1 files changed, 118 insertions, 0 deletions
diff --git a/src/util/sss_iobuf.h b/src/util/sss_iobuf.h
new file mode 100644
index 000000000..eae357a40
--- /dev/null
+++ b/src/util/sss_iobuf.h
@@ -0,0 +1,118 @@
+#ifndef __SSS_IOBUF_H_
+#define __SSS_IOBUF_H_
+
+#include <talloc.h>
+#include <stdint.h>
+#include <errno.h>
+
+#include "util/util_errors.h"
+
+struct sss_iobuf;
+
+/*
+ * @brief Allocate an empty IO buffer
+ *
+ * @param[in]  mem_ctx      The talloc context that owns the iobuf
+ *
+ * When this buffer is written into, but the capacity is exceeded, the write
+ * function will return an error.
+ *
+ * @param[in]  mem_ctx      The talloc context that owns the iobuf
+ * @param[in]  size         The size of the data buffer
+ * @param[in]  capacity     The maximum capacity the buffer can grow into.
+ *                          Use 0 for an 'unlimited' buffer that will grow
+ *                          until SIZE_MAX/2.
+ *
+ * @return The newly created buffer on success or NULL on an error.
+ *
+ */
+struct sss_iobuf *sss_iobuf_init_empty(TALLOC_CTX *mem_ctx,
+                                       size_t size,
+                                       size_t capacity);
+
+/*
+ * @brief Allocate an IO buffer with a fixed size
+ *
+ * This function is useful for parsing an input buffer from an existing
+ * buffer pointed to by data.
+ *
+ * The iobuf does not assume ownership of the data buffer in talloc terms,
+ * but copies the data instead.
+ *
+ * @param[in]  mem_ctx      The talloc context that owns the iobuf
+ * @param[in]  data         The data to initialize the IO buffer with. This
+ *                          data is copied into the iobuf-owned buffer.
+ * @param[in]  size         The size of the data buffer
+ *
+ * @return The newly created buffer on success or NULL on an error.
+ */
+struct sss_iobuf *sss_iobuf_init_readonly(TALLOC_CTX *mem_ctx,
+                                          uint8_t *data,
+                                          size_t size);
+
+/*
+ * @brief Returns the number of bytes currently stored in the iobuf
+ *
+ * @return The number of bytes (the data pointer offset)
+ */
+size_t sss_iobuf_get_len(struct sss_iobuf *iobuf);
+
+/*
+ * @brief Returns the capacity of the IO buffer
+ *
+ * @return The capacity of the IO buffer. Returns zero
+ * for an unlimited buffer.
+ */
+size_t sss_iobuf_get_capacity(struct sss_iobuf *iobuf);
+
+/*
+ * @brief Returns the current size of the IO buffer
+ */
+size_t sss_iobuf_get_size(struct sss_iobuf *iobuf);
+
+/*
+ * @brief Returns the data pointer of the IO buffer
+ */
+uint8_t *sss_iobuf_get_data(struct sss_iobuf *iobuf);
+
+/*
+ * @brief Read from an IO buffer
+ *
+ * Read up to len bytes from an IO buffer. It is not an error to request
+ * more bytes than the buffer actually has - the function will succeed, but
+ * return the actual number of bytes read. Reading from an empty buffer just
+ * returns zero bytes read.
+ *
+ * @param[in]  iobuf        The IO buffer to read from
+ * @param[in]  len          The maximum number of bytes to read
+ * @param[out] _buf         The buffer to read data into from iobuf
+ * @param[out] _read        The actual number of bytes read from IO buffer.
+ *
+ * @return EOK on success, errno otherwise
+ */
+errno_t sss_iobuf_read(struct sss_iobuf *iobuf,
+                       size_t len,
+                       uint8_t *_buf,
+                       size_t *_read);
+
+/*
+ * @brief Write into an IO buffer
+ *
+ * Attempts to write len bytes into the iobuf. If the capacity is exceeded,
+ * the iobuf module tries to extend the buffer up to the maximum capacity.
+ *
+ * If reallocating the internal buffer fails, the data pointers are not
+ * touched.
+ *
+ * @param[in]  iobuf        The IO buffer to write to
+ * @param[in]  buf          The data to write into the buffer
+ * @param[in]  len          The number of bytes to write
+ *
+ * @return EOK on success, errno otherwise. Notably returns ENOBUFS if
+ * the buffer capacity is exceeded.
+ */
+errno_t sss_iobuf_write_len(struct sss_iobuf *iobuf,
+                            uint8_t *buf,
+                            size_t len);
+
+#endif /* __SSS_IOBUF_H_ */