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https://github.com/ruby/ruby.git
synced 2022-11-09 12:17:21 -05:00
60 lines
1.2 KiB
C
60 lines
1.2 KiB
C
/*
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* Public domain dup2() lookalike
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* by Curtis Jackson @ AT&T Technologies, Burlington, NC
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* electronic address: burl!rcj
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*
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* dup2 performs the following functions:
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*
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* Check to make sure that fd1 is a valid open file descriptor.
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* Check to see if fd2 is already open; if so, close it.
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* Duplicate fd1 onto fd2; checking to make sure fd2 is a valid fd.
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* Return fd2 if all went well; return BADEXIT otherwise.
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*/
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#include "ruby/internal/config.h"
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#if defined(HAVE_FCNTL)
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# include <fcntl.h>
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#endif
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#if !defined(HAVE_FCNTL) || !defined(F_DUPFD)
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# include <errno.h>
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#endif
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#define BADEXIT -1
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int
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dup2(int fd1, int fd2)
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{
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#if defined(HAVE_FCNTL) && defined(F_DUPFD)
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if (fd1 != fd2) {
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#ifdef F_GETFL
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if (fcntl(fd1, F_GETFL) < 0)
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return BADEXIT;
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if (fcntl(fd2, F_GETFL) >= 0)
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close(fd2);
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#else
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close(fd2);
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#endif
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if (fcntl(fd1, F_DUPFD, fd2) < 0)
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return BADEXIT;
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}
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return fd2;
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#else
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extern int errno;
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int i, fd, fds[256];
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if (fd1 == fd2) return 0;
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close(fd2);
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for (i=0; i<256; i++) {
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fd = fds[i] = dup(fd1);
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if (fd == fd2) break;
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}
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while (i) {
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close(fds[i--]);
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}
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if (fd == fd2) return 0;
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errno = EMFILE;
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return BADEXIT;
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#endif
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}
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