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fs: Implement file_mmap and file_munmap API

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Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
This commit is contained in:
Xiang Xiao
2021-03-20 05:06:08 +08:00
committed by Masayuki Ishikawa
parent 2b0b298ab6
commit 8612af4ae5
5 changed files with 346 additions and 234 deletions
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fs/mmap/fs_mmap.c
+150 -116
View File
@@ -37,10 +37,156 @@
#include "inode/inode.h"
#include "fs_rammap.h"
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: file_mmap_
****************************************************************************/
static int file_mmap_(FAR struct file *filep, FAR void *start,
size_t length, int prot, int flags,
off_t offset, bool kernel, FAR void **mapped)
{
FAR void *addr;
int ret;
/* Since only a tiny subset of mmap() functionality, we have to verify many
* things.
*/
#ifdef CONFIG_DEBUG_FEATURES
/* Fixed mappings and protections are not currently supported. These
* options could be supported in the KERNEL build with an MMU, but that
* logic is not in place.
*/
if ((flags & (MAP_FIXED | MAP_DENYWRITE)) != 0)
{
ferr("ERROR: Unsupported options, prot=%x flags=%04x\n", prot, flags);
return -ENOSYS;
}
#ifndef CONFIG_FS_RAMMAP
if ((flags & MAP_PRIVATE) != 0)
{
ferr("ERROR: MAP_PRIVATE is not supported without file mapping"
"emulation\n");
return -ENOSYS;
}
#endif /* CONFIG_FS_RAMMAP */
/* A length of 0 is invalid. */
if (length == 0)
{
ferr("ERROR: Invalid length, length=%zu\n", length);
return -EINVAL;
}
#endif /* CONFIG_DEBUG_FEATURES */
if ((filep->f_oflags & O_WROK) == 0 && prot == PROT_WRITE &&
(flags & MAP_SHARED) != 0)
{
ferr("ERROR: Unsupported options for read-only file descriptor,"
"prot=%x flags=%04x\n", prot, flags);
return -EACCES;
}
if ((filep->f_oflags & O_RDOK) == 0)
{
ferr("ERROR: File descriptor does not have read permission\n");
return -EACCES;
}
/* Check if we are just be asked to allocate memory, i.e., MAP_ANONYMOUS
* set meaning that the memory is not backed up from a file. The file
* descriptor should be -1 (or refer to opened /dev/zero) in this case.
* The file descriptor is ignored in either case.
*/
if ((flags & MAP_ANONYMOUS) != 0)
{
/* REVISIT: Should reside outside of the heap. That is really the
* only purpose of MAP_ANONYMOUS: To get non-heap memory. In KERNEL
* build, this could be accomplished using pgalloc(), provided that
* you had logic in place to assign a virtual address to the mapping.
*/
*mapped = kernel ? kmm_zalloc(length) : kumm_zalloc(length);
if (*mapped == NULL)
{
ferr("ERROR: kumm_alloc() failed: %d\n", ret);
return -ENOMEM;
}
return OK;
}
if ((flags & MAP_PRIVATE) != 0)
{
#ifdef CONFIG_FS_RAMMAP
/* Allocate memory and copy the file into memory. We would, of course,
* do much better in the KERNEL build using the MMU.
*/
return rammap(filep, length, offset, kernel, mapped);
#endif
}
/* Perform the ioctl to get the base address of the file in 'mapped'
* in memory. (casting to uintptr_t first eliminates complaints on some
* architectures where the sizeof long is different from the size of
* a pointer).
*/
ret = file_ioctl(filep, FIOC_MMAP, (unsigned long)((uintptr_t)&addr));
if (ret < 0)
{
/* Not directly mappable, probably because the underlying media does
* not support random access.
*/
#ifdef CONFIG_FS_RAMMAP
/* Allocate memory and copy the file into memory. We would, of course,
* do much better in the KERNEL build using the MMU.
*/
return rammap(filep, length, offset, kernel, mapped);
#else
ferr("ERROR: file_ioctl(FIOC_MMAP) failed: %d\n", ret);
return ret;
#endif
}
/* Return the offset address */
*mapped = (FAR void *)(((FAR uint8_t *)addr) + offset);
return OK;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: file_mmap
*
* Description:
* Equivalent to the standard mmap() function except that is accepts
* a struct file instance instead of a file descriptor and it does not set
* the errno variable.
