Initial commit

1 files changed, 245 insertions, 0 deletions

diff --git a/unix/os/zgtenv.c b/unix/os/zgtenv.c
new file mode 100644
index 00000000..fbe838b1
--- /dev/null
+++ b/unix/os/zgtenv.c
@@ -0,0 +1,245 @@
+/* Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <ctype.h>
+#define import_spp
+#define	import_kernel
+#define	import_knames
+#include <iraf.h>
+
+static char *_ev_scaniraf (char *envvar);
+static int   _ev_loadcache (char *fname);
+static int   _ev_streq (char *s1, char *s2, int n);
+
+
+/* ZGTENV -- Get the value of a host system environment variable.  Look first
+ * in the process environment.  If no entry is found there and the variable is
+ * one of the standard named variables, get the system wide default value from
+ * the file <iraf.h>, which is assumed to be located in /usr/include.
+ */
+int
+ZGTENV (
+  PKCHAR  *envvar,		/* name of variable to be fetched	*/
+  PKCHAR  *outstr,		/* output string			*/
+  XINT	  *maxch, 
+  XINT    *status
+)
+{
+	register char	*ip, *op;
+	register int	n;
+	char	*getenv();
+
+
+	op = (char *)outstr;
+	if ((ip = getenv ((char *)envvar)) == NULL)
+	    ip = _ev_scaniraf ((char *)envvar);
+
+	if (ip == NULL) {
+	    *op = EOS;
+	    *status = XERR;
+	} else {
+	    *status = 0;
+	    op[*maxch] = EOS;
+	    for (n = *maxch;  --n >= 0 && (*op++ = *ip++);  )
+		(*status)++;
+	}
+
+	return (XOK);
+}
+
+
+/*
+ * Code to bootstrap the IRAF environment list for UNIX.
+ */
+
+#define	TABLE		"/usr/include/iraf.h"	/* table file		*/
+#define	DELIM		"/* ###"		/* delimits defs area	*/
+#define	NENV		3			/* n variables		*/
+#define	SZ_NAME		10
+#define	SZ_VALUE	80
+
+struct	env {
+	char	ev_name[SZ_NAME+1];
+	char	ev_value[SZ_VALUE+1];
+};
+
+int	ev_cacheloaded = 0;
+struct	env ev_table[NENV] = {
+	{ "host",		""},
+	{ "iraf",		""},
+	{ "tmp",		""}
+};
+
+
+/* SCANIRAF -- If the referenced environment variable is a well known standard
+ * variable, scan the file <iraf.h> for its system wide default value.  This
+ * is done at run time rather than compile time to make it possible to make
+ * changes to these variables (e.g., relocate iraf to a different root
+ * directory) without recompiling major parts of the system.
+ *
+ * Virtually all IRAF environment variables are defined in the source code and
+ * are portable.  In particular, virtually all source directories are defined
+ * relative to the IRAF root directory "iraf$".  Only those definitions which
+ * are both necessarily machine dependent and required for operation of the
+ * bootstrap C programs (e.g., the CL, XC, etc.) are satisfied at this level.
+ * These variables are the following.
+ *
+ *	iraf		The root directory of IRAF; if this is incorrect,
+ *			    bootstrap programs like the CL will not be able
+ *			    to find IRAF files.
+ *
+ *	host		The machine dependent subdirectory of iraf$.  The
+ *			    actual name of this directory varies from system
+ *			    to system (to avoid name collisions on tar tapes),
+ *		 	    hence we cannot use "iraf$host/".
+ *			    Examples: iraf$unix/, iraf$vms/, iraf$sun/, etc.
+ *
+ *	tmp		The place where IRAF is to put its temporary files.
+ *			    This is normally /tmp/ for a UNIX system.  TMP
+ *			    also serves as the default IMDIR.
+ *	
+ * The entries for these variables in the <iraf.h> must adhere to a standard
+ * format, e.g. (substituting @ for *):
+ *
+ *	/@ ### Start of run time definitions @/
+ *	#define	iraf		"/iraf/"
+ *	#define	host		"/iraf/unix/"
+ *	#define	tmp		"/tmp/"
+ *	/@ ### End of run time definitions @/
+ *
+ * Although the definitions are entered as standard C #defines, they should not
+ * be directly referenced in C programs.
