src/os/unix/ngx_files.c - nginx - Git at Google


 /*
  * Copyright (C) Igor Sysoev
  * Copyright (C) Nginx, Inc.
  */


 #include <ngx_config.h>
 #include <ngx_core.h>


 #if (NGX_HAVE_FILE_AIO)

 ngx_uint_t  ngx_file_aio = 1;

 #endif


 ssize_t
 ngx_read_file(ngx_file_t *file, u_char *buf, size_t size, off_t offset)
 {
     ssize_t  n;

     ngx_log_debug4(NGX_LOG_DEBUG_CORE, file->log, 0,
                    "read: %d, %p, %uz, %O", file->fd, buf, size, offset);

 #if (NGX_HAVE_PREAD)

     n = pread(file->fd, buf, size, offset);

     if (n == -1) {
         ngx_log_error(NGX_LOG_CRIT, file->log, ngx_errno,
                       "pread() \"%s\" failed", file->name.data);
         return NGX_ERROR;
     }

 #else

     if (file->sys_offset != offset) {
         if (lseek(file->fd, offset, SEEK_SET) == -1) {
             ngx_log_error(NGX_LOG_CRIT, file->log, ngx_errno,
                           "lseek() \"%s\" failed", file->name.data);
             return NGX_ERROR;
         }

         file->sys_offset = offset;
     }

     n = read(file->fd, buf, size);

     if (n == -1) {
         ngx_log_error(NGX_LOG_CRIT, file->log, ngx_errno,
                       "read() \"%s\" failed", file->name.data);
         return NGX_ERROR;
     }

     file->sys_offset += n;

 #endif

     file->offset += n;

     return n;
 }


 ssize_t
 ngx_write_file(ngx_file_t *file, u_char *buf, size_t size, off_t offset)
 {
     ssize_t  n, written;

     ngx_log_debug4(NGX_LOG_DEBUG_CORE, file->log, 0,
                    "write: %d, %p, %uz, %O", file->fd, buf, size, offset);

     written = 0;

 #if (NGX_HAVE_PWRITE)

     for ( ;; ) {
         n = pwrite(file->fd, buf + written, size, offset);

         if (n == -1) {
             ngx_log_error(NGX_LOG_CRIT, file->log, ngx_errno,
                           "pwrite() \"%s\" failed", file->name.data);
             return NGX_ERROR;
         }

         file->offset += n;
         written += n;

         if ((size_t) n == size) {
             return written;
         }

         offset += n;
         size -= n;
     }

 #else

     if (file->sys_offset != offset) {
         if (lseek(file->fd, offset, SEEK_SET) == -1) {
             ngx_log_error(NGX_LOG_CRIT, file->log, ngx_errno,
                           "lseek() \"%s\" failed", file->name.data);
             return NGX_ERROR;
         }

         file->sys_offset = offset;
     }

     for ( ;; ) {
         n = write(file->fd, buf + written, size);

         if (n == -1) {
             ngx_log_error(NGX_LOG_CRIT, file->log, ngx_errno,
                           "write() \"%s\" failed", file->name.data);
             return NGX_ERROR;
         }

         file->offset += n;
         written += n;

         if ((size_t) n == size) {
             return written;
         }

         size -= n;
     }
 #endif
 }


 ngx_fd_t
 ngx_open_tempfile(u_char *name, ngx_uint_t persistent, ngx_uint_t access)
 {
     ngx_fd_t  fd;

     fd = open((const char *) name, O_CREAT|O_EXCL|O_RDWR,
               access ? access : 0600);

     if (fd != -1 && !persistent) {
         unlink((const char *) name);
     }

     return fd;
 }


 #define NGX_IOVS  8

 ssize_t
 ngx_write_chain_to_file(ngx_file_t *file, ngx_chain_t *cl, off_t offset,
     ngx_pool_t *pool)
 {
     u_char        *prev;
     size_t         size;
     ssize_t        total, n;
     ngx_array_t    vec;
     struct iovec  *iov, iovs[NGX_IOVS];

