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126 lines
3.6 KiB
C++
126 lines
3.6 KiB
C++
// See the file "COPYING" in the main distribution directory for copyright.
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#pragma once
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namespace zeek::detail {
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class Pipe {
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public:
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/**
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* Create a pair of file descriptors via pipe(), or aborts if it cannot.
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* @param flags0 file descriptor flags to set on read end of pipe.
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* @param flags1 file descriptor flags to set on write end of pipe.
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* @param status_flags0 descriptor status flags to set on read end of pipe.
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* @param status_flags1 descriptor status flags to set on write end of pipe.
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* @param fds may be supplied to open an existing file descriptors rather
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* than create ones from a new pipe. Should point to memory containing
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* two consecutive file descriptors, the "read" one and then the "write" one.
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*/
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explicit Pipe(int flags0 = 0, int flags1 = 0, int status_flags0 = 0, int status_flags1 = 0, int* fds = nullptr);
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/**
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* Close the pair of file descriptors owned by the object.
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*/
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~Pipe();
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/**
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* Make a copy of another Pipe object (file descriptors are dup'd).
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*/
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Pipe(const Pipe& other);
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/**
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* Assign a Pipe object by closing file descriptors and duping those of
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* the other.
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*/
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Pipe& operator=(const Pipe& other);
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/**
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* @return the file descriptor associated with the read-end of the pipe.
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*/
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int ReadFD() const { return fds[0]; }
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/**
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* @return the file descriptor associated with the write-end of the pipe.
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*/
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int WriteFD() const { return fds[1]; }
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/**
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* Sets the given file descriptor flags for both the read and write end
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* of the pipe.
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*/
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void SetFlags(int flags);
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/**
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* Unsets the given file descriptor flags for both the read and write end
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* of the pipe.
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*/
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void UnsetFlags(int flags);
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private:
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int fds[2] = {-1, -1};
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int flags[2] = {0};
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int status_flags[2] = {0};
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};
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/**
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* A pair of pipes that can be used for bi-directional IPC.
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*/
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class PipePair {
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public:
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/**
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* Create a pair of pipes
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* @param flags file descriptor flags to set on pipes
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* @status_flags descriptor status flags to set on pipes
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* @fds may be supplied to open existing file descriptors rather
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* than create ones from a new pair of pipes. Should point to memory
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* containing four consecutive file descriptors, "read" end and "write" end
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* of the first pipe followed by the "read" end and "write" end of the
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* second pipe.
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*/
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PipePair(int flags, int status_flags, int* fds = nullptr);
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/**
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* @return the pipe used for receiving input
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*/
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Pipe& In() { return pipes[swapped]; }
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/**
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* @return the pipe used for sending output
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*/
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Pipe& Out() { return pipes[! swapped]; }
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/**
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* @return the pipe used for receiving input
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*/
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const Pipe& In() const { return pipes[swapped]; }
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/**
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* @return the pipe used for sending output
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*/
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const Pipe& Out() const { return pipes[! swapped]; }
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/**
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* @return a file descriptor that may used for receiving messages by
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* polling/reading it.
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*/
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int InFD() const { return In().ReadFD(); }
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/**
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* @return a file descriptor that may be used for sending messages by
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* writing to it.
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*/
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int OutFD() const { return Out().WriteFD(); }
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/**
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* Swaps the meaning of the pipes in the pair. E.g. call this after
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* fork()'ing so that the child process uses the right pipe for
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* reading/writing.
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*/
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void Swap() { swapped = ! swapped; }
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private:
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Pipe pipes[2]; // NOLINT(modernize-use-default-member-init)
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bool swapped = false;
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};
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} // namespace zeek::detail
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