From 0ad8c5f46bc0173c09fa5e7e91f917de82389068 Mon Sep 17 00:00:00 2001 From: Lukas Larsson Date: Fri, 11 Sep 2015 16:35:48 +0200 Subject: erts: Move os_pid to port hash to child setup Had to move the hashing because of a race that can otherwise happen where a new os_pid value was inserted into the hash before the previous value had been removed. Also replaced the protocol inbetween erts and child setup to be a binary protocol. This was done in order to deal with the varying size of Eterm. --- erts/emulator/sys/unix/sys_drivers.c | 211 +++++++++++------------------------ 1 file changed, 66 insertions(+), 145 deletions(-) (limited to 'erts/emulator/sys/unix/sys_drivers.c') diff --git a/erts/emulator/sys/unix/sys_drivers.c b/erts/emulator/sys/unix/sys_drivers.c index 6a1f2f6b2c..82096e5779 100644 --- a/erts/emulator/sys/unix/sys_drivers.c +++ b/erts/emulator/sys/unix/sys_drivers.c @@ -76,6 +76,8 @@ static Eterm forker_port; #include "erl_sys_driver.h" #include "sys_uds.h" +#include "erl_child_setup.h" + #if defined IOV_MAX #define MAXIOV IOV_MAX #elif defined UIO_MAXIOV @@ -120,12 +122,6 @@ typedef struct driver_data { ErtsSysBlocking *blocking; } ErtsSysDriverData; -typedef struct exit_status { - HashBucket hb; - pid_t os_pid; - Eterm port_id; -} ErtsSysExitStatus; - #define DIR_SEPARATOR_CHAR '/' #if defined(__ANDROID__) @@ -241,21 +237,18 @@ static void outputv(ErlDrvData, ErlIOVec*); static void stop_select(ErlDrvEvent, void*); /* II.V Forker prototypes */ -static int forker_init(void); static ErlDrvData forker_start(ErlDrvPort, char*, SysDriverOpts*); static void forker_stop(ErlDrvData); static void forker_ready_input(ErlDrvData, ErlDrvEvent); static void forker_ready_output(ErlDrvData, ErlDrvEvent); static ErlDrvSSizeT forker_control(ErlDrvData, unsigned int, char *, ErlDrvSizeT, char **, ErlDrvSizeT); -static void forker_add_os_pid_mapping(ErtsSysDriverData *); -static void forker_remove_os_pid_mapping(ErtsSysDriverData *); /* III Driver entries */ /* III.I The spawn driver */ struct erl_drv_entry spawn_driver_entry = { - forker_init, + NULL, spawn_start, stop, output, @@ -794,12 +787,16 @@ static ErlDrvData spawn_start(ErlDrvPort port_num, char* name, { /* send ofd[0] + ifd[1] + stderrfd to forker port */ - int *fds = erts_alloc(ERTS_ALC_T_DRV_CTRL_DATA, sizeof(int)*3); - memset(fds, 0, sizeof(int)*3); - fds[0] = ofd[0]; - fds[1] = ifd[1]; - fds[2] = stderrfd; - if (erl_drv_port_control(forker_port, 'S', (char*)fds, sizeof(int)*3)) { + ErtsSysForkerProto *proto = + erts_alloc(ERTS_ALC_T_DRV_CTRL_DATA, + sizeof(ErtsSysForkerProto)); + memset(proto, 0, sizeof(ErtsSysForkerProto)); + proto->action = ErtsSysForkerProtoAction_Start; + proto->u.start.fds[0] = ofd[0]; + proto->u.start.fds[1] = ifd[1]; + proto->u.start.fds[2] = stderrfd; + proto->u.start.port_id = opts->exit_status ? erts_drvport2id(port_num) : THE_NON_VALUE; + if (erl_drv_port_control(forker_port, 'S', (char*)proto, sizeof(*proto))) { /* The forker port has been killed, we