fusl/src/misc/setrlimit.c

#include <sys/resource.h>
#include <errno.h>
#include "syscall.h"
#include "libc.h"

#define MIN(a, b) ((a) < (b) ? (a) : (b))
#define FIX(x)                        \
  do {                                \
    if ((x) >= SYSCALL_RLIM_INFINITY) \
      (x) = RLIM_INFINITY;            \
  } while (0)

int __setrlimit(int resource, const struct rlimit* rlim) {
  unsigned long k_rlim[2];
  struct rlimit tmp;
  if (SYSCALL_RLIM_INFINITY != RLIM_INFINITY) {
    tmp = *rlim;
    FIX(tmp.rlim_cur);
    FIX(tmp.rlim_max);
    rlim = &tmp;
  }
  int ret = __syscall(SYS_prlimit64, 0, resource, rlim, 0);
  if (ret != -ENOSYS)
    return ret;
  k_rlim[0] = MIN(rlim->rlim_cur, MIN(-1UL, SYSCALL_RLIM_INFINITY));
  k_rlim[1] = MIN(rlim->rlim_max, MIN(-1UL, SYSCALL_RLIM_INFINITY));
  return __syscall(SYS_setrlimit, resource, k_rlim);
}

struct ctx {
  const struct rlimit* rlim;
  int res;
  int err;
};

static void do_setrlimit(void* p) {
  struct ctx* c = p;
  if (c->err > 0)
    return;
  c->err = -__setrlimit(c->res, c->rlim);
}

int setrlimit(int resource, const struct rlimit* rlim) {
  struct ctx c = {.res = resource, .rlim = rlim, .err = -1};
  __synccall(do_setrlimit, &c);
  if (c.err) {
    if (c.err > 0)
      errno = c.err;
    return -1;
  }
  return 0;
}