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#include "network_backends.h"
#include "network.h"
#include "log.h"
#include "sys-mmap.h"
#include <setjmp.h>
#include <signal.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#define MMAP_CHUNK_SIZE (512*1024)
off_t mmap_align_offset(off_t start) {
static long pagesize = 0;
if (0 == pagesize) {
pagesize = sysconf(_SC_PAGESIZE);
force_assert(pagesize < MMAP_CHUNK_SIZE);
}
force_assert(start >= (start % pagesize));
return start - (start % pagesize);
}
#if defined(USE_MMAP)
static volatile int sigbus_jmp_valid;
static sigjmp_buf sigbus_jmp;
static void sigbus_handler(int sig) {
UNUSED(sig);
if (sigbus_jmp_valid) siglongjmp(sigbus_jmp, 1);
log_failed_assert(__FILE__, __LINE__, "SIGBUS");
}
#if 0
/* read mmap()ed data into local buffer */
#define LOCAL_BUFFERING 1
#endif
int network_write_file_chunk_mmap(server *srv, connection *con, int fd, chunkqueue *cq, off_t *p_max_bytes) {
chunk* const c = cq->first;
off_t offset, toSend, file_end;
ssize_t r;
size_t mmap_offset, mmap_avail;
const char *data;
force_assert(NULL != c);
force_assert(FILE_CHUNK == c->type);
force_assert(c->offset >= 0 && c->offset <= c->file.length);
offset = c->file.start + c->offset;
toSend = c->file.length - c->offset;
if (toSend > *p_max_bytes) toSend = *p_max_bytes;
file_end = c->file.start + c->file.length; /* offset to file end in this chunk */
if (0 == toSend) {
chunkqueue_remove_finished_chunks(cq);
return 0;
}
if (0 != network_open_file_chunk(srv, con, cq)) return -1;
/* setup SIGBUS handler, but don't activate sigbus_jmp_valid yet */
if (0 != sigsetjmp(sigbus_jmp, 1)) {
sigbus_jmp_valid = 0;
log_error_write(srv, __FILE__, __LINE__, "sbd", "SIGBUS in mmap:",
c->file.name, c->file.fd);
munmap(c->file.mmap.start, c->file.mmap.length);
c->file.mmap.start = MAP_FAILED;
#ifdef LOCAL_BUFFERING
buffer_reset(c->mem);
#endif
return -1;
}
signal(SIGBUS, sigbus_handler);
/* mmap the buffer if offset is outside old mmap area or not mapped at all */
if (MAP_FAILED == c->file.mmap.start
|| offset < c->file.mmap.offset
|| offset >= (off_t)(c->file.mmap.offset + c->file.mmap.length)) {
if (MAP_FAILED != c->file.mmap.start) {
munmap(c->file.mmap.start, c->file.mmap.length);
c->file.mmap.start = MAP_FAILED;
}
/* Optimizations for the future:
*
* adaptive mem-mapping
* the problem:
* we mmap() the whole file. If someone has alot large files and 32bit
* machine the virtual address area will be unrun and we will have a failing
* mmap() call.
* solution:
* only mmap 16M in one chunk and move the window as soon as we have finished
* the first 8M
*
* read-ahead buffering
* the problem:
* sending out several large files in parallel trashes the read-ahead of the
* kernel leading to long wait-for-seek times.
* solutions: (increasing complexity)
* 1. use madvise
* 2. use a internal read-ahead buffer in the chunk-structure
* 3. use non-blocking IO for file-transfers
* */
c->file.mmap.offset = mmap_align_offset(offset);
/* all mmap()ed areas are MMAP_CHUNK_SIZE except the last which might be smaller */
c->file.mmap.length = MMAP_CHUNK_SIZE;
if (c->file.mmap.offset > file_end - (off_t)c->file.mmap.length) {
c->file.mmap.length = file_end - c->file.mmap.offset;
}
if (MAP_FAILED == (c->file.mmap.start = mmap(NULL, c->file.mmap.length, PROT_READ, MAP_SHARED, c->file.fd, c->file.mmap.offset))) {
log_error_write(srv, __FILE__, __LINE__, "ssbdoo", "mmap failed:",
strerror(errno), c->file.name, c->file.fd, c->file.mmap.offset, (off_t) c->file.mmap.length);
return -1;
}
#if defined(LOCAL_BUFFERING)
sigbus_jmp_valid = 1;
buffer_copy_string_len(c->mem, c->file.mmap.start, c->file.mmap.length);
sigbus_jmp_valid = 0;
#else
# if defined(HAVE_MADVISE)
/* don't advise files < 64Kb */
if (c->file.mmap.length > (64*1024)) {
/* darwin 7 is returning EINVAL all the time and I don't know how to
* detect this at runtime.
*
* ignore the return value for now */
madvise(c->file.mmap.start, c->file.mmap.length, MADV_WILLNEED);
}
# endif
#endif
}
force_assert(offset >= c->file.mmap.offset);
mmap_offset = offset - c->file.mmap.offset;
force_assert(c->file.mmap.length > mmap_offset);
mmap_avail = c->file.mmap.length - mmap_offset;
if (toSend > (off_t) mmap_avail) toSend = mmap_avail;
#if defined(LOCAL_BUFFERING)
data = c->mem->ptr + mmap_offset;
#else
data = c->file.mmap.start + mmap_offset;
#endif
sigbus_jmp_valid = 1;
#if defined(__WIN32)
r = send(fd, data, toSend, 0);
#else /* __WIN32 */
r = write(fd, data, toSend);
#endif /* __WIN32 */
sigbus_jmp_valid = 0;
#if defined(__WIN32)
if (r < 0) {
int lastError = WSAGetLastError();
switch (lastError) {
case WSAEINTR:
case WSAEWOULDBLOCK:
break;
case WSAECONNRESET:
case WSAETIMEDOUT:
case WSAECONNABORTED:
return -2;
default:
log_error_write(srv, __FILE__, __LINE__, "sdd",
"send failed: ", lastError, fd);
return -1;
}
}
#else /* __WIN32 */
if (r < 0) {
switch (errno) {
case EAGAIN:
case EINTR:
break;
case EPIPE:
case ECONNRESET:
return -2;
default:
log_error_write(srv, __FILE__, __LINE__, "ssd",
"write failed:", strerror(errno), fd);
return -1;
}
}
#endif /* __WIN32 */
if (r >= 0) {
*p_max_bytes -= r;
chunkqueue_mark_written(cq, r);
}
return (r > 0 && r == toSend) ? 0 : -3;
}
#endif /* USE_MMAP */