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lighttpd1.4/src/network_write.c

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#include "first.h"
#include "network_write.h"
#include "base.h"
#include "log.h"
#include <sys/types.h>
#include "sys-socket.h"
#include <errno.h>
#include <string.h>
#include <unistd.h>
/* on linux 2.4.x you get either sendfile or LFS */
#if defined HAVE_SYS_SENDFILE_H && defined HAVE_SENDFILE \
&& (!defined _LARGEFILE_SOURCE || defined HAVE_SENDFILE64) \
&& defined(__linux__) && !defined HAVE_SENDFILE_BROKEN
# ifdef NETWORK_WRITE_USE_SENDFILE
# error "can't have more than one sendfile implementation"
# endif
# define NETWORK_WRITE_USE_SENDFILE "linux-sendfile"
# define NETWORK_WRITE_USE_LINUX_SENDFILE
#endif
#if defined HAVE_SENDFILE && (defined(__FreeBSD__) || defined(__DragonFly__))
# ifdef NETWORK_WRITE_USE_SENDFILE
# error "can't have more than one sendfile implementation"
# endif
# define NETWORK_WRITE_USE_SENDFILE "freebsd-sendfile"
# define NETWORK_WRITE_USE_FREEBSD_SENDFILE
#endif
#if defined HAVE_SENDFILE && defined(__APPLE__)
# ifdef NETWORK_WRITE_USE_SENDFILE
# error "can't have more than one sendfile implementation"
# endif
# define NETWORK_WRITE_USE_SENDFILE "darwin-sendfile"
# define NETWORK_WRITE_USE_DARWIN_SENDFILE
#endif
#if defined HAVE_SYS_SENDFILE_H && defined HAVE_SENDFILEV && defined(__sun)
# ifdef NETWORK_WRITE_USE_SENDFILE
# error "can't have more than one sendfile implementation"
# endif
# define NETWORK_WRITE_USE_SENDFILE "solaris-sendfilev"
# define NETWORK_WRITE_USE_SOLARIS_SENDFILEV
#endif
/* not supported so far
#if defined HAVE_SEND_FILE && defined(__aix)
# ifdef NETWORK_WRITE_USE_SENDFILE
# error "can't have more than one sendfile implementation"
# endif
# define NETWORK_WRITE_USE_SENDFILE "aix-sendfile"
# define NETWORK_WRITE_USE_AIX_SENDFILE
#endif
*/
#if defined HAVE_SYS_UIO_H && defined HAVE_WRITEV
# define NETWORK_WRITE_USE_WRITEV
#endif
#if defined HAVE_SYS_MMAN_H && defined HAVE_MMAP && defined ENABLE_MMAP
# define NETWORK_WRITE_USE_MMAP
#endif
static int network_write_error(int fd, log_error_st *errh) {
#if defined(__WIN32)
int lastError = WSAGetLastError();
switch (lastError) {
case WSAEINTR:
case WSAEWOULDBLOCK:
return -3;
case WSAECONNRESET:
case WSAETIMEDOUT:
case WSAECONNABORTED:
return -2;
default:
log_error(errh,__FILE__,__LINE__,"send failed: %d %d",lastError,fd);
return -1;
}
#else /* __WIN32 */
switch (errno) {
case EAGAIN:
case EINTR:
return -3;
case EPIPE:
case ECONNRESET:
return -2;
default:
log_perror(errh,__FILE__,__LINE__,"write failed: %d",fd);
return -1;
}
#endif /* __WIN32 */
}
inline
static ssize_t network_write_data_len(int fd, const char *data, off_t len) {
#if defined(__WIN32)
return send(fd, data, len, 0);
#else /* __WIN32 */
return write(fd, data, len);
#endif /* __WIN32 */
}
/* write next chunk(s); finished chunks are removed afterwards after successful writes.
