1 files changed, 205 insertions, 0 deletions
diff --git a/src/util/sss_iobuf.c b/src/util/sss_iobuf.c
new file mode 100644
index 000000000..7c72ea94d
--- /dev/null
+++ b/src/util/sss_iobuf.c
@@ -0,0 +1,205 @@
+#include <talloc.h>
+
+#include "util/util.h"
+#include "util/sss_iobuf.h"
+
+/**
+ * @brief The iobuf structure that holds the data, its capacity and
+ * a pointer to the data.
+ *
+ * @see sss_iobuf_init_empty()
+ * @see sss_iobuf_init_readonly()
+ */
+struct sss_iobuf {
+    uint8_t *data;          /* Start of the data buffer */
+
+    size_t dp;              /* Data pointer */
+    size_t size;            /* Current data buffer size */
+    size_t capacity;        /* Maximum capacity */
+};
+
+struct sss_iobuf *sss_iobuf_init_empty(TALLOC_CTX *mem_ctx,
+                                       size_t size,
+                                       size_t capacity)
+{
+    struct sss_iobuf *iobuf;
+    uint8_t *buf;
+
+    iobuf = talloc_zero(mem_ctx, struct sss_iobuf);
+    if (iobuf == NULL) {
+        return NULL;
+    }
+
+    buf = talloc_zero_array(iobuf, uint8_t, size);
+    if (buf == NULL) {
+        talloc_free(iobuf);
+        return NULL;
+    }
+
+    if (capacity == 0) {
+        capacity = SIZE_MAX / 2;
+    }
+
+    iobuf->data = buf;
+    iobuf->size = size;
+    iobuf->capacity = capacity;
+    iobuf->dp = 0;
+
+    return iobuf;
+}
+
+struct sss_iobuf *sss_iobuf_init_readonly(TALLOC_CTX *mem_ctx,
+                                          uint8_t *data,
+                                          size_t size)
+{
+    struct sss_iobuf *iobuf;
+
+    iobuf = sss_iobuf_init_empty(mem_ctx, size, size);
+    if (iobuf == NULL) {
+        return NULL;
+    }
+
+    if (data != NULL) {
+        memcpy(iobuf->data, data, size);
+    }
+
+    return iobuf;
+}
+
+size_t sss_iobuf_get_len(struct sss_iobuf *iobuf)
+{
+    if (iobuf == NULL) {
+        return 0;
+    }
+
+    return iobuf->dp;
+}
+
+size_t sss_iobuf_get_capacity(struct sss_iobuf *iobuf)
+{
+    if (iobuf == NULL) {
+        return 0;
+    }
+
+    return iobuf->capacity;
+}
+
+size_t sss_iobuf_get_size(struct sss_iobuf *iobuf)
+{
+    if (iobuf == NULL) {
+        return 0;
+    }
+
+    return iobuf->size;
+}
+
+uint8_t *sss_iobuf_get_data(struct sss_iobuf *iobuf)
+{
+    if (iobuf == NULL) {
+        return NULL;
+    }
+
+    return iobuf->data;
+}
+
+static size_t iobuf_get_len(struct sss_iobuf *iobuf)
+{
+    if (iobuf == NULL) {
+        return 0;
+    }
+
+    return (iobuf->size - iobuf->dp);
+}
+
+static errno_t ensure_bytes(struct sss_iobuf *iobuf,
+                            size_t nbytes)
+{
+    size_t wantsize;
+    size_t newsize;
+    uint8_t *newdata;
+
+    if (iobuf == NULL) {
+        return EINVAL;
+    }
+
+    wantsize = iobuf->dp + nbytes;
+    if (wantsize <= iobuf->size) {
+        /* Enough space already */
+        return EOK;
+    }
+
+    /* Else, try to extend the iobuf */
+    if (wantsize > iobuf->capacity) {
+        /* We will never grow past capacity */
+        return ENOBUFS;
+    }
+
+    /* Double the size until we add at least nbytes, but stop if we double past capacity */
+    for (newsize = iobuf->size;
+         (newsize < wantsize) && (newsize < iobuf->capacity);
+         newsize *= 2)
+        ;
+
+    if (newsize > iobuf->capacity) {
+        newsize = iobuf->capacity;
+    }
+
+    newdata = talloc_realloc(iobuf, iobuf->data, uint8_t, newsize);
+    if (newdata == NULL) {
+        return ENOMEM;
+    }
+
+    iobuf->data = newdata;
+    iobuf->size = newsize;
+
+    return EOK;
+}
+
+static inline uint8_t *iobuf_ptr(struct sss_iobuf *iobuf)
+{
+    return iobuf->data + iobuf->dp;
+}
+
+errno_t sss_iobuf_read(struct sss_iobuf *iobuf,
+                       size_t len,
+                       uint8_t *_buf,
+                       size_t *_read)
+{
+    size_t remaining;
+
+    if (iobuf == NULL || _buf == NULL) {
+        return EINVAL;
+    }
+
+    remaining = iobuf_get_len(iobuf);
+    if (len > remaining) {
+        len = remaining;
+    }
+
+    safealign_memcpy(_buf, iobuf_ptr(iobuf), len, &iobuf->dp);
+    if (_read != NULL) {
+        *_read = len;
+    }
+
+    return EOK;
+}
+
+errno_t sss_iobuf_write_len(struct sss_iobuf *iobuf,
+                            uint8_t *buf,
+                            size_t len)
+{
+    errno_t ret;
+
+    if (iobuf == NULL || buf == NULL) {
+        return EINVAL;
+    }
+
+    ret = ensure_bytes(iobuf, len);
+    if (ret != EOK) {
+        return ret;
+    }
+
+    safealign_memcpy(iobuf_ptr(iobuf), buf, len, &iobuf->dp);
+
+    return EOK;
+}