From 2e84a2ab5e0f0c82c2d79f69cd2f4bff762762a4 Mon Sep 17 00:00:00 2001 From: Lukas Larsson Date: Thu, 26 Jun 2014 18:50:51 +0200 Subject: erts: Make tty driver non-blocking Instead of using blocking call to fwrite, the tty driver now uses non-blocking calls to writev and queues any output data that cannot be written into the driver queue. Without this change an stdout write could block an entire scheduler if for some reason the pseudo tty on the other side does not consume the output of the Erlang shell. OTP-12239 --- erts/emulator/drivers/unix/ttsl_drv.c | 130 ++++++++++++++++++++++++++++++---- erts/emulator/sys/unix/sys.c | 23 ++++-- 2 files changed, 135 insertions(+), 18 deletions(-) (limited to 'erts') diff --git a/erts/emulator/drivers/unix/ttsl_drv.c b/erts/emulator/drivers/unix/ttsl_drv.c index 491e0a090e..73ce27c6ec 100644 --- a/erts/emulator/drivers/unix/ttsl_drv.c +++ b/erts/emulator/drivers/unix/ttsl_drv.c @@ -32,6 +32,10 @@ static ErlDrvData ttysl_start(ErlDrvPort, char*); #ifdef HAVE_TERMCAP /* else make an empty driver that can not be opened */ +#ifndef WANT_NONBLOCKING +#define WANT_NONBLOCKING +#endif + #include "sys.h" #include #include @@ -39,6 +43,7 @@ static ErlDrvData ttysl_start(ErlDrvPort, char*); #include #include #include +#include #include #include #include @@ -57,6 +62,14 @@ static ErlDrvData ttysl_start(ErlDrvPort, char*); #include #endif +#if defined IOV_MAX +#define MAXIOV IOV_MAX +#elif defined UIO_MAXIOV +#define MAXIOV UIO_MAXIOV +#else +#define MAXIOV 16 +#endif + #define TRUE 1 #define FALSE 0 @@ -85,7 +98,9 @@ static volatile int cols_needs_update = FALSE; #define CTRL_OP_GET_UNICODE_STATE 101 #define CTRL_OP_SET_UNICODE_STATE 102 - +/* We use 1024 as the buf size as that was the default buf size of FILE streams + on all platforms that I checked. */ +#define TTY_BUFFSIZE 1024 static int lbuf_size = BUFSIZ; static Uint32 *lbuf; /* The current line buffer */ @@ -113,13 +128,18 @@ static int lpos; /* The current "cursor position" in the line buf /* Main interface functions. */ static void ttysl_stop(ErlDrvData); static void ttysl_from_erlang(ErlDrvData, char*, ErlDrvSizeT); +static void ttysl_to_tty(ErlDrvData, ErlDrvEvent); +static void ttysl_flush_tty(ErlDrvData); static void ttysl_from_tty(ErlDrvData, ErlDrvEvent); static void ttysl_stop_select(ErlDrvEvent, void*); static Sint16 get_sint16(char*); static ErlDrvPort ttysl_port; static int ttysl_fd; -static FILE *ttysl_out; +static int ttysl_terminate = 0; +static ErlDrvBinary *putcbuf; +static int putcpos; +static int putclen; /* Functions that work on the line buffer. */ static int start_lbuf(void); @@ -201,22 +221,22 @@ struct erl_drv_entry ttsl_driver_entry = { IF_IMPL(ttysl_stop), IF_IMPL(ttysl_from_erlang), IF_IMPL(ttysl_from_tty), - NULL, - "tty_sl", - NULL, - NULL, + IF_IMPL(ttysl_to_tty), + "tty_sl", /* driver_name */ + NULL, /* finish */ + NULL, /* handle */ IF_IMPL(ttysl_control), NULL, /* timeout */ NULL, /* outputv */ NULL, /* ready_async */ - NULL, /* flush */ + IF_IMPL(ttysl_flush_tty), NULL, /* call */ NULL, /* event */ ERL_DRV_EXTENDED_MARKER, ERL_DRV_EXTENDED_MAJOR_VERSION, ERL_DRV_EXTENDED_MINOR_VERSION, 0, /* ERL_DRV_FLAGs */ - NULL, + NULL, /* handle2 */ NULL, /* process_exit */ IF_IMPL(ttysl_stop_select) }; @@ -296,8 +316,7 @@ static ErlDrvData ttysl_start(ErlDrvPort port, char* buf) return ERL_DRV_ERROR_GENERAL; } - /* Open the terminal and set the terminal */ - ttysl_out = fdopen(ttysl_fd, "w"); + SET_NONBLOCKING(ttysl_fd); #ifdef PRIMITIVE_UTF8_CHECK setlocale(LC_CTYPE, ""); /* Set international environment, @@ -400,12 +419,14 @@ static void ttysl_stop(ErlDrvData ttysl_data) stop_lbuf(); stop_termcap(); tty_reset(ttysl_fd); - driver_select(ttysl_port, (ErlDrvEvent)(UWord)ttysl_fd, ERL_DRV_READ|ERL_DRV_USE, 0); + driver_select(ttysl_port, (ErlDrvEvent)(UWord)ttysl_fd, + ERL_DRV_WRITE|ERL_DRV_READ|ERL_DRV_USE, 0); sys_sigset(SIGCONT, SIG_DFL); sys_sigset(SIGWINCH, SIG_DFL); } ttysl_port = (ErlDrvPort)-1; ttysl_fd = -1; + ttysl_terminate = 0; /* return TRUE; */ } @@ -650,6 +671,14 @@ static int check_buf_size(byte *s, int n) static void ttysl_from_erlang(ErlDrvData ttysl_data, char* buf, ErlDrvSizeT count) { + ErlDrvSizeT sz; + + sz = driver_sizeq(ttysl_port); + + putclen = count > TTY_BUFFSIZE ? TTY_BUFFSIZE : count; + putcbuf = driver_alloc_binary(putclen); + putcpos = 0; + if (lpos > MAXSIZE) put_chars((byte*)"\n", 1); @@ -678,10 +707,78 @@ static void ttysl_from_erlang(ErlDrvData ttysl_data, char* buf, ErlDrvSizeT coun /* Unknown op, just ignore. */ break; } - fflush(ttysl_out); + + driver_enq_bin(ttysl_port,putcbuf,0,putcpos); + + if (sz == 0) { + for (;;) { + int written, qlen; + SysIOVec *iov; + + iov = driver_peekq(ttysl_port,&qlen); + if (iov) + written = writev(ttysl_fd, iov, qlen > MAXIOV ? MAXIOV : qlen); + else + written = 0; + if (written < 0) { + if (errno == EAGAIN) { + driver_select(ttysl_port,(ErlDrvEvent)(long)ttysl_fd, + ERL_DRV_USE|ERL_DRV_WRITE,1); + break; + } else { + /* we ignore all other errors */ + break; + } + } else { + if (driver_deq(ttysl_port, written) == 0) + break; + } + } + } + return; /* TRUE; */ } +static void ttysl_to_tty(ErlDrvData ttysl_data, ErlDrvEvent fd) { + for (;;) { + int written, qlen; + SysIOVec *iov; + ErlDrvSizeT sz; + + iov = driver_peekq(ttysl_port,&qlen); + if (iov) + written = writev(ttysl_fd, iov, qlen > MAXIOV ? MAXIOV : qlen); + else + written = 0; + if (written < 0) { + if (errno == EAGAIN) { + break; + } else { + /* we ignore all other errors */ + } + } else { + sz = driver_deq(ttysl_port, written); + if (sz == 0) { + driver_select(ttysl_port,(ErlDrvEvent)(long)ttysl_fd, + ERL_DRV_WRITE,0); + if (ttysl_terminate) + /* flush has been called, which means we should terminate + when queue is empty. This will not send any exit + message */ + driver_failure_atom(ttysl_port, "normal"); + break; + } + } + } + + return; +} + +static void ttysl_flush_tty(ErlDrvData ttysl_data) { + ttysl_terminate = 1; + return; +} + static void ttysl_from_tty(ErlDrvData ttysl_data, ErlDrvEvent fd) { byte b[1024]; @@ -1070,7 +1167,14 @@ static int write_buf(Uint32 *s, int n) /* The basic procedure for outputting one character. */ static int outc(int c) { - return (int)putc(c, ttysl_out); + putcbuf->orig_bytes[putcpos++] = c; + if (putcpos == putclen) { + driver_enq_bin(ttysl_port,putcbuf,0,putclen); + putcpos = 0; + putclen = TTY_BUFFSIZE; + putcbuf = driver_alloc_binary(BUFSIZ); + } + return 