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/*******************************************************************************
* Header Files *
*******************************************************************************/
#include <string.h>
#include <locale.h>
#include "shinstance.h"
#include <Windows.h>
/*******************************************************************************
* Defined Constants And Macros *
*******************************************************************************/
/** The stack size. This is also defined in shforkA-win.asm. */
#define SHFORK_STACK_SIZE (1*1024*1024)
/*******************************************************************************
* Global Variables *
*******************************************************************************/
static void *g_stack_base = 0;
static void *g_stack_limit = 0;
/*******************************************************************************
* Internal Functions *
*******************************************************************************/
static void *shfork_string_to_ptr(const char *str, const char *argv0, const char *what);
/* in shforkA-win.asm: */
extern void shfork_resume(void *cur, void *base, void *limit);
/* called by shforkA-win.asm: */
void *shfork_maybe_forked(int argc, char **argv, char **envp);
extern int shfork_body(shinstance *psh, void *stack_ptr);
/***
* Called by shforkA-win.asm to check whether we're a forked child
* process or not.
*
* In the former case we will resume execution at the fork resume
* point. In the latter we'll allocate a new stack of the forkable
* heap and return it to the caller so real_main() in main.c can be
* invoked on it.
*
* @returns Stack or not at all.
* @param argc Argument count.
* @param argv Argument vector.
* @param envp Environment vector.
*/
void *shfork_maybe_forked(int argc, char **argv, char **envp)
{
void *stack_ptr;
/*
* Are we actually forking?
*/
if ( argc != 8
|| strcmp(argv[1], "--!forked!--")
|| strcmp(argv[2], "--stack-address")
|| strcmp(argv[4], "--stack-base")
|| strcmp(argv[6], "--stack-limit"))
{
char *stack;
shheap_init();
stack = (char *)sh_malloc(NULL, SHFORK_STACK_SIZE) + SHFORK_STACK_SIZE;
g_stack_base = stack + SHFORK_STACK_SIZE;
g_stack_limit = stack;
return stack;
}
/*
* Do any init that needs to be done before resuming the
* fork() call.
*/
setlocale(LC_ALL, "");
/*
* Convert the stack addresses.
*/
stack_ptr = shfork_string_to_ptr(argv[3], argv[0], "--stack-address");
g_stack_base = shfork_string_to_ptr(argv[5], argv[0], "--stack-base");
g_stack_limit = shfork_string_to_ptr(argv[7], argv[0], "--stack-limit");
/*
* Switch stack and jump to the fork resume point.
*/
shfork_resume(stack_ptr, g_stack_base, g_stack_limit);
/* (won't get here) */
return NULL;
}
/***
* Converts a string into a pointer.
*
* @returns Pointer.
* @param argv0 The program name in case of error.
* @param str The string to convert.
*/
static void *shfork_string_to_ptr(const char *str, const char *argv0, const char *what)
{
const char *start = str;
intptr_t ptr = 0;
if (str[0] == '0' && (str[1] == 'x' || str[1] == 'X'))
str += 2;
while (*str)
{
unsigned digit;
switch (*str)
{
case '0': digit = 0; break;
case '1': digit = 1; break;
case '2': digit = 2; break;
case '3': digit = 3; break;
case '4': digit = 4; break;
case '5': digit = 5; break;
case '6': digit = 6; break;
case '7': digit = 7; break;
case '8': digit = 8; break;
case '9': digit = 9; break;
case 'a': case 'A': digit = 0xa; break;
case 'b': case 'B': digit = 0xb; break;
case 'c': case 'C': digit = 0xc; break;
case 'd': case 'D': digit = 0xd; break;
case 'e': case 'E': digit = 0xe; break;
case 'f': case 'F': digit = 0xf; break;
default:
fprintf(stderr, "%s: fatal error: Invalid %s '%s'\n", argv0, what, start);
exit(2);
}
ptr <<= 4;
ptr |= digit;
str++;
}
return (void *)ptr;
}
/***
* Create the child process making sure it inherits all our handles,
* copy of the forkable heap and kick it off.
