#include <signal.h>
#include <stdio.h>
#include <string.h>
+#include <unistd.h>
#include <sys/mman.h>
static __thread char ebuf[ALTSTACK_ERR_MAXLEN];
}
static __thread void *rsp_save_[2];
+static __thread rlim_t max_;
+
+rlim_t altstack_max(void) {
+ return max_;
+}
static ptrdiff_t rsp_save(unsigned i) {
assert(i < 2);
int altstack(rlim_t max, void *(*fn)(void *), void *arg, void **out)
{
+ long pgsz = sysconf(_SC_PAGESIZE);
int ret = -1, undo = 0;
char *m;
struct rlimit rl_save;
fn_ = fn;
arg_ = arg;
out_ = 0;
+ max_ = max;
ebuf[elen = 0] = '\0';
if (out) *out = 0;
+ // if the first page below the mapping is in use, we get max-pgsz usable bytes
+ // add pgsz to max to guarantee at least max usable bytes
+ max += pgsz;
+
ok(getrlimit(RLIMIT_STACK, &rl_save), 1);
- ok(setrlimit(RLIMIT_STACK, &(struct rlimit) { max, rl_save.rlim_max }), 1);
+ ok(setrlimit(RLIMIT_STACK, &(struct rlimit) { max_, rl_save.rlim_max }), 1);
undo++;
ok(m = mmap(0, max, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_GROWSDOWN|MAP_NORESERVE, -1, 0), 1);
ok(sigaction(SIGSEGV, &sa, &sa_save), 1);
undo++;
- asm volatile ("movq %%rsp, %%r10\nmov %0, %%rsp\npush %%r10" : : "g" (m + max) : "r10");
- rsp_save(0);
+ asm volatile (
+ "mov %%rsp, %%r10\n\t"
+ "mov %1, %%rsp\n\t"
+ "sub $8, %%rsp\n\t"
+ "push %%r10"
+ : "=r" (rsp_save_[0]) : "0" (m + max) : "r10");
out_ = fn_(arg_);
asm volatile ("pop %rsp");
ret = 0;
#include <setjmp.h>
#include <signal.h>
#include <string.h>
+#include <unistd.h>
#include <sys/mman.h>
#include <ccan/tap/tap.h>
#include <ccan/altstack/altstack.h>
};
int fail, call1, call2;
char *m_;
-rlim_t max_;
+rlim_t msz_;
#define e(x) (900+(x))
#define seterr(x) (errno = e(x))
#define setcall(x) ((call1 |= !errno ? (x) : 0), (call2 |= errno || out_ ? (x) : 0))
#define getrlimit(...) (fail&getrlimit_ ? (seterr(getrlimit_), -1) : (setcall(getrlimit_), getrlimit(__VA_ARGS__)))
#define mmap(...) (fail&mmap_ ? (seterr(mmap_), (void *)-1) : (setcall(mmap_), mmap(__VA_ARGS__)))
-#define munmap(a, b) (fail&munmap_ ? (seterr(munmap_), -1) : (setcall(munmap_), munmap(m_=(a), max_=(b))))
+#define munmap(a, b) (fail&munmap_ ? (seterr(munmap_), -1) : (setcall(munmap_), munmap(m_=(a), msz_=(b))))
#define setrlimit(...) (fail&setrlimit_ ? (seterr(setrlimit_), -1) : (setcall(setrlimit_), setrlimit(__VA_ARGS__)))
#define sigaltstack(...) (fail&sigaltstack_ ? (seterr(sigaltstack_), -1) : (setcall(sigaltstack_), sigaltstack(__VA_ARGS__)))
#define sigaction(...) (fail&sigaction_ ? (seterr(sigaction_), -1) : (setcall(sigaction_), sigaction(__VA_ARGS__)))
int main(void)
{
- plan_tests(16);
+ long pgsz = sysconf(_SC_PAGESIZE);
+
+ plan_tests(17);
#define chkfail(x, y, z, c1, c2) (call1 = 0, call2 = 0, errno = 0, ok1((fail = x) && (y) && errno == (z) && call1 == (c1) && call2 == (c2)));
#define chkok( y, z, c1, c2) (call1 = 0, call2 = 0, errno = 0, fail = 0, ok1((y) && errno == (z) && call1 == (c1) && call2 == (c2)));
chkfail(munmap_, altstack(8*MiB, wrap, 0, 0) == 1, e(munmap_),
getrlimit_|setrlimit_|mmap_|sigaltstack_|sigaction_,
setrlimit_|sigaltstack_|sigaction_);
- if (fail = 0, munmap(m_, max_) == -1)
+ if (fail = 0, munmap(m_, msz_) == -1)
err(1, "munmap");
chkok( altstack(1*MiB, wrap, (void *) 1000000, 0) == -1, EOVERFLOW,
chkfail(munmap_, altstack(1*MiB, wrap, (void *) 1000000, 0) == -1, EOVERFLOW,
getrlimit_|setrlimit_|mmap_|sigaltstack_|sigaction_,
setrlimit_|sigaltstack_|sigaction_);
- if (fail = 0, munmap(m_, max_) == -1)
+ if (fail = 0, munmap(m_, msz_) == -1)
err(1, "munmap");
- ok1(used > 1*MiB-1*KiB && used < 1*MiB);
+ ok1(altstack_max() == 1*MiB);
+ diag("used: %lu", used);
+ ok1(used >= 1*MiB - pgsz && used <= 1*MiB + pgsz);
char *p;
for(p = altstack_geterr(); *p; p++)
getrlimit_|setrlimit_|mmap_|sigaltstack_|sigaction_,
setrlimit_|munmap_|sigaltstack_|sigaction_);
- ok1(used > 8*MiB-8*KiB && used < 8*MiB);
+ diag("used: %lu", used);
+ ok1(used >= 8*MiB - pgsz && used <= 8*MiB + pgsz);
used = 0;
chkok( altstack(8*MiB, wrap, (void *) 100000, 0) == 0, 0,
used = 1;
altstack_rsp_save();
dn(0);
- ok1(used == 32);
+ diag("used: %lu", used);
+ ok1(used == 32 || used == 40);
return exit_status();
}