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Feature(qtest): Add the rand option to generate a random string #16

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Merged
jserv merged 1 commit into from
Jan 29, 2020
Merged

Feature(qtest): Add the rand option to generate a random string #16

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48 changes: 43 additions & 5 deletions qtest.c
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Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,7 @@
#include <strings.h> /* strcasecmp */
#include <sys/stat.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>

/* Our program needs to use regular malloc/free */
Expand Down Expand Up @@ -56,6 +57,10 @@ static int fail_count = 0;

static int string_length = MAXSTRING;

#define MIN_RANDSTR_LEN 5
#define MAX_RANDSTR_LEN 10
static const char charset[] = "abcdefghijklmnopqrstuvwxyz";

/* Forward declarations */
static bool show_queue(int vlevel);
static bool do_new(int argc, char *argv[]);
Expand All @@ -76,11 +81,11 @@ static void console_init()
add_cmd("new", do_new, " | Create new queue");
add_cmd("free", do_free, " | Delete queue");
add_cmd("ih", do_insert_head,
" str [n] | Insert string str at head of queue n times "
"(default: n == 1)");
" str [n] | Insert string str at head of queue n times. "
"Generate random string(s) if str == RAND. (default: n == 1)");
add_cmd("it", do_insert_tail,
" str [n] | Insert string str at tail of queue n times "
"(default: n == 1)");
"Generate random string(s) if str == RAND. (default: n == 1)");
add_cmd("rh", do_remove_head,
" [str] | Remove from head of queue. Optionally compare "
"to expected value str");
Expand Down Expand Up @@ -155,12 +160,28 @@ static bool do_free(int argc, char *argv[])

return ok && !error_check();
}
/*
* TODO: Add a buf_size check of if the buf_size may be less
* than MIN_RANDSTR_LEN.
*/
static void fill_rand_string(char *buf, size_t buf_size)
{
size_t len = 0;
while (len < MIN_RANDSTR_LEN)
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@jserv jserv Jan 29, 2020

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What if buf_size < MIN_RANDSTR_LEN?

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@YuShuanHsieh YuShuanHsieh Jan 29, 2020

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That is a good question. But I think the function is for internal usage and both buf_size and minimum length are defined by MIN_RANDSTR_LEN and MAX_RANDSTR_LEN. So It may reduce the chance that maintainer set wrong numbers to cause segmentation fault. My question is do I still need to add a logic to prevent error occurred for these kind of functions?

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@jserv jserv Jan 29, 2020

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You can place FIXME or TODO comments for the above considerations.

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@YuShuanHsieh YuShuanHsieh Jan 29, 2020

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I decided to place TODO comments. And could you share your experiences about the question? Cause in my experience, I only make sure that the internal function works without much error checks. I want to know how do experienced programmers think. Thanks 😄

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@jserv jserv Jan 29, 2020

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I am thinking of the feasibility to re-use fill_rand_string to perform fuzzing: https://en.wikipedia.org/wiki/Fuzzing
Typically speaking, fuzzer might expect shorter strings to validate interpreter and/or qtest internals.

len = rand() % buf_size;

for (size_t n = 0; n < len; n++) {
buf[n] = charset[rand() % (sizeof charset - 1)];
}
buf[len] = '\0';
}

static bool do_insert_head(int argc, char *argv[])
{
char *lasts = NULL;
char randstr_buf[MAX_RANDSTR_LEN];
int reps = 1;
bool ok = true;
bool ok = true, need_rand = false;
if (argc != 2 && argc != 3) {
report(1, "%s needs 1-2 arguments", argv[0]);
return false;
Expand All @@ -174,12 +195,19 @@ static bool do_insert_head(int argc, char *argv[])
}
}

if (!strcmp(inserts, "RAND")) {
need_rand = true;
inserts = randstr_buf;
}

if (!q)
report(3, "Warning: Calling insert head on null queue");
error_check();

if (exception_setup(true)) {
for (int r = 0; ok && r < reps; r++) {
if (need_rand)
fill_rand_string(randstr_buf, sizeof(randstr_buf));
bool rval = q_insert_head(q, inserts);
if (rval) {
qcnt++;
Expand Down Expand Up @@ -222,8 +250,9 @@ static bool do_insert_head(int argc, char *argv[])

static bool do_insert_tail(int argc, char *argv[])
{
char randstr_buf[MAX_RANDSTR_LEN];
int reps = 1;
bool ok = true;
bool ok = true, need_rand = false;
if (argc != 2 && argc != 3) {
report(1, "%s needs 1-2 arguments", argv[0]);
return false;
Expand All @@ -236,12 +265,20 @@ static bool do_insert_tail(int argc, char *argv[])
return false;
}
}

if (!strcmp(inserts, "RAND")) {
need_rand = true;
inserts = randstr_buf;
}

if (!q)
report(3, "Warning: Calling insert tail on null queue");
error_check();

if (exception_setup(true)) {
for (int r = 0; ok && r < reps; r++) {
if (need_rand)
fill_rand_string(randstr_buf, sizeof(randstr_buf));
bool rval = q_insert_tail(q, inserts);
if (rval) {
qcnt++;
Expand Down Expand Up @@ -686,6 +723,7 @@ int main(int argc, char *argv[])
}
}

srand((unsigned int) (time(NULL)));
queue_init();
init_cmd();
console_init();
Expand Down