4 files changed, 187 insertions, 1 deletions

diff --git a/usr/src/lib/libcmdutils/Makefile.com b/usr/src/lib/libcmdutils/Makefile.com
index 2f98fe5f25..ffe3c9cba5 100644
--- a/usr/src/lib/libcmdutils/Makefile.com
+++ b/usr/src/lib/libcmdutils/Makefile.com
@@ -25,7 +25,8 @@
 
 LIBRARY=	libcmdutils.a
 VERS=		.1
-CMD_OBJS=	avltree.o sysattrs.o writefile.o process_xattrs.o uid.o gid.o
+CMD_OBJS=	avltree.o sysattrs.o writefile.o process_xattrs.o uid.o gid.o \
+		custr.o
 COM_OBJS=	list.o
 OBJECTS=	$(CMD_OBJS) $(COM_OBJS)
 
diff --git a/usr/src/lib/libcmdutils/common/custr.c b/usr/src/lib/libcmdutils/common/custr.c
new file mode 100644
index 0000000000..1ec72de9dd
--- /dev/null
+++ b/usr/src/lib/libcmdutils/common/custr.c
@@ -0,0 +1,135 @@
+/*
+ * This file and its contents are supplied under the terms of the
+ * Common Development and Distribution License ("CDDL"), version 1.0.
+ * You may only use this file in accordance with the terms of version
+ * 1.0 of the CDDL.
+ *
+ * A full copy of the text of the CDDL should have accompanied this
+ * source.  A copy of the CDDL is also available via the Internet at
+ * http://www.illumos.org/license/CDDL.
+ */
+
+/*
+ * String utility functions with dynamic memory management.
+ */
+
+/*
+ * Copyright 2014, Joyent, Inc.
+ */
+
+#include <stdlib.h>
+#include <err.h>
+#include <string.h>
+
+#include "libcmdutils.h"
+
+struct custr {
+	size_t cus_strlen;
+	size_t cus_datalen;
+	char *cus_data;
+};
+
+#define	STRING_CHUNK_SIZE	64
+
+void
+custr_reset(custr_t *cus)
+{
+	if (cus->cus_data == NULL)
+		return;
+
+	cus->cus_strlen = 0;
+	cus->cus_data[0] = '\0';
+}
+
+size_t
+custr_len(custr_t *cus)
+{
+	return (cus->cus_strlen);
+}
+
+const char *
+custr_cstr(custr_t *cus)
+{
+	return (cus->cus_data);
+}
+
+int
+custr_appendc(custr_t *cus, char newc)
+{
+	char news[2];
+
+	news[0] = newc;
+	news[1] = '\0';
+
+	return (custr_append(cus, news));
+}
+
+int
+custr_append(custr_t *cus, const char *news)
+{
+	size_t len = strlen(news);
+	size_t chunksz = STRING_CHUNK_SIZE;
+
+	while (chunksz < len) {
+		chunksz *= 2;
+	}
+
+	if (len + cus->cus_strlen + 1 >= cus->cus_datalen) {
+		char *new_data;
+		size_t new_datalen = cus->cus_datalen + chunksz;
+
+		/*
+		 * Allocate replacement memory:
+		 */
+		if ((new_data = malloc(new_datalen)) == NULL) {
+			return (-1);
+		}
+
+		/*
+		 * Copy existing data into replacement memory and free
+		 * the old memory.
+		 */
+		if (cus->cus_data != NULL) {
+			(void) memcpy(new_data, cus->cus_data,
+			    cus->cus_strlen + 1);
+			free(cus->cus_data);
+		}
+
+		/*
+		 * Swap in the replacement buffer:
+		 */
+		cus->cus_data = new_data;
+		cus->cus_datalen = new_datalen;
+	}
+	/*
+	 * Append new string to existing string:
+	 */
+	(void) memcpy(cus->cus_data + cus->cus_strlen, news, len + 1);
+	cus->cus_strlen += len;
+
+	return (0);
+}
+
+int
+custr_alloc(custr_t **cus)
+{
+	custr_t *t;
+
+	if ((t = calloc(1, sizeof (*t))) == NULL) {
+		*cus = NULL;
+		return (-1);
+	}
+
+	*cus = t;
+	return (0);
+}
+
+void
+custr_free(custr_t *cus)
+{
+	if (cus == NULL)
+		return;
+
+	free(cus->cus_data);
+	free(cus);
+}
diff --git a/usr/src/lib/libcmdutils/common/mapfile-vers b/usr/src/lib/libcmdutils/common/mapfile-vers
index e4c5940c31..640959e4b5 100644
--- a/usr/src/lib/libcmdutils/common/mapfile-vers
+++ b/usr/src/lib/libcmdutils/common/mapfile-vers
@@ -42,6 +42,13 @@ $mapfile_version 2
 SYMBOL_VERSION SUNWprivate_1.1 {
     global:
 	add_tnode;
+	custr_alloc;
+	custr_append;
+	custr_appendc;
+	custr_cstr;
+	custr_free;
+	custr_len;
+	custr_reset;
 	destroy_tree;
 	findnextgid;
 	findnextuid;
diff --git a/usr/src/lib/libcmdutils/libcmdutils.h b/usr/src/lib/libcmdutils/libcmdutils.h
index c315e0fbef..a280751c27 100644
--- a/usr/src/lib/libcmdutils/libcmdutils.h
+++ b/usr/src/lib/libcmdutils/libcmdutils.h
@@ -25,6 +25,9 @@
 /*
  * Copyright (c) 2013 RackTop Systems.
  */
+/*
+ * Copyright 2014 Joyent, Inc.
+ */
 
 /*
  * Declarations for the functions in libcmdutils.
@@ -140,6 +143,46 @@ extern int findnextuid(uid_t, uid_t, uid_t *);
  */
 extern int findnextgid(gid_t, gid_t, gid_t *);
 
+
+
+		/* dynamic string utilities */
+
+typedef struct custr custr_t;
+
+/*
+ * Allocate and free a "custr_t" dynamic string object.  Returns 0 on success
+ * and -1 otherwise.
+ */
+extern int custr_alloc(custr_t **);
+extern void custr_free(custr_t *);
+
+/*
+ * Append a single character, or a NUL-terminated string of characters, to a
+ * dynamic string.  Returns 0 on success and -1 otherwise.  The dynamic string
+ * will be unmodified if the function returns -1.
+ */
+extern int custr_appendc(custr_t *, char);
+extern int custr_append(custr_t *, const char *);
+
+/*
+ * Determine the length in bytes, not including the NUL terminator, of the
+ * dynamic string.
+ */
+extern size_t custr_len(custr_t *);
+
+/*
+ * Clear the contents of a dynamic string.  Does not free the underlying
+ * memory.
+ */
+extern void custr_reset(custr_t *);
+
+/*
+ * Retrieve a const pointer to a NUL-terminated string version of the contents
+ * of the dynamic string.  Storage for this string should not be freed, and
+ * the pointer will be invalidated by any mutations to the dynamic string.
+ */
+extern const char *custr_cstr(custr_t *str);
+
 #ifdef	__cplusplus
 }
 #endif