Merge pull request #1363 from navytux/y/probe-read-const

bpf_probe_read*: src argument should be const void *.

docs/reference_guide.md

@@ -235,7 +235,7 @@ Examples in situ:
 
 ### 1. bpf_probe_read()
 
-Syntax: ```int bpf_probe_read(void *dst, int size, void *src)```
+Syntax: ```int bpf_probe_read(void *dst, int size, const void *src)```
 
 Return: 0 on success
 
@@ -247,7 +247,7 @@ Examples in situ:
 
 ### 2. bpf_probe_read_str()
 
-Syntax: ```int bpf_probe_read_str(void *dst, int size, void *src)```
+Syntax: ```int bpf_probe_read_str(void *dst, int size, const void *src)```
 
 Return:
   - \> 0 length of the string including the trailing NUL on success

src/cc/compat/linux/bpf.h

@@ -244,7 +244,7 @@ union bpf_attr {
  * int bpf_map_delete_elem(&map, &key)
  *     Return: 0 on success or negative error
  *
- * int bpf_probe_read(void *dst, int size, void *src)
+ * int bpf_probe_read(void *dst, int size, const void *src)
  *     Return: 0 on success or negative error
  *
  * u64 bpf_ktime_get_ns(void)

src/cc/compat/linux/virtual_bpf.h

@@ -245,7 +245,7 @@ union bpf_attr {
  * int bpf_map_delete_elem(&map, &key)
  *     Return: 0 on success or negative error
  *
- * int bpf_probe_read(void *dst, int size, void *src)
+ * int bpf_probe_read(void *dst, int size, const void *src)
  *     Return: 0 on success or negative error
  *
  * u64 bpf_ktime_get_ns(void)

src/cc/export/helpers.h

@@ -200,7 +200,7 @@ static int (*bpf_map_update_elem)(void *map, void *key, void *value, u64 flags)
   (void *) BPF_FUNC_map_update_elem;
 static int (*bpf_map_delete_elem)(void *map, void *key) =
   (void *) BPF_FUNC_map_delete_elem;
-static int (*bpf_probe_read)(void *dst, u64 size, void *unsafe_ptr) =
+static int (*bpf_probe_read)(void *dst, u64 size, const void *unsafe_ptr) =
   (void *) BPF_FUNC_probe_read;
 static u64 (*bpf_ktime_get_ns)(void) =
   (void *) BPF_FUNC_ktime_get_ns;
@@ -208,7 +208,7 @@ static u32 (*bpf_get_prandom_u32)(void) =
   (void *) BPF_FUNC_get_prandom_u32;
 static int (*bpf_trace_printk_)(const char *fmt, u64 fmt_size, ...) =
   (void *) BPF_FUNC_trace_printk;
-static int (*bpf_probe_read_str)(void *dst, u64 size, void *unsafe_ptr) =
+static int (*bpf_probe_read_str)(void *dst, u64 size, const void *unsafe_ptr) =
   (void *) BPF_FUNC_probe_read_str;
 int bpf_trace_printk(const char *fmt, ...) asm("llvm.bpf.extra");
 static inline __attribute__((always_inline))