From 46e16383d62990b4b07eac32560ca8abec82b710 Mon Sep 17 00:00:00 2001 From: Lukas Larsson Date: Tue, 21 Jun 2016 14:49:03 +0200 Subject: erts: Improve error printouts in erl_child_setup Add prints to stderr with a small description of the error so that errors will be easier to debug. Also if a protocol error is detected, erl_child_setup will abort instead of exit. --- erts/emulator/sys/unix/erl_child_setup.c | 51 +++++++++++++++++++++++++------- 1 file changed, 40 insertions(+), 11 deletions(-) (limited to 'erts/emulator/sys/unix/erl_child_setup.c') diff --git a/erts/emulator/sys/unix/erl_child_setup.c b/erts/emulator/sys/unix/erl_child_setup.c index 6beb316350..b2263371dd 100644 --- a/erts/emulator/sys/unix/erl_child_setup.c +++ b/erts/emulator/sys/unix/erl_child_setup.c @@ -123,6 +123,7 @@ static int sigchld_pipe[2]; static int start_new_child(int pipes[]) { + int errln = -1; int size, res, i, pos = 0; char *buff, *o_buff; @@ -137,6 +138,7 @@ start_new_child(int pipes[]) } while(res < 0 && (errno == EINTR || errno == ERRNO_BLOCK)); if (res <= 0) { + errln = __LINE__; goto child_error; } @@ -148,10 +150,12 @@ start_new_child(int pipes[]) if ((res = read(pipes[0], buff + pos, size - pos)) < 0) { if (errno == ERRNO_BLOCK || errno == EINTR) continue; + errln = __LINE__; goto child_error; } if (res == 0) { errno = EPIPE; + errln = __LINE__; goto child_error; } pos += res; @@ -201,7 +205,12 @@ start_new_child(int pipes[]) if (o_buff + size != buff) { errno = EINVAL; - goto child_error; + errln = __LINE__; + fprintf(stderr,"erl_child_setup: failed with protocol " + "error %d on line %d", errno, errln); + /* we abort here as it is most likely a symptom of an + emulator/erl_child_setup bug */ + abort(); } DEBUG_PRINT("read ack"); @@ -215,11 +224,17 @@ start_new_child(int pipes[]) } while(res < 0 && (errno == EINTR || errno == ERRNO_BLOCK)); if (res < 1) { errno = EPIPE; + errln = __LINE__; goto child_error; } DEBUG_PRINT("Do that forking business: '%s'\n",cmd); + if (wd && chdir(wd) < 0) { + errln = __LINE__; + goto child_error; + } + /* When the dup2'ing below is done, only fd's 0, 1, 2 and maybe 3, 4 should survive the exec. All other fds (i.e. the unix domain sockets @@ -228,25 +243,34 @@ start_new_child(int pipes[]) if (flags & FORKER_FLAG_USE_STDIO) { /* stdin for process */ if (flags & FORKER_FLAG_DO_WRITE && - dup2(pipes[0], 0) < 0) + dup2(pipes[0], 0) < 0) { + errln = __LINE__; goto child_error; + } /* stdout for process */ if (flags & FORKER_FLAG_DO_READ && - dup2(pipes[1], 1) < 0) + dup2(pipes[1], 1) < 0) { + errln = __LINE__; goto child_error; + } } else { /* XXX will fail if pipes[0] == 4 (unlikely..) */ - if (flags & FORKER_FLAG_DO_READ && dup2(pipes[1], 4) < 0) + if (flags & FORKER_FLAG_DO_READ && dup2(pipes[1], 4) < 0) { + errln = __LINE__; goto child_error; - if (flags & FORKER_FLAG_DO_WRITE && dup2(pipes[0], 3) < 0) + } + if (flags & FORKER_FLAG_DO_WRITE && dup2(pipes[0], 3) < 0) { + errln = __LINE__; goto child_error; + } } - if (dup2(pipes[2], 2) < 0) - goto child_error; - - if (wd && chdir(wd) < 0) + /* we do the dup2 of stderr last so that errors + in child_error will be printed to stderr */ + if (dup2(pipes[2], 2) < 0) { + errln = __LINE__; goto child_error; + } #if defined(USE_SETPGRP_NOARGS) /* SysV */ (void) setpgrp(); @@ -268,9 +292,14 @@ start_new_child(int pipes[]) } else { execle(SHELL, "sh", "-c", cmd, (char *) NULL, new_environ); } + + DEBUG_PRINT("exec error: %d",errno); + _exit(errno); + child_error: - DEBUG_PRINT("exec error: %d\r\n",errno); - _exit(128 + errno); + fprintf(stderr,"erl_child_setup: failed with error %d on line %d", + errno, errln); + _exit(errno); } -- cgit v1.2.3 From 3411d9e13bd8a4b3aee530d8f66b5118e14e447b Mon Sep 17 00:00:00 2001 From: Lukas Larsson Date: Tue, 21 Jun 2016 14:57:37 +0200 Subject: erts: Fix HARD_DEBUG printouts in erl_child_setup --- erts/emulator/sys/unix/erl_child_setup.