1; } static int move_cursor(int from, int to) diff --git a/erts/emulator/sys/unix/sys.c b/erts/emulator/sys/unix/sys.c index c3d7440409..ad8b60fe7c 100644 --- a/erts/emulator/sys/unix/sys.c +++ b/erts/emulator/sys/unix/sys.c @@ -34,6 +34,7 @@ #include #include #include +#include #ifdef ISC32 #include @@ -2658,18 +2659,30 @@ void sys_preload_end(Preload* p) /* Nothing */ } -/* Read a key from console (?) */ - +/* Read a key from console, used by break.c + Here we assume that all schedulers are stopped so that erl_poll + does not interfere with the select below. +*/ int sys_get_key(fd) int fd; { - int c; + int c, ret; unsigned char rbuf[64]; + fd_set fds; fflush(stdout); /* Flush query ??? */ - if ((c = read(fd,rbuf,64)) <= 0) { - return c; + FD_ZERO(&fds); + FD_SET(fd,&fds); + + ret = select(fd+1, &fds, NULL, NULL, NULL); + + if (ret == 1) { + do { + c = read(fd,rbuf,64); + } while (c < 0 && errno == EAGAIN); + if (c <= 0) + return c; } return rbuf[0]; -- cgit v1.2.3 From 5ab275d6554f4db877624a152dda90c0e3c4cddc Mon Sep 17 00:00:00 2001 From: Lukas Larsson Date: Mon, 30 Jun 2014 17:14:11 +0200 Subject: erts: Make writing to non-tty fds non-blocking If the fd_driver is given non-tty fds it will now use an async thread instead of doing a blocking write. An example of a non-tty fd is the fd used by stderr, but could be anything handed down to the driver. --- erts/emulator/beam/erl_alloc.types | 2 + erts/emulator/sys/unix/sys.c | 230 ++++++++++++++++++++++++++++++++++--- 2 files changed, 217 insertions(+), 15 deletions(-) (limited to 'erts') diff --git a/erts/emulator/beam/erl_alloc.types b/erts/emulator/beam/erl_alloc.types index 17ac6316b7..d23d26a0fc 100644 --- a/erts/emulator/beam/erl_alloc.types +++ b/erts/emulator/beam/erl_alloc.types @@ -411,6 +411,8 @@ type CS_PROG_PATH LONG_LIVED SYSTEM cs_prog_path type ENVIRONMENT TEMPORARY SYSTEM environment type PUTENV_STR SYSTEM SYSTEM putenv_string type PRT_REP_EXIT STANDARD SYSTEM port_report_exit +type SYS_BLOCKING STANDARD SYSTEM sys_blocking +type SYS_WRITE_BUF TEMPORARY SYSTEM sys_write_buf +endif diff --git a/erts/emulator/sys/unix/sys.c b/erts/emulator/sys/unix/sys.c index ad8b60fe7c..eed93cb2a0 100644 --- a/erts/emulator/sys/unix/sys.c +++ b/erts/emulator/sys/unix/sys.c @@ -92,8 +92,10 @@ static erts_smp_rwmtx_t environ_rwmtx; # else # define CHLDWTHR 0 # endif +# define FDBLOCK 1 #else # define CHLDWTHR 0 +# define FDBLOCK 0 #endif /* * [OTP-3906] @@ -122,6 +124,15 @@ struct ErtsSysReportExit_ { #endif }; +/* Used by the fd driver iff the fd could not be set to non-blocking */ +typedef struct ErtsSysBlocking_ { + ErlDrvPDL pdl; + int res; + int err; + unsigned int pkey; +} ErtsSysBlocking; + + /* This data is shared by these drivers - initialized by spawn_init() */ static struct driver_data { ErlDrvPort port_num; @@ -130,6 +141,8 @@ static struct driver_data { int pid; int alive; int status; + int terminating; + ErtsSysBlocking *blocking; } *driver_data; /* indexed by fd */ static ErtsSysReportExit *report_exit_list; @@ -1109,11 +1122,16 @@ void fini_getenv_state(GETENV_STATE *state) /* Driver interfaces */ static ErlDrvData spawn_start(ErlDrvPort, char*, SysDriverOpts*); static ErlDrvData fd_start(ErlDrvPort, char*, SysDriverOpts*); +#if