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Get fork() working on Windows

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This is done without using Microsoft's internal APIs. MAP_PRIVATE
mappings are copied to the subprocess via a pipe, since Microsoft
doesn't want us to have proper COW pages. MAP_SHARED mappings are
remapped without needing to do any copying. Global variables need
copying along with the stack and the whole heap of anonymous mem.
This actually improves the reliability of the redbean http server
although one shouldn't expect 10k+ connections on a home computer
that isn't running software built to serve like Linux or FreeBSD.
This commit is contained in:
Justine Tunney 2020-11-13 01:27:49 -08:00
parent aea89fe832
commit db33973e0a
105 changed files with 1476 additions and 912 deletions
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54
libc/mem/putenv.c
View file

@ -24,53 +24,49 @@
#include "libc/str/str.h"
#include "libc/sysv/errfuns.h"
static size_t g_environcap;
#define MAX_VARS 512
int PutEnvImpl(char *string, bool overwrite) {
if (!environ) {
g_environcap = 0;
if ((environ = calloc(8, sizeof(char *)))) {
g_environcap = 8;
}
}
char *equalp = strchr(string, '=');
if (!equalp) return einval();
unsigned namelen = equalp + 1 - string;
unsigned i;
int PutEnvImpl(char *s, bool overwrite) {
char *p;
unsigned i, namelen;
p = strchr(s, '=');
if (!p) goto fail;
namelen = p + 1 - s;
for (i = 0; environ[i]; ++i) {
if (strncmp(environ[i], string, namelen) == 0) {
if (strncmp(environ[i], s, namelen) == 0) {
if (!overwrite) {
free_s(&string);
free(s);
return 0;
}
goto replace;
}
}
if (i + 1 >= g_environcap) {
if (!g_environcap) g_environcap = i + 1;
if (!grow(&environ, &g_environcap, sizeof(char *), 0)) {
free_s(&string);
return -1;
}
}
if (i + 1 >= MAX_VARS) goto fail;
environ[i + 1] = NULL;
replace:
free_s(&environ[i]);
environ[i] = string;
free(environ[i]);
environ[i] = s;
return 0;
fail:
free(s);
return einval();
}
/**
* Emplaces environment key=value.
* @see setenv(), getenv()
*/
int putenv(char *string) { return PutEnvImpl(string, true); }
textexit static void putenv_fini(void) {
for (char **envp = environ; *envp; ++envp) free_s(envp);
free_s(&environ);
int putenv(char *string) {
return PutEnvImpl(strdup(string), true);
}
textstartup static void putenv_init(void) { atexit(putenv_fini); }
textstartup static void putenv_init(void) {
char **pin, **pout;
pin = environ;
pout = malloc(sizeof(char *) * MAX_VARS);
environ = pout;
while (*pin) *pout++ = strdup(*pin++);
*pout = NULL;
}
const void *const putenv_ctor[] initarray = {putenv_init};