     /* use pwrite() if there is the only buf in a chain */

     if (cl->next == NULL) {
         return ngx_write_file(file, cl->buf->pos,
                               (size_t) (cl->buf->last - cl->buf->pos),
                               offset);
     }

     total = 0;

     vec.elts = iovs;
     vec.size = sizeof(struct iovec);
     vec.nalloc = NGX_IOVS;
     vec.pool = pool;

     do {
         prev = NULL;
         iov = NULL;
         size = 0;

         vec.nelts = 0;

         /* create the iovec and coalesce the neighbouring bufs */

         while (cl && vec.nelts < IOV_MAX) {
             if (prev == cl->buf->pos) {
                 iov->iov_len += cl->buf->last - cl->buf->pos;

             } else {
                 iov = ngx_array_push(&vec);
                 if (iov == NULL) {
                     return NGX_ERROR;
                 }

                 iov->iov_base = (void *) cl->buf->pos;
                 iov->iov_len = cl->buf->last - cl->buf->pos;
             }

             size += cl->buf->last - cl->buf->pos;
             prev = cl->buf->last;
             cl = cl->next;
         }

         /* use pwrite() if there is the only iovec buffer */

         if (vec.nelts == 1) {
             iov = vec.elts;

             n = ngx_write_file(file, (u_char *) iov[0].iov_base,
                                iov[0].iov_len, offset);

             if (n == NGX_ERROR) {
                 return n;
             }

             return total + n;
         }

         if (file->sys_offset != offset) {
             if (lseek(file->fd, offset, SEEK_SET) == -1) {
                 ngx_log_error(NGX_LOG_CRIT, file->log, ngx_errno,
                               "lseek() \"%s\" failed", file->name.data);
                 return NGX_ERROR;
             }

             file->sys_offset = offset;
         }

         n = writev(file->fd, vec.elts, vec.nelts);

         if (n == -1) {
             ngx_log_error(NGX_LOG_CRIT, file->log, ngx_errno,
                           "writev() \"%s\" failed", file->name.data);
             return NGX_ERROR;
         }

         if ((size_t) n != size) {
             ngx_log_error(NGX_LOG_CRIT, file->log, 0,
                           "writev() \"%s\" has written only %z of %uz",
                           file->name.data, n, size);
             return NGX_ERROR;
         }

         file->sys_offset += n;
         file->offset += n;
         total += n;

     } while (cl);

     return total;
 }


 ngx_int_t
 ngx_set_file_time(u_char *name, ngx_fd_t fd, time_t s)
 {
     struct timeval  tv[2];

     tv[0].tv_sec = ngx_time();
     tv[0].tv_usec = 0;
     tv[1].tv_sec = s;
     tv[1].tv_usec = 0;

     if (utimes((char *) name, tv) != -1) {
         return NGX_OK;
     }

     return NGX_ERROR;
 }


 ngx_int_t
 ngx_create_file_mapping(ngx_file_mapping_t *fm)
 {
     fm->fd = ngx_open_file(fm->name, NGX_FILE_RDWR, NGX_FILE_TRUNCATE,
                            NGX_FILE_DEFAULT_ACCESS);
     if (fm->fd == NGX_INVALID_FILE) {
         ngx_log_error(NGX_LOG_CRIT, fm->log, ngx_errno,
                       ngx_open_file_n " \"%s\" failed", fm->name);
         return NGX_ERROR;
     }

     if (ftruncate(fm->fd, fm->size) == -1) {
         ngx_log_error(NGX_LOG_CRIT, fm->log, ngx_errno,
                       "ftruncate() \"%s\" failed", fm->name);
         goto failed;
     }

     fm->addr = mmap(NULL, fm->size, PROT_READ|PROT_WRITE, MAP_SHARED,
                     fm->fd, 0);
     if (fm->addr != MAP_FAILED) {
         return NGX_OK;
     }

     ngx_log_error(NGX_LOG_CRIT, fm->log, ngx_errno,
                   "mmap(%uz) \"%s\" failed", fm->size, fm->name);