FDBLOCK +static void fd_async(void *); +static void fd_ready_async(ErlDrvData drv_data, ErlDrvThreadData thread_data); +#endif static ErlDrvSSizeT fd_control(ErlDrvData, unsigned int, char *, ErlDrvSizeT, char **, ErlDrvSizeT); static ErlDrvData vanilla_start(ErlDrvPort, char*, SysDriverOpts*); static int spawn_init(void); static void fd_stop(ErlDrvData); +static void fd_flush(ErlDrvData); static void stop(ErlDrvData); static void ready_input(ErlDrvData, ErlDrvEvent); static void ready_output(ErlDrvData, ErlDrvEvent); @@ -1158,8 +1176,12 @@ struct erl_drv_entry fd_driver_entry = { fd_control, NULL, outputv, - NULL, /* ready_async */ - NULL, /* flush */ +#if FDBLOCK + fd_ready_async, /* ready_async */ +#else + NULL, +#endif + fd_flush, /* flush */ NULL, /* call */ NULL, /* event */ ERL_DRV_EXTENDED_MARKER, @@ -1213,13 +1235,28 @@ static RETSIGTYPE onchld(int signum) #endif } +static int set_blocking_data(struct driver_data *dd) { + + dd->blocking = erts_alloc(ERTS_ALC_T_SYS_BLOCKING, sizeof(ErtsSysBlocking)); + + erts_smp_atomic_add_nob(&sys_misc_mem_sz, sizeof(ErtsSysBlocking)); + + dd->blocking->pdl = driver_pdl_create(dd->port_num); + dd->blocking->res = 0; + dd->blocking->err = 0; + dd->blocking->pkey = driver_async_port_key(dd->port_num); + + return 1; +} + static int set_driver_data(ErlDrvPort port_num, int ifd, int ofd, int packet_bytes, int read_write, int exit_status, - int pid) + int pid, + int is_blocking) { Port *prt; ErtsSysReportExit *report_exit; @@ -1251,8 +1288,13 @@ static int set_driver_data(ErlDrvPort port_num, driver_data[ifd].pid = pid; driver_data[ifd].alive = 1; driver_data[ifd].status = 0; + driver_data[ifd].terminating = 0; + driver_data[ifd].blocking = NULL; if (read_write & DO_WRITE) { driver_data[ifd].ofd = ofd; + if (is_blocking && FDBLOCK) + if (!set_blocking_data(driver_data+ifd)) + return -1; if (ifd != ofd) driver_data[ofd] = driver_data[ifd]; /* structure copy */ } else { /* DO_READ only */ @@ -1268,6 +1310,11 @@ static int set_driver_data(ErlDrvPort port_num, driver_data[ofd].pid = pid; driver_data[ofd].alive = 1; driver_data[ofd].status = 0; + driver_data[ofd].terminating = 0; + driver_data[ofd].blocking = NULL; + if (is_blocking && FDBLOCK) + if (!set_blocking_data(driver_data+ofd)) + return -1; return(ofd); } } @@ -1277,6 +1324,7 @@ static int spawn_init() int i; #if CHLDWTHR erts_thr_opts_t thr_opts = ERTS_THR_OPTS_DEFAULT_INITER; + thr_opts.detached = 0; thr_opts.suggested_stack_size = 0; /* Smallest possible */ #endif @@ -1756,7 +1804,7 @@ static ErlDrvData spawn_start(ErlDrvPort port_num, char* name, SysDriverOpts* op } res = set_driver_data(port_num, ifd[0], ofd[1], opts->packet_bytes, - opts->read_write, opts->exit_status, pid); + opts->read_write, opts->exit_status, pid, 0); /* Don't unblock SIGCHLD until now, since the call above must first complete putting away the info about our new subprocess. */ unblock_signals(); @@ -1841,6 +1889,7 @@ static ErlDrvData fd_start(ErlDrvPort port_num, char* name, SysDriverOpts* opts) { ErlDrvData res; + int non_blocking = 0; if (((opts->read_write & DO_READ) && opts->ifd >= max_files) || ((opts->read_write & DO_WRITE) && opts->ofd >= max_files)) @@ -1913,6 +1962,20 @@ static ErlDrvData fd_start(ErlDrvPort port_num, char* name, * case - it can be called with any old pre-existing file descriptors, * the relations between which (if they're even two) we can only guess * at - still, we try our best... + * + * Added note OTP 18: Some systems seem to use stdout/stderr to log data + * using unix pipes, so we cannot allow the system to block on a write. + * Therefore we use an async thread to write the data to fd's that could + * not be set to non-blocking. When no async threads are available we + * fall back on the old behaviour. + * + * Also the guarantee about what is delivered to the OS has changed. + * Pre 18 the fd driver did no flushing of data before terminating. + * Now it does. This is because we want to be able to guarantee that things + * such as escripts and friends really have outputted all data before + * terminating. This could potentially block the termination of the system + * for a very long time, but if the user wants to terminate fast she should + * use erlang:halt with flush=false. */ if (opts->read_write & DO_READ) { @@ -1935,6 +1998,7 @@ static ErlDrvData fd_start(ErlDrvPort port_num, char* name, imagine a scenario where setting non-blocking mode here would cause problems - go ahead and do it. */ + non_blocking = 1; SET_NONBLOCKING(opts->ofd); } else { /* output fd is a tty, input fd isn't */ @@ -1977,6 +2041,7 @@ static ErlDrvData fd_start(ErlDrvPort port_num, char* name, (nfd = open(tty, O_WRONLY)) != -1) { dup2(nfd, opts->ofd); close(nfd); + non_blocking = 1; SET_NONBLOCKING(opts->ofd); } } @@ -1985,8 +2050,9 @@ static ErlDrvData fd_start(ErlDrvPort port_num, char* name, } CHLD_STAT_LOCK; res = (ErlDrvData)(long)set_driver_data(port_num, opts->ifd, opts->ofd, - opts->packet_bytes, - opts->read_write, 0, -1); + opts->packet_bytes, + opts->read_write, 0, -1, + !non_blocking); CHLD_STAT_UNLOCK; return res; } @@ -2012,14 +2078,30 @@ static void nbio_stop_fd(ErlDrvPort prt, int fd) SET_BLOCKING(fd); } -static void fd_stop(ErlDrvData fd) /* Does not close the fds */ +static void fd_stop(ErlDrvData ev) /* Does not close the fds */ { int ofd; + int fd = (int)(long)ev; + ErlDrvPort prt = driver_data[fd].port_num; - nbio_stop_fd(driver_data[(int)(long)fd].port_num, (int)(long)fd); - ofd = driver_data[(int)(long)fd].ofd; - if (ofd != (int)(long)fd && ofd != -1) - nbio_stop_fd(driver_data[(int)(long)fd].port_num, (int)(long)ofd); +#if FDBLOCK + if (driver_data[fd].blocking) { + erts_free(ERTS_ALC_T_SYS_BLOCKING,driver_data[fd].blocking); + driver_data[fd].blocking = NULL; + erts_smp_atomic_add_nob(&sys_misc_mem_sz, -1*sizeof(ErtsSysBlocking)); + } +#endif + + nbio_stop_fd(prt, fd); + ofd = driver_data[fd].ofd; + if (ofd != fd && ofd != -1) + nbio_stop_fd(prt, ofd); +} + +static void fd_flush(ErlDrvData fd) +{ + if (!driver_data[(int)(long)fd].terminating) + driver_data[(int)(long)fd].terminating = 1; } static ErlDrvData vanilla_start(ErlDrvPort port_num, char* name, @@ -2042,8 +2124,8 @@ static ErlDrvData vanilla_start(ErlDrvPort port_num, char* name, CHLD_STAT_LOCK; res = (ErlDrvData)(long)set_driver_data(port_num, fd, fd, - opts->packet_bytes, - opts->read_write, 0, -1); + opts->packet_bytes, + opts->read_write, 0, -1, 