summaryrefslogtreecommitdiffstats
path: root/libmisc/xgetXXbyYY.c
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--libmisc/xgetXXbyYY.c144
1 files changed, 144 insertions, 0 deletions
diff --git a/libmisc/xgetXXbyYY.c b/libmisc/xgetXXbyYY.c
new file mode 100644
index 0000000..1b0b001
--- /dev/null
+++ b/libmisc/xgetXXbyYY.c
@@ -0,0 +1,144 @@
+/*
+ * Copyright (c) 2007 - 2009, Nicolas François
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ * 3. The name of the copyright holders or contributors may not be used to
+ * endorse or promote products derived from this software without
+ * specific prior written permission.
+ *
+ * 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
+ * HOLDERS 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.
+ */
+
+/*
+ * According to the Linux-PAM documentation:
+ *
+ * 4.1. Care about standard library calls
+ *
+ * In general, writers of authorization-granting applications should
+ * assume that each module is likely to call any or all 'libc' functions.
+ * For 'libc' functions that return pointers to static/dynamically
+ * allocated structures (ie. the library allocates the memory and the
+ * user is not expected to 'free()' it) any module call to this function
+ * is likely to corrupt a pointer previously obtained by the application.
+ * The application programmer should either re-call such a 'libc'
+ * function after a call to the Linux-PAM library, or copy the structure
+ * contents to some safe area of memory before passing control to the
+ * Linux-PAM library.
+ *
+ * Two important function classes that fall into this category are
+ * getpwnam(3) and syslog(3).
+ *
+ * This file provide wrapper to the getpwnam or getpwnam_r functions.
+ */
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#include "prototypes.h"
+
+#define XFUNCTION_NAME XPREFIX (FUNCTION_NAME)
+#define XPREFIX(name) XPREFIX1 (name)
+#define XPREFIX1(name) x##name
+#define REENTRANT_NAME APPEND_R (FUNCTION_NAME)
+#define APPEND_R(name) APPEND_R1 (name)
+#define APPEND_R1(name) name##_r
+#define STRINGIZE(name) STRINGIZE1 (name)
+#define STRINGIZE1(name) #name
+
+/*@null@*/ /*@only@*/LOOKUP_TYPE *XFUNCTION_NAME (ARG_TYPE ARG_NAME)
+{
+#if HAVE_FUNCTION_R
+ LOOKUP_TYPE *result=NULL;
+ char *buffer=NULL;
+ /* we have to start with something */
+ size_t length = 0x100;
+
+ result = malloc(sizeof(LOOKUP_TYPE));
+ if (NULL == result) {
+ fprintf (stderr, _("%s: out of memory\n"),
+ "x" STRINGIZE(FUNCTION_NAME));
+ exit (13);
+ }
+
+ while (true) {
+ int status;
+ LOOKUP_TYPE *resbuf = NULL;
+ buffer = (char *)realloc (buffer, length);
+ if (NULL == buffer) {
+ fprintf (stderr, _("%s: out of memory\n"),
+ "x" STRINGIZE(FUNCTION_NAME));
+ exit (13);
+ }
+ errno = 0;
+ status = REENTRANT_NAME(ARG_NAME, result, buffer,
+ length, &resbuf);
+ if ((0 == status) && (resbuf == result)) {
+ /* Build a result structure that can be freed by
+ * the shadow *_free functions. */
+ LOOKUP_TYPE *ret_result = DUP_FUNCTION(result);
+ free(buffer);
+ free(result);
+ return ret_result;
+ }
+
+ if (ERANGE != errno) {
+ free (buffer);
+ free (result);
+ return NULL;
+ }
+
+ if (length <= ((size_t)-1 / 4)) {
+ length *= 4;
+ } else if (length == (size_t) -1) {
+ break;
+ } else {
+ length = (size_t) -1;
+ }
+ }
+
+ free(buffer);
+ free(result);
+ return NULL;
+
+#else /* !HAVE_FUNCTION_R */
+
+ /* No reentrant function.
+ * Duplicate the structure to avoid other call to overwrite it.
+ *
+ * We should also restore the initial structure. But that would be
+ * overkill.
+ */
+ LOOKUP_TYPE *result = FUNCTION_NAME(ARG_NAME);
+
+ if (result) {
+ result = DUP_FUNCTION(result);
+ if (NULL == result) {
+ fprintf (stderr, _("%s: out of memory\n"),
+ "x" STRINGIZE(FUNCTION_NAME));
+ exit (13);
+ }
+ }
+
+ return result;
+#endif
+}
+