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#include <unistd.h>
#include <errno.h>
#include <sys/resource.h>
#include "syscall.h"
#include "libc.h"
struct ctx {
int id, eid, sid;
int nr, rlim, err;
};
/* We jump through hoops to eliminate the possibility of partial failures. */
static void do_setxid(void *p)
{
struct ctx *c = p;
if (c->err) return;
if (c->rlim && c->id >= 0 && c->id != getuid()) {
struct rlimit inf = { RLIM_INFINITY, RLIM_INFINITY }, old;
getrlimit(RLIMIT_NPROC, &old);
if (setrlimit(RLIMIT_NPROC, &inf) && libc.threads_minus_1) {
c->err = errno;
return;
}
if (__syscall(c->nr, c->id, c->eid, c->sid))
c->err = errno;
setrlimit(RLIMIT_NPROC, &old);
return;
}
if (__syscall(c->nr, c->id, c->eid, c->sid))
c->err = errno;
}
int __setxid(int nr, int id, int eid, int sid)
{
struct ctx c = { .nr = nr, .id = id, .eid = eid, .sid = sid };
switch (nr) {
case SYS_setuid:
case SYS_setreuid:
case SYS_setresuid:
c.rlim = 1;
}
__synccall(do_setxid, &c);
if (c.err) {
errno = c.err;
return -1;
}
return 0;
}
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