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