tracing/probes: Implement 'memory' fetch method for uprobes

[~andy/linux] / kernel / trace / trace_uprobe.c

diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 24ef6a33d93fc6cf1852fbd153bc87652cdd8a65..bebd2f5d9ea3d2d63fea802fd26ee47d6ce2f201 100644 (file)
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -114,6 +114,58 @@ DEFINE_BASIC_FETCH_FUNCS(stack)
 #define fetch_stack_string     NULL
 #define fetch_stack_string_size        NULL
 
+#define DEFINE_FETCH_memory(type)                                      \
+static __kprobes void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs,\
+                                               void *addr, void *dest) \
+{                                                                      \
+       type retval;                                                    \
+       void __user *vaddr = (void __force __user *) addr;              \
+                                                                       \
+       if (copy_from_user(&retval, vaddr, sizeof(type)))               \
+               *(type *)dest = 0;                                      \
+       else                                                            \
+               *(type *) dest = retval;                                \
+}
+DEFINE_BASIC_FETCH_FUNCS(memory)
+/*
+ * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
+ * length and relative data location.
+ */
+static __kprobes void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
+                                                     void *addr, void *dest)
+{
+       long ret;
+       u32 rloc = *(u32 *)dest;
+       int maxlen  = get_rloc_len(rloc);
+       u8 *dst = get_rloc_data(dest);
+       void __user *src = (void __force __user *) addr;
+
+       if (!maxlen)
+               return;
+
+       ret = strncpy_from_user(dst, src, maxlen);
+
+       if (ret < 0) {  /* Failed to fetch string */
+               ((u8 *)get_rloc_data(dest))[0] = '\0';
+               *(u32 *)dest = make_data_rloc(0, get_rloc_offs(rloc));
+       } else {
+               *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(rloc));
+       }
+}
+
+static __kprobes void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
+                                                     void *addr, void *dest)
+{
+       int len;
+       void __user *vaddr = (void __force __user *) addr;
+
+       len = strnlen_user(vaddr, MAX_STRING_SIZE);
+
+       if (len == 0 || len > MAX_STRING_SIZE)  /* Failed to check length */
+               *(u32 *)dest = 0;
+       else
+               *(u32 *)dest = len;
+}
 
 /* uprobes do not support symbol fetch methods */
 #define fetch_symbol_u8                        NULL