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https://code.videolan.org/videolan/vlc
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block_File: loads a file into a block_t
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@ -148,17 +148,8 @@ static inline void block_Release( block_t *p_block )
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p_block->pf_release( p_block );
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}
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/**
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* Creates a block from a virtual address memory mapping (mmap).
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* This is provided by LibVLC so that mmap blocks can safely be deallocated
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* even after the allocating plugin has been unloaded from memory.
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*
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* @param addr base address of the mapping (as returned by mmap)
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* @param length length (bytes) of the mapping (as passed to mmap)
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* @return NULL if addr is MAP_FAILED, or an error occurred (in the later
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* case, munmap(addr, length) is invoked before returning).
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*/
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VLC_EXPORT( block_t *, block_mmap_Alloc, (void *addr, size_t length) );
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VLC_EXPORT( block_t *, block_File, (int fd) );
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/****************************************************************************
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* Chains of blocks functions helper
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@ -41,6 +41,7 @@ block_FifoRelease
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block_FifoShow
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block_FifoSize
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block_FifoWake
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block_File
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block_Init
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block_mmap_Alloc
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block_Realloc
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@ -29,6 +29,7 @@
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#endif
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#include <vlc/vlc.h>
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#include <sys/stat.h>
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#include "vlc_block.h"
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/*****************************************************************************
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@ -208,6 +209,16 @@ static void block_mmap_Release (block_t *block)
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free (p_sys);
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}
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/**
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* Creates a block from a virtual address memory mapping (mmap).
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* This is provided by LibVLC so that mmap blocks can safely be deallocated
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* even after the allocating plugin has been unloaded from memory.
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*
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* @param addr base address of the mapping (as returned by mmap)
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* @param length length (bytes) of the mapping (as passed to mmap)
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* @return NULL if addr is MAP_FAILED, or an error occurred (in the later
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* case, munmap(addr, length) is invoked before returning).
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*/
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block_t *block_mmap_Alloc (void *addr, size_t length)
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{
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if (addr == MAP_FAILED)
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@ -247,6 +258,79 @@ ssize_t pread (int fd, void *buf, size_t count, off_t offset)
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}
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#endif
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/**
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* Loads a file into a block of memory. If possible a private file mapping is
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* created. Otherwise, the file is read normally. On 32-bits platforms, this
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* function will not work for very large files, due to memory space
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* constraints.
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*
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* @param fd file descriptor to load from
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* @return a new block with the file content at p_buffer, and file length at
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* i_buffer (release it with block_Release()), or NULL upon error (see errno).
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*/
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block_t *block_File (int fd)
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{
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size_t length;
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struct stat st;
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/* First, get the file size */
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if (fstat (fd, &st))
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return NULL;
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/* st_size is meaningful for regular files, shared memory and typed memory.
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* It's also meaning for symlinks, but that's not possible with fstat().
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* In other cases, it's undefined, and we should really not go further. */
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#ifndef S_TYPEISSHM
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# define S_TYPEISSHM( buf ) (0)
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#endif
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if (S_ISDIR (st.st_mode))
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{
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errno = EISDIR;
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return NULL;
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}
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if (!S_ISREG (st.st_mode) && !S_TYPEISSHM (&st))
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{
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errno = ESPIPE;
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return NULL;
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}
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/* Prevent an integer overflow in mmap() and malloc() */
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if (st.st_size >= SIZE_MAX)
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{
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errno = ENOMEM;
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return NULL;
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}
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length = (size_t)st.st_size;
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#ifdef HAVE_MMAP
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if (length > 0)
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{
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void *addr;
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addr = mmap (NULL, length, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
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if (addr != MAP_FAILED)
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return block_mmap_Alloc (addr, length);
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}
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#endif
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/* If mmap() is not implemented by the OS _or_ the filesystem... */
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block_t *block = block_Alloc (length);
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if (block == NULL)
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return NULL;
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for (size_t i = 0; i < length;)
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{
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ssize_t len = pread (fd, block->p_buffer + i, length - i, i);
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if (len == -1)
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{
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block_Release (block);
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return NULL;
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}
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i += len;
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}
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return block;
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}
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/*****************************************************************************
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* block_fifo_t management
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*****************************************************************************/
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