 failed:

     if (ngx_close_file(fm->fd) == NGX_FILE_ERROR) {
         ngx_log_error(NGX_LOG_ALERT, fm->log, ngx_errno,
                       ngx_close_file_n " \"%s\" failed", fm->name);
     }

     return NGX_ERROR;
 }


 void
 ngx_close_file_mapping(ngx_file_mapping_t *fm)
 {
     if (munmap(fm->addr, fm->size) == -1) {
         ngx_log_error(NGX_LOG_CRIT, fm->log, ngx_errno,
                       "munmap(%uz) \"%s\" failed", fm->size, fm->name);
     }

     if (ngx_close_file(fm->fd) == NGX_FILE_ERROR) {
         ngx_log_error(NGX_LOG_ALERT, fm->log, ngx_errno,
                       ngx_close_file_n " \"%s\" failed", fm->name);
     }
 }


 ngx_int_t
 ngx_open_dir(ngx_str_t *name, ngx_dir_t *dir)
 {
     dir->dir = opendir((const char *) name->data);

     if (dir->dir == NULL) {
         return NGX_ERROR;
     }

     dir->valid_info = 0;

     return NGX_OK;
 }


 ngx_int_t
 ngx_read_dir(ngx_dir_t *dir)
 {
     dir->de = readdir(dir->dir);

     if (dir->de) {
 #if (NGX_HAVE_D_TYPE)
         dir->type = dir->de->d_type;
 #else
         dir->type = 0;
 #endif
         return NGX_OK;
     }

     return NGX_ERROR;
 }


 ngx_int_t
 ngx_open_glob(ngx_glob_t *gl)
 {
     int  n;

     n = glob((char *) gl->pattern, GLOB_NOSORT, NULL, &gl->pglob);

     if (n == 0) {
         return NGX_OK;
     }

 #ifdef GLOB_NOMATCH

     if (n == GLOB_NOMATCH && gl->test) {
         return NGX_OK;
     }

 #endif

     return NGX_ERROR;
 }


 ngx_int_t
 ngx_read_glob(ngx_glob_t *gl, ngx_str_t *name)
 {
     size_t  count;

 #ifdef GLOB_NOMATCH
     count = (size_t) gl->pglob.gl_pathc;
 #else
     count = (size_t) gl->pglob.gl_matchc;
 #endif

     if (gl->n < count) {

         name->len = (size_t) ngx_strlen(gl->pglob.gl_pathv[gl->n]);
         name->data = (u_char *) gl->pglob.gl_pathv[gl->n];
         gl->n++;

         return NGX_OK;
     }

     return NGX_DONE;
 }


 void
 ngx_close_glob(ngx_glob_t *gl)
 {
     globfree(&gl->pglob);
 }


 ngx_err_t
 ngx_trylock_fd(ngx_fd_t fd)
 {
     struct flock  fl;

     fl.l_start = 0;
     fl.l_len = 0;
     fl.l_pid = 0;
     fl.l_type = F_WRLCK;
     fl.l_whence = SEEK_SET;

     if (fcntl(fd, F_SETLK, &fl) == -1) {
         return ngx_errno;
     }

     return 0;
 }


 ngx_err_t
 ngx_lock_fd(ngx_fd_t fd)
 {
     struct flock  fl;

     fl.l_start = 0;
     fl.l_len = 0;
     fl.l_pid = 0;
     fl.l_type = F_WRLCK;
     fl.l_whence = SEEK_SET;

     if (fcntl(fd, F_SETLKW, &fl) == -1) {
         return ngx_errno;
     }

     return 0;
 }


 ngx_err_t
 ngx_unlock_fd(ngx_fd_t fd)
 {
     struct flock  fl;

     fl.l_start = 0;
     fl.l_len = 0;
     fl.l_pid = 0;
     fl.l_type = F_UNLCK;
     fl.l_whence = SEEK_SET;

