Python/getcwd.c

   1
   2 /* Two PD getcwd() implementations.
   3    Author: Guido van Rossum, CWI Amsterdam, Jan 1991, <guido@cwi.nl>. */
   4
   5 #include <stdio.h>
   6 #include <errno.h>
   7
   8 #ifdef HAVE_GETWD
   9
  10 /* Version for BSD systems -- use getwd() */
  11
  12 #ifdef HAVE_SYS_PARAM_H
  13 #include <sys/param.h>
  14 #endif
  15
  16 #ifndef MAXPATHLEN
  17 #define MAXPATHLEN 1024
  18 #endif
  19
  20 extern char *getwd(char *);
  21
  22 char *
  23 getcwd(char *buf, int size)
  24 {
  25         char localbuf[MAXPATHLEN+1];
  26         char *ret;
  27
  28         if (size <= 0) {
  29                 errno = EINVAL;
  30                 return NULL;
  31         }
  32         ret = getwd(localbuf);
  33         if (ret != NULL && strlen(localbuf) >= (size_t)size) {
  34                 errno = ERANGE;
  35                 return NULL;
  36         }
  37         if (ret == NULL) {
  38                 errno = EACCES; /* Most likely error */
  39                 return NULL;
  40         }
  41         strncpy(buf, localbuf, size);
  42         return buf;
  43 }
  44
  45 #else /* !HAVE_GETWD */
  46
  47 /* Version for really old UNIX systems -- use pipe from pwd */
  48
  49 #ifndef PWD_CMD
  50 #define PWD_CMD "/bin/pwd"
  51 #endif
  52
  53 char *
  54 getcwd(char *buf, int size)
  55 {
  56         FILE *fp;
  57         char *p;
  58         int sts;
  59         if (size <= 0) {
  60                 errno = EINVAL;
  61                 return NULL;
  62         }
  63         if ((fp = popen(PWD_CMD, "r")) == NULL)
  64                 return NULL;
  65         if (fgets(buf, size, fp) == NULL || (sts = pclose(fp)) != 0) {
  66                 errno = EACCES; /* Most likely error */
  67                 return NULL;
  68         }
  69         for (p = buf; *p != '\n'; p++) {
  70                 if (*p == '\0') {
  71                         errno = ERANGE;
  72                         return NULL;
  73                 }
  74         }
  75         *p = '\0';
  76         return buf;
  77 }
  78
  79 #endif /* !HAVE_GETWD */