Unsafe and Obsolete Functions

Thread Unsafe Library Functions

Most OpenSAF programs are multi-threaded, and code in shared libraries can be linked with application programs, which we must assume can also be multi-threaded. Therefore, you should always be careful to avoid using C library functions that are not thread-safe. Below is a list of C library functions that are categorized as MT-Unsafe (see POSIX Safety Concepts) in the Linux man pages. Some of these functions can however be used safely in a multithreaded program, provided that certain conditions are met. For example, the readdir function is safe provided that no other thread is accessing the same stream concurrently. If possible, avoid using these functions. If you do use them, you must ensure that the conditions for using them safely are met. For details regarding each function, please refer to the Linux man pages.

| | |
---------- | ---------- | ---------- | ----------
__after_morecore_hook | __free_hook | __malloc_check_init | __malloc_hook
__malloc_initialize_hook | __memalign_hook | __realloc_hook | asctime
clearenv | crypt | ctime | cuserid
dbm_clearerr | dbm_close | dbm_delete | dbm_error
dbm_fetch | dbm_firstkey | dbm_nextkey | dbm_open
dbm_store | drand48 | ecvt | encrypt
endfsent | endgrent | endhostent | endnetent
endnetgrent | endprotoent | endpwent | endservent
endspent | endttyent | endusershell | endutent
endutxent | erand48 | error_at_line | ether_aton
ether_ntoa | exit | fcloseall | fcvt
fgetgrent | fgetpwent | fgetspent | fts_children
fts_read | gamma | gammaf | gammal
getaliasbyname | getaliasent | getchar_unlocked | getdate
getfsent | getfsfile | getfsspec | getgrent
getgrent_r | getgrgid | getgrnam | gethostbyaddr
gethostbyname | gethostbyname2 | gethostent | gethostent_r
getlogin | getlogin_r | getmntent | getnetbyaddr
getnetbyname | getnetent | getnetgrent | getnetgrent_r
getopt | getopt_long | getopt_long_only | getpass
getprotobyname | getprotobynumber | getprotoent | getpwent
getpwent_r | getpwnam | getpwuid | getrpcbyname
getrpcbynumber | getrpcent | getservbyname | getservbyport
getservent | getspent | getspent_r | getspnam
getttyent | getttynam | getusershell | getutent
getutid | getutline | getutxent | getutxid
getutxline | getwchar_unlocked | glob | gmtime
hcreate | hdestroy | hsearch | innetgr
jrand48 | l64a | lcong48 | lgamma
lgammaf | lgammal | localeconv | localtime
login | login_tty | logout | logwtmp
lrand48 | mallinfo | mblen | mbrlen
mbrtowc | mbsnrtowcs | mbsrtowcs | mbtowc
mcheck | mcheck_check_all | mcheck_pedantic | mprobe
mrand48 | mtrace | muntrace | nrand48
profil | ptsname | putchar_unlocked | putenv
pututline | pututxline | putwchar_unlocked | pvalloc
qecvt | qfcvt | rcmd | rcmd_af
re_comp | re_exec | readdir | rexec
rexec_af | seed48 | setenv | setfsent
setgrent | sethostent | sethostid | setkey
setlocale | setlogmask | setnetent | setnetgrent
setprotoent | setpwent | setservent | setspent
setttyent | setusershell | setutent | setutxent
sgetspent | siginterrupt | signal | sleep
srand48 | strerror | strsignal | strtok
tmpnam | ttyname | ttyslot | unsetenv
updwtmp | utmpname | valloc | wcrtomb
wcsnrtombs | wcsrtombs | wctomb | wordexp

Obsolete and Deprecated Symbols

Below is a list of functions, variables and macros that are documented as obsolete, deprecated or legacy. We should avoid using them. For details regarding each function, please refer to the Linux man pages.

| | |
---------- | ---------- | ---------- | ----------
INADDR_NONE | LOG_NOWAIT | _BSD_SOURCE | _LARGEFILE_SOURCE
_SVID_SOURCE | _GNU_LIBRARY | _after_morecore_hook | free_hook
__malloc_check_init | __malloc_hook | __malloc_initialize_hook | __memalign_hook
__realloc_hook | __setfpucw | _fini | _init
_res | asctime | asctime_r | atoq
bcmp | bcopy | bzero | ctime
ctime_r | drem | dremf | dreml
ecvt | ecvt_r | endfsent | endutent
fcvt | fcvt_r | finite | finitef
finitel | freehostent | ftime | ftw
gamma | gammaf | gammal | gcvt
getfsent | getfsfile | getfsspec | gethostbyaddr
gethostbyaddr_r | gethostbyname | gethostbyname2 | gethostbyname2_r
gethostbyname_r | getipnodebyaddr | getipnodebyname | getpass
getpw | gets | getutent | getutid
getutline | getwd | gsignal | h_errno
herror | hstrerror | index | inet_addr
inet_lnaof | inet_makeaddr | inet_netof | infnan
isascii | isinf | isinff | isinfl
isnan | isnanf | isnanl | matherr
memalign | mktemp | pthread_attr_getstackaddr | pthread_attr_setstackaddr
pthread_kill_other_threads_np | pututline | pvalloc | qecvt
qecvt_r | qfcvt | qfcvt_r | qgcvt
rand_r | re_comp | re_exec | readdir64_r
readdir_r | res_init | res_mkquery | res_query
res_querydomain | res_search | res_send | rexec
rexec_af | rindex | scalb | scalbf
scalbl | setfsent | setutent | sigblock
siggetmask | sighold | sigignore | siginterrupt
sigmask | sigpause | sigrelse | sigset
sigsetmask | sigstack | sigvec | ssignal
svc_fds | svc_getreq | sys_errlist | sys_nerr
tempnam | tkill | tmpnam | toascii
towlower | towupper | ttyslot | ualarm
ulimit | usleep | utmpname | valloc
wctob

IPv4-Only Functions

Some old functions that only support IPv4 have been replaced with new functions supporting both IPv4 and IPv6. Although the old functions are not (yet) officially deprecated, we should use the new function in OpenSAF since OpenSAF supports both IPv4 and IPv6. Below is a list of functions that only support IPv4, and therefore should not be used:

| | |
---------- | ---------- | ---------- | ----------
inet_addr | inet_aton | inet_lnaof | inet_makeaddr
inet_netof | inet_network | inet_ntoa

Unsecure Functions

The following functions should be avoided since they are difficult to use in a secure way. For more information about why these functions are unsecure, see e.g. Banned Function Calls

| | |
---------- | ---------- | ---------- | ----------
alloca | gets | scanf | sprintf
sscanf | strcat | strcpy | strncat
strncpy | strtok | swprintf | swscanf
vsprintf | vswprintf | wcscat | wcscpy
wcsncat | wcsncpy | wcstok | wmemcpy
wscanf | | |