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| -rw-r--r-- | libstore/unzipstore.c | 267 |
1 files changed, 267 insertions, 0 deletions
diff --git a/libstore/unzipstore.c b/libstore/unzipstore.c new file mode 100644 index 00000000..35e9e7af --- /dev/null +++ b/libstore/unzipstore.c @@ -0,0 +1,267 @@ +/* Decompressing store backend (common code for gunzip and bunzip2) + + Copyright (C) 1998, 1999, 2002 Free Software Foundation, Inc. + Written by okuji@kuicr.kyoto-u.ac.jp <okuji@kuicr.kyoto-u.ac.jp> + This file is part of the GNU Hurd. + + The GNU Hurd is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License as + published by the Free Software Foundation; either version 2, or (at + your option) any later version. + + The GNU Hurd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA. */ + +#include <stdio.h> +#include <string.h> +#include <setjmp.h> +#include <cthreads.h> +#include <sys/mman.h> + +#include "store.h" + +#define IN_BUFFERING (256*1024) +#define OUT_BUFFERING (512*1024) + +static struct mutex unzip_lock = MUTEX_INITIALIZER; + +#define STORE_UNZIP(name) STORE_UNZIP_1 (UNZIP, name) +#define STORE_UNZIP_1(unzip,name) STORE_UNZIP_2 (unzip, name) +#define STORE_UNZIP_2(unzip,name) store_##unzip##_##name +#define STORE_STD_CLASS_1(name) STORE_STD_CLASS(name) +#define STRINGIFY(name) STRINGIFY_1(name) +#define STRINGIFY_1(name) #name + + +/* Uncompress the contents of FROM, which should contain a valid bzip2 file, + into memory, returning the result buffer in BUF & BUF_LEN. */ +static error_t +unzip_store (struct store *from, void **buf, size_t *buf_len) +{ + /* Callbacks from decompression engine for I/O and error interface. */ + extern int (*unzip_read) (char *buf, size_t maxread); + extern void (*unzip_write) (const char *buf, size_t nwrite); + extern void (*unzip_read_error) (void); + extern void (*unzip_error) (const char *msg); + + /* How we return errors from our hook functions. */ + jmp_buf zerr_jmp_buf; + error_t zerr; + + /* vm_alloced buffer for the input store. */ + void *in_buf = 0; + size_t in_buf_len = 0; /* Amount of valid data in IN_BUF. */ + size_t in_buf_size = 0; /* Allocated space for IN_BUF. */ + size_t in_buf_offs = 0; /* Offset of read point in IN_BUF. */ + off_t in_buf_addr = 0; /* Address in FROM of *next* IN_BUF. */ + + /* Buffer input in units that are least IN_BUFFERING bytes, but are also a + multiple of FROM's block size. */ + size_t in_addr_mask = ((1 << from->log2_block_size) - 1); + size_t in_buffering = ((IN_BUFFERING + in_addr_mask) & ~in_addr_mask); + + /* Read at most MAXREAD (or 0 if eof) bytes into BUF from our current + position in FROM. */ + int zread (char *buf, size_t maxread) + { + size_t did_read = 0; + + while (maxread > 0) + { + size_t left = in_buf_len - in_buf_offs; + + if (left > 0) + /* Fill BUF with what we can from IN_BUF. */ + { + if (left > maxread) + left = maxread; + bcopy (in_buf + in_buf_offs, buf, left); + in_buf_offs += left; + buf += left; + maxread -= left; + did_read += left; + } + + /* Limit MAXREAD to the number of bytes left in the input. */ + if (maxread > (from->size - (in_buf_addr << from->log2_block_size))) + maxread = from->size - (in_buf_addr << from->log2_block_size); + + if (maxread > 0) + /* Have to fill IN_BUF again. */ + { + void *new_in_buf = in_buf; + size_t new_in_buf_len = in_buf_len; + + zerr = store_read (from, in_buf_addr, in_buffering, + &new_in_buf, &new_in_buf_len); + if (zerr) + longjmp (zerr_jmp_buf, 1); + + in_buf_addr += (new_in_buf_len >> from->log2_block_size); + + if (new_in_buf != in_buf) + { + if (in_buf_size > 