* return values: similar as backends (0 success, -1 error, -2 remote close, -3 try again later (EINTR/EAGAIN)) */
/* next chunk must be MEM_CHUNK. use write()/send() */
static int network_write_mem_chunk(int fd, chunkqueue *cq, off_t *p_max_bytes, log_error_st *errh) {
chunk* const c = cq->first;
ssize_t wr;
off_t c_len = (off_t)buffer_string_length(c->mem);
force_assert(c->offset >= 0 && c->offset <= c_len);
c_len -= c->offset;
if (c_len > *p_max_bytes) c_len = *p_max_bytes;
if (0 == c_len) {
chunkqueue_remove_finished_chunks(cq);
return 0;
}
wr = network_write_data_len(fd, c->mem->ptr + c->offset, c_len);
if (wr >= 0) {
*p_max_bytes -= wr;
chunkqueue_mark_written(cq, wr);
return (wr > 0 && wr == c_len) ? 0 : -3;
} else {
return network_write_error(fd, errh);
}
}
#if !defined(NETWORK_WRITE_USE_MMAP)
static int network_write_file_chunk_no_mmap(int fd, chunkqueue *cq, off_t *p_max_bytes, log_error_st *errh) {
chunk* const c = cq->first;
off_t offset, toSend;
ssize_t wr;
char buf[16384]; /* max read 16kb in one step */
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;
if (0 == toSend) {
chunkqueue_remove_finished_chunks(cq);
return 0;
}
if (0 != chunkqueue_open_file_chunk(cq, errh)) return -1;
if (toSend > (off_t)sizeof(buf)) toSend = (off_t)sizeof(buf);
if (-1 == lseek(c->file.fd, offset, SEEK_SET)) {
log_perror(errh, __FILE__, __LINE__, "lseek");
return -1;
}
if (-1 == (toSend = read(c->file.fd, buf, toSend))) {
log_perror(errh, __FILE__, __LINE__, "read");
return -1;
}
wr = network_write_data_len(fd, buf, toSend);
if (wr >= 0) {
*p_max_bytes -= wr;
chunkqueue_mark_written(cq, wr);
return (wr > 0 && wr == toSend) ? 0 : -3;
} else {
return network_write_error(fd, errh);
}
}
#endif
#if defined(NETWORK_WRITE_USE_MMAP)
#include "sys-mmap.h"
#include <setjmp.h>
#include <signal.h>
#define MMAP_CHUNK_SIZE (512*1024)
static 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);
}
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");
}
/* next chunk must be FILE_CHUNK. send mmap()ed file with write() */
static int network_write_file_chunk_mmap(int fd, chunkqueue *cq, off_t *p_max_bytes, log_error_st *errh) {
chunk* const c = cq->first;
off_t offset, toSend, file_end;
ssize_t wr;
size_t mmap_offset, mmap_avail;
const char *data;
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; /*file end offset in this chunk*/
if (0 == toSend) {
chunkqueue_remove_finished_chunks(cq);
return 0;
}
if (0 != chunkqueue_open_file_chunk(cq, errh)) return -1;
/* mmap 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 a lot of large files and
* 32-bit machine the virtual address area will be exhausted 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 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;
}
c->file.mmap.start = mmap(NULL, c->file.mmap.length, PROT_READ,
MAP_SHARED, c->file.fd, c->file.mmap.offset);
if (MAP_FAILED == c->file.mmap.start) {
log_perror(errh, __FILE__, __LINE__,
"mmap failed: %s %d %lld %zu", c->mem->ptr, c->file.fd,
(long long)c->file.mmap.offset, c->file.mmap.length);
return -1;
}
#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
}
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;