0); CHLD_STAT_UNLOCK; return res; } @@ -2080,6 +2162,7 @@ static void stop(ErlDrvData fd) } } +/* used by fd_driver */ static void outputv(ErlDrvData e, ErlIOVec* ev) { int fd = (int)(long)e; @@ -2105,12 +2188,21 @@ static void outputv(ErlDrvData e, ErlIOVec* ev) ev->iov[0].iov_base = lbp; ev->iov[0].iov_len = pb; ev->size += pb; + + if (driver_data[fd].blocking && FDBLOCK) + driver_pdl_lock(driver_data[fd].blocking->pdl); + if ((sz = driver_sizeq(ix)) > 0) { driver_enqv(ix, ev, 0); + + if (driver_data[fd].blocking && FDBLOCK) + driver_pdl_unlock(driver_data[fd].blocking->pdl); + if (sz + ev->size >= (1 << 13)) set_busy_port(ix, 1); } - else { + else if (!driver_data[fd].blocking || !FDBLOCK) { + /* We try to write directly if the fd in non-blocking */ int vsize = ev->vsize > MAX_VSIZE ? MAX_VSIZE : ev->vsize; n = writev(ofd, (const void *) (ev->iov), vsize); @@ -2126,10 +2218,22 @@ static void outputv(ErlDrvData e, ErlIOVec* ev) driver_enqv(ix, ev, n); /* n is the skip value */ driver_select(ix, ofd, ERL_DRV_WRITE|ERL_DRV_USE, 1); } +#if FDBLOCK + else { + if (ev->size != 0) { + driver_enqv(ix, ev, 0); + driver_pdl_unlock(driver_data[fd].blocking->pdl); + driver_async(ix, &driver_data[fd].blocking->pkey, + fd_async, driver_data+fd, NULL); + } else { + driver_pdl_unlock(driver_data[fd].blocking->pdl); + } + } +#endif /* return 0;*/ } - +/* Used by spawn_driver and vanilla driver */ static void output(ErlDrvData e, char* buf, ErlDrvSizeT len) { int fd = (int)(long)e; @@ -2192,6 +2296,23 @@ static int port_inp_failure(ErlDrvPort port_num, int ready_fd, int res) ASSERT(res <= 0); (void) driver_select(port_num, ready_fd, ERL_DRV_READ|ERL_DRV_WRITE, 0); clear_fd_data(ready_fd); + + if (driver_data[ready_fd].blocking && FDBLOCK) { + driver_pdl_lock(driver_data[ready_fd].blocking->pdl); + if (driver_sizeq(driver_data[ready_fd].port_num) > 0) { + driver_pdl_unlock(driver_data[ready_fd].blocking->pdl); + /* We have stuff in the output queue, so we just + set the state to terminating and wait for fd_async_ready + to terminate the port */ + if (res == 0) + driver_data[ready_fd].terminating = 2; + else + driver_data[ready_fd].terminating = -err; + return 0; + } + driver_pdl_unlock(driver_data[ready_fd].blocking->pdl); + } + if (res == 0) { if (driver_data[ready_fd].report_exit) { CHLD_STAT_LOCK; @@ -2242,6 +2363,7 @@ static void ready_input(ErlDrvData e, ErlDrvEvent ready_fd) port_num = driver_data[fd].port_num; packet_bytes = driver_data[fd].packet_bytes; + if (packet_bytes == 0) { byte *read_buf = (byte *) erts_alloc(ERTS_ALC_T_SYS_READ_BUF, ERTS_SYS_READ_BUF_SZ); @@ -2365,6 +2487,8 @@ static void ready_output(ErlDrvData e, ErlDrvEvent ready_fd) if ((iv = (struct iovec*) driver_peekq(ix, &vsize)) == NULL) { driver_select(ix, ready_fd, ERL_DRV_WRITE, 0); + if (driver_data[fd].terminating) + driver_failure_atom(driver_data[fd].port_num,"normal"); return; /* 0; */ } vsize = vsize > MAX_VSIZE ? MAX_VSIZE : vsize; @@ -2390,6 +2514,82 @@ static void stop_select(ErlDrvEvent fd, void* _) close((int)fd); } +#if FDBLOCK + +static void +fd_async(void *async_data) +{ + int res; + struct driver_data *dd = (struct driver_data*)async_data; + SysIOVec *iov0; + SysIOVec *iov; + int iovlen; + int iovcnt; + int