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Diffstat (limited to 'package/heirloom-cpio/src/sfile.c')
| -rw-r--r-- | package/heirloom-cpio/src/sfile.c | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/package/heirloom-cpio/src/sfile.c b/package/heirloom-cpio/src/sfile.c new file mode 100644 index 000000000..089d85fdf --- /dev/null +++ b/package/heirloom-cpio/src/sfile.c @@ -0,0 +1,99 @@ +/* + * Copyright (c) 2003 Gunnar Ritter + * + * This software is provided 'as-is', without any express or implied + * warranty. In no event will the authors be held liable for any damages + * arising from the use of this software. + * + * Permission is granted to anyone to use this software for any purpose, + * including commercial applications, and to alter it and redistribute + * it freely, subject to the following restrictions: + * + * 1. The origin of this software must not be misrepresented; you must not + * claim that you wrote the original software. If you use this software + * in a product, an acknowledgment in the product documentation would be + * appreciated but is not required. + * + * 2. Altered source versions must be plainly marked as such, and must not be + * misrepresented as being the original software. + * + * 3. This notice may not be removed or altered from any source distribution. + */ +/* Sccsid @(#)sfile.c 1.9 (gritter) 6/7/04 */ + +#ifdef __linux__ +#undef _FILE_OFFSET_BITS + +#include <sys/types.h> +#include <sys/sendfile.h> +#include <sys/stat.h> +#include <unistd.h> +#include <limits.h> +#include <errno.h> +#include "sfile.h" + +long long +sfile(int dfd, int sfd, mode_t mode, long long count) +{ + static int enosys, einval, success; + off_t offset; + ssize_t sent, total; + extern void writerr(void *, int, int); + /* + * A process is not interruptible while executing a sendfile() + * system call. So it is not advisable to to send an entire + * file with one call; it is sent in parts so signals can + * be delivered in between. + */ + const ssize_t chunk = 196608; + + /* + * If a previous call returned ENOSYS, the operating system does + * not support sendfile() at all and it makes no sense to try it + * again. + * + * If a previous call returned EINVAL and there was no successful + * call yet, it is very likely that this is a permanent error + * condition (on Linux 2.6.0-test4, sendfile() may be used for + * socket targets only; older versions don't support tmpfs as + * source file system etc.). + */ + if (enosys || !success && einval || + (mode&S_IFMT) != S_IFREG || count > SSIZE_MAX) + return 0; + offset = lseek(sfd, 0, SEEK_CUR); + sent = 0, total = 0; + while (count > 0 && (sent = sendfile(dfd, sfd, &offset, + count > chunk ? chunk : count)) > 0) { + count -= sent, total += sent; + } + if (total && lseek(sfd, offset, SEEK_SET) == (off_t)-1) + return -1; + if (count == 0 || sent == 0) { + success = 1; + return total; + } + switch (errno) { + case ENOSYS: + enosys = 1; + return 0; + case EINVAL: + einval = 1; + return 0; + case ENOMEM: + return 0; + default: + writerr(NULL, count > chunk ? chunk : count, 0); + return -1; + } +} +#else /* !__linux__ */ +#include <sys/types.h> + +/*ARGSUSED*/ +long long +sfile(int dfd, int sfd, mode_t mode, long long count) +{ + return 0; +} +#endif /* __linux__ */ |