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Add torture test for zipos file descriptors

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This change hardens the code for opening /zip/ files using the system
call interface. Thread safety and signal safety has been improved for
file descriptors in general. We now document fixed addresses that are
needed for low level allocations.
This commit is contained in:
Justine Tunney 2022-06-15 16:19:50 -07:00
parent 579080cd4c
commit e466dd0553
44 changed files with 2981 additions and 307 deletions
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40
libc/zipos/get.c
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@ -16,27 +16,15 @@
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/bits/safemacros.internal.h"
#include "libc/calls/calls.h"
#include "libc/calls/internal.h"
#include "libc/calls/strace.internal.h"
#include "libc/calls/struct/stat.h"
#include "libc/dce.h"
#include "libc/errno.h"
#include "libc/intrin/cmpxchg.h"
#include "libc/intrin/kprintf.h"
#include "libc/intrin/pthread.h"
#include "libc/intrin/spinlock.h"
#include "libc/limits.h"
#include "libc/macros.internal.h"
#include "libc/mem/alloca.h"
#include "libc/runtime/runtime.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/auxv.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/o.h"
#include "libc/sysv/consts/prot.h"
#include "libc/sysv/consts/sig.h"
#include "libc/zip.h"
#include "libc/zipos/zipos.internal.h"
@ -63,52 +51,52 @@ static void __zipos_munmap_unneeded(const uint8_t *base, const uint8_t *cdir,
/**
* Returns pointer to zip central directory of current executable.
* @asyncsignalsafe (TODO: verify this)
* @asyncsignalsafe
* @threadsafe
*/
struct Zipos *__zipos_get(void) {
int fd;
char *path;
ssize_t size;
const char *msg;
static bool once;
sigset_t neu, old;
struct Zipos *res;
const char *progpath;
static struct Zipos zipos;
uint8_t *map, *base, *cdir;
static pthread_mutex_t lock;
pthread_mutex_lock(&lock);
if (_cmpxchg(&once, false, true)) {
sigfillset(&neu);
if (!once) {
__zipos_lock();
progpath = GetProgramExecutableName();
if ((fd = open(progpath, O_RDONLY)) != -1) {
if ((size = getfiledescriptorsize(fd)) != SIZE_MAX &&
if ((size = getfiledescriptorsize(fd)) != -1ul &&
(map = mmap(0, size, PROT_READ, MAP_SHARED, fd, 0)) != MAP_FAILED) {
if ((base = FindEmbeddedApe(map, size))) {
size -= base - map;
} else {
base = map;
}
if ((cdir = GetZipCdir(base, size))) {
if ((cdir = GetZipCdir(base, size)) && _cmpxchg(&zipos.map, 0, base)) {
__zipos_munmap_unneeded(base, cdir, map);
zipos.map = base;
zipos.cdir = cdir;
STRACE("__zipos_get(%#s)", progpath);
msg = "ok";
} else {
munmap(map, size);
STRACE("__zipos_get(%#s) → eocd not found", progpath);
msg = "eocd not found";
}
} else {
msg = "map failed";
}
close(fd);
} else {
STRACE("__zipos_get(%#s) → open failed %m", progpath);
msg = "open failed";
}
once = true;
__zipos_unlock();
STRACE("__zipos_get(%#s) → %s% m", progpath, msg);
}
if (zipos.cdir) {
res = &zipos;
} else {
res = 0;
}
pthread_mutex_unlock(&lock);
return res;
}