p; + /* much of this code is stolen from efile_drv:invoke_writev */ + driver_pdl_lock(dd->blocking->pdl); + iov0 = driver_peekq(dd->port_num, &iovlen); + /* Calculate iovcnt */ + for (p = 0, iovcnt = 0; iovcnt < iovlen; + p += iov0[iovcnt++].iov_len) + ; + iov = erts_alloc_fnf(ERTS_ALC_T_SYS_WRITE_BUF, + sizeof(SysIOVec)*iovcnt); + if (!iov) { + res = -1; + errno = ENOMEM; + erts_free(ERTS_ALC_T_SYS_WRITE_BUF, iov); + driver_pdl_unlock(dd->blocking->pdl); + } else { + memcpy(iov,iov0,iovcnt*sizeof(SysIOVec)); + driver_pdl_unlock(dd->blocking->pdl); + + res = writev(dd->ofd, iov, iovlen); + + erts_free(ERTS_ALC_T_SYS_WRITE_BUF, iov); + } + dd->blocking->res = res; + dd->blocking->err = errno; +} + +void fd_ready_async(ErlDrvData drv_data, + ErlDrvThreadData thread_data) { + struct driver_data *dd = (struct driver_data *)thread_data; + ErlDrvPort port_num = dd->port_num; + + ASSERT(dd->blocking); + ASSERT(dd == (driver_data + (int)(long)drv_data)); + + if (dd->blocking->res > 0) { + driver_pdl_lock(dd->blocking->pdl); + if (driver_deq(port_num, dd->blocking->res) == 0) { + driver_pdl_unlock(dd->blocking->pdl); + set_busy_port(port_num, 0); + if (dd->terminating) { + /* The port is has been ordered to terminate + from either fd_flush or port_inp_failure */ + if (dd->terminating == 1) + driver_failure_atom(port_num, "normal"); + else if (dd->terminating == 2) + driver_failure_eof(port_num); + else if (dd->terminating < 0) + driver_failure_posix(port_num, -dd->terminating); + return; /* -1; */ + } + } else { + driver_pdl_unlock(dd->blocking->pdl); + /* still data left to write in queue */ + driver_async(port_num, &dd->blocking->pkey, fd_async, dd, NULL); + return /* 0; */; + } + } else if (dd->blocking->res < 0) { + driver_failure_posix(port_num, dd->blocking->err); + return; /* -1; */ + } + return; /* 0; */ +} + +#endif void erts_do_break_handling(void) { -- cgit v1.2.3 From 48083e54b502afb2768066394074d29423162dc8 Mon Sep 17 00:00:00 2001 From: Lukas Larsson Date: Thu, 26 Jun 2014 18:55:47 +0200 Subject: kernel,ssh: Add synchronous user_drv protocol Added a put_chars_sync to the protocol that can be used to talk to user_drv and made group use it. This is needed in order to guarantee that bytes has been pushed to the tty port when doing something like this: io:format("halting\n"),erlang:halt(0). Before this change the halting message could be lost in the message queue of the user_drv process, this is no longer possible. This commit also fixes ssh_cli as that plugs itself in as a user_drv process. OTP-12240 --- erts/emulator/drivers/unix/ttsl_drv.c | 36 ++++++++++++++++++++++++++++++++++ erts/emulator/drivers/win32/ttsl_drv.c | 16 +++++++++++++++ 2 files changed, 52 insertions(+) (limited to 'erts') diff --git a/erts/emulator/drivers/unix/ttsl_drv.c b/erts/emulator/drivers/unix/ttsl_drv.c index 73ce27c6ec..be2fee1f25 100644 --- a/erts/emulator/drivers/unix/ttsl_drv.c +++ b/erts/emulator/drivers/unix/ttsl_drv.c @@ -93,6 +93,7 @@ static volatile int cols_needs_update = FALSE; #define OP_INSC 2 #define OP_DELC 3 #define OP_BEEP 4 +#define OP_PUTC_SYNC 5 /* Control op */ #define CTRL_OP_GET_WINSIZE 100 #define CTRL_OP_GET_UNICODE_STATE 101 @@ -137,6 +138,7 @@ static Sint16 