31 lines
983 B
C
31 lines
983 B
C
#define _GNU_SOURCE
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#include <sys/socket.h>
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#include <limits.h>
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#include <errno.h>
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#include "syscall.h"
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int sendmmsg(int fd, struct mmsghdr *msgvec, unsigned int vlen, unsigned int flags)
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{
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#if LONG_MAX > INT_MAX
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/* Can't use the syscall directly because the kernel has the wrong
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* idea for the types of msg_iovlen, msg_controllen, and cmsg_len,
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* and the cmsg blocks cannot be modified in-place. */
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int i;
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if (vlen > IOV_MAX) vlen = IOV_MAX; /* This matches the kernel. */
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if (!vlen) return 0;
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for (i=0; i<vlen; i++) {
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/* As an unfortunate inconsistency, the sendmmsg API uses
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* unsigned int for the resulting msg_len, despite sendmsg
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* returning ssize_t. However Linux limits the total bytes
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* sent by sendmsg to INT_MAX, so the assignment is safe. */
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ssize_t r = sendmsg(fd, &msgvec[i].msg_hdr, flags);
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if (r < 0) goto error;
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msgvec[i].msg_len = r;
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}
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error:
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return i ? i : -1;
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#else
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return syscall_cp(SYS_sendmmsg, fd, msgvec, vlen, flags);
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#endif
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}
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