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tracing: probeevent: Return consumed bytes of dynamic area

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Cleanup string fetching routine so that returns the consumed
bytes of dynamic area and store the string information as
data_loc format instead of data_rloc.
This simplifies the fetcharg loop.

Link: http://lkml.kernel.org/r/152465874163.26224.12125143907501289031.stgit@devbox

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Masami Hiramatsu
2018-04-25 21:19:01 +09:00
committed by Steven Rostedt (VMware)
parent f451bc89d8
commit 9178412ddf
4 changed files with 88 additions and 110 deletions
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61
kernel/trace/trace_uprobe.c
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@@ -111,43 +111,38 @@ probe_user_read(void *dest, void *src, size_t size)
* Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
* length and relative data location.
*/
static nokprobe_inline void
fetch_store_string(unsigned long addr, void *dest)
static nokprobe_inline int
fetch_store_string(unsigned long addr, void *dest, void *base)
{
long ret;
u32 rloc = *(u32 *)dest;
int maxlen = get_rloc_len(rloc);
u8 *dst = get_rloc_data(dest);
u32 loc = *(u32 *)dest;
int maxlen = get_loc_len(loc);
u8 *dst = get_loc_data(dest, base);
void __user *src = (void __force __user *) addr;
if (!maxlen)
return;
if (unlikely(!maxlen))
return -ENOMEM;
ret = strncpy_from_user(dst, src, maxlen);
if (ret == maxlen)
dst[--ret] = '\0';
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));
if (ret >= 0) {
if (ret == maxlen)
dst[ret - 1] = '\0';
*(u32 *)dest = make_data_loc(ret, (void *)dst - base);
}
return ret;
}
/* Return the length of string -- including null terminal byte */
static nokprobe_inline void
fetch_store_strlen(unsigned long addr, void *dest)
static nokprobe_inline int
fetch_store_strlen(unsigned long addr)
{
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;
return (len > MAX_STRING_SIZE) ? 0 : len;
}
static unsigned long translate_user_vaddr(unsigned long file_offset)
@@ -164,10 +159,10 @@ static unsigned long translate_user_vaddr(unsigned long file_offset)
/* Note that we don't verify it, since the code does not come from user space */
static int
process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
bool pre)
void *base)
{
unsigned long val;
int ret;
int ret = 0;
/* 1st stage: get value from context */
switch (code->op) {
@@ -204,18 +199,22 @@ process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
}
/* 3rd stage: store value to buffer */
if (unlikely(!dest)) {
if (code->op == FETCH_OP_ST_STRING)
return fetch_store_strlen(val + code->offset);
else
return -EILSEQ;
}
switch (code->op) {
case FETCH_OP_ST_RAW:
fetch_store_raw(val, code, dest);
break;
case FETCH_OP_ST_MEM:
probe_user_read(dest, (void *)val + code->offset, code->size);
probe_kernel_read(dest, (void *)val + code->offset, code->size);
break;
case FETCH_OP_ST_STRING:
if (pre)
fetch_store_strlen(val + code->offset, dest);
else
fetch_store_string(val + code->offset, dest);
ret = fetch_store_string(val + code->offset, dest, base);
break;
default:
return -EILSEQ;
@@ -228,7 +227,7 @@ process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
code++;
}
return code->op == FETCH_OP_END ? 0 : -EILSEQ;
return code->op == FETCH_OP_END ? ret : -EILSEQ;
}
NOKPROBE_SYMBOL(process_fetch_insn)
@@ -1300,7 +1299,7 @@ static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs)
esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
ucb = uprobe_buffer_get();
store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize);
store_trace_args(ucb->buf, &tu->tp, regs, esize, dsize);
if (tu->tp.flags & TP_FLAG_TRACE)
ret |= uprobe_trace_func(tu, regs, ucb, dsize);
@@ -1335,7 +1334,7 @@ static int uretprobe_dispatcher(struct uprobe_consumer *con,
esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
ucb = uprobe_buffer_get();
store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize);
store_trace_args(ucb->buf, &tu->tp, regs, esize, dsize);
if (tu->tp.flags & TP_FLAG_TRACE)
uretprobe_trace_func(tu, func, regs, ucb, dsize);