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 *
getpwd(void)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 *
getpwd(void)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__ */
134