Initial revision

From-SVN: r1911

gcc/getpwd.c

+/* getpwd.c - get the working directory */
+
+#include "config.h"
+
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#ifndef errno
+extern int errno;
+#endif
+
+/* Virtually every UN*X system now in common use (except for pre-4.3-tahoe
+   BSD systems) now provides getcwd as called for by POSIX.  Allow for
+   the few exceptions to the general rule here.  */
+
+#if !(defined (POSIX) || defined (USG) || defined (VMS))
+#include <sys/param.h>
+extern char *getwd ();
+#define getcwd(buf,len) getwd(buf)
+#define GUESSPATHLEN (MAXPATHLEN + 1)
+#else /* (defined (USG) || defined (VMS)) */
+extern char *getcwd ();
+/* We actually use this as a starting point, not a limit.  */
+#define GUESSPATHLEN 100
+#endif /* (defined (USG) || defined (VMS)) */
+
+char *getenv ();
+char *xmalloc ();
+
+#ifndef VMS
+
+/* Get the working directory.  Use the PWD environment variable if it's
+   set correctly, since this is faster and gives more uniform answers
+   to the user.  Yield the working directory if successful; otherwise,
+   yield 0 and set errno.  */
+
+char *
+getpwd ()
+{
+  static char *pwd;
+  static int failure_errno;
+
+  char *p = pwd;
+  size_t s;
+  struct stat dotstat, pwdstat;
+
+  if (!p && !(errno = failure_errno))
+    {
+      if (! ((p = getenv ("PWD")) != 0
+	     && *p == '/'
+	     && stat (p, &pwdstat) == 0
+	     && stat (".", &dotstat) == 0
+	     && dotstat.st_ino == pwdstat.st_ino
+	     && dotstat.st_dev == pwdstat.st_dev))
+
+	/* The shortcut didn't work.  Try the slow, ``sure'' way.  */
+	for (s = GUESSPATHLEN;  ! getcwd (p = xmalloc (s), s);  s *= 2)
+	  {
+	    int e = errno;
+	    free (p);
+	    if (e != ERANGE)
+	      {
+		errno = failure_errno = e;
+		p = 0;
+		break;
+	      }
+	  }
+
+      /* Cache the result.  This assumes that the program does
+	 not invoke chdir between calls to getpwd.  */
+      pwd = p;
+    }
+  return p;
+}
+
+#else	/* VMS */
+
+#ifndef MAXPATHLEN
+#define MAXPATHLEN 255
+#endif
+
+char *
+getpwd ()
+{
+  static char *pwd = 0;
+
+  if (!pwd) pwd = getcwd (xmalloc (MAXPATHLEN+1), MAXPATHLEN+1);
+  return pwd;
+}
+
+#endif	/* VMS */