cosmopolitan/tool/build/lib/xlaterrno.c

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/*-*- 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
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA
*/
#include "libc/errno.h"
#include "libc/mem/mem.h"
#include "libc/runtime/carsort.h"
#include "tool/build/lib/xlaterrno.h"
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struct LinuxErrno {
int32_t local;
int32_t linux;
};
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extern const char kLinuxErrnosLength[];
extern const struct LinuxErrno kLinuxErrnos[];
static struct LinuxErrno *errnos;
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/**
* Turns local errno into Linux errno.
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*/
int XlatErrno(int local) {
static bool once;
long i, n, m, l, r;
n = (uintptr_t)kLinuxErrnosLength;
if (!once) {
errnos = malloc(sizeof(struct LinuxErrno) * n);
for (i = 0; i < n; ++i) {
errnos[i].local =
*(int *)((intptr_t)kLinuxErrnos + kLinuxErrnos[i].local);
errnos[i].linux = kLinuxErrnos[i].linux;
}
carsort100(n, (void *)errnos);
once = true;
}
l = 0;
r = n - 1;
while (l <= r) {
m = (l + r) / 2;
if (errnos[m].local < local) {
l = m + 1;
} else if (errnos[m].local > local) {
r = m - 1;
} else {
return errnos[m].linux;
}
}
return ENOSYS;
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}