1 files changed, 86 insertions, 0 deletions
diff --git a/percent_x.c b/percent_x.c
new file mode 100644
index 0000000..c95a1ea
--- /dev/null
+++ b/percent_x.c
@@ -0,0 +1,86 @@
+ /*
+  * percent_x() takes a string and performs %<char> expansions. It aborts the
+  * program when the expansion would overflow the output buffer. The result
+  * of %<char> expansion may be passed on to a shell process. For this
+  * reason, characters with a special meaning to shells are replaced by
+  * underscores.
+  * 
+  * Diagnostics are reported through syslog(3).
+  * 
+  * Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
+  */
+
+#ifndef lint
+static char sccsid[] = "@(#) percent_x.c 1.4 94/12/28 17:42:37";
+#endif
+
+/* System libraries. */
+
+#include <stdio.h>
+#include <syslog.h>
+#include <string.h>
+
+extern void exit();
+
+/* Local stuff. */
+
+#include "tcpd.h"
+
+/* percent_x - do %<char> expansion, abort if result buffer is too small */
+
+char   *percent_x(result, result_len, string, request)
+char   *result;
+int     result_len;
+char   *string;
+struct request_info *request;
+{
+    char   *bp = result;
+    char   *end = result + result_len - 1;	/* end of result buffer */
+    char   *expansion;
+    int     expansion_len;
+    static char ok_chars[] = "1234567890!@%-_=+:,./\
+abcdefghijklmnopqrstuvwxyz\
+ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+    char   *str = string;
+    char   *cp;
+    int     ch;
+
+    /*
+     * Warning: we may be called from a child process or after pattern
+     * matching, so we cannot use clean_exit() or tcpd_jump().
+     */
+
+    while (*str) {
+	if (*str == '%' && (ch = str[1]) != 0) {
+	    str += 2;
+	    expansion =
+		ch == 'a' ? eval_hostaddr(request->client) :
+		ch == 'A' ? eval_hostaddr(request->server) :
+		ch == 'c' ? eval_client(request) :
+		ch == 'd' ? eval_daemon(request) :
+		ch == 'h' ? eval_hostinfo(request->client) :
+		ch == 'H' ? eval_hostinfo(request->server) :
+		ch == 'n' ? eval_hostname(request->client) :
+		ch == 'N' ? eval_hostname(request->server) :
+		ch == 'p' ? eval_pid(request) :
+		ch == 's' ? eval_server(request) :
+		ch == 'u' ? eval_user(request) :
+		ch == '%' ? "%" : (tcpd_warn("unrecognized %%%c", ch), "");
+	    for (cp = expansion; *(cp += strspn(cp, ok_chars)); /* */ )
+		*cp = '_';
+	    expansion_len = cp - expansion;
+	} else {
+	    expansion = str++;
+	    expansion_len = 1;
+	}
+	if (bp + expansion_len >= end) {
+	    tcpd_warn("percent_x: expansion too long: %.30s...", result);
+	    sleep(5);
+	    exit(0);
+	}
+	memcpy(bp, expansion, expansion_len);
+	bp += expansion_len;
+    }
+    *bp = 0;
+    return (result);
+}