From 679fcb9fc3829eca0df014482d4cc531dcb5030f Mon Sep 17 00:00:00 2001
From: Michael Whittaker <mjwhittaker@berkeley.edu>
Date: Fri, 17 Nov 2017 11:37:07 -0800
Subject: [PATCH] A couple small lockserver client improvements.
1. Previously, typing ` `, `lock`, or `unlock` into a lockserver
client's REPL would cause the client to crash because of some
`strtok` calls that were returning `NULL`. Now, this bug is fixed;
`strtok` returns are checked to be `NULL`, and no input should crash
the client.
2. Previously, typing in an unrecognized command into the lockserver
client's repl would print `Unknown command.. Try again!`. Now, it
also prints out the set of legal commands `Usage: exit | q | lock
<key> | unlock <key>`. This makes it a bit easier for someone
tinkering around with TAPIR for the first time (like me) to know what
to type.
---
lockserver/client.cc | 23 +++++++++++++++++++++--
1 file changed, 21 insertions(+), 2 deletions(-)
diff --git a/lockserver/client.cc b/lockserver/client.cc
index ccce2d6..45e2266 100644
--- a/lockserver/client.cc
+++ b/lockserver/client.cc
@@ -30,6 +30,17 @@
#include "lockserver/client.h"
+namespace {
+
+void
+usage()
+{
+ printf("Unknown command.. Try again!\n");
+ printf("Usage: exit | q | lock <key> | unlock <key>\n");
+}
+
+} // namespace
+
int
main(int argc, char **argv)
{
@@ -68,14 +79,18 @@ main(int argc, char **argv)
cmd[clen++] = c;
cmd[clen] = '\0';
- if (clen == 0) continue;
tok = strtok(cmd, " ,.-");
+ if (tok == NULL) continue;
if (strcasecmp(tok, "exit") == 0 || strcasecmp(tok, "q") == 0) {
printf("Exiting..\n");
break;
} else if (strcasecmp(tok, "lock") == 0) {
tok = strtok(NULL, " ,.-");
+ if (tok == NULL) {
+ usage();
+ continue;
+ }
key = string(tok);
status = locker.lock(key);
@@ -86,11 +101,15 @@ main(int argc, char **argv)
}
} else if (strcasecmp(tok, "unlock") == 0) {
tok = strtok(NULL, " ,.-");
+ if (tok == NULL) {
+ usage();
+ continue;
+ }
key = string(tok);
locker.unlock(key);
printf("Unlock Successful\n");
} else {
- printf("Unknown command.. Try again!\n");
+ usage();
}
fflush(stdout);
}
--
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