close both fd's which will make open_port throw an epipe error */ close(ofd[0]); @@ -824,8 +821,12 @@ static ErlDrvSSizeT spawn_control(ErlDrvData e, unsigned int cmd, char *buf, ErlDrvSizeT len, char **rbuf, ErlDrvSizeT rlen) { ErtsSysDriverData *dd = (ErtsSysDriverData*)e; + ErtsSysForkerProto *proto = (ErtsSysForkerProto *)buf; - memcpy(&dd->status, buf, sizeof(dd->status)); + ASSERT(len == sizeof(*proto)); + ASSERT(proto->action == ErtsSysForkerProtoAction_SigChld); + + dd->status = proto->u.sigchld.error_number; dd->alive = -1; if (dd->ifd) @@ -1134,10 +1135,6 @@ static void stop(ErlDrvData ev) ErtsSysDriverData* dd = (ErtsSysDriverData*)ev; ErlDrvPort prt = dd->port_num; - if (dd->alive == 1) - /* Stop has been called before the exit status has been reported */ - forker_remove_os_pid_mapping(dd); - if (dd->ifd) { nbio_stop_fd(prt, dd->ifd); driver_select(prt, abs(dd->ifd->fd), ERL_DRV_USE, 0); /* close(ifd); */ @@ -1354,10 +1351,10 @@ static void ready_input(ErlDrvData e, ErlDrvEvent ready_fd) if (dd->pid == 0) { /* the pid is sent from erl_child_setup. spawn driver only. */ - char message_buffer[3 + 10 + 1 + 10 + 1]; - int reason, res; + ErtsSysForkerProto proto; + int res; - if((res = read(ready_fd, message_buffer, sizeof(message_buffer))) <= 0) { + if((res = read(ready_fd, &proto, sizeof(proto))) <= 0) { /* hmm, child setup seems to have closed the pipe too early... we close the port as there is not much else we can do */ if (res < 0 && errno == ERRNO_BLOCK) @@ -1369,21 +1366,25 @@ static void ready_input(ErlDrvData e, ErlDrvEvent ready_fd) return; } - if(sscanf(message_buffer,"GO:%010d:%010d", &dd->pid, &reason) == 2) { - if (dd->pid == -1) { - /* Setup failed! The only reason why this should happen is if - the fork fails. */ - errno = reason; - port_inp_failure(dd, -1); - return; - } + ASSERT(proto.action == ErtsSysForkerProtoAction_Go); + dd->pid = proto.u.go.os_pid; + + if (dd->pid == -1) { + /* Setup failed! The only reason why this should happen is if + the fork fails. */ + errno = proto.u.go.error_number; + port_inp_failure(dd, -1); + return; + } + + proto.action = ErtsSysForkerProtoAction_Ack; - if (driver_sizeq(port_num) > 0) { - driver_enq(port_num, "A", 1); + if (driver_sizeq(port_num) > 0) { + driver_enq(port_num, (char*)&proto, sizeof(proto)); } else { - if (write(abs(dd->ofd->fd), "A", 1) < 0) + if (write(abs(dd->ofd->fd), &proto, sizeof(proto)) < 0) if (errno == ERRNO_BLOCK || errno == EINTR) - driver_enq(port_num, "A", 1); + driver_enq(port_num, (char*)&proto, sizeof(proto)); /* do nothing on failure here. If the ofd is broken, then the ifd will probably also be broken and trigger a port_inp_failure */ @@ -1400,15 +1401,9 @@ static void ready_input(ErlDrvData e, ErlDrvEvent ready_fd) child setup will close this fd if fd < 0 */ driver_select(port_num, abs(dd->ofd->fd), ERL_DRV_WRITE|ERL_DRV_USE, 1); - if (dd->alive == 1) - forker_add_os_pid_mapping(dd); - erl_drv_set_os_pid(port_num, dd->pid); erl_drv_init_ack(port_num, e); return; - } - ASSERT(0); - return; } if (packet_bytes == 0) { @@ -1652,10 +1647,6 @@ void fd_ready_async(ErlDrvData drv_data, /* Forker driver */ static int forker_fd; -static Hash *forker_hash; -static erts_smp_mtx_t forker_hash_mtx; - -static void ffree(void *e); static ErlDrvData forker_start(ErlDrvPort port_num, char* name, SysDriverOpts* opts) @@ -1749,16 +1740,18 @@ static ErlDrvData forker_start(ErlDrvPort port_num, char* name, static void forker_stop(ErlDrvData e) { - /* we probably should do something here */ + /* we probably should do something here, + the port has been closed by the user. */ } static void forker_ready_input(ErlDrvData e, ErlDrvEvent fd) { - int res, *exit_status; - char buff[8+10+1+10+1] = {0}; - ErtsSysExitStatus est, *es; + int res; + ErtsSysForkerProto *proto; + + proto = erts_alloc(ERTS_ALC_T_DRV_CTRL_DATA, sizeof(*proto)); - if ((res = read(fd, buff, sizeof(buff))) < 0) { + if ((res = read(fd, proto, sizeof(*proto))) < 0) { if (errno == ERRNO_BLOCK) return; erl_exit(ERTS_DUMP_EXIT, "Failed to read from erl_child_setup: %d\n", errno); @@ -1767,26 +1760,15 @@ static void forker_ready_input(ErlDrvData e, ErlDrvEvent fd) if (res == 0) erl_exit(ERTS_DUMP_EXIT, "erl_child_setup closed\n"); - if (sscanf(buff, "SIGCHLD:%010d:%010d", &est.os_pid, &res) != 2) - erl_exit(ERTS_DUMP_EXIT, "Got corrupt data from erl_child_setup: %.s\n", - buff, sizeof(buff)); - - erts_smp_mtx_lock(&forker_hash_mtx); - es = hash_remove(forker_hash, &est); - erts_smp_mtx_unlock(&forker_hash_mtx); + ASSERT(res == sizeof(*proto)); + ASSERT(proto->action == ErtsSysForkerProtoAction_SigChld); - if (!es) - return; - - exit_status = erts_alloc(ERTS_ALC_T_DRV_CTRL_DATA, sizeof(int)); - exit_status[0] = res; /* ideally this would be a port_command call, but as command is already used by the spawn_driver, we use control instead. Note that when using erl_drv_port_control it is an asynchronous control. */ - erl_drv_port_control(es->port_id, 'S', (char*)exit_status, sizeof(int)); - - ffree(es); + erl_drv_port_control(proto->u.sigchld.port_id, 'S', + (char*)proto, sizeof(*proto)); } @@ -1797,18 +1779,19 @@ static void forker_ready_output(ErlDrvData e, ErlDrvEvent fd) while(driver_sizeq(port_num) > 0) { int vlen; SysIOVec *iov = driver_peekq(port_num, &vlen); - int *fds = (int*)iov[0].iov_base; - ASSERT(iov[0].iov_len >= sizeof(int)*3); - if (sys_uds_write(forker_fd, "S", 1, fds, 3, 0) < 0) { + ErtsSysForkerProto *proto = (ErtsSysForkerProto *)iov[0].iov_base; + ASSERT(iov[0].iov_len >= (sizeof(*proto))); + if (sys_uds_write(forker_fd, (char*)proto, sizeof(*proto), + proto->u.start.fds, 3, 0) < 0) { if (errno == ERRNO_BLOCK) return; erl_exit(ERTS_DUMP_EXIT, "Failed to write to erl_child_setup: %d\n", errno); } - close(fds[0]); - close(fds[1]); - if (fds[1] != fds[2]) - close(fds[2]); - driver_deq(port_num, sizeof(int)*3); + close(proto->u.start.fds[0]); + close(proto->u.start.fds[1]); + if (proto->u.start.fds[1] != proto->u.start.fds[2]) + close(proto->u.start.fds[2]); + driver_deq(port_num, sizeof(*proto)); } driver_select(port_num, forker_fd, ERL_DRV_WRITE, 0); @@ -1817,7 +1800,7 @@ static void forker_ready_output(ErlDrvData e, ErlDrvEvent fd) static ErlDrvSSizeT forker_control(ErlDrvData e, unsigned int cmd, char *buf, ErlDrvSizeT len, char **rbuf, ErlDrvSizeT rlen) { - int *fds = (int*)buf; + ErtsSysForkerProto *proto = (ErtsSysForkerProto *)buf; ErlDrvPort port_num = (ErlDrvPort)e; int res; @@ -1826,7 +1809,8 @@ static ErlDrvSSizeT forker_control(ErlDrvData e, unsigned int cmd, char *buf, return 0; } - if ((res = sys_uds_write(forker_fd, "S", 1, fds, 3, 0)) < 0) { + if ((res = sys_uds_write(forker_fd, (char*)proto, sizeof(*proto), + proto->u.start.fds, 3, 0)) < 0) { if (errno == ERRNO_BLOCK) { driver_enq(port_num, buf, len); driver_select(port_num, forker_fd, ERL_DRV_WRITE|ERL_DRV_USE, 1); @@ -1834,74 +1818,11 @@ static ErlDrvSSizeT forker_control(ErlDrvData e, unsigned int cmd, char *buf, } erl_exit(ERTS_DUMP_EXIT, "Failed to write to erl_child_setup: %d\n", errno); } - close(fds[0]); - close(fds[1]); - if (fds[1] != fds[2]) - close(fds[2]); - return 0; -} -static void forker_add_os_pid_mapping(ErtsSysDriverData *dd) -{ - Eterm port_id = erts_drvport2id(dd->port_num); - ErtsSysExitStatus es; - es.os_pid = dd->pid; - es.port_id = port_id; - erts_smp_mtx_lock(&forker_hash_mtx); - hash_put(forker_hash, &es); - erts_smp_mtx_unlock(&forker_hash_mtx); -} - -static void forker_remove_os_pid_mapping(ErtsSysDriverData *dd) -{ - ErtsSysExitStatus est, *es; - est.os_pid = dd->pid; - erts_smp_mtx_lock(&forker_hash_mtx); - es = hash_remove(forker_hash, &est); - erts_smp_mtx_unlock(&forker_hash_mtx); - if (es) - ffree(es); -} - -static int fcmp(void *a, void *b) -{ - ErtsSysExitStatus *sa = a; - ErtsSysExitStatus *sb = b; - return !(sa->os_pid == sb->os_pid); -} - -static HashValue fhash(void *e) -{ - ErtsSysExitStatus *se = e; - return make_hash2(make_small(se->os_pid)); -} - -static void *falloc(void *e) -{ - ErtsSysExitStatus *se = e; - ErtsSysExitStatus *ne = erts_alloc(ERTS_ALC_T_DRV, sizeof(ErtsSysExitStatus)); - erts_smp_atomic_add_nob(&sys_misc_mem_sz, sizeof(ErtsSysBlocking)); - ne->os_pid = se->os_pid; - ne->port_id = se->port_id; - return ne; -} - -static void ffree(void *e) -{ - erts_free(ERTS_ALC_T_DRV, e); - erts_smp_atomic_add_nob(&sys_misc_mem_sz, -sizeof(ErtsSysBlocking)); -} - -static int forker_init(void) -{ - HashFunctions forker_hash_functions; - forker_hash_functions.hash = fhash; - forker_hash_functions.cmp = fcmp; - forker_hash_functions.alloc = falloc; - forker_hash_functions.free = ffree; - forker_hash = hash_new(ERTS_ALC_T_DRV, "forker_hash", - 16, forker_hash_functions); - erts_smp_mtx_init(&forker_hash_mtx, "forker_hash_mtx"); - - return 1; + ASSERT(res == sizeof(*proto)); + close(proto->u.start.fds[0]); + close(proto->u.start.fds[1]); + if (proto->u.start.fds[1] != proto->u.start.fds[2]) + close(proto->u.start.fds[2]); + return 0; } -- cgit v1.2.3