98 lines
1.7 KiB
C
98 lines
1.7 KiB
C
/*
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* freopen.c - open a file and associate a stream with it
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*/
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/* $Id$ */
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#include <stdlib.h>
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#include <stdio.h>
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#include <fcntl.h>
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#include <unistd.h>
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#if ACKCONF_WANT_STDIO && ACKCONF_WANT_EMULATED_FILE
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#define PMODE 0666
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/* Do not "optimize" this file to use the open with O_CREAT if the file
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* does not exist. The reason is given in fopen.c.
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*/
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FILE* freopen(const char* name, const char* mode, FILE* stream)
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{
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register int i;
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int rwmode = 0, rwflags = 0;
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int fd, flags = stream->_flags & (_IONBF | _IOFBF | _IOLBF | _IOMYBUF);
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(void)fflush(stream); /* ignore errors */
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(void)close(fileno(stream));
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switch (*mode++)
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{
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case 'r':
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flags |= _IOREAD;
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rwmode = O_RDONLY;
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break;
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case 'w':
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flags |= _IOWRITE;
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rwmode = O_WRONLY;
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rwflags = O_CREAT | O_TRUNC;
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break;
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case 'a':
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flags |= _IOWRITE | _IOAPPEND;
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rwmode = O_WRONLY;
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rwflags |= O_APPEND | O_CREAT;
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break;
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default:
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return (FILE*)NULL;
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}
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while (*mode)
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{
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switch (*mode++)
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{
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case 'b':
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continue;
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case '+':
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rwmode = O_RDWR;
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flags |= _IOREAD | _IOWRITE;
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continue;
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/* The sequence may be followed by aditional characters */
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default:
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break;
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}
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break;
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}
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if ((rwflags & O_TRUNC)
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|| (((fd = open(name, rwmode)) < 0)
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&& (rwflags & O_CREAT)))
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{
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if (((fd = creat(name, PMODE)) < 0) && flags | _IOREAD)
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{
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(void)close(fd);
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fd = open(name, rwmode);
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}
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}
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if (fd < 0)
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{
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for (i = 0; i < FOPEN_MAX; i++)
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{
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if (stream == __iotab[i])
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{
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__iotab[i] = 0;
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break;
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}
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}
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if (stream != stdin && stream != stdout && stream != stderr)
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free((void*)stream);
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return (FILE*)NULL;
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}
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stream->_count = 0;
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stream->_fd = fd;
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stream->_flags = flags;
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return stream;
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}
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#endif
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