get_sint16(char*); static ErlDrvPort ttysl_port; static int ttysl_fd; static int ttysl_terminate = 0; +static int ttysl_send_ok = 0; static ErlDrvBinary *putcbuf; static int putcpos; static int putclen; @@ -683,6 +685,14 @@ static void ttysl_from_erlang(ErlDrvData ttysl_data, char* buf, ErlDrvSizeT coun put_chars((byte*)"\n", 1); switch (buf[0]) { + case OP_PUTC_SYNC: + /* Using sync means that we have to send an ok to the + controlling process for each command call. We delay + sending ok if the driver queue exceeds a certain size. + We do not set ourselves as a busy port, as this + could be very bad for user_drv, if it gets blocked on + the port_command. */ + /* fall through */ case OP_PUTC: DEBUGLOG(("OP: Putc(%lu)",(unsigned long) count-1)); if (check_buf_size((byte*)buf+1, count-1) == 0) @@ -736,6 +746,22 @@ static void ttysl_from_erlang(ErlDrvData ttysl_data, char* buf, ErlDrvSizeT coun } } + if (buf[0] == OP_PUTC_SYNC) { + if (driver_sizeq(ttysl_port) > TTY_BUFFSIZE && !ttysl_terminate) { + /* We delay sending the ack until the buffer has been consumed */ + ttysl_send_ok = 1; + } else { + ErlDrvTermData spec[] = { + ERL_DRV_PORT, driver_mk_port(ttysl_port), + ERL_DRV_ATOM, driver_mk_atom("ok"), + ERL_DRV_TUPLE, 2 + }; + ASSERT(ttysl_send_ok == 0); + erl_drv_output_term(driver_mk_port(ttysl_port), spec, + sizeof(spec) / sizeof(spec[0])); + } + } + return; /* TRUE; */ } @@ -758,6 +784,16 @@ static void ttysl_to_tty(ErlDrvData ttysl_data, ErlDrvEvent fd) { } } else { sz = driver_deq(ttysl_port, written); + if (sz < TTY_BUFFSIZE && ttysl_send_ok) { + ErlDrvTermData spec[] = { + ERL_DRV_PORT, driver_mk_port(ttysl_port), + ERL_DRV_ATOM, driver_mk_atom("ok"), + ERL_DRV_TUPLE, 2 + }; + ttysl_send_ok = 0; + erl_drv_output_term(driver_mk_port(ttysl_port), spec, + sizeof(spec) / sizeof(spec[0])); + } if (sz == 0) { driver_select(ttysl_port,(ErlDrvEvent)(long)ttysl_fd, ERL_DRV_WRITE,0); diff --git a/erts/emulator/drivers/win32/ttsl_drv.c b/erts/emulator/drivers/win32/ttsl_drv.c index 502cb58dfa..851c336a11 100644 --- a/erts/emulator/drivers/win32/ttsl_drv.c +++ b/erts/emulator/drivers/win32/ttsl_drv.c @@ -46,6 +46,7 @@ static int rows; /* Number of rows available. */ #define OP_INSC 2 #define OP_DELC 3 #define OP_BEEP 4 +#define OP_PUTC_SYNC 5 /* Control op */ #define CTRL_OP_GET_WINSIZE 100 @@ -458,6 +459,7 @@ static void ttysl_from_erlang(ErlDrvData ttysl_data, char* buf, ErlDrvSizeT coun switch (buf[0]) { case OP_PUTC: + case OP_PUTC_SYNC: DEBUGLOG(("OP: Putc(%I64u)",(unsigned long long)count-1)); if (check_buf_size((byte*)buf+1, count-1) == 0) return; @@ -481,6 +483,20 @@ static void ttysl_from_erlang(ErlDrvData ttysl_data, char* buf, ErlDrvSizeT coun /* Unknown op, just ignore. */ break; } + + if (buf[0] == OP_PUTC_SYNC) { + /* On windows we do a blocking write to the tty so we just + send the ack immidiately. If at some point in the future + someone has a problem with tty output being blocking + this has to be changed. */ + ErlDrvTermData spec[] = { + ERL_DRV_PORT, driver_mk_port(ttysl_port), + ERL_DRV_ATOM, driver_mk_atom("ok"), + ERL_DRV_TUPLE, 2 + }; + erl_drv_output_term(driver_mk_port(ttysl_port), spec, + sizeof(spec) / sizeof(spec[0])); + } return; } -- cgit v1.2.3