| 1 | /* getpwd.c - get the working directory */ |
| 2 | |
| 3 | #include "config.h" |
| 4 | |
| 5 | #include <errno.h> |
| 6 | #include <sys/types.h> |
| 7 | #include <sys/stat.h> |
| 8 | |
| 9 | #ifndef errno |
| 10 | extern int errno; |
| 11 | #endif |
| 12 | |
| 13 | /* Virtually every UN*X system now in common use (except for pre-4.3-tahoe |
| 14 | BSD systems) now provides getcwd as called for by POSIX. Allow for |
| 15 | the few exceptions to the general rule here. */ |
| 16 | |
| 17 | #if !(defined (POSIX) || defined (USG) || defined (VMS)) |
| 18 | #include <sys/param.h> |
| 19 | extern char *getwd (); |
| 20 | #define getcwd(buf,len) getwd(buf) |
| 21 | #define GUESSPATHLEN (MAXPATHLEN + 1) |
| 22 | #else /* (defined (USG) || defined (VMS)) */ |
| 23 | extern char *getcwd (); |
| 24 | /* We actually use this as a starting point, not a limit. */ |
| 25 | #define GUESSPATHLEN 100 |
| 26 | #endif /* (defined (USG) || defined (VMS)) */ |
| 27 | |
| 28 | char *getenv (); |
| 29 | char *xmalloc (); |
| 30 | |
| 31 | #ifndef VMS |
| 32 | |
| 33 | /* Get the working directory. Use the PWD environment variable if it's |
| 34 | set correctly, since this is faster and gives more uniform answers |
| 35 | to the user. Yield the working directory if successful; otherwise, |
| 36 | yield 0 and set errno. */ |
| 37 | |
| 38 | char * |
| 39 | getpwd () |
| 40 | { |
| 41 | static char *pwd; |
| 42 | static int failure_errno; |
| 43 | |
| 44 | char *p = pwd; |
| 45 | size_t s; |
| 46 | struct stat dotstat, pwdstat; |
| 47 | |
| 48 | if (!p && !(errno = failure_errno)) |
| 49 | { |
| 50 | if (! ((p = getenv ("PWD")) != 0 |
| 51 | && *p == '/' |
| 52 | && stat (p, &pwdstat) == 0 |
| 53 | && stat (".", &dotstat) == 0 |
| 54 | && dotstat.st_ino == pwdstat.st_ino |
| 55 | && dotstat.st_dev == pwdstat.st_dev)) |
| 56 | |
| 57 | /* The shortcut didn't work. Try the slow, ``sure'' way. */ |
| 58 | for (s = GUESSPATHLEN; ! getcwd (p = xmalloc (s), s); s *= 2) |
| 59 | { |
| 60 | int e = errno; |
| 61 | free (p); |
| 62 | #ifdef ERANGE |
| 63 | if (e != ERANGE) |
| 64 | #endif |
| 65 | { |
| 66 | errno = failure_errno = e; |
| 67 | p = 0; |
| 68 | break; |
| 69 | } |
| 70 | } |
| 71 | |
| 72 | /* Cache the result. This assumes that the program does |
| 73 | not invoke chdir between calls to getpwd. */ |
| 74 | pwd = p; |
| 75 | } |
| 76 | return p; |
| 77 | } |
| 78 | |
| 79 | #else /* VMS */ |
| 80 | |
| 81 | #ifndef MAXPATHLEN |
| 82 | #define MAXPATHLEN 255 |
| 83 | #endif |
| 84 | |
| 85 | char * |
| 86 | getpwd () |
| 87 | { |
| 88 | static char *pwd = 0; |
| 89 | |
| 90 | if (!pwd) pwd = getcwd (xmalloc (MAXPATHLEN+1), MAXPATHLEN+1); |
| 91 | return pwd; |
| 92 | } |
| 93 | |
| 94 | #endif /* VMS */ |