Python/getcwd.c

   1 /***********************************************************
   2 Copyright 1991-1995 by Stichting Mathematisch Centrum, Amsterdam,
   3 The Netherlands.
   4
   5                         All Rights Reserved
   6
   7 Permission to use, copy, modify, and distribute this software and its
   8 documentation for any purpose and without fee is hereby granted,
   9 provided that the above copyright notice appear in all copies and that
  10 both that copyright notice and this permission notice appear in
  11 supporting documentation, and that the names of Stichting Mathematisch
  12 Centrum or CWI or Corporation for National Research Initiatives or
  13 CNRI not be used in advertising or publicity pertaining to
  14 distribution of the software without specific, written prior
  15 permission.
  16
  17 While CWI is the initial source for this software, a modified version
  18 is made available by the Corporation for National Research Initiatives
  19 (CNRI) at the Internet address ftp://ftp.python.org.
  20
  21 STICHTING MATHEMATISCH CENTRUM AND CNRI DISCLAIM ALL WARRANTIES WITH
  22 REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF
  23 MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH
  24 CENTRUM OR CNRI BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL
  25 DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  26 PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
  27 TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  28 PERFORMANCE OF THIS SOFTWARE.
  29
  30 ******************************************************************/
  31
  32 /* Two PD getcwd() implementations.
  33    Author: Guido van Rossum, CWI Amsterdam, Jan 1991, <guido@cwi.nl>. */
  34
  35 #include <stdio.h>
  36 #include <errno.h>
  37
  38 #ifdef HAVE_GETWD
  39
  40 /* Version for BSD systems -- use getwd() */
  41
  42 #ifdef HAVE_SYS_PARAM_H
  43 #include <sys/param.h>
  44 #endif
  45
  46 #ifndef MAXPATHLEN
  47 #define MAXPATHLEN 1024
  48 #endif
  49
  50 extern char *getwd();
  51
  52 char *
  53 getcwd(buf, size)
  54         char *buf;
  55         int size;
  56 {
  57         char localbuf[MAXPATHLEN+1];
  58         char *ret;
  59
  60         if (size <= 0) {
  61                 errno = EINVAL;
  62                 return NULL;
  63         }
  64         ret = getwd(localbuf);
  65         if (ret != NULL && strlen(localbuf) >= size) {
  66                 errno = ERANGE;
  67                 return NULL;
  68         }
  69         if (ret == NULL) {
  70                 errno = EACCES; /* Most likely error */
  71                 return NULL;
  72         }
  73         strncpy(buf, localbuf, size);
  74         return buf;
  75 }
  76
  77 #else /* !HAVE_GETWD */
  78
  79 /* Version for really old UNIX systems -- use pipe from pwd */
  80
  81 #ifndef PWD_CMD
  82 #define PWD_CMD "/bin/pwd"
  83 #endif
  84
  85 char *
  86 getcwd(buf, size)
  87         char *buf;
  88         int size;
  89 {
  90         FILE *fp;
  91         char *p;
  92         int sts;
  93         if (size <= 0) {
  94                 errno = EINVAL;
  95                 return NULL;
  96         }
  97         if ((fp = popen(PWD_CMD, "r")) == NULL)
  98                 return NULL;
  99         if (fgets(buf, size, fp) == NULL || (sts = pclose(fp)) != 0) {
 100                 errno = EACCES; /* Most likely error */
 101                 return NULL;
 102         }
 103         for (p = buf; *p != '\n'; p++) {
 104                 if (*p == '\0') {
 105                         errno = ERANGE;
 106                         return NULL;
 107                 }
 108         }
 109         *p = '\0';
 110         return buf;
 111 }
 112
 113 #endif /* !HAVE_GETWD */