     if (fcntl(fd, F_SETLK, &fl) == -1) {
         return  ngx_errno;
     }

     return 0;
 }


 #if (NGX_HAVE_POSIX_FADVISE) && !(NGX_HAVE_F_READAHEAD)

 ngx_int_t
 ngx_read_ahead(ngx_fd_t fd, size_t n)
 {
     int  err;

     err = posix_fadvise(fd, 0, 0, POSIX_FADV_SEQUENTIAL);

     if (err == 0) {
         return 0;
     }

     ngx_set_errno(err);
     return NGX_FILE_ERROR;
 }

 #endif


 #if (NGX_HAVE_O_DIRECT)

 ngx_int_t
 ngx_directio_on(ngx_fd_t fd)
 {
     int  flags;

     flags = fcntl(fd, F_GETFL);

     if (flags == -1) {
         return NGX_FILE_ERROR;
     }

     return fcntl(fd, F_SETFL, flags | O_DIRECT);
 }


 ngx_int_t
 ngx_directio_off(ngx_fd_t fd)
 {
     int  flags;

     flags = fcntl(fd, F_GETFL);

     if (flags == -1) {
         return NGX_FILE_ERROR;
     }

     return fcntl(fd, F_SETFL, flags & ~O_DIRECT);
 }

 #endif


 #if (NGX_HAVE_STATFS)

 size_t
 ngx_fs_bsize(u_char *name)
 {
     struct statfs  fs;

     if (statfs((char *) name, &fs) == -1) {
         return 512;
     }

     if ((fs.f_bsize % 512) != 0) {
         return 512;
     }

     return (size_t) fs.f_bsize;
 }

 #elif (NGX_HAVE_STATVFS)

 size_t
 ngx_fs_bsize(u_char *name)
 {
     struct statvfs  fs;

     if (statvfs((char *) name, &fs) == -1) {
         return 512;
     }

     if ((fs.f_frsize % 512) != 0) {
         return 512;
     }

     return (size_t) fs.f_frsize;
 }

 #else

 size_t
 ngx_fs_bsize(u_char *name)
 {
     return 512;
 }

 #endif

	/*
	* Copyright (C) Igor Sysoev
	* Copyright (C) Nginx, Inc.
	*/


	#include <ngx_config.h>
	#include <ngx_core.h>


	#if (NGX_HAVE_FILE_AIO)

	ngx_uint_t ngx_file_aio = 1;

	#endif


	ssize_t
	ngx_read_file(ngx_file_t file, u_char buf, size_t size, off_t offset)
	{
	ssize_t n;

	ngx_log_debug4(NGX_LOG_DEBUG_CORE, file->log, 0,
	"read: %d, %p, %uz, %O", file->fd, buf, size, offset);

	#if (NGX_HAVE_PREAD)

	n = pread(file->fd, buf, size, offset);

	if (n == -1) {
	ngx_log_error(NGX_LOG_CRIT, file->log, ngx_errno,
	"pread() \"%s\" failed", file->name.data);
	return NGX_ERROR;
	}

	#else

	if (file->sys_offset != offset) {
	if (lseek(file->fd, offset, SEEK_SET) == -1) {
	ngx_log_error(NGX_LOG_CRIT, file->log, ngx_errno,
	"lseek() \"%s\" failed", file->name.data);
	return NGX_ERROR;
	}

	file->sys_offset = offset;
	}

	n = read(file->fd, buf, size);

	if (n == -1) {
	ngx_log_error(NGX_LOG_CRIT, file->log, ngx_errno,
	"read() \"%s\" failed", file->name.data);
	return NGX_ERROR;
	}

	file->sys_offset += n;

	#endif

	file->offset += n;

	return n;
	}


	ssize_t
	ngx_write_file(ngx_file_t file, u_char buf, size_t size, off_t offset)
	{
	ssize_t n, written;

	ngx_log_debug4(NGX_LOG_DEBUG_CORE, file->log, 0,
	"write: %d, %p, %uz, %O", file->fd, buf, size, offset);

	written = 0;

