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35 lines
1.4 KiB
C
35 lines
1.4 KiB
C
// FLING: Exchanging file descriptors over sockets
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//
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// This is a little library for sending file descriptors over a socket
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// between processes. The reason for doing that (as opposed to using
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// filenames to share the files) is so (a) no files remain in the
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// filesystem after all the processes terminate, (b) to make sure that
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// there are no name collisions and (c) to be able to control who has
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// access to the data.
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//
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// Most of the code is from https://github.com/sharvil/flingfd
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#include <unistd.h>
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#include <errno.h>
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <sys/un.h>
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// This is neccessary for Mac OS X, see http://www.apuebook.com/faqs2e.html (10).
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#if !defined(CMSG_SPACE) && !defined(CMSG_LEN)
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#define CMSG_SPACE(len) (__DARWIN_ALIGN32(sizeof(struct cmsghdr)) + __DARWIN_ALIGN32(len))
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#define CMSG_LEN(len) (__DARWIN_ALIGN32(sizeof(struct cmsghdr)) + (len))
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#endif
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void init_msg(struct msghdr *msg, struct iovec *iov,
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char *buf, size_t buf_len);
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// Send a file descriptor "fd" and a payload "payload" of size "size"
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// over the socket "conn". Return 0 on success.
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int send_fd(int conn, int fd, const char* payload, int size);
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// Receive a file descriptor and a payload of size up to "size" from a
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// socket "conn". The payload will be written to "payload" and the file
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// descriptor will be returned. Returns -1 on failure.
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int recv_fd(int conn, char* payload, int size);
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