1 files changed, 118 insertions, 0 deletions
diff --git a/libpam/include/pam_inline.h b/libpam/include/pam_inline.h
new file mode 100644
index 0000000..ec2f3bf
--- /dev/null
+++ b/libpam/include/pam_inline.h
@@ -0,0 +1,118 @@
+/*
+ * Copyright (c) 2020 Dmitry V. Levin <ldv@altlinux.org>
+ *
+ * Handy inline functions and macros providing some convenient functionality
+ * to libpam and its modules.
+ */
+
+#ifndef PAM_INLINE_H
+#define PAM_INLINE_H
+
+#include "pam_cc_compat.h"
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+
+/*
+ * Evaluates to
+ * - a syntax error if the argument is 0,
+ * 0, otherwise.
+ */
+#define PAM_FAIL_BUILD_ON_ZERO(e_)	(sizeof(int[-1 + 2 * !!(e_)]) * 0)
+
+/*
+ * Evaluates to
+ * 1, if the given type is known to be a non-array type
+ * 0, otherwise.
+ */
+#define PAM_IS_NOT_ARRAY(a_)		PAM_IS_SAME_TYPE((a_), &(a_)[0])
+
+/*
+ * Evaluates to
+ * - a syntax error if the argument is not an array,
+ * 0, otherwise.
+ */
+#define PAM_MUST_BE_ARRAY(a_)		PAM_FAIL_BUILD_ON_ZERO(!PAM_IS_NOT_ARRAY(a_))
+
+/* Evaluates to the number of elements in the specified array.  */
+#define PAM_ARRAY_SIZE(a_)		(sizeof(a_) / sizeof((a_)[0]) + PAM_MUST_BE_ARRAY(a_))
+
+/*
+ * Returns NULL if STR does not start with PREFIX,
+ * or a pointer to the first char in STR after PREFIX.
+ * The length of PREFIX is specified by PREFIX_LEN.
+ */
+static inline const char *
+pam_str_skip_prefix_len(const char *str, const char *prefix, size_t prefix_len)
+{
+	return strncmp(str, prefix, prefix_len) ? NULL : str + prefix_len;
+}
+
+#define pam_str_skip_prefix(str_, prefix_)	\
+	pam_str_skip_prefix_len((str_), (prefix_), sizeof(prefix_) - 1 + PAM_MUST_BE_ARRAY(prefix_))
+
+/*
+ * Returns NULL if STR does not start with PREFIX
+ * (ignoring the case of the characters),
+ * or a pointer to the first char in STR after PREFIX.
+ * The length of PREFIX is specified by PREFIX_LEN.
+ */
+static inline const char *
+pam_str_skip_icase_prefix_len(const char *str, const char *prefix, size_t prefix_len)
+{
+	return strncasecmp(str, prefix, prefix_len) ? NULL : str + prefix_len;
+}
+
+#define pam_str_skip_icase_prefix(str_, prefix_)	\
+	pam_str_skip_icase_prefix_len((str_), (prefix_), sizeof(prefix_) - 1 + PAM_MUST_BE_ARRAY(prefix_))
+
+static inline int
+pam_read_passwords(int fd, int npass, char **passwords)
+{
+	/*
+	 * The passwords array must contain npass preallocated
+	 * buffers of length PAM_MAX_RESP_SIZE + 1.
+	 */
+	int rbytes = 0;
+	int offset = 0;
+	int i = 0;
+	char *pptr;
+	while (npass > 0) {
+		rbytes = read(fd, passwords[i]+offset, PAM_MAX_RESP_SIZE+1-offset);
+
+		if (rbytes < 0) {
+			if (errno == EINTR) {
+				continue;
+			}
+			break;
+		}
+		if (rbytes == 0) {
+			break;
+		}
+
+		while (npass > 0 &&
+		       (pptr = memchr(passwords[i] + offset, '\0', rbytes)) != NULL) {
+			++pptr; /* skip the '\0' */
+			rbytes -= pptr - (passwords[i] + offset);
+			i++;
+			offset = 0;
+			npass--;
+			if (rbytes > 0) {
+				if (npass > 0) {
+					memcpy(passwords[i], pptr, rbytes);
+				}
+				memset(pptr, '\0', rbytes);
+			}
+		}
+		offset += rbytes;
+	}
+
+	/* clear up */
+	if (offset > 0 && npass > 0) {
+		memset(passwords[i], '\0', offset);
+	}
+
+	return i;
+}
+
+#endif /* PAM_INLINE_H */