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Code Issues 1 Releases Wiki Activity

Address #242

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Synchronize critical sections in setenv/getenv/environ.
This commit is contained in:
Calvin Rose 2020-01-06 19:30:44 -06:00
parent c4047f3f88
commit ed5027db5d
4 changed files with 67 additions and 10 deletions
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7
src/core/capi.c
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@ -150,6 +150,13 @@ DEFINE_OPTLEN(buffer, BUFFER, JanetBuffer *)
DEFINE_OPTLEN(table, TABLE, JanetTable *)
DEFINE_OPTLEN(array, ARRAY, JanetArray *)
const char *janet_optcstring(const Janet *argv, int32_t argc, int32_t n, const char *dflt) {
if (n >= argc || janet_checktype(argv[n], JANET_NIL)) {
return dflt;
}
return janet_getcstring(argv, n);
}
#undef DEFINE_GETTER
#undef DEFINE_OPT
#undef DEFINE_OPTLEN

58
src/core/os.c
View File

@ -52,6 +52,9 @@
#include <sys/types.h>
#include <sys/wait.h>
extern char **environ;
#ifdef JANET_THREADS
#include <pthread.h>
#endif
#endif
/* For macos */
@ -66,6 +69,34 @@ extern char **environ;
void arc4random_buf(void *buf, size_t nbytes);
#endif
/* Access to some global variables should be synchronized if not in single threaded mode, as
* setenv/getenv are not thread safe. */
#ifdef JANET_THREADS
# ifdef JANET_WINDOWS
static int env_lock_initialized = 0;
static CRITICAL_SECTION env_lock;
static void janet_lock_environ(void) {
EnterCriticalSection(env_lock);
}
static void janet_unlock_environ(void) {
LeaveCriticalSection(env_lock);
}
# else
static pthread_mutex_t env_lock = PTHREAD_MUTEX_INITIALIZER;
static void janet_lock_environ(void) {
pthread_mutex_lock(&env_lock);
}
static void janet_unlock_environ(void) {
pthread_mutex_unlock(&env_lock);
}
# endif
#else
static void janet_lock_environ(void) {
}
static void janet_unlock_environ(void) {
}
#endif
#endif /* JANET_REDCUED_OS */
/* Core OS functions */
@ -386,6 +417,7 @@ static Janet os_environ(int32_t argc, Janet *argv) {
(void) argv;
janet_fixarity(argc, 0);
int32_t nenv = 0;
janet_lock_environ();
char **env = environ;
while (*env++)
nenv += 1;
@ -393,7 +425,10 @@ static Janet os_environ(int32_t argc, Janet *argv) {
for (int32_t i = 0; i < nenv; i++) {
char *e = environ[i];
char *eq = strchr(e, '=');
if (!eq) janet_panic("no '=' in environ");
if (!eq) {
janet_unlock_environ();
janet_panic("no '=' in environ");
}
char *v = eq + 1;
int32_t full_len = (int32_t) strlen(e);
int32_t val_len = (int32_t) strlen(v);
@ -403,6 +438,7 @@ static Janet os_environ(int32_t argc, Janet *argv) {
janet_stringv((const uint8_t *)v, val_len)
);
}
janet_unlock_environ();
return janet_wrap_table(t);
}
@ -410,11 +446,14 @@ static Janet os_getenv(int32_t argc, Janet *argv) {
janet_arity(argc, 1, 2);
const char *cstr = janet_getcstring(argv, 0);
const char *res = getenv(cstr);
return res
janet_lock_environ();
Janet ret = res
? janet_cstringv(res)
: argc == 2
? argv[1]
: janet_wrap_nil();
janet_unlock_environ();
return ret;
}
static Janet os_setenv(int32_t argc, Janet *argv) {
@ -427,11 +466,14 @@ static Janet os_setenv(int32_t argc, Janet *argv) {
#endif
janet_arity(argc, 1, 2);
const char *ks = janet_getcstring(argv, 0);
if (argc == 1 || janet_checktype(argv[1], JANET_NIL)) {
const char *vs = janet_optcstring(argv, argc, 1, NULL);
janet_lock_environ();
if (NULL == vs) {
UNSETENV(ks);
} else {
SETENV(ks, janet_getcstring(argv, 1));
SETENV(ks, vs);
}
janet_unlock_environ();
return janet_wrap_nil();
}
@ -1085,5 +1127,13 @@ static const JanetReg os_cfuns[] = {
/* Module entry point */
void janet_lib_os(JanetTable *env) {
#if !defined(JANET_REDUCED_OS) && defined(JANET_WINDOWS) && defined(JANET_THREADS)
/* During start up, the top-most abstract machine (thread)
* in the thread tree sets up the critical section. */
if (!env_lock_initialized) {
InitializeCriticalSection(env_lock);
env_lock_initialized = 1;
}
#endif
janet_core_cfuns(env, NULL, os_cfuns);
}