ref: fed44bd6dee3c21a0b5ac0c11c13b4271e20f6f3
dir: /kern/sysproc.c/
#include "u.h"
#include "lib.h"
#include "dat.h"
#include "fns.h"
#include "error.h"
#include "user.h"
#include "mem.h"
#include <a.out.h>
#include <signal.h>
#include <sys/mman.h>
#include <setjmp.h>
#undef rfork
jmp_buf exec_jmp;
static void
nop(int x)
{
USED(x);
}
static void
sigsegv(int sig)
{
print("Segfault: %d: %r\n", sig);
longjmp(exec_jmp, 2);
}
static void
sigquit(int sig)
{
print("Sigquittin': %r\n");
longjmp(exec_jmp, 1);
}
static void
sigbus(int sig)
{
print("Bussin': %r\n");
longjmp(exec_jmp, 2);
}
static void
sigsys(int sig)
{
print("We here!!! sig %d\n", sig);
}
int
sysrfork(int flags)
{
int pid, status;
int p[2];
int n;
char buf[128], *q;
extern char **environ;
struct sigaction oldchld;
memset(&oldchld, 0, sizeof oldchld);
if((flags&(RFPROC|RFFDG|RFMEM)) == (RFPROC|RFFDG)){
flags &= ~(RFPROC|RFFDG|RFENVG);
n = (flags & ~(RFNOTEG|RFNAMEG|RFNOWAIT|RFCENVG));
if(n){
werrstr("unknown flags %08ux in rfork", n);
return -1;
}
if(flags&RFNOWAIT){
sigaction(SIGCHLD, nil, &oldchld);
signal(SIGCHLD, nop);
if(pipe(p) < 0)
return -1;
}
pid = fork();
if(pid == -1)
return -1;
if(flags&RFNOWAIT){
flags &= ~RFNOWAIT;
if(pid){
close(p[1]);
status = 0;
if(wait4(pid, &status, 0, 0) < 0){
werrstr("pipe dance - wait4 - %r");
close(p[0]);
return -1;
}
n = readn(p[0], buf, sizeof buf-1);
close(p[0]);
if(!WIFEXITED(status) || WEXITSTATUS(status)!=0 || n <= 0){
if(!WIFEXITED(status))
werrstr("pipe dance - !exited 0x%ux", status);
else if(WEXITSTATUS(status) != 0)
werrstr("pipe dance - non-zero status 0x%ux", status);
else if(n < 0)
werrstr("pipe dance - pipe read error - %r");
else if(n == 0)
werrstr("pipe dance - pipe read eof");
else
werrstr("pipe dance - unknown failure");
return -1;
}
buf[n] = 0;
if(buf[0] == 'x'){
werrstr("%s", buf+2);
return -1;
}
pid = strtol(buf, &q, 0);
}else{
signal(SIGCHLD, SIG_IGN);
close(p[0]);
pid = fork();
if(pid){
if(pid > 0)
fprint(p[1], "%d", pid);
else
fprint(p[1], "x %r");
close(p[1]);
_exit(0);
}else{
close(p[1]);
}
}
sigaction(SIGCHLD, &oldchld, nil);
}
if(pid != 0)
return pid;
if(flags&RFCENVG)
if(environ)
*environ = nil;
}
if(flags&RFPROC){
werrstr("cannot use rfork for shared memory -- use libthread");
return -1;
}
if(flags&RFNAMEG){
flags &= ~RFNAMEG;
}
if(flags&RFNOTEG){
setpgid(0, getpid());
flags &= ~RFNOTEG;
}
if(flags&RFNOWAIT){
werrstr("cannot use RFNOWAIT without RFPROC");
return -1;
}
if(flags){
werrstr("unknown flags %08ux in rfork", flags);
return -1;
}
return 0;
}
static int
shargs(char *s, int n, char **ap, int nap)
{
char *p;
int i;
if(n <= 2 || s[0] != '#' || s[1] != '!')