+ */
+static char *
+_ev_scaniraf (char *envvar)
+{
+	int	i;
+
+
+	for (i=0;  i < NENV;  i++)
+	    if (strcmp (ev_table[i].ev_name, envvar) == 0)
+		break;
+
+	if (i >= NENV)
+	    return (NULL);
+
+	if (!ev_cacheloaded) {
+	    if (_ev_loadcache (TABLE) == ERR)
+		return (NULL);
+	    else
+		ev_cacheloaded++;
+	}
+
+	return (ev_table[i].ev_value);
+}
+
+
+/* _EV_LOADCACHE -- Scan <iraf.h> for the values of the standard variables.
+ * Cache these in case we are called again (they do not change so often that we
+ * cannot cache them in memory).  Any errors in accessing the table probably
+ * indicate an error in installing IRAF hence should be reported immediately.
+ */
+static int
+_ev_loadcache (char *fname)
+{
+	register char	*ip, *op;
+	register FILE	*fp;
+	register int	n;
+
+	static  char   *home, hpath[SZ_PATHNAME+1];
+	static	char	delim[] = DELIM;
+	char	lbuf[SZ_LINE+1];
+	int	len_delim, i;
+
+
+	if ((home = getenv ("HOME"))) {
+	    memset (hpath, 0, SZ_PATHNAME);
+	    sprintf (hpath, "%s/.iraf.h", home);
+	    if ((fp = fopen (hpath, "r")) == NULL) {
+		/*  No personal $HOME/.iraf.h file, try the system request.
+		 */
+		if ((fp = fopen (fname, "r")) == NULL) {
+	            fprintf (stderr, "os.zgtenv: cannot open `%s'\n", fname);
+	            return (ERR);
+	    	}
+	    }
+	} else {
+	    /*  We should always have a $HOME, but try this to be safe.
+	     */
+	    if ((fp = fopen (fname, "r")) == NULL) {
+	        fprintf (stderr, "os.zgtenv: cannot open `%s'\n", fname);
+	        return (ERR);
+	    }
+	}
+
+	len_delim = strlen (delim);
+	while (fgets (lbuf, SZ_LINE, fp) != NULL) {
+	    if (strncmp (lbuf, delim, len_delim) == 0)
+		break;
+	}
+
+	/* Extract the values of the variables from the table.  The format is
+	 * rather rigid; in particular, the variables must be given in the
+	 * table in the same order in which they appear in the in core table,
+	 * i.e., alphabetic order.
+	 */
+	for (i=0;  i < NENV;  i++) {
+	    if (fgets (lbuf, SZ_LINE, fp) == NULL)
+		goto error;
+	    if (strncmp (lbuf, "#define", 7) != 0)
+		goto error;
+
+	    /* Verify the name of the variable.  */
+	    ip = ev_table[i].ev_name;
+	    if (!_ev_streq (lbuf+8, ip, strlen(ip)))
+		goto error;
+
+	    /* Extract the quoted value string.  */
+	    for (ip=lbuf+8;  *ip++ != '"';  )
+		;
+	    op = ev_table[i].ev_value;
+	    for (n=SZ_VALUE;  --n >= 0 && (*op = *ip++) != '"';  op++)
+		;
+	    *op = EOS;
+	}
+
+	if (fgets (lbuf, SZ_LINE, fp) == NULL)
+	    goto error;
+	if (strncmp (lbuf, delim, len_delim) != 0)
+	    goto error;
+
+	fclose (fp);
+	return (OK);
+error:
+	fprintf (stderr, "os.zgtenv: error scanning `%s'\n", fname);
+	fclose (fp);
+	return (ERR);
+}
+
+
+#define	to_lower(c)        ((c)+'a'-'A')
+
+/* EV_STREQ -- Compare two strings for equality, ignoring case.  The logical
+ * names are given in upper case in <iraf.h> since they are presented as
+ * macro defines.
+ */
+static int
+_ev_streq (char *s1, char *s2, int n)
+{
+	register int	ch1, ch2;
+
+	while (--n >= 0) {
+	    ch1 = *s1++;
+	    if (isupper (ch1))
+		ch1 = to_lower(ch1);
+	    ch2 = *s2++;
+	    if (isupper (ch2))
+		ch2 = to_lower(ch2);
+	    if (ch1 != ch2)
+		return (0);
+	}
+
+	return (1);
+}