pool_data; __free_pages(element, order); } EXPORT_SYMBOL(mempool_free_pages);
generated by cgit v1.2.2 (git 2.25.0) at 2025-09-20 11:09:04 -0400