krb5 commit: Add k5_dir_filenames() to libkrb5support

https://github.com/krb5/krb5/commit/b240e23897e86fbb4519173a7a70f9f157f64dfe
commit b240e23897e86fbb4519173a7a70f9f157f64dfe
Author: Greg Hudson <[email protected]>
Date:   Tue Jun 5 14:01:05 2018 -0400

    Add k5_dir_filenames() to libkrb5support
    
    Add a support function to get a list of filenames from a directory in
    sorted order.

 src/include/k5-platform.h                     |    7 ++
 src/util/support/Makefile.in                  |    3 +
 src/util/support/dir_filenames.c              |  135 +++++++++++++++++++++++++
 src/util/support/libkrb5support-fixed.exports |    2 +
 4 files changed, 147 insertions(+), 0 deletions(-)

diff --git a/src/include/k5-platform.h b/src/include/k5-platform.h
index 07ef6a4..763408a 100644
--- a/src/include/k5-platform.h
+++ b/src/include/k5-platform.h
@@ -44,6 +44,8 @@
  * + constant time memory comparison
  * + path manipulation
  * + _, N_, dgettext, bindtextdomain (for localization)
+ * + getopt_long
+ * + fetching filenames from a directory
  */
 
 #ifndef K5_PLATFORM_H
@@ -1148,4 +1150,9 @@ extern int k5_getopt_long(int nargc, char **nargv, char *options,
 #define getopt_long k5_getopt_long
 #endif /* HAVE_GETOPT_LONG */
 
+/* Set *fnames_out to a null-terminated list of filenames within dirname,
+ * sorted according to strcmp().  Return 0 on success, or ENOENT/ENOMEM. */
+int k5_dir_filenames(const char *dirname, char ***fnames_out);
+void k5_free_filenames(char **fnames);
+
 #endif /* K5_PLATFORM_H */
diff --git a/src/util/support/Makefile.in b/src/util/support/Makefile.in
index 7393826..2799af1 100644
--- a/src/util/support/Makefile.in
+++ b/src/util/support/Makefile.in
@@ -84,6 +84,7 @@ STLIBOBJS= \
 	hex.o \
 	bcmp.o \
 	strerror_r.o \
+	dir_filenames.o \
 	$(GETTIMEOFDAY_ST_OBJ) \
 	$(IPC_ST_OBJ) \
 	$(STRLCPY_ST_OBJ) \
@@ -110,6 +111,7 @@ LIBOBJS= \
 	$(OUTPRE)hex.$(OBJEXT) \
 	$(OUTPRE)bcmp.$(OBJEXT) \
 	$(OUTPRE)strerror_r.$(OBJEXT) \
+	$(OUTPRE)dir_filenames.$(OBJEXT) \
 	$(GETTIMEOFDAY_OBJ) \
 	$(IPC_OBJ) \
 	$(STRLCPY_OBJ) \
@@ -146,6 +148,7 @@ SRCS=\
 	$(srcdir)/hex.c \
 	$(srcdir)/bcmp.c \
 	$(srcdir)/strerror_r.c \
+	$(srcdir)/dir_filenames.c \
 	$(srcdir)/t_utf8.c \
 	$(srcdir)/t_utf16.c \
 	$(srcdir)/getopt.c \
diff --git a/src/util/support/dir_filenames.c b/src/util/support/dir_filenames.c
new file mode 100644
index 0000000..9312b02
--- /dev/null
+++ b/src/util/support/dir_filenames.c
@@ -0,0 +1,135 @@
+/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
+/* util/support/dir_filenames.c - fetch filenames in a directory */
+/*
+ * Copyright (C) 2018 by the Massachusetts Institute of Technology.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in
+ *   the documentation and/or other materials provided with the
+ *   distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "k5-platform.h"
+
+void
+k5_free_filenames(char **fnames)
+{
+    char **fn;
+
+    for (fn = fnames; fn != NULL && *fn != NULL; fn++)
+        free(*fn);
+    free(fnames);
+}
+
+/* Resize the filename list and add a name. */
+static int
+add_filename(char ***fnames, int *n_fnames, const char *name)
+{
+    char **newlist;
+
+    newlist = realloc(*fnames, (*n_fnames + 2) * sizeof(*newlist));
+    if (newlist == NULL)
+        return ENOMEM;
+    *fnames = newlist;
+    newlist[*n_fnames] = strdup(name);
+    if (newlist[*n_fnames] == NULL)
+        return ENOMEM;
+    (*n_fnames)++;
+    newlist[*n_fnames] = NULL;
+    return 0;
+}
+
+static int
+compare_with_strcmp(const void *a, const void *b)
+{
+    return strcmp(*(char **)a, *(char **)b);
+}
+
+#ifdef _WIN32
+
+int
+k5_dir_filenames(const char *dirname, char ***fnames_out)
+{
+    char *wildcard;
+    WIN32_FIND_DATA ffd;
+    HANDLE handle;
+    char **fnames = NULL;
+    int n_fnames = 0;
+
+    *fnames_out = NULL;
+
+    if (asprintf(&wildcard, "%s\\*", dirname) < 0)
+        return ENOMEM;
+    handle = FindFirstFile(wildcard, &ffd);
+    free(wildcard);
+    if (handle == INVALID_HANDLE_VALUE)
+        return ENOENT;
+
+    do {
+        if (add_filename(&fnames, &n_fnames, &ffd.cFileName) != 0) {
+            k5_free_filenames(fnames);
+            FindClose(handle);
+            return ENOMEM;
+        }
+    } while (FindNextFile(handle, &ffd) != 0);
+
+    FindClose(handle);
+    qsort(fnames, n_fnames, sizeof(*fnames), compare_with_strcmp);
+    *fnames_out = fnames;
+    return 0;
+}
+
+#else /* _WIN32 */
+
+#include <dirent.h>
+
+int
+k5_dir_filenames(const char *dirname, char ***fnames_out)
+{
+    DIR *dir;
+    struct dirent *ent;
+    char **fnames = NULL;
+    int n_fnames = 0;
+
+    *fnames_out = NULL;
+
+    dir = opendir(dirname);
+    if (dir == NULL)
+        return ENOENT;
+
+    while ((ent = readdir(dir)) != NULL) {
+        if (add_filename(&fnames, &n_fnames, ent->d_name) != 0) {
+            k5_free_filenames(fnames);
+            closedir(dir);
+            return ENOMEM;
+        }
+    }
+
+    closedir(dir);
+    qsort(fnames, n_fnames, sizeof(*fnames), compare_with_strcmp);
+    *fnames_out = fnames;
+    return 0;
+}
+
+#endif /* not _WIN32 */
diff --git a/src/util/support/libkrb5support-fixed.exports b/src/util/support/libkrb5support-fixed.exports
index a5e2ade..16ed5a6 100644
--- a/src/util/support/libkrb5support-fixed.exports
+++ b/src/util/support/libkrb5support-fixed.exports
@@ -58,6 +58,8 @@ k5_path_split
 k5_strerror_r
 k5_utf8_to_utf16le
 k5_utf16le_to_utf8
+k5_dir_filenames
+k5_free_filenames
 krb5int_key_register
 krb5int_key_delete
 krb5int_getspecific