Relevant BUGIDs: 490938

Purpose of commit: new feature

Commit summary:
---------------
Added libpammodutil and link it with every module as its built.
The issue here is that there is a lot of code that the various modules
use in common, and this staic library can be used to help make this code
more maintainable. I do not intend to make this library dynamic. Especially
right now, as I want to be free to chop and change the API and don't want
to deal with revision control and third party modules.

This checkin makes the pam_rhost_auth module make some use of this new
library. I don't intend to add support for any other module prior to
releasing 0.76.

1 files changed, 80 insertions, 0 deletions

diff --git a/modules/pammodutil/modutil_getpwuid.c b/modules/pammodutil/modutil_getpwuid.c
new file mode 100644
index 00000000..e200dd1e
--- /dev/null
+++ b/modules/pammodutil/modutil_getpwuid.c
@@ -0,0 +1,80 @@
+/*
+ * $Id$
+ *
+ * This function provides a thread safer version of getpwuid() for use
+ * with PAM modules that care about this sort of thing.
+ *
+ * XXX - or at least it should provide a thread-safe alternative.
+ */
+
+#include "pammodutil.h"
+
+#include <pwd.h>
+#include <stdlib.h>
+
+struct passwd *_pammodutil_getpwuid(pam_handle_t *pamh, uid_t uid)
+{
+#ifdef HAVE_GETPWNAM_R
+
+    void *buffer=NULL;
+    size_t length = PWD_INITIAL_LENGTH;
+
+    do {
+	int status;
+	void *new_buffer;
+	struct passwd *result = NULL;
+
+	new_buffer = realloc(buffer, sizeof(struct passwd) + length);
+	if (new_buffer == NULL) {
+
+	    D(("out of memory"));
+
+	    /* no memory for the user - so delete the memory */
+	    if (buffer) {
+		free(buffer);
+	    }
+	    return NULL;
+	}
+	buffer = new_buffer;
+
+	/* make the re-entrant call to get the pwd structure */
+	status = getpwuid_r(uid, buffer,
+			    sizeof(struct passwd) + (char *) buffer,
+			    length, &result);
+	if (!status && result) {
+	    status = pam_set_data(pamh, "_pammodutil_getpwuid", result,
+				  _pammodutil_cleanup);
+	    if (status == PAM_SUCCESS) {
+		D(("success"));
+		return result;
+	    }
+
+	    D(("was unable to register the data item [%s]",
+	       pam_strerror(pamh, status)));
+
+	    free(buffer);
+	    return NULL;
+
+	}
+	
+	length <<= 1;
+
+    } while (length < PWD_ABSURD_PWD_LENGTH);
+
+    D(("pwd structure took %u bytes or so of memory",
+       length+sizeof(struct passwd)));
+
+    free(buffer);
+    return NULL;
+
+#else /* ie. ifndef HAVE_GETPWNAM_R */
+
+    /*
+     * Sorry, there does not appear to be a reentrant version of
+     * getpwnam(). So, we use the standard libc function.
+     */
+    
+    return getpwuid(uid);
+
+#endif /* def HAVE_GETPWNAM_R */
+}