sdcc/support/sdbinutils/libiberty/getpwd.c

   1 /* getpwd.c - get the working directory */
   2
   3 /*
   4
   5 @deftypefn Supplemental char* getpwd (void)
   6
   7 Returns the current working directory.  This implementation caches the
   8 result on the assumption that the process will not call @code{chdir}
   9 between calls to @code{getpwd}.
  10
  11 @end deftypefn
  12
  13 */
  14
  15 #ifdef HAVE_CONFIG_H
  16 #include "config.h"
  17 #endif
  18
  19 #include <sys/types.h>
  20
  21 #include <errno.h>
  22 #ifndef errno
  23 extern int errno;
  24 #endif
  25
  26 #ifdef HAVE_STDLIB_H
  27 #include <stdlib.h>
  28 #endif
  29 #ifdef HAVE_UNISTD_H
  30 #include <unistd.h>
  31 #endif
  32 #ifdef HAVE_SYS_PARAM_H
  33 #include <sys/param.h>
  34 #endif
  35 #if HAVE_SYS_STAT_H
  36 #include <sys/stat.h>
  37 #endif
  38 #if HAVE_LIMITS_H
  39 #include <limits.h>
  40 #endif
  41
  42 #include "libiberty.h"
  43
  44 /* Virtually every UN*X system now in common use (except for pre-4.3-tahoe
  45    BSD systems) now provides getcwd as called for by POSIX.  Allow for
  46    the few exceptions to the general rule here.  */
  47
  48 #if !defined(HAVE_GETCWD) && defined(HAVE_GETWD)
  49 /* Prototype in case the system headers doesn't provide it. */
  50 extern char *getwd ();
  51 #define getcwd(buf,len) getwd(buf)
  52 #endif
  53
  54 #ifdef MAXPATHLEN
  55 #define GUESSPATHLEN (MAXPATHLEN + 1)
  56 #else
  57 #define GUESSPATHLEN 100
  58 #endif
  59
  60 #if !(defined (VMS) || (defined(_WIN32) && !defined(__CYGWIN__)))
  61
  62 #ifdef _WIN32
  63 #include <direct.h>
  64 #define getcwd  _getcwd
  65 #endif
  66
  67 /* Get the working directory.  Use the PWD environment variable if it's
  68    set correctly, since this is faster and gives more uniform answers
  69    to the user.  Yield the working directory if successful; otherwise,
  70    yield 0 and set errno.  */
  71
  72 char *
  73 getpwd (void)
  74 {
  75   static char *pwd;
  76   static int failure_errno;
  77
  78   char *p = pwd;
  79   size_t s;
  80   struct stat dotstat, pwdstat;
  81
  82   if (!p && !(errno = failure_errno))
  83     {
  84       if (! ((p = getenv ("PWD")) != 0
  85              && *p == '/'
  86              && stat (p, &pwdstat) == 0
  87              && stat (".", &dotstat) == 0
  88              && dotstat.st_ino == pwdstat.st_ino
  89              && dotstat.st_dev == pwdstat.st_dev))
  90
  91         /* The shortcut didn't work.  Try the slow, ``sure'' way.  */
  92         for (s = GUESSPATHLEN;  !getcwd (p = XNEWVEC (char, s), s);  s *= 2)
  93           {
  94             int e = errno;
  95             free (p);
  96 #ifdef ERANGE
  97             if (e != ERANGE)
  98 #endif
  99               {
 100                 errno = failure_errno = e;
 101                 p = 0;
 102                 break;
 103               }
 104           }
 105
 106       /* Cache the result.  This assumes that the program does
 107          not invoke chdir between calls to getpwd.  */
 108       pwd = p;
 109     }
 110   return p;
 111 }
 112
 113 #else   /* VMS || _WIN32 && !__CYGWIN__ */
 114
 115 #ifndef MAXPATHLEN
 116 #define MAXPATHLEN 255
 117 #endif
 118
 119 char *
 120 getpwd (void)
 121 {
 122   static char *pwd = 0;
 123
 124   if (!pwd)
 125     pwd = getcwd (XNEWVEC (char, MAXPATHLEN + 1), MAXPATHLEN + 1
 126 #ifdef VMS
 127                   , 0
 128 #endif
 129                   );
 130   return pwd;
 131 }
 132
 133 #endif  /* VMS || _WIN32 && !__CYGWIN__ */