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Code Issues Wiki

Fix mmap offset calculation in chunk.c

personal/stbuehler/wip
Stefan Bühler 2008-08-09 22:11:52 +02:00
parent a863b6f7e9
commit 0d4b5ee989
1 changed files with 11 additions and 9 deletions
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20
src/chunk.c
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@ -96,15 +96,17 @@ handler_t chunkiter_read(server *srv, connection *con, chunkiter iter, off_t sta
case FILE_CHUNK:
if (HANDLER_GO_ON != (res = chunkfile_open(srv, con, c->file.file))) return res;
if (length > MAX_MMAP_CHUNK) length = MAX_MMAP_CHUNK;
if ( !(c->file.mmap.data != MAP_FAILED || c->mem) /* no data present */
|| !( /* or in the wrong range */
(start + c->offset >= c->file.mmap.offset)
&& (start + c->offset + length <= c->file.mmap.offset + (ssize_t) c->file.mmap.length)) ) {
(start + c->offset + c->file.start >= c->file.mmap.offset)
&& (start + c->offset + c->file.start + length <= c->file.mmap.offset + (ssize_t) c->file.mmap.length)) ) {
/* then find new range */
our_offset = start % MMAP_CHUNK_ALIGN;
our_start = start - our_offset;
our_start = start + c->offset + c->file.start; /* "start" maps to this offset in the file */
our_offset = our_start % MMAP_CHUNK_ALIGN; /* offset for "start" in new mmap block */
our_start -= our_offset; /* file offset for mmap */
if (length > MAX_MMAP_CHUNK) length = MAX_MMAP_CHUNK;
we_want = length + MAX_MMAP_CHUNK;
if (we_want > we_have) we_want = we_have;
we_want += our_offset;
@ -113,10 +115,10 @@ handler_t chunkiter_read(server *srv, connection *con, chunkiter iter, off_t sta
munmap(c->file.mmap.data, c->file.mmap.length);
c->file.mmap.data = MAP_FAILED;
}
c->file.mmap.offset = our_offset;
c->file.mmap.offset = our_start;
c->file.mmap.length = we_want;
if (!c->mem) { /* mmap did not fail till now */
c->file.mmap.data = mmap(0, we_want, PROT_READ, MAP_SHARED, c->file.file->fd, our_offset);
c->file.mmap.data = mmap(0, we_want, PROT_READ, MAP_SHARED, c->file.file->fd, our_start);
mmap_errno = errno;
}
if (MAP_FAILED == c->file.mmap.data) {
@ -126,7 +128,7 @@ handler_t chunkiter_read(server *srv, connection *con, chunkiter iter, off_t sta
} else {
g_string_set_size(c->mem, we_want);
}
if (-1 == lseek(c->file.file->fd, our_offset, SEEK_SET)) {
if (-1 == lseek(c->file.file->fd, our_start, SEEK_SET)) {
/* prefer the error of the first syscall */
if (0 != mmap_errno) {
CON_ERROR(srv, con, "mmap failed for '%s' (fd = %i): %s (%i)",
@ -177,7 +179,7 @@ read_chunk:
#endif
}
}
*data_start = (c->mem ? c->mem->str : c->file.mmap.data) + start + c->offset - c->file.mmap.offset;
*data_start = (c->mem ? c->mem->str : c->file.mmap.data) + start + c->offset + c->file.start - c->file.mmap.offset;
*data_len = length;
break;
}