0) + munmap (in_buf, in_buf_size); + in_buf = new_in_buf; + in_buf_size = new_in_buf_len; + } + + in_buf_len = new_in_buf_len; + in_buf_offs = 0; + } + } + return did_read; + } + + size_t out_buf_offs = 0; /* Position in the output buffer. */ + + /* Write compress data to our output buffer. */ + void zwrite (const char *wbuf, size_t nwrite) + { + size_t old_buf_len = *buf_len; + + if (out_buf_offs + nwrite > old_buf_len) + /* Have to grow the output buffer. */ + { + void *old_buf = *buf; + void *new_buf = old_buf + old_buf_len; /* First try. */ + size_t new_buf_len = round_page (old_buf_len + old_buf_len + nwrite); + + /* Try to grow the buffer. */ + zerr = + vm_allocate (mach_task_self (), + (vm_address_t *)&new_buf, new_buf_len - old_buf_len, + 0); + if (zerr) + /* Can't do that, try to make a bigger buffer elsewhere. */ + { + new_buf = mmap (0, new_buf_len, PROT_READ|PROT_WRITE, + MAP_ANON, 0, 0); + zerr = (new_buf == (void *) -1) ? errno : 0; + if (zerr) + longjmp (zerr_jmp_buf, 1); + + if (out_buf_offs > 0) + /* Copy the old buffer into the start of the new & free it. */ + bcopy (old_buf, new_buf, out_buf_offs); + + munmap (old_buf, old_buf_len); + + *buf = new_buf; + } + + *buf_len = new_buf_len; + } + + bcopy (wbuf, *buf + out_buf_offs, nwrite); + out_buf_offs += nwrite; + } + + void zreaderr (void) + { + zerr = EIO; + longjmp (zerr_jmp_buf, 1); + } + void zerror (const char *msg) + { + zerr = EINVAL; + longjmp (zerr_jmp_buf, 2); + } + + /* Try to guess a reasonable output buffer size. */ + *buf_len = round_page (from->size * 2); + *buf = mmap (0, *buf_len, PROT_READ|PROT_WRITE, MAP_ANON, 0, 0); + zerr = (*buf == (void *) -1) ? errno : 0; + if (zerr) + return zerr; + + mutex_lock (&unzip_lock); + + unzip_read = zread; + unzip_write = zwrite; + unzip_read_error = zreaderr; + unzip_error = zerror; + + if (! setjmp (zerr_jmp_buf)) + { + /* Call the decompression engine. */ + zerr = DO_UNZIP (); + } + + mutex_unlock (&unzip_lock); + + if (in_buf_size > 0) + munmap (in_buf, in_buf_size); + + if (zerr) + { + if (*buf_len > 0) + munmap (*buf, *buf_len); + } + else if (out_buf_offs < *buf_len) + /* Trim the output buffer to be the right length. */ + { + size_t end = round_page (out_buf_offs); + if (end < *buf_len) + munmap (*buf + end, *buf_len - end); + *buf_len = out_buf_offs; + } + + return zerr; +} + + +/* Return a new store in STORE which contains a snapshot of the uncompressed + contents of the store FROM; FROM is consumed. */ +error_t +STORE_UNZIP(create) (struct store *from, int flags, struct store **store) +{ + void *buf; + size_t buf_len; + error_t err = unzip_store (from, &buf, &buf_len); + + if (! err) + { + err = store_buffer_create (buf, buf_len, flags, store); + if (err) + munmap (buf, buf_len); + else + store_free (from); + } + + return err; +} + +/* Open the compressed store NAME -- which consists of another store-class + name, a ':', and a name for that store class to open -- and return the + corresponding store in STORE. CLASSES is used to select classes + specified by the type name; if it is 0, STORE_STD_CLASSES is used. */ +error_t +STORE_UNZIP(open) (const char *name, int flags, + const struct store_class *const *classes, + struct store **store) +{ + struct store *from; + error_t err = + store_typed_open (name, flags | STORE_HARD_READONLY, classes, &from); + + if (! err) + { + err = STORE_UNZIP(create) (from, flags, store); + if (err) + store_free (from); + } + + return err; +} + +const struct store_class STORE_UNZIP(class) = +{ -1, STRINGIFY(UNZIP), open: STORE_UNZIP(open) }; +STORE_STD_CLASS_1 (UNZIP); |