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107 lines
3.4 KiB
C
107 lines
3.4 KiB
C
/* Get full pathname of current working directory. The pathname is
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copied to the parameter array 'cwd', and a pointer to this array
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is also returned as function result. If an error occurred, however,
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the return value is NULL but 'cwd' is filled with an error message.
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BUG: expect spectacular crashes when called from a directory whose
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path would be over MAXPATH bytes long (files in such directories are
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not reachable by full pathname).
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Starting with the dir ID returned by PBHGetVol, we do successive
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PBGetCatInfo's to get a component of the path until we reach the
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root (recognized by a dir ID of 2). We move up along the path
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using the dir ID of the parent directory returned by PBGetCatInfo.
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Then we catenate the components found in reverse order with the volume
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name (already gotten from PBHGetVol), with intervening and trailing
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colons
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The code works correctly on MFS disks (where it always returns the
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volume name) by simply skipping the PBGetCatinfo calls in that case.
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There is a 'bug' in PBGetCatInfo when called for an MFS disk (with
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HFS running): it then seems to call PBHGetVInfo, which returns a
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larger parameter block. But we won't run into this problem because
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we never call PBGetCatInfo for the root (assuming that PBHGetVol
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still sets the root ID in this case).
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Public domain by Guido van Rossum, CWI, Amsterdam (July 1987).
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*/
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#include "macdefs.h"
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#define ROOTID 2 /* Root directory ID */
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char *
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getwd(cwd)
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char *cwd;
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{
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/* Universal parameter block. */
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union {
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#ifdef THINK_C
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HFileInfo f;
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DirInfo d;
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WDPBRec w;
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#else /* MPW */
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struct HFileInfo f;
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struct DirInfo d;
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struct WDPBRec w;
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#endif
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} pb;
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char buf[MAXPATH]; /* Buffer to store the name components */
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char *ecwd, *ebuf; /* Pointers to end of used part of cwd and buf */
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int err; /* Error code of last I/O call */
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/* First, get the default volume name and working directory ID. */
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pb.w.ioNamePtr= (unsigned char *)cwd;
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err= PBHGetVolSync(&pb.w);
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if (err != noErr) {
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sprintf(cwd, "I/O error %d in PBHGetVolSync", err);
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return NULL;
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}
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ecwd= strchr((const char *)p2cstr((unsigned char*)cwd), EOS);
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ebuf= buf;
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*ebuf = EOS;
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/* Next, if at least we're running HFS, walk up the path. */
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if (hfsrunning()) {
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long dirid= pb.w.ioWDDirID;
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pb.d.ioVRefNum= pb.w.ioWDVRefNum;
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while (dirid != ROOTID) {
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pb.d.ioNamePtr= (unsigned char *) ++ebuf;
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pb.d.ioFDirIndex= -1;
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pb.d.ioDrDirID= dirid;
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err= PBGetCatInfoSync((CInfoPBPtr)&pb.d);
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if (err != noErr) {
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sprintf(cwd, "I/O error %d in PBGetCatInfoSync", err);
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return NULL;
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}
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dirid= pb.d.ioDrParID;
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ebuf += strlen((const char *)p2cstr((unsigned char *)ebuf));
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/* Should check for buf overflow */
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}
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}
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/* Finally, reverse the list of components and append it to cwd.
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Ebuf points at the EOS after last component,
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and there is an EOS before the first component.
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If there are no components, ebuf equals buf (but there
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is still an EOS where it points).
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Ecwd points at the EOS after the path built up so far,
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initially the volume name.
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We break out of the loop in the middle, thus
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appending a colon at the end in all cases. */
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for (;;) {
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*ecwd++ = ':';
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if (ebuf == buf)
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break;
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do { } while (*--ebuf != EOS); /* Find component start */
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strcpy(ecwd, ebuf+1);
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ecwd= strchr(ecwd, EOS);
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}
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*ecwd= EOS;
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return cwd;
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}
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