data = c->file.mmap.start + mmap_offset;
/* setup SIGBUS handler, but don't activate sigbus_jmp_valid yet */
if (0 == sigsetjmp(sigbus_jmp, 1)) {
signal(SIGBUS, sigbus_handler);
sigbus_jmp_valid = 1;
wr = network_write_data_len(fd, data, toSend);
sigbus_jmp_valid = 0;
} else {
sigbus_jmp_valid = 0;
log_error(errh, __FILE__, __LINE__,
"SIGBUS in mmap: %s %d", c->mem->ptr, c->file.fd);
munmap(c->file.mmap.start, c->file.mmap.length);
c->file.mmap.start = MAP_FAILED;
return -1;
}
if (wr >= 0) {
*p_max_bytes -= wr;
chunkqueue_mark_written(cq, wr);
return (wr > 0 && wr == toSend) ? 0 : -3;
} else {
return network_write_error(fd, errh);
}
}
#endif /* NETWORK_WRITE_USE_MMAP */
#if defined(NETWORK_WRITE_USE_WRITEV)
#if defined(HAVE_SYS_UIO_H)
# include <sys/uio.h>
#endif
#if defined(UIO_MAXIOV)
# define SYS_MAX_CHUNKS UIO_MAXIOV
#elif defined(IOV_MAX)
/* new name for UIO_MAXIOV since IEEE Std 1003.1-2001 */
# define SYS_MAX_CHUNKS IOV_MAX
#elif defined(_XOPEN_IOV_MAX)
/* minimum value for sysconf(_SC_IOV_MAX); posix requires this to be at least 16, which is good enough - no need to call sysconf() */
# define SYS_MAX_CHUNKS _XOPEN_IOV_MAX
#else
# error neither UIO_MAXIOV nor IOV_MAX nor _XOPEN_IOV_MAX are defined
#endif
/* allocate iovec[MAX_CHUNKS] on stack, so pick a sane limit:
* - each entry will use 1 pointer + 1 size_t
* - 32 chunks -> 256 / 512 bytes (32-bit/64-bit pointers)
*/
#define STACK_MAX_ALLOC_CHUNKS 32
#if SYS_MAX_CHUNKS > STACK_MAX_ALLOC_CHUNKS
# define MAX_CHUNKS STACK_MAX_ALLOC_CHUNKS
#else
# define MAX_CHUNKS SYS_MAX_CHUNKS
#endif
/* next chunk must be MEM_CHUNK. send multiple mem chunks using writev() */
static int network_writev_mem_chunks(int fd, chunkqueue *cq, off_t *p_max_bytes, log_error_st *errh) {
struct iovec chunks[MAX_CHUNKS];
size_t num_chunks = 0;
off_t max_bytes = *p_max_bytes;
off_t toSend = 0;
ssize_t wr;
for (const chunk *c = cq->first;
NULL != c && MEM_CHUNK == c->type
&& num_chunks < MAX_CHUNKS && toSend < max_bytes;
c = c->next) {
size_t c_len = buffer_string_length(c->mem);
force_assert(c->offset >= 0 && c->offset <= (off_t)c_len);
c_len -= c->offset;
if (c_len > 0) {
toSend += c_len;
chunks[num_chunks].iov_base = c->mem->ptr + c->offset;
chunks[num_chunks].iov_len = c_len;
++num_chunks;
}
}
if (0 == num_chunks) {
chunkqueue_remove_finished_chunks(cq);
return 0;
}
wr = writev(fd, chunks, num_chunks);
if (wr < 0) switch (errno) {
case EAGAIN:
case EINTR:
break;
case EPIPE:
case ECONNRESET:
return -2;
default:
log_perror(errh, __FILE__, __LINE__, "writev failed: %d", fd);
return -1;
}
if (wr >= 0) {
*p_max_bytes -= wr;
chunkqueue_mark_written(cq, wr);
}
return (wr > 0 && wr == toSend) ? 0 : -3;
}
#endif /* NETWORK_WRITE_USE_WRITEV */
#if defined(NETWORK_WRITE_USE_SENDFILE)
#if defined(NETWORK_WRITE_USE_LINUX_SENDFILE) \
|| defined(NETWORK_WRITE_USE_SOLARIS_SENDFILEV)
#include <sys/sendfile.h>
#endif
#if defined(NETWORK_WRITE_USE_FREEBSD_SENDFILE) \
|| defined(NETWORK_WRITE_USE_DARWIN_SENDFILE)
#include <sys/uio.h>
#endif
static int network_write_file_chunk_sendfile(int fd, chunkqueue *cq, off_t *p_max_bytes, log_error_st *errh) {
chunk * const c = cq->first;
ssize_t wr;
off_t offset;
off_t toSend;
off_t written = 0;
