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-rw-r--r--src/util/support/k5buf.c243
1 files changed, 243 insertions, 0 deletions
diff --git a/src/util/support/k5buf.c b/src/util/support/k5buf.c
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+++ b/src/util/support/k5buf.c
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+/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
+/* util/support/k5buf.c - string buffer functions */
+
+/*
+ * Copyright 2008 Massachusetts Institute of Technology.
+ * All Rights Reserved.
+ *
+ * Export of this software from the United States of America may
+ * require a specific license from the United States Government.
+ * It is the responsibility of any person or organization contemplating
+ * export to obtain such a license before exporting.
+ *
+ * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
+ * distribute this software and its documentation for any purpose and
+ * without fee is hereby granted, provided that the above copyright
+ * notice appear in all copies and that both that copyright notice and
+ * this permission notice appear in supporting documentation, and that
+ * the name of M.I.T. not be used in advertising or publicity pertaining
+ * to distribution of the software without specific, written prior
+ * permission. Furthermore if you modify this software you must label
+ * your software as modified software and not distribute it in such a
+ * fashion that it might be confused with the original M.I.T. software.
+ * M.I.T. makes no representations about the suitability of
+ * this software for any purpose. It is provided "as is" without express
+ * or implied warranty.
+ */
+
+/*
+ * Can't include krb5.h here, or k5-int.h which includes it, because krb5.h
+ * needs to be generated with error tables, after util/et, which builds after
+ * this directory.
+ */
+#include "k5-platform.h"
+#include "k5-buf.h"
+#include <assert.h>
+
+/*
+ * Structure invariants:
+ *
+ * buftype is K5BUF_FIXED, K5BUF_DYNAMIC, or K5BUF_ERROR
+ * if buftype is K5BUF_ERROR, the other fields are NULL or 0
+ * if buftype is not K5BUF_ERROR:
+ * space > 0
+ * len < space
+ * data[len] = '\0'
+ */
+
+/* Return a character pointer to the current end of buf. */
+static inline char *
+endptr(struct k5buf *buf)
+{
+ return (char *)buf->data + buf->len;
+}
+
+static inline void
+set_error(struct k5buf *buf)
+{
+ buf->buftype = K5BUF_ERROR;
+ buf->data = NULL;
+ buf->space = buf->len = 0;
+}
+
+/*
+ * Make sure there is room for LEN more characters in BUF, in addition to the
+ * null terminator and what's already in there. Return true on success. On
+ * failure, set the error flag and return false.
+ */
+static int
+ensure_space(struct k5buf *buf, size_t len)
+{
+ size_t new_space;
+ char *new_data;
+
+ if (buf->buftype == K5BUF_ERROR)
+ return 0;
+ if (buf->space - 1 - buf->len >= len) /* Enough room already. */
+ return 1;
+ if (buf->buftype == K5BUF_FIXED) /* Can't resize a fixed buffer. */
+ goto error_exit;
+ assert(buf->buftype == K5BUF_DYNAMIC);
+ new_space = buf->space * 2;
+ while (new_space - buf->len - 1 < len) {
+ if (new_space > SIZE_MAX / 2)
+ goto error_exit;
+ new_space *= 2;
+ }
+ new_data = realloc(buf->data, new_space);
+ if (new_data == NULL)
+ goto error_exit;
+ buf->data = new_data;
+ buf->space = new_space;
+ return 1;
+
+error_exit:
+ if (buf->buftype == K5BUF_DYNAMIC)
+ free(buf->data);
+ set_error(buf);
+ return 0;
+}
+
+void
+k5_buf_init_fixed(struct k5buf *buf, char *data, size_t space)
+{
+ assert(space > 0);
+ buf->buftype = K5BUF_FIXED;
+ buf->data = data;
+ buf->space = space;
+ buf->len = 0;
+ *endptr(buf) = '\0';
+}
+
+void
+k5_buf_init_dynamic(struct k5buf *buf)
+{
+ buf->buftype = K5BUF_DYNAMIC;
+ buf->space = 128;
+ buf->data = malloc(buf->space);
+ if (buf->data == NULL) {
+ set_error(buf);
+ return;
+ }
+ buf->len = 0;
+ *endptr(buf) = '\0';
+}
+
+void
+k5_buf_add(struct k5buf *buf, const char *data)
+{
+ k5_buf_add_len(buf, data, strlen(data));
+}
+
+void
+k5_buf_add_len(struct k5buf *buf, const void *data, size_t len)
+{
+ if (!ensure_space(buf, len))
+ return;
+ if (len > 0)
+ memcpy(endptr(buf), data, len);
+ buf->len += len;
+ *endptr(buf) = '\0';
+}
+
+void
+k5_buf_add_fmt(struct k5buf *buf, const char *fmt, ...)
+{
+ va_list ap;
+ int r;
+ size_t remaining;
+ char *tmp;
+
+ if (buf->buftype == K5BUF_ERROR)
+ return;
+ remaining = buf->space - buf->len;
+
+ if (buf->buftype == K5BUF_FIXED) {
+ /* Format the data directly into the fixed buffer. */
+ va_start(ap, fmt);
+ r = vsnprintf(endptr(buf), remaining, fmt, ap);
+ va_end(ap);
+ if (SNPRINTF_OVERFLOW(r, remaining))
+ set_error(buf);
+ else
+ buf->len += (unsigned int) r;
+ return;
+ }
+
+ /* Optimistically format the data directly into the dynamic buffer. */
+ assert(buf->buftype == K5BUF_DYNAMIC);
+ va_start(ap, fmt);
+ r = vsnprintf(endptr(buf), remaining, fmt, ap);
+ va_end(ap);
+ if (!SNPRINTF_OVERFLOW(r, remaining)) {
+ buf->len += (unsigned int) r;
+ return;
+ }
+
+ if (r >= 0) {
+ /* snprintf correctly told us how much space is required. */
+ if (!ensure_space(buf, r))
+ return;
+ remaining = buf->space - buf->len;
+ va_start(ap, fmt);
+ r = vsnprintf(endptr(buf), remaining, fmt, ap);
+ va_end(ap);
+ if (SNPRINTF_OVERFLOW(r, remaining)) /* Shouldn't ever happen. */
+ k5_buf_free(buf);
+ else
+ buf->len += (unsigned int) r;
+ return;
+ }
+
+ /* It's a pre-C99 snprintf implementation, or something else went wrong.
+ * Fall back to asprintf. */
+ va_start(ap, fmt);
+ r = vasprintf(&tmp, fmt, ap);
+ va_end(ap);
+ if (r < 0) {
+ k5_buf_free(buf);
+ return;
+ }
+ if (ensure_space(buf, r)) {
+ /* Copy the temporary string into buf, including terminator. */
+ memcpy(endptr(buf), tmp, r + 1);
+ buf->len += r;
+ }
+ free(tmp);
+}
+
+void *
+k5_buf_get_space(struct k5buf *buf, size_t len)
+{
+ if (!ensure_space(buf, len))
+ return NULL;
+ buf->len += len;
+ *endptr(buf) = '\0';
+ return endptr(buf) - len;
+}
+
+void
+k5_buf_truncate(struct k5buf *buf, size_t len)
+{
+ if (buf->buftype == K5BUF_ERROR)
+ return;
+ assert(len <= buf->len);
+ buf->len = len;
+ *endptr(buf) = '\0';
+}
+
+int
+k5_buf_status(struct k5buf *buf)
+{
+ return (buf->buftype == K5BUF_ERROR) ? ENOMEM : 0;
+}
+
+void
+k5_buf_free(struct k5buf *buf)
+{
+ if (buf->buftype == K5BUF_ERROR)
+ return;
+ assert(buf->buftype == K5BUF_DYNAMIC);
+ free(buf->data);
+ set_error(buf);
+}
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