93 lines
2.0 KiB
C
93 lines
2.0 KiB
C
/* getpwd.c - get the working directory */
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#include "config.h"
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#include <errno.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#ifndef errno
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extern int errno;
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#endif
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/* Virtually every UN*X system now in common use (except for pre-4.3-tahoe
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BSD systems) now provides getcwd as called for by POSIX. Allow for
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the few exceptions to the general rule here. */
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#if !(defined (POSIX) || defined (USG) || defined (VMS))
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#include <sys/param.h>
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extern char *getwd ();
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#define getcwd(buf,len) getwd(buf)
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#define GUESSPATHLEN (MAXPATHLEN + 1)
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#else /* (defined (USG) || defined (VMS)) */
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extern char *getcwd ();
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/* We actually use this as a starting point, not a limit. */
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#define GUESSPATHLEN 100
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#endif /* (defined (USG) || defined (VMS)) */
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char *getenv ();
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char *xmalloc ();
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#ifndef VMS
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/* Get the working directory. Use the PWD environment variable if it's
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set correctly, since this is faster and gives more uniform answers
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to the user. Yield the working directory if successful; otherwise,
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yield 0 and set errno. */
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char *
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getpwd ()
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{
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static char *pwd;
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static int failure_errno;
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char *p = pwd;
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size_t s;
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struct stat dotstat, pwdstat;
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if (!p && !(errno = failure_errno))
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{
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if (! ((p = getenv ("PWD")) != 0
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&& *p == '/'
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&& stat (p, &pwdstat) == 0
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&& stat (".", &dotstat) == 0
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&& dotstat.st_ino == pwdstat.st_ino
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&& dotstat.st_dev == pwdstat.st_dev))
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/* The shortcut didn't work. Try the slow, ``sure'' way. */
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for (s = GUESSPATHLEN; ! getcwd (p = xmalloc (s), s); s *= 2)
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{
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int e = errno;
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free (p);
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if (e != ERANGE)
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{
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errno = failure_errno = e;
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p = 0;
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break;
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}
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}
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/* Cache the result. This assumes that the program does
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not invoke chdir between calls to getpwd. */
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pwd = p;
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}
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return p;
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}
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#else /* VMS */
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#ifndef MAXPATHLEN
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#define MAXPATHLEN 255
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#endif
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char *
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getpwd ()
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{
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static char *pwd = 0;
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if (!pwd) pwd = getcwd (xmalloc (MAXPATHLEN+1), MAXPATHLEN+1);
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return pwd;
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}
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#endif /* VMS */
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