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;
if (0 == toSend) {
chunkqueue_remove_finished_chunks(cq);
return 0;
}
if (0 != chunkqueue_open_file_chunk(cq, errh)) return -1;
/* Darwin, FreeBSD, and Solaris variants support iovecs and could
* be optimized to send more than just file in single syscall */
#if defined(NETWORK_WRITE_USE_LINUX_SENDFILE)
wr = sendfile(fd, c->file.fd, &offset, toSend);
if (wr > 0) written = (off_t)wr;
#elif defined(NETWORK_WRITE_USE_DARWIN_SENDFILE)
written = toSend;
wr = sendfile(c->file.fd, fd, offset, &written, NULL, 0);
/* (for EAGAIN/EINTR written still contains the sent bytes) */
#elif defined(NETWORK_WRITE_USE_FREEBSD_SENDFILE)
wr = sendfile(c->file.fd, fd, offset, toSend, NULL, &written, 0);
/* (for EAGAIN/EINTR written still contains the sent bytes) */
#elif defined(NETWORK_WRITE_USE_SOLARIS_SENDFILEV)
{
sendfilevec_t fvec;
fvec.sfv_fd = c->file.fd;
fvec.sfv_flag = 0;
fvec.sfv_off = offset;
fvec.sfv_len = toSend;
/* Solaris sendfilev() */
wr = sendfilev(fd, &fvec, 1, (size_t *)&written);
/* (for EAGAIN/EINTR written still contains the sent bytes) */
}
#else
wr = -1;
errno = ENOSYS;
#endif
if (-1 == wr) {
switch(errno) {
case EAGAIN:
case EINTR:
break; /* try again later */
case EPIPE:
case ECONNRESET:
case ENOTCONN:
return -2;
case EINVAL:
case ENOSYS:
#if defined(ENOTSUP) && (!defined(EOPNOTSUPP) || EOPNOTSUPP != ENOTSUP)
case ENOTSUP:
#endif
#ifdef EOPNOTSUPP
case EOPNOTSUPP:
#endif
#ifdef ESOCKTNOSUPPORT
case ESOCKTNOSUPPORT:
#endif
#ifdef EAFNOSUPPORT
case EAFNOSUPPORT:
#endif
#ifdef NETWORK_WRITE_USE_MMAP
return network_write_file_chunk_mmap(fd, cq, p_max_bytes, errh);
#else
return network_write_file_chunk_no_mmap(fd, cq, p_max_bytes, errh);
#endif
default:
log_perror(errh, __FILE__, __LINE__, "sendfile(): fd: %d", fd);
return -1;
}
}
if (written >= 0) { /*(always true)*/
chunkqueue_mark_written(cq, written);
*p_max_bytes -= written;
}
return (wr >= 0 && written == toSend) ? 0 : -3;
}
#endif
/* return values:
* >= 0 : no error
* -1 : error (on our side)
* -2 : remote close
*/
static int network_write_chunkqueue_write(int fd, chunkqueue *cq, off_t max_bytes, log_error_st *errh) {
while (max_bytes > 0 && NULL != cq->first) {
int rc = -1;
switch (cq->first->type) {
case MEM_CHUNK:
rc = network_write_mem_chunk(fd, cq, &max_bytes, errh);
break;
case FILE_CHUNK:
#ifdef NETWORK_WRITE_USE_MMAP
rc = network_write_file_chunk_mmap(fd, cq, &max_bytes, errh);
#else
rc = network_write_file_chunk_no_mmap(fd, cq, &max_bytes, errh);
#endif
break;
}
if (-3 == rc) return 0;
if (0 != rc) return rc;
}
return 0;
}
#if defined(NETWORK_WRITE_USE_WRITEV)
static int network_write_chunkqueue_writev(int fd, chunkqueue *cq, off_t max_bytes, log_error_st *errh) {
while (max_bytes > 0 && NULL != cq->first) {
int rc = -1;
switch (cq->first->type) {
case MEM_CHUNK:
#if defined(NETWORK_WRITE_USE_WRITEV)
rc = network_writev_mem_chunks(fd, cq, &max_bytes, errh);
#else
rc = network_write_mem_chunk(fd, cq, &max_bytes, errh);
#endif
break;
case FILE_CHUNK:
#ifdef NETWORK_WRITE_USE_MMAP
rc = network_write_file_chunk_mmap(fd, cq, &max_bytes, errh);
#else
rc = network_write_file_chunk_no_mmap(fd, cq, &max_bytes, errh);
#endif
break;
}
if (-3 == rc) return 0;
if (0 != rc) return rc;
}
return 0;
}
#endif
#if defined(NETWORK_WRITE_USE_SENDFILE)
static int network_write_chunkqueue_sendfile(int fd, chunkqueue *cq, off_t max_bytes, log_error_st *errh) {
while (max_bytes > 0 && NULL != cq->first) {
int rc = -1;
switch (cq->first->type) {
case MEM_CHUNK:
#if defined(NETWORK_WRITE_USE_WRITEV)
rc = network_writev_mem_chunks(fd, cq, &max_bytes, errh);
#else
rc = network_write_mem_chunk(fd, cq, &max_bytes, errh);
#endif
break;
case FILE_CHUNK:
#if defined(NETWORK_WRITE_USE_SENDFILE)
rc = network_write_file_chunk_sendfile(fd, cq, &max_bytes, errh);
#elif defined(NETWORK_WRITE_USE_MMAP)
rc = network_write_file_chunk_mmap(fd, cq, &max_bytes, errh);
#else
rc = network_write_file_chunk_no_mmap(fd, cq, &max_bytes, errh);
#endif
break;
}
if (-3 == rc) return 0;
if (0 != rc) return rc;
}
return 0;
}
#endif
int network_write_init(server *srv) {
typedef enum {
NETWORK_BACKEND_UNSET,
NETWORK_BACKEND_WRITE,
NETWORK_BACKEND_WRITEV,
NETWORK_BACKEND_SENDFILE,
} network_backend_t;
network_backend_t backend;
struct nb_map {
network_backend_t nb;
const char *name;
} network_backends[] = {
/* lowest id wins */
{ NETWORK_BACKEND_SENDFILE, "sendfile" },
{ NETWORK_BACKEND_SENDFILE, "linux-sendfile" },
{ NETWORK_BACKEND_SENDFILE, "freebsd-sendfile" },
{ NETWORK_BACKEND_SENDFILE, "solaris-sendfilev" },
{ NETWORK_BACKEND_WRITEV, "writev" },
{ NETWORK_BACKEND_WRITE, "write" },
{ NETWORK_BACKEND_UNSET, NULL }
};
/* get a useful default */
backend = network_backends[0].nb;
/* match name against known types */
if (!buffer_string_is_empty(srv->srvconf.network_backend)) {
const char *name, *confname = srv->srvconf.network_backend->ptr;
for (size_t i = 0; NULL != (name = network_backends[i].name); ++i) {
if (0 == strcmp(confname, name)) {
backend = network_backends[i].nb;
break;
}
}
if (NULL == name) {
log_error(srv->errh, __FILE__, __LINE__,
"server.network-backend has an unknown value: %s", confname);
return -1;
}
}
switch(backend) {
case NETWORK_BACKEND_SENDFILE:
#if defined(NETWORK_WRITE_USE_SENDFILE)
srv->network_backend_write = network_write_chunkqueue_sendfile;
break;
#endif
case NETWORK_BACKEND_WRITEV:
#if defined(NETWORK_WRITE_USE_WRITEV)
srv->network_backend_write = network_write_chunkqueue_writev;
break;
#endif
case NETWORK_BACKEND_WRITE:
srv->network_backend_write = network_write_chunkqueue_write;
break;
default:
return -1;
}
return 0;
}
const char * network_write_show_handlers(void) {
return
"\nNetwork handler:\n\n"
#if defined NETWORK_WRITE_USE_LINUX_SENDFILE
"\t+ linux-sendfile\n"
#else
"\t- linux-sendfile\n"
#endif
#if defined NETWORK_WRITE_USE_FREEBSD_SENDFILE
"\t+ freebsd-sendfile\n"
#else
"\t- freebsd-sendfile\n"
#endif
#if defined NETWORK_WRITE_USE_DARWIN_SENDFILE
"\t+ darwin-sendfile\n"
#else
"\t- darwin-sendfile\n"
#endif
#if defined NETWORK_WRITE_USE_SOLARIS_SENDFILEV
"\t+ solaris-sendfilev\n"
#else
"\t- solaris-sendfilev\n"
#endif
#if defined NETWORK_WRITE_USE_WRITEV
"\t+ writev\n"
#else
"\t- writev\n"
#endif
"\t+ write\n"
#ifdef NETWORK_WRITE_USE_MMAP
"\t+ mmap support\n"
#else
"\t- mmap support\n"
#endif
;
}
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