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) (limited to 'erts/emulator/sys/unix/erl_child_setup.c') diff --git a/erts/emulator/sys/unix/erl_child_setup.c b/erts/emulator/sys/unix/erl_child_setup.c index b2263371dd..219ca98c71 100644 --- a/erts/emulator/sys/unix/erl_child_setup.c +++ b/erts/emulator/sys/unix/erl_child_setup.c @@ -74,7 +74,7 @@ //#define HARD_DEBUG #ifdef HARD_DEBUG -#define DEBUG_PRINT(fmt, ...) fprintf(stderr, fmt "\r\n", ##__VA_ARGS__) +#define DEBUG_PRINT(fmt, ...) fprintf(stderr, "%d:" fmt "\r\n", getpid(), ##__VA_ARGS__) #else #define DEBUG_PRINT(fmt, ...) #endif @@ -129,7 +129,7 @@ start_new_child(int pipes[]) char *cmd, *wd, **new_environ, **args = NULL; - Sint cnt, flags; + Sint32 cnt, flags; /* only child executes here */ @@ -164,7 +164,7 @@ start_new_child(int pipes[]) o_buff = buff; flags = get_int32(buff); - buff += sizeof(Sint32); + buff += sizeof(flags); DEBUG_PRINT("flags = %d", flags); @@ -181,10 +181,10 @@ start_new_child(int pipes[]) DEBUG_PRINT("wd = %s", wd); cnt = get_int32(buff); - buff += sizeof(Sint32); + buff += sizeof(cnt); new_environ = malloc(sizeof(char*)*(cnt + 1)); - DEBUG_PRINT("env_len = %ld", cnt); + DEBUG_PRINT("env_len = %d", cnt); for (i = 0; i < cnt; i++, buff++) { new_environ[i] = buff; while(*buff != '\0') buff++; @@ -194,7 +194,7 @@ start_new_child(int pipes[]) if (o_buff + size != buff) { /* This is a spawn executable call */ cnt = get_int32(buff); - buff += sizeof(Sint32); + buff += sizeof(cnt); args = malloc(sizeof(char*)*(cnt + 1)); for (i = 0; i < cnt; i++, buff++) { args[i] = buff; @@ -228,13 +228,15 @@ start_new_child(int pipes[]) goto child_error; } - DEBUG_PRINT("Do that forking business: '%s'\n",cmd); + DEBUG_PRINT("Set wd to: '%s'",wd); if (wd && chdir(wd) < 0) { errln = __LINE__; goto child_error; } + DEBUG_PRINT("Do that forking business: '%s'",cmd); + /* When the dup2'ing below is done, only fd's 0, 1, 2 and maybe 3, 4 should survive the exec. All other fds (i.e. the unix domain sockets @@ -297,7 +299,7 @@ start_new_child(int pipes[]) _exit(errno); child_error: - fprintf(stderr,"erl_child_setup: failed with error %d on line %d", + fprintf(stderr,"erl_child_setup: failed with error %d on line %d\r\n", errno, errln); _exit(errno); } @@ -490,7 +492,7 @@ main(int argc, char *argv[]) proto.action = ErtsSysForkerProtoAction_SigChld; proto.u.sigchld.error_number = ibuff[1]; - DEBUG_PRINT("send %s to %d", buff, uds_fd); + DEBUG_PRINT("send sigchld to %d (errno = %d)", uds_fd, ibuff[1]); if (write(uds_fd, &proto, sizeof(proto)) < 0) { if (errno == EINTR) continue; -- cgit v1.2.3 From 412d7dfcfb667bb2b329b8e35c929c2b5abcc2b1 Mon Sep 17 00:00:00 2001 From: Lukas Larsson Date: Mon, 27 Jun 2016 18:40:36 +0200 Subject: erts: Fix spawn driver with relative cd option --- erts/emulator/sys/unix/erl_child_setup.c | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-) (limited to 'erts/emulator/sys/unix/erl_child_setup.c') diff --git a/erts/emulator/sys/unix/erl_child_setup.c b/erts/emulator/sys/unix/erl_child_setup.c index 219ca98c71..fa4750a6e9 100644 --- a/erts/emulator/sys/unix/erl_child_setup.c +++ b/erts/emulator/sys/unix/erl_child_setup.c @@ -127,7 +127,7 @@ start_new_child(int pipes[]) int size, res, i, pos = 0; char *buff, *o_buff; - char *cmd, *wd, **new_environ, **args = NULL; + char *cmd, *cwd, *wd, **new_environ, **args = NULL; Sint32 cnt, flags; @@ -170,6 +170,10 @@ start_new_child(int pipes[]) cmd = buff; buff += strlen(buff) + 1; + + cwd = buff; + buff += strlen(buff) + 1; + if (*buff == '\0') { wd = NULL; } else { @@ -222,17 +226,29 @@ start_new_child(int pipes[]) ASSERT(res == sizeof(proto)); } } while(res < 0 && (errