C-Splint

Step 1 : Install splint - Static analyser

$ sudo apt-get install splint Reading package lists... Done Building dependency tree Reading state information... Done The following packages were automatically installed and are no longer required: g++-7 gcc-8-base:i386 gir1.2-mutter-2 libargon2-0 libbind9-160 libbison-dev libboost-date-time1.65.1 libboost-filesystem1.65.1 libboost-iostreams1.65.1 libboost-locale1.65.1 libboost-system1.65.1 libboost-thread1.65.1 libcapnp-0.6.1 libcdio17 libclang1-6.0 libcomerr2:i386 libcommons-dbcp-java libcommons-pool-java libcwidget3v5 libdns-export1100 libdns1100 libdouble-conversion1 libecj-java libevent-2.1-6 libffi6:i386 libgdbm5 libgl1-mesa-glx:i386 libgmime-3.0-0 libgnome-desktop-3-17 libgspell-1-1 libgweather-3-15 libhogweed4:i386 libhunspell-1.6-0 libicu60:i386 libip4tc0 libip6tc0 libiptc0 libirs-export160 libirs160 libisc-export169 libisc169 libisccc160 libisccfg-export160 libisccfg160 libisl19 libjs-sphinxdoc libjs-underscore libjson-c3 liblinear3 libllvm10:i386 libllvm11 libllvm11:i386 libllvm6.0 liblouis14 liblouisutdml8 liblwres160 libmagickcore-6.q16-3 libmagickcore-6.q16-3-extra libmagickwand-6.q16-3 libmozjs-52-0 libmutter-2-0 libncurses5:i386 libnettle6:i386 libnss-myhostname libntfs-3g88 liborcus-0.13-0 libperl5.26 libpoppler73 libpotrace0 libprocps6 libprotobuf-lite10 libprotobuf10 libprotoc10 libpython-all-dev libpython3.6 libpython3.6-dev libpython3.6-minimal libpython3.6-stdlib libqgsttools-p1 libqpdf21 libraw16 libreadline7 libruby2.5 libsane1 libsane1:i386 libsndio6.1:i386 libspeexdsp1:i386 libstdc++-7-dev libsynctex1 libtexlua52 libtinfo5:i386 libtomcat8-java libvpx5 libwireshark11 libwiretap8 libwscodecs2 libwsutil9 linux-cloud-tools-5.4.0-88 linux-cloud-tools-5.4.0-88-generic linux-headers-5.4.0-88 linux-headers-5.4.0-88-generic linux-image-5.4.0-88-generic linux-modules-5.4.0-88-generic linux-modules-extra-5.4.0-88-generic linux-tools-5.4.0-88 linux-tools-5.4.0-88-generic nplan python-all python-all-dev python-asn1crypto python-bzrlib python-cffi-backend python-configobj python-configparser python-crypto python-cryptography python-entrypoints python-enum34 python-httplib2 python-idna python-ipaddress python-keyring python-launchpadlib python-lazr.restfulclient python-lazr.uri python-oauth python-pycurl python-secretstorage python-simplejson python-wadllib python-wheel python-xdg python-zope.interface python3-asn1crypto python3-oauth python3-zope.interface python3.6 python3.6-dev python3.6-minimal ruby-did-you-mean ruby2.5 shim wireshark-gtk Use 'sudo apt autoremove' to remove them. The following additional packages will be installed: splint-data Suggested packages: splint-doc-html The following NEW packages will be installed: splint splint-data 0 upgraded, 2 newly installed, 0 to remove and 0 not upgraded. Need to get 740 kB of archives. After this operation, 2,883 kB of additional disk space will be used. Do you want to continue? [Y/n] Get:1 http://in.archive.ubuntu.com/ubuntu focal/universe amd64 splint-data all 1:3.1.2+dfsg-1build1 [57.5 kB] Get:2 http://in.archive.ubuntu.com/ubuntu focal/universe amd64 splint amd64 1:3.1.2+dfsg-1build1 [683 kB] Fetched 740 kB in 1s (808 kB/s) Selecting previously unselected package splint-data. (Reading database ... 461017 files and directories currently installed.) Preparing to unpack .../splint-data_1%3a3.1.2+dfsg-1build1_all.deb ... Unpacking splint-data (1:3.1.2+dfsg-1build1) ... Selecting previously unselected package splint. Preparing to unpack .../splint_1%3a3.1.2+dfsg-1build1_amd64.deb ... Unpacking splint (1:3.1.2+dfsg-1build1) ... Setting up splint-data (1:3.1.2+dfsg-1build1) ... Setting up splint (1:3.1.2+dfsg-1build1) ... Processing triggers for man-db (2.9.1-1) ...

Step 2 : Create a file test.c with programming mistake

#include <stdio.h> #include <stdlib.h> void fun_2() { int a[5] = {1,2,3,4,5}; int *p = a; a[5] = 400; a[6] = 400; } void fun_1() { int a[5] = {1,2,3,4,5}; int *p; p += 3; *p = 100; p += 3; *p = 200; } int main() { char *p; // Allocation #1 of 30 bytes p = (char *) malloc(30); // Allocation #2 of 12 bytes p = (char *) malloc(8); // Allocation #3 of 16 bytes p = (char *) malloc(25); free(p); return 0; }

Step 3 : Run splint on test.c to do Static analysis

$ splint test.c Splint 3.1.2 --- 20 Feb 2018 test.c: (in function fun_2) test.c:7:7: Variable p declared but not used A variable is declared but never used. Use /*@unused@*/ in front of declaration to suppress message. (Use -varuse to inhibit warning) test.c: (in function fun_1) test.c:18:2: Variable p used before definition An rvalue is used that may not be initialized to a value on some execution path. (Use -usedef to inhibit warning) test.c:15:6: Variable a declared but not used test.c: (in function main) test.c:35:3: Fresh storage p (type char *) not released before assignment: p = (char *)malloc(8) A memory leak has been detected. Storage allocated locally is not released before the last reference to it is lost. (Use -mustfreefresh to inhibit warning) test.c:32:3: Fresh storage p created test.c:38:3: Fresh storage p (type char *) not released before assignment: p = (char *)malloc(25) test.c:35:3: Fresh storage p created Finished checking --- 5 code warnings

Step 4 : Fix Programming mistakes in file test.c and check splint

#include <stdio.h> #include <stdlib.h> void fun_2() { int a[5] = {1,2,3,4,5}; int *p = a; a[5] = 400; a[6] = 400; *p = 100; } void fun_1() { int a[5] = {1,2,3,4,5}; int *p = a; p += 3; *p = 100; p += 3; *p = 200; } int main() { char *p; // Allocation #1 of 30 bytes p = (char *) malloc(30); free(p); // Allocation #2 of 12 bytes p = (char *) malloc(8); free(p); // Allocation #3 of 16 bytes p = (char *) malloc(25); free(p); return 0; }

Step 5 : Run splint on test.c to do Static analysis
$ splint test.c Splint 3.1.2 --- 20 Feb 2018 Finished checking --- no warnings