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Subject[PATCH v2] tools lib traceevent: Take care of return value of asprintf
Date
From: He Zhe <zhe.he@windriver.com>

According to the API, if memory allocation wasn't possible, or some other
error occurs, asprintf will return -1, and the contents of strp below are
undefined.

int asprintf(char **strp, const char *fmt, ...);

This patch takes care of return value of asprintf to make it less error
prone and prevent the following build warning.

ignoring return value of ‘asprintf’, declared with attribute warn_unused_result [-Wunused-result]

Signed-off-by: He Zhe <zhe.he@windriver.com>
---
v2: directly check the return value without saving to a variable

tools/lib/traceevent/parse-filter.c | 35 +++++++++++++++++++++--------------
1 file changed, 21 insertions(+), 14 deletions(-)

diff --git a/tools/lib/traceevent/parse-filter.c b/tools/lib/traceevent/parse-filter.c
index 20eed71..6cd0228 100644
--- a/tools/lib/traceevent/parse-filter.c
+++ b/tools/lib/traceevent/parse-filter.c
@@ -274,8 +274,7 @@ find_event(struct tep_handle *tep, struct event_list **events,
sys_name = NULL;
}

- ret = asprintf(&reg, "^%s$", event_name);
- if (ret < 0)
+ if (asprintf(&reg, "^%s$", event_name) < 0)
return TEP_ERRNO__MEM_ALLOC_FAILED;

ret = regcomp(&ereg, reg, REG_ICASE|REG_NOSUB);
@@ -285,8 +284,7 @@ find_event(struct tep_handle *tep, struct event_list **events,
return TEP_ERRNO__INVALID_EVENT_NAME;

if (sys_name) {
- ret = asprintf(&reg, "^%s$", sys_name);
- if (ret < 0) {
+ if (asprintf(&reg, "^%s$", sys_name) < 0) {
regfree(&ereg);
return TEP_ERRNO__MEM_ALLOC_FAILED;
}
@@ -1958,7 +1956,8 @@ static char *op_to_str(struct tep_event_filter *filter, struct tep_filter_arg *a
default:
break;
}
- asprintf(&str, val ? "TRUE" : "FALSE");
+ if (asprintf(&str, val ? "TRUE" : "FALSE") < 0)
+ str = NULL;
break;
}
}
@@ -1976,7 +1975,8 @@ static char *op_to_str(struct tep_event_filter *filter, struct tep_filter_arg *a
break;
}

- asprintf(&str, "(%s) %s (%s)", left, op, right);
+ if (asprintf(&str, "(%s) %s (%s)", left, op, right) < 0)
+ str = NULL;
break;

case TEP_FILTER_OP_NOT:
@@ -1992,10 +1992,12 @@ static char *op_to_str(struct tep_event_filter *filter, struct tep_filter_arg *a
right_val = 0;
if (right_val >= 0) {
/* just return the opposite */
- asprintf(&str, right_val ? "FALSE" : "TRUE");
+ if (asprintf(&str, right_val ? "FALSE" : "TRUE") < 0)
+ str = NULL;
break;
}
- asprintf(&str, "%s(%s)", op, right);
+ if (asprintf(&str, "%s(%s)", op, right) < 0)
+ str = NULL;
break;

default:
@@ -2011,7 +2013,8 @@ static char *val_to_str(struct tep_event_filter *filter, struct tep_filter_arg *
{
char *str = NULL;

- asprintf(&str, "%lld", arg->value.val);
+ if (asprintf(&str, "%lld", arg->value.val) < 0)
+ str = NULL;

return str;
}
@@ -2069,7 +2072,8 @@ static char *exp_to_str(struct tep_event_filter *filter, struct tep_filter_arg *
break;
}

- asprintf(&str, "%s %s %s", lstr, op, rstr);
+ if (asprintf(&str, "%s %s %s", lstr, op, rstr) < 0)
+ str = NULL;
out:
free(lstr);
free(rstr);
@@ -2113,7 +2117,8 @@ static char *num_to_str(struct tep_event_filter *filter, struct tep_filter_arg *
if (!op)
op = "<=";

- asprintf(&str, "%s %s %s", lstr, op, rstr);
+ if (asprintf(&str, "%s %s %s", lstr, op, rstr) < 0)
+ str = NULL;
break;

default:
@@ -2148,8 +2153,9 @@ static char *str_to_str(struct tep_event_filter *filter, struct tep_filter_arg *
if (!op)
op = "!~";

- asprintf(&str, "%s %s \"%s\"",
- arg->str.field->name, op, arg->str.val);
+ if (asprintf(&str, "%s %s \"%s\"",
+ arg->str.field->name, op, arg->str.val) < 0)
+ str = NULL;
break;

default:
@@ -2165,7 +2171,8 @@ static char *arg_to_str(struct tep_event_filter *filter, struct tep_filter_arg *

switch (arg->type) {
case TEP_FILTER_ARG_BOOLEAN:
- asprintf(&str, arg->boolean.value ? "TRUE" : "FALSE");
+ if (asprintf(&str, arg->boolean.value ? "TRUE" : "FALSE") < 0)
+ str = NULL;
return str;

case TEP_FILTER_ARG_OP:
--
2.7.4
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