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Fix bugs in termios library and cleanup code

Browse source 
This change fixes an issue with the tcflow() magic numbers that was
causing bash to freeze up on Linux. While auditing termios polyfills,
several other issues were identified with XNU/BSD compatibility.

Out of an abundance of caution this change undefines as much surface
area from libc/calls/struct/termios.h as possible, so that autoconf
scripts are less likely to detect non-POSIX teletypewriter APIs that
haven't been polyfilled by Cosmopolitan.

This is a *breaking change* for your static archives in /opt/cosmos if
you use the cosmocc toolchain. That's because this change disables the
ioctl() undiamonding trick for code outside the monorepo, specifically
because it'll lead to brittle ABI breakages like this. If you're using
the cosmocc toolchain, you'll need to rebuild libraries like ncurses,
readline, etc. Yes diamonds cause bloat. To work around that, consider
using tcgetwinsize() instead of ioctl(TIOCGWINSZ) since it'll help you
avoid pulling every single ioctl-related polyfill into the linkage.

The cosmocc script was specifying -DNDEBUG for some reason. It's fixed.
This commit is contained in:
Justine Tunney 2023-06-14 17:02:57 -07:00
parent 06b749ae03
commit 4778cd4d27
No known key found for this signature in database
GPG key ID: BE714B4575D6E328
187 changed files with 1025 additions and 1848 deletions
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86
libc/calls/tcflow.c
View file

@ -17,6 +17,7 @@
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/internal.h"
#include "libc/calls/struct/metatermios.internal.h"
#include "libc/calls/struct/termios.h"
#include "libc/calls/syscall-sysv.internal.h"
#include "libc/calls/syscall_support-nt.internal.h"
@ -32,6 +33,13 @@
#define kNtPurgeTxabort 1
#define kNtPurgeRxabort 2
#define TCXONC 0x0000540A // linux
#define TIOCGETA 0x40487413 // bsd
#define TIOCSTOP 0x2000746f // bsd
#define TIOCSTART 0x2000746e // bsd
#define TIOCIXON 0x20007481 // xnu
#define TIOCIXOFF 0x20007480 // xnu
static const char *DescribeFlow(char buf[12], int action) {
if (action == TCOOFF) return "TCOOFF";
if (action == TCOON) return "TCOON";
@ -41,33 +49,61 @@ static const char *DescribeFlow(char buf[12], int action) {
return buf;
}
static int sys_tcflow_bsd(int fd, int action) {
int rc;
uint8_t c;
struct termios t;
if (action == TCOOFF) return sys_ioctl(fd, TIOCSTOP, 0);
if (action == TCOON) return sys_ioctl(fd, TIOCSTART, 0);
if (action != TCIOFF && action != TCION) return einval();
if (sys_ioctl(fd, TCGETS, &t) == -1) return -1;
c = t.c_cc[action == TCIOFF ? VSTOP : VSTART];
if (c == 255) return 0; // code is disabled
if (sys_write(fd, &c, 1) == -1) return -1;
static int sys_tcflow_bsd_write(int fd, int cc) {
unsigned char c;
struct termios_bsd term;
if (sys_ioctl(fd, TIOCGETA, &term) == -1) {
return -1;
}
if ((c = term.c_cc[cc]) != _POSIX_VDISABLE &&
sys_write(fd, &c, sizeof(c)) == -1) {
return -1;
}
return 0;
}
static int sys_tcflow_bsd(int fd, int action) {
switch (action) {
case TCOOFF:
return sys_ioctl(fd, TIOCSTOP, 0);
case TCOON:
return sys_ioctl(fd, TIOCSTART, 0);
case TCION:
if (IsXnu()) {
return sys_ioctl(fd, TIOCIXON, 0);
} else {
return sys_tcflow_bsd_write(fd, VSTART);
}
case TCIOFF:
if (IsXnu()) {
return sys_ioctl(fd, TIOCIXOFF, 0);
} else {
return sys_tcflow_bsd_write(fd, VSTOP);
}
return 0;
default:
return einval();
}
}
static dontinline textwindows int sys_tcflow_nt(int fd, int action) {
bool32 ok;
int64_t h;
if (!__isfdopen(fd)) return ebadf();
h = g_fds.p[fd].handle;
if (action == TCOOFF) {
ok = PurgeComm(h, kNtPurgeTxabort);
} else if (action == TCIOFF) {
ok = PurgeComm(h, kNtPurgeRxabort);
} else if (action == TCOON || action == TCION) {
ok = ClearCommBreak(h);
} else {
return einval();
switch (action) {
case TCOON:
case TCION:
ok = ClearCommBreak(h);
break;
case TCOOFF:
ok = PurgeComm(h, kNtPurgeTxabort);
break;
case TCIOFF:
ok = PurgeComm(h, kNtPurgeRxabort);
break;
default:
return einval();
}
return ok ? 0 : __winerr();
}
@ -92,14 +128,14 @@ static dontinline textwindows int sys_tcflow_nt(int fd, int action) {
*/
int tcflow(int fd, int action) {
int rc;
if (IsMetal()) {
rc = enosys();
if (IsLinux()) {
rc = sys_ioctl(fd, TCXONC, action);
} else if (IsBsd()) {
rc = sys_ioctl(fd, TCXONC, action);
} else if (!IsWindows()) {
rc = sys_ioctl(fd, TCXONC, action);
} else {
rc = sys_tcflow_bsd(fd, action);
} else if (IsWindows()) {
rc = sys_tcflow_nt(fd, action);
} else {
rc = enosys();
}
STRACE("tcflow(%d, %s) → %d% m", fd, DescribeFlow(alloca(12), action), rc);
return rc;