cosmopolitan/libc/intrin/getenv.c
Justine Tunney dc0ea6640e Fix bugs with recent change
This change makes further effort towards improving our poll()
implementation on the New Technology. The stdin worker didn't work out
so well for Python so it's not being used for now. System call tracing
with the --strace flag should now be less noisy now on Windows unless
you modify the strace.internal.h defines to turn on some optional ones
that are most useful for debugging the system call wrappers.
2022-04-16 10:40:23 -07:00

77 lines
3 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/assert.h"
#include "libc/calls/strace.internal.h"
#include "libc/dce.h"
#include "libc/errno.h"
#include "libc/intrin/kprintf.h"
#include "libc/log/libfatal.internal.h"
#include "libc/runtime/runtime.h"
forceinline int Identity(int c) {
return c;
}
forceinline int ToUpper(int c) {
return 'a' <= c && c <= 'z' ? c - ('a' - 'A') : c;
}
forceinline char *GetEnv(const char *s, int xlat(int)) {
char **p;
size_t i, j;
if ((p = environ)) {
for (i = 0; p[i]; ++i) {
for (j = 0;; ++j) {
if (!s[j]) {
if (p[i][j] == '=') {
return p[i] + j + 1;
}
break;
}
if (xlat(s[j]) != xlat(p[i][j])) {
break;
}
}
}
}
return 0;
}
/**
* Returns value of environment variable, or NULL if not found.
*
* Environment variables can store empty string on Unix but not Windows.
*
* @note should not be used after __cxa_finalize() is called
*/
char *getenv(const char *s) {
char *r;
if (!IsWindows()) {
r = GetEnv(s, Identity);
} else {
r = GetEnv(s, ToUpper);
}
#if SYSDEBUG
if (!(s[0] == 'T' && s[1] == 'Z' && !s[2])) {
// TODO(jart): memoize TZ or something
STRACE("getenv(%#s) → %#s", s, r);
}
#endif
return r;
}