[Crash-utility] [PATCH 10/12] crash-trace-command: add new read_long_string() for print_fmt
The read_string() of crash can not read strings with
len>MIN_PAGE_SIZE(otherwise we will get segment fault)
but some print_fmt 's size is larger than MIN_PAGE_SIZE,
so we have to add read_long_string() for it.
Signed-off-by: Lai Jiangshan <laijs(a)cn.fujitsu.com>
---
diff --git a/extensions/trace.c b/extensions/trace.c
index b07f739..4b6144f 100755
--- a/extensions/trace.c
+++ b/extensions/trace.c
@@ -995,8 +995,48 @@ work:
return 0;
}
+static int read_long_string(ulong kvaddr, char **buf)
+{
+ char strbuf[MIN_PAGE_SIZE], *ret_buf = NULL;
+ ulong kp;
+ int cnt1, cnt2, size;
+
+again:
+ kp = kvaddr;
+ size = 0;
+
+ for (;;) {
+ cnt1 = MIN_PAGE_SIZE - (kp & (MIN_PAGE_SIZE-1));
+
+ if (!readmem(kp, KVADDR, strbuf, cnt1,
+ "readstring characters", QUIET|RETURN_ON_ERROR))
+ return -1;
+
+ cnt2 = strnlen(strbuf, cnt1);
+ if (ret_buf)
+ memcpy(ret_buf + size, strbuf, cnt2);
+ kp += cnt2;
+ size += cnt2;
+
+ if (cnt2 < cnt1) {
+ if (ret_buf) {
+ break;
+ } else {
+ ret_buf = malloc(size + 1);
+ if (!ret_buf)
+ return -1;
+ goto again;
+ }
+ }
+ }
+
+ ret_buf[size] = '\0';
+ *buf = ret_buf;
+ return size;
+}
+
static
-int ftrace_get_event_type_print_fmt(ulong call, char *print_fmt, int len)
+int ftrace_get_event_type_print_fmt(ulong call, char **print_fmt)
{
static int inited;
static int fmt_offset;
@@ -1015,10 +1055,7 @@ int ftrace_get_event_type_print_fmt(ulong call, char *print_fmt,
int len)
"read ftrace_event_call fmt_addr", RETURN_ON_ERROR))
return -1;
- if (!read_string(fmt_addr, print_fmt, len))
- return -1;
-
- return 0;
+ return read_long_string(fmt_addr, print_fmt);
}
static
@@ -1064,7 +1101,7 @@ static int ftrace_init_event_types(void)
read_value(event, ftrace_events, list_head, next);
while (event != ftrace_events) {
ulong call;
- char name[128], system[128], print_fmt[4096];
+ char name[128], system[128], *print_fmt;
int id;
call = event - koffset(ftrace_event_call, list);
@@ -1073,7 +1110,7 @@ static int ftrace_init_event_types(void)
if (ftrace_get_event_type_id(call, &id) < 0 ||
ftrace_get_event_type_name(call, name, 128) < 0 ||
ftrace_get_event_type_system(call, system, 128) < 0 ||
- ftrace_get_event_type_print_fmt(call, print_fmt, 4096) < 0)
+ ftrace_get_event_type_print_fmt(call, &print_fmt) < 0)
goto out_fail;
/* Enlarge event types array when need */
@@ -1083,20 +1120,24 @@ static int ftrace_init_event_types(void)
max_types = 2 * nr_event_types;
tmp = realloc(event_types,
sizeof(*event_types) * max_types);
- if (tmp == NULL)
+ if (tmp == NULL) {
+ free(print_fmt);
goto out_fail;
+ }
event_types = tmp;
}
/* Create a event type */
aevent_type = malloc(sizeof(*aevent_type));
- if (aevent_type == NULL)
+ if (aevent_type == NULL) {
+ free(print_fmt);
goto out_fail;
+ }
aevent_type->system = strdup(system);
aevent_type->name = strdup(name);
- aevent_type->print_fmt = strdup(print_fmt);
+ aevent_type->print_fmt = print_fmt;
aevent_type->id = id;
aevent_type->nfields = 0;
aevent_type->fields = NULL;