*
****************************************************************************/
int file_mmap(FAR struct file *filep, FAR void *start, size_t length,
int prot, int flags, off_t offset, FAR void **mapped)
{
return file_mmap_(filep, start, length,
prot, flags, offset, true, mapped);
}
/****************************************************************************
* Name: mmap
*
@@ -118,47 +264,10 @@
FAR void *mmap(FAR void *start, size_t length, int prot, int flags,
int fd, off_t offset)
{
FAR void *addr;
FAR struct file *filep;
FAR void *mapped;
int ret;
/* Since only a tiny subset of mmap() functionality, we have to verify many
* things.
*/
#ifdef CONFIG_DEBUG_FEATURES
/* Fixed mappings and protections are not currently supported. These
* options could be supported in the KERNEL build with an MMU, but that
* logic is not in place.
*/
if ((flags & (MAP_FIXED | MAP_DENYWRITE)) != 0)
{
ferr("ERROR: Unsupported options, prot=%x flags=%04x\n", prot, flags);
ret = -ENOSYS;
goto errout;
}
#ifndef CONFIG_FS_RAMMAP
if ((flags & MAP_PRIVATE) != 0)
{
ferr("ERROR: MAP_PRIVATE is not supported without file mapping"
"emulation\n");
ret = -ENOSYS;
goto errout;
}
#endif /* CONFIG_FS_RAMMAP */
/* A length of 0 is invalid. */
if (length == 0)
{
ferr("ERROR: Invalid length, length=%zu\n", length);
ret = -EINVAL;
goto errout;
}
#endif /* CONFIG_DEBUG_FEATURES */
if (fs_getfilep(fd, &filep) < 0)
{
ferr("ERROR: Invalid file descriptor, fd=%d\n", fd);
@@ -166,89 +275,14 @@ FAR void *mmap(FAR void *start, size_t length, int prot, int flags,
goto errout;
}
if ((filep->f_oflags & O_WROK) == 0 && prot == PROT_WRITE &&
(flags & MAP_SHARED) != 0)
{
ferr("ERROR: Unsupported options for read-only file descriptor,"
"fd=%d prot=%x flags=%04x\n", fd, prot, flags);
ret = -EACCES;
goto errout;
}
if ((filep->f_oflags & O_RDOK) == 0)
{
ferr("ERROR: File descriptor does not have read permission,"
"fd=%d\n", fd);
ret = -EACCES;
goto errout;
}
/* Check if we are just be asked to allocate memory, i.e., MAP_ANONYMOUS
* set meaning that the memory is not backed up from a file. The file
* descriptor should be -1 (or refer to opened /dev/zero) in this case.
* The file descriptor is ignored in either case.
*/
if ((flags & MAP_ANONYMOUS) != 0)
{
FAR void *alloc;
/* REVISIT: Should reside outside of the heap. That is really the
* only purpose of MAP_ANONYMOUS: To get non-heap memory. In KERNEL
* build, this could be accomplished using pgalloc(), provided that
* you had logic in place to assign a virtual address to the mapping.
*/
alloc = kumm_zalloc(length);
if (alloc == NULL)
{
ferr("ERROR: kumm_alloc() failed: %d\n", ret);
ret = -ENOMEM;
goto errout;
}
return alloc;
}
if ((flags & MAP_PRIVATE) != 0)
{
#ifdef CONFIG_FS_RAMMAP
/* Allocate memory and copy the file into memory. We would, of course,
* do much better in the KERNEL build using the MMU.
*/
return rammap(fd, length, offset);
#endif
}
/* Perform the ioctl to get the base address of the file in 'mapped'
* in memory. (casting to uintptr_t first eliminates complaints on some
* architectures where the sizeof long is different from the size of
* a pointer).
*/
ret = nx_ioctl(fd, FIOC_MMAP, (unsigned long)((uintptr_t)&addr));
ret = file_mmap_(filep, start, length,
prot, flags, offset, false, &mapped);
if (ret < 0)
{
/* Not directly mappable, probably because the underlying media does
* not support random access.
*/
#ifdef CONFIG_FS_RAMMAP
/* Allocate memory and copy the file into memory. We would, of course,
* do much better in the KERNEL build using the MMU.
*/
return rammap(fd, length, offset);
#else
ferr("ERROR: nx_ioctl(FIOC_MMAP) failed: %d\n", ret);
goto errout;
#endif
}
/* Return the offset address */
return (FAR void *)(((FAR uint8_t *)addr) + offset);
return mapped;
errout:
set_errno(-ret);