return -1;
s += 2;
n -= 2;
if((p = memchr(s, '\n', n)) == nil)
return 0;
*p = 0;
i = tokenize(s, ap, nap-1);
ap[i] = nil;
return i;
}
ulong
beswal(ulong l)
{
uchar *p;
p = (uchar*)&l;
return (p[0]<<24) | (p[1]<<16) | (p[2]<<8) | p[3];
}
uvlong
beswav(uvlong v)
{
uchar *p;
p = (uchar*)&v;
return ((uvlong)p[0]<<56) | ((uvlong)p[1]<<48) | ((uvlong)p[2]<<40)
| ((uvlong)p[3]<<32) | ((uvlong)p[4]<<24)
| ((uvlong)p[5]<<16) | ((uvlong)p[6]<<8)
| (uvlong)p[7];
}
void
evenaddr(uintptr addr)
{
if(addr & 3){
postnote(up, 1, "sys: odd address", NDebug);
error(Ebadarg);
}
}
void*
vmemchr(void *s, int c, ulong n)
{
uintptr a;
ulong m, i;
void *t;
i = n;
a = (uintptr)s;
for(;;){
m = BY2PG - (a & (BY2PG-1));
if(i <= m)
break;
t = memchr((void*)a, c, m);
if(t != nil)
return t;
a += m;
i -= m;
if(a < KZERO)
validaddr(a, 1, 0);
}
return memchr((void*)a, c, i);
}
#undef read
int
sysexec(int argc, char **argv)
{
union {
struct {
Exec ex;
uvlong hdr[1];
} ehdr;
char buf[256];
} u;
void (*_main)(int, char*[]);
char line[256];
char *progarg[32+1];
char *file, *elem;
void *base;
Chan *tc;
ulong magic;
uintptr t, b, entry, text, data, bss, align;
int n, indir;
elem = nil;
align = BY2PG-1;
indir = 0;
file = argv[0];
for(;;){
tc = namec(file, Aopen, OEXEC, 0);
if(waserror()){
cclose(tc);
nexterror();
}
if(!indir)
kstrdup(&elem, up->genbuf);
n = devtab[tc->type]->read(tc, u.buf, sizeof(u.buf), 0);
if (n >= sizeof(Exec)){
magic = beswal(u.ehdr.ex.magic);
if(magic & AOUT_MAGIC) {
if(magic & HDR_MAGIC){
if(n < sizeof(u.ehdr))
error(Ebadexec);
entry = beswav(u.ehdr.hdr[0]);
text = UTZERO+sizeof(u.ehdr);
} else {
entry = beswal(u.ehdr.ex.entry);
text = UTZERO+sizeof(u.ehdr);
}
if(entry < text)
error(Ebadexec);
text += beswal(u.ehdr.ex.text);
if(text <= entry || text >= (USTKTOP-USTKSIZE))
error(Ebadexec);
switch(magic){
case S_MAGIC:
align = 0x1fffff;
break;
case P_MAGIC:
case V_MAGIC:
align = 0x3fff;
break;
case R_MAGIC:
align = 0xffff;
break;
}
break;
}
}
if(indir++)
error(Ebadexec);
memmove(line, u.buf, sizeof(u.buf));
n = shargs(line, n, progarg, nelem(progarg));
if(n < 1)
error(Ebadexec);
progarg[n++] = file;
progarg[n] = nil;
file = progarg[0];
progarg[0] = elem;
poperror();
cclose(tc);
}
text -= UTZERO;
entry -= UTZERO;
data = beswal(u.ehdr.ex.data);
bss = beswal(u.ehdr.ex.bss);
/* Set up text, data, and bss. OS dependent. */
base = osbuildmem(tc, text, data, bss, sizeof(u.ehdr), align);
b = ((uintptr)base + align) & ~align;
/* Handle alignment, BSS setup, and memory protection. OS dependent. */
osprepmem(base, b, text, data, bss);
poperror();
cclose(tc);
/* Meaningful signals to us */
signal(SIGSEGV, sigsegv);
signal(SIGQUIT, sigquit);
signal(SIGINT, sigquit);
signal(SIGSYS, sigsys);
signal(SIGBUS, sigbus);
switch(setjmp(exec_jmp)) {
case 0:
print("Base %p, Aligned base %p, Entry offset %lx, Text %lx\n", base, (void*)b, entry, text);
_main = (void (*)(int, char*[]))(b+entry);
_main(argc, argv);
longjmp(exec_jmp, 1);
break;
case 1:
osclrmem((uintptr)b, text+data+bss);
break;
case 2:
//error("Signal: %r");
return -1;
}
return 0;
}