*
* Called by shfork_do_it() in shforkA-win.asm.
*
* @returns child pid on success, -1 and errno on failure.
* @param psh The shell that's forking.
* @param stack_ptr The stack address at which the guest is suppost to resume.
*/
int shfork_body(shinstance *psh, void *stack_ptr)
{
PROCESS_INFORMATION ProcInfo;
STARTUPINFO StrtInfo;
intptr_t hndls[3];
char szExeName[1024];
char szCmdLine[1024+256];
DWORD cch;
int rc = 0;
/*
* Mark all handles inheritable and get the three standard handles.
*/
shfile_fork_win(&psh->fdtab, 1 /* set */, &hndls[0]);
/*
* Create the process.
*/
cch = GetModuleFileName(GetModuleHandle(NULL), szExeName, sizeof(szExeName));
if (cch > 0)
{
#if 0 /* quoting the program name doesn't seems to be working :/ */
szCmdLine[0] = '"';
memcpy(&szCmdLine[1], szExeName, cch);
szCmdLine[++cch] = '"';
#else
memcpy(&szCmdLine[0], szExeName, cch);
#endif
cch += sprintf(&szCmdLine[cch], " --!forked!-- --stack-address %p --stack-base %p --stack-limit %p",
stack_ptr, g_stack_base, g_stack_limit);
szCmdLine[cch+1] = '\0';
memset(&StrtInfo, '\0', sizeof(StrtInfo)); /* just in case. */
StrtInfo.cb = sizeof(StrtInfo);
StrtInfo.lpReserved = NULL;
StrtInfo.lpDesktop = NULL;
StrtInfo.lpTitle = NULL;
StrtInfo.dwX = 0;
StrtInfo.dwY = 0;
StrtInfo.dwXSize = 0;
StrtInfo.dwYSize = 0;
StrtInfo.dwXCountChars = 0;
StrtInfo.dwYCountChars = 0;
StrtInfo.dwFillAttribute = 0;
StrtInfo.dwFlags = 0;
StrtInfo.wShowWindow = 0;
StrtInfo.cbReserved2 = 0;
StrtInfo.lpReserved2 = NULL;
StrtInfo.hStdInput = (HANDLE)hndls[0];
StrtInfo.hStdOutput = (HANDLE)hndls[1];
StrtInfo.hStdError = (HANDLE)hndls[2];
if (CreateProcess(szExeName,
szCmdLine,
NULL, /* pProcessAttributes */
NULL, /* pThreadAttributes */
TRUE, /* bInheritHandles */
CREATE_SUSPENDED,
NULL, /* pEnvironment */
NULL, /* pCurrentDirectory */
&StrtInfo,
&ProcInfo))
{
/*
* Copy the memory to the child.
*/
rc = shheap_fork_copy_to_child(ProcInfo.hProcess);
if (!rc)
{
if (ResumeThread(ProcInfo.hThread) != (DWORD)-1)
{
rc = sh_add_child(psh, ProcInfo.dwProcessId, ProcInfo.hProcess);
if (!rc)
rc = (int)ProcInfo.dwProcessId;
}
else
{
DWORD dwErr = GetLastError();
fprintf(stderr, "shfork: ResumeThread() -> %d\n", dwErr);
errno = EINVAL;
rc = -1;
}
}
if (rc == -1)
{
TerminateProcess(ProcInfo.hProcess, 127);
/* needed?: ResumeThread(ProcInfo.hThread); */
CloseHandle(ProcInfo.hProcess);
}
CloseHandle(ProcInfo.hThread);
}
else
{
DWORD dwErr = GetLastError();
fprintf(stderr, "shfork: CreateProcess(%s) -> %d\n", szExeName, dwErr);
errno = EINVAL;
rc = -1;
}
}
else
{
DWORD dwErr = GetLastError();
fprintf(stderr, "shfork: GetModuleFileName() -> %d\n", dwErr);
errno = EINVAL;
rc = -1;
}
/*
* Restore the handle inherit property.
*/
shfile_fork_win(&psh->fdtab, 0 /* restore */, NULL);
return rc;
}
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