	#if (NGX_HAVE_PWRITE)

	for ( ;; ) {
	n = pwrite(file->fd, buf + written, size, offset);

	if (n == -1) {
	ngx_log_error(NGX_LOG_CRIT, file->log, ngx_errno,
	"pwrite() \"%s\" failed", file->name.data);
	return NGX_ERROR;
	}

	file->offset += n;
	written += n;

	if ((size_t) n == size) {
	return written;
	}

	offset += n;
	size -= n;
	}

	#else

	if (file->sys_offset != offset) {
	if (lseek(file->fd, offset, SEEK_SET) == -1) {
	ngx_log_error(NGX_LOG_CRIT, file->log, ngx_errno,
	"lseek() \"%s\" failed", file->name.data);
	return NGX_ERROR;
	}

	file->sys_offset = offset;
	}

	for ( ;; ) {
	n = write(file->fd, buf + written, size);

	if (n == -1) {
	ngx_log_error(NGX_LOG_CRIT, file->log, ngx_errno,
	"write() \"%s\" failed", file->name.data);
	return NGX_ERROR;
	}

	file->offset += n;
	written += n;

	if ((size_t) n == size) {
	return written;
	}

	size -= n;
	}
	#endif
	}


	ngx_fd_t
	ngx_open_tempfile(u_char *name, ngx_uint_t persistent, ngx_uint_t access)
	{
	ngx_fd_t fd;

	fd = open((const char *) name, O_CREAT\|O_EXCL\|O_RDWR,
	access ? access : 0600);

	if (fd != -1 && !persistent) {
	unlink((const char *) name);
	}

	return fd;
	}


	#define NGX_IOVS 8

	ssize_t
	ngx_write_chain_to_file(ngx_file_t file, ngx_chain_t cl, off_t offset,
	ngx_pool_t *pool)
	{
	u_char *prev;
	size_t size;
	ssize_t total, n;
	ngx_array_t vec;
	struct iovec *iov, iovs[NGX_IOVS];

	/* use pwrite() if there is the only buf in a chain */

	if (cl->next == NULL) {
	return ngx_write_file(file, cl->buf->pos,
	(size_t) (cl->buf->last - cl->buf->pos),
	offset);
	}

	total = 0;

	vec.elts = iovs;
	vec.size = sizeof(struct iovec);
	vec.nalloc = NGX_IOVS;
	vec.pool = pool;

	do {
	prev = NULL;
	iov = NULL;
	size = 0;

	vec.nelts = 0;

	/* create the iovec and coalesce the neighbouring bufs */

	while (cl && vec.nelts < IOV_MAX) {
	if (prev == cl->buf->pos) {
	iov->iov_len += cl->buf->last - cl->buf->pos;

	} else {
	iov = ngx_array_push(&vec);
	if (iov == NULL) {
	return NGX_ERROR;
	}

	iov->iov_base = (void *) cl->buf->pos;
	iov->iov_len = cl->buf->last - cl->buf->pos;
	}

	size += cl->buf->last - cl->buf->pos;
	prev = cl->buf->last;
	cl = cl->next;
	}

	/* use pwrite() if there is the only iovec buffer */

	if (vec.nelts == 1) {
	iov = vec.elts;

	n = ngx_write_file(file, (u_char *) iov[0].iov_base,
	iov[0].iov_len, offset);

	if (n == NGX_ERROR) {
	return n;
	}

	return total + n;
	}

	if (file->sys_offset != offset) {
	if (lseek(file->fd, offset, SEEK_SET) == -1) {
	ngx_log_error(NGX_LOG_CRIT, file->log, ngx_errno,
	"lseek() \"%s\" failed", file->name.data);
	return NGX_ERROR;
	}

	file->sys_offset = offset;
	}

	n = writev(file->fd, vec.elts, vec.nelts);

	if (n == -1) {
	ngx_log_error(NGX_LOG_CRIT, file->log, ngx_errno,
	"writev() \"%s\" failed", file->name.data);
	return NGX_ERROR;
	}

	if ((size_t) n != size) {
	ngx_log_error(NGX_LOG_CRIT, file->log, 0,
	"writev() \"%s\" has written only %z of %uz",
	file->name.data, n, size);
	return NGX_ERROR;
	}

	file->sys_offset += n;
	file->offset += n;
	total += n;

	} while (cl);

	return total;
	}


	ngx_int_t
	ngx_set_file_time(u_char *name, ngx_fd_t fd, time_t s)
	{
	struct timeval tv[2];

	tv[0].tv_sec = ngx_time();
	tv[0].tv_usec = 0;
	tv[1].tv_sec = s;
	tv[1].tv_usec = 0;

	if (utimes((char *) name, tv) != -1) {
	return NGX_OK;
	}

	return NGX_ERROR;
	}


	ngx_int_t
	ngx_create_file_mapping(ngx_file_mapping_t *fm)
	{
	fm->fd = ngx_open_file(fm->name, NGX_FILE_RDWR, NGX_FILE_TRUNCATE,
	NGX_FILE_DEFAULT_ACCESS);
	if (fm->fd == NGX_INVALID_FILE) {
	ngx_log_error(NGX_LOG_CRIT, fm->log, ngx_errno,
	ngx_open_file_n " \"%s\" failed", fm->name);
	return NGX_ERROR;
	}

	if (ftruncate(fm->fd, fm->size) == -1) {
	ngx_log_error(NGX_LOG_CRIT, fm->log, ngx_errno,
	"ftruncate() \"%s\" failed", fm->name);
	goto failed;
	}

	fm->addr = mmap(NULL, fm->size, PROT_READ\|PROT_WRITE, MAP_SHARED,
	fm->fd, 0);
	if (fm->addr != MAP_FAILED) {
	return NGX_OK;
	}

	ngx_log_error(NGX_LOG_CRIT, fm->log, ngx_errno,
	"mmap(%uz) \"%s\" failed", fm->size, fm->name);

	failed:

	if (ngx_close_file(fm->fd) == NGX_FILE_ERROR) {
	ngx_log_error(NGX_LOG_ALERT, fm->log, ngx_errno,
	ngx_close_file_n " \"%s\" failed", fm->name);
	}

	return NGX_ERROR;
	}


	void
	ngx_close_file_mapping(ngx_file_mapping_t *fm)
	{
	if (munmap(fm->addr, fm->size) == -1) {
	ngx_log_error(NGX_LOG_CRIT, fm->log, ngx_errno,
	"munmap(%uz) \"%s\" failed", fm->size, fm->name);
	}

	if (ngx_close_file(fm->fd) == NGX_FILE_ERROR) {
	ngx_log_error(NGX_LOG_ALERT, fm->log, ngx_errno,
	ngx_close_file_n " \"%s\" failed", fm->name);
	}
	}


	ngx_int_t
	ngx_open_dir(ngx_str_t name, ngx_dir_t dir)
	{
	dir->dir = opendir((const char *) name->data);

	if (dir->dir == NULL) {
	return NGX_ERROR;
	}

	dir->valid_info = 0;

	return NGX_OK;
	}


	ngx_int_t
	ngx_read_dir(ngx_dir_t *dir)
	{
	dir->de = readdir(dir->dir);

	if (dir->de) {
	#if (NGX_HAVE_D_TYPE)
	dir->type = dir->de->d_type;
	#else
	dir->type = 0;
	#endif
	return NGX_OK;
	}

	return NGX_ERROR;
	}


	ngx_int_t
	ngx_open_glob(ngx_glob_t *gl)
	{
	int n;

	n = glob((char *) gl->pattern, GLOB_NOSORT, NULL, &gl->pglob);

	if (n == 0) {
	return NGX_OK;
	}

	#ifdef GLOB_NOMATCH

	if (n == GLOB_NOMATCH && gl->test) {
	return NGX_OK;
	}

	#endif

	return NGX_ERROR;
	}


	ngx_int_t
	ngx_read_glob(ngx_glob_t gl, ngx_str_t name)
	{
	size_t count;

	#ifdef GLOB_NOMATCH
	count = (size_t) gl->pglob.gl_pathc;
	#else
	count = (size_t) gl->pglob.gl_matchc;
	#endif

	if (gl->n < count) {

	name->len = (size_t) ngx_strlen(gl->pglob.gl_pathv[gl->n]);
	name->data = (u_char *) gl->pglob.gl_pathv[gl->n];
	gl->n++;

	return NGX_OK;
	}

	return NGX_DONE;
	}


	void
	ngx_close_glob(ngx_glob_t *gl)
	{
	globfree(&gl->pglob);
	}


	ngx_err_t
	ngx_trylock_fd(ngx_fd_t fd)
	{
	struct flock fl;

	fl.l_start = 0;
	fl.l_len = 0;
	fl.l_pid = 0;
	fl.l_type = F_WRLCK;
	fl.l_whence = SEEK_SET;

	if (fcntl(fd, F_SETLK, &fl) == -1) {
	return ngx_errno;
	}

	return 0;
	}


	ngx_err_t
	ngx_lock_fd(ngx_fd_t fd)
	{
	struct flock fl;

	fl.l_start = 0;
	fl.l_len = 0;
	fl.l_pid = 0;
	fl.l_type = F_WRLCK;
	fl.l_whence = SEEK_SET;

	if (fcntl(fd, F_SETLKW, &fl) == -1) {
	return ngx_errno;
	}

	return 0;
	}


	ngx_err_t
	ngx_unlock_fd(ngx_fd_t fd)
	{
	struct flock fl;

	fl.l_start = 0;
	fl.l_len = 0;
	fl.l_pid = 0;
	fl.l_type = F_UNLCK;
	fl.l_whence = SEEK_SET;

	if (fcntl(fd, F_SETLK, &fl) == -1) {
	return ngx_errno;
	}

	return 0;
	}


	#if (NGX_HAVE_POSIX_FADVISE) && !(NGX_HAVE_F_READAHEAD)

	ngx_int_t
	ngx_read_ahead(ngx_fd_t fd, size_t n)
	{
	int err;

	err = posix_fadvise(fd, 0, 0, POSIX_FADV_SEQUENTIAL);

	if (err == 0) {
	return 0;
	}

	ngx_set_errno(err);
	return NGX_FILE_ERROR;
	}

	#endif


	#if (NGX_HAVE_O_DIRECT)

	ngx_int_t
	ngx_directio_on(ngx_fd_t fd)
	{
	int flags;

	flags = fcntl(fd, F_GETFL);

	if (flags == -1) {
	return NGX_FILE_ERROR;
	}

	return fcntl(fd, F_SETFL, flags \| O_DIRECT);
	}


	ngx_int_t
	ngx_directio_off(ngx_fd_t fd)
	{
	int flags;

	flags = fcntl(fd, F_GETFL);

	if (flags == -1) {
	return NGX_FILE_ERROR;
	}

	return fcntl(fd, F_SETFL, flags & ~O_DIRECT);
	}

	#endif


	#if (NGX_HAVE_STATFS)

	size_t
	ngx_fs_bsize(u_char *name)
	{
	struct statfs fs;

	if (statfs((char *) name, &fs) == -1) {
	return 512;
	}

	if ((fs.f_bsize % 512) != 0) {
	return 512;
	}

	return (size_t) fs.f_bsize;
	}

	#elif (NGX_HAVE_STATVFS)

	size_t
	ngx_fs_bsize(u_char *name)
	{
	struct statvfs fs;

	if (statvfs((char *) name, &fs) == -1) {
	return 512;
	}

	if ((fs.f_frsize % 512) != 0) {
	return 512;
	}

	return (size_t) fs.f_frsize;
	}

	#else

	size_t
	ngx_fs_bsize(u_char *name)
	{
	return 512;
	}

	#endif