1 files changed, 164 insertions, 0 deletions
diff --git a/src/common/string.c b/src/common/string.c
new file mode 100644
index 0000000..de97413
--- /dev/null
+++ b/src/common/string.c
@@ -0,0 +1,164 @@
+/*-------------------------------------------------------------------------
+ *
+ * string.c
+ *		string handling helpers
+ *
+ *
+ * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ *	  src/common/string.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+
+#ifndef FRONTEND
+#include "postgres.h"
+#else
+#include "postgres_fe.h"
+#endif
+
+#include "common/string.h"
+#include "lib/stringinfo.h"
+
+
+/*
+ * Returns whether the string `str' has the postfix `end'.
+ */
+bool
+pg_str_endswith(const char *str, const char *end)
+{
+	size_t		slen = strlen(str);
+	size_t		elen = strlen(end);
+
+	/* can't be a postfix if longer */
+	if (elen > slen)
+		return false;
+
+	/* compare the end of the strings */
+	str += slen - elen;
+	return strcmp(str, end) == 0;
+}
+
+
+/*
+ * strtoint --- just like strtol, but returns int not long
+ */
+int
+strtoint(const char *pg_restrict str, char **pg_restrict endptr, int base)
+{
+	long		val;
+
+	val = strtol(str, endptr, base);
+	if (val != (int) val)
+		errno = ERANGE;
+	return (int) val;
+}
+
+
+/*
+ * pg_clean_ascii -- Replace any non-ASCII chars with a "\xXX" string
+ *
+ * Makes a newly allocated copy of the string passed in, which must be
+ * '\0'-terminated. In the backend, additional alloc_flags may be provided and
+ * will be passed as-is to palloc_extended(); in the frontend, alloc_flags is
+ * ignored and the copy is malloc'd.
+ *
+ * This function exists specifically to deal with filtering out
+ * non-ASCII characters in a few places where the client can provide an almost
+ * arbitrary string (and it isn't checked to ensure it's a valid username or
+ * database name or similar) and we don't want to have control characters or other
+ * things ending up in the log file where server admins might end up with a
+ * messed up terminal when looking at them.
+ *
+ * In general, this function should NOT be used- instead, consider how to handle
+ * the string without needing to filter out the non-ASCII characters.
+ *
+ * Ultimately, we'd like to improve the situation to not require replacing all
+ * non-ASCII but perform more intelligent filtering which would allow UTF or
+ * similar, but it's unclear exactly what we should allow, so stick to ASCII only
+ * for now.
+ */
+char *
+pg_clean_ascii(const char *str, int alloc_flags)
+{
+	size_t		dstlen;
+	char	   *dst;
+	const char *p;
+	size_t		i = 0;
+
+	/* Worst case, each byte can become four bytes, plus a null terminator. */
+	dstlen = strlen(str) * 4 + 1;
+
+#ifdef FRONTEND
+	dst = malloc(dstlen);
+#else
+	dst = palloc_extended(dstlen, alloc_flags);
+#endif
+
+	if (!dst)
+		return NULL;
+
+	for (p = str; *p != '\0'; p++)
+	{
+
+		/* Only allow clean ASCII chars in the string */
+		if (*p < 32 || *p > 126)
+		{
+			Assert(i < (dstlen - 3));
+			snprintf(&dst[i], dstlen - i, "\\x%02x", (unsigned char) *p);
+			i += 4;
+		}
+		else
+		{
+			Assert(i < dstlen);
+			dst[i] = *p;
+			i++;
+		}
+	}
+
+	Assert(i < dstlen);
+	dst[i] = '\0';
+	return dst;
+}
+
+
+/*
+ * pg_is_ascii -- Check if string is made only of ASCII characters
+ */
+bool
+pg_is_ascii(const char *str)
+{
+	while (*str)
+	{
+		if (IS_HIGHBIT_SET(*str))
+			return false;
+		str++;
+	}
+	return true;
+}
+
+
+/*
+ * pg_strip_crlf -- Remove any trailing newline and carriage return
+ *
+ * Removes any trailing newline and carriage return characters (\r on
+ * Windows) in the input string, zero-terminating it.
+ *
+ * The passed in string must be zero-terminated.  This function returns
+ * the new length of the string.
+ */
+int
+pg_strip_crlf(char *str)
+{
+	int			len = strlen(str);
+
+	while (len > 0 && (str[len - 1] == '\n' ||
+					   str[len - 1] == '\r'))
+		str[--len] = '\0';
+
+	return len;
+}