From: Alexander Nezhinsky <nezhinsky@xxxxxxxxx>
To assist safe generation of data-in buffer for SPC-type read commands
two new utility functions are defined:
int mem_copy_n32(uint8_t *dst, uint8_t *src, uint32_t src_len,
uint32_t *avail_len, uint32_t *remain_len)
Copies up to src_len bytes from src, making sure
not to exceed *remain_len bytes available at dst.
Returns actually copied length, updates remaining space
in *remain_len (mandatory parameter),
accumulate copied length in *avail_len (optional parameter).
void set_byte_n32(int val, uint8_t *dst, uint32_t index, uint32_t max_len)
Sets a byte at the given index within dst buffer to val,
making sure not to exceed max_len bytes available at dst.
Signed-off-by: Alexander Nezhinsky <nezhinsky@xxxxxxxxx>
---
usr/util.c | 31 +++++++++++++++++++++++++++++++
usr/util.h | 4 ++++
2 files changed, 35 insertions(+)
diff --git a/usr/util.c b/usr/util.c
index 6c9bad7..3392b0b 100644
--- a/usr/util.c
+++ b/usr/util.c
@@ -196,3 +196,34 @@ int get_blk_shift(unsigned int size)
return shift;
}
+/*
+ * Copy up to src_len bytes from src,
+ * not exceeding *remain_len bytes available at dst.
+ * Return actually copied length.
+ * Reflect decreased space in *remain_len (mandatory).
+ * Accumulate copied length in *avail_len (optional).
+ */
+int mem_copy_n32(uint8_t *dst, uint8_t *src, uint32_t src_len,
+ uint32_t *avail_len, uint32_t *remain_len)
+{
+ int copy_len = min_t(uint32_t, *remain_len, src_len);
+
+ if (copy_len) {
+ memcpy(dst, src, copy_len);
+ *remain_len -= copy_len;
+ }
+ if (avail_len)
+ *avail_len += src_len;
+ return copy_len;
+}
+
+/*
+ * Set a byte at the given index within dst buffer to val,
+ * not exceeding max_len bytes available at dst.
+ */
+void set_byte_n32(int val, uint8_t *dst, uint32_t index, uint32_t max_len)
+{
+ if (index < max_len)
+ dst[index] = (uint8_t)val;
+}
+
diff --git a/usr/util.h b/usr/util.h
index 76cff2a..d4c7d59 100644
--- a/usr/util.h
+++ b/usr/util.h
@@ -67,6 +67,10 @@ extern int backed_file_open(char *path, int oflag, uint64_t *size,
extern int set_non_blocking(int fd);
extern int str_to_open_flags(char *buf);
extern char *open_flags_to_str(char *dest, int flags);
+extern int mem_copy_n32(uint8_t *dst, uint8_t *src, uint32_t src_len,
+ uint32_t *avail_len, uint32_t *remain_len);
+extern void set_byte_n32(int val, uint8_t *dst, uint32_t index,
+ uint32_t max_len);
#define zalloc(size) \
({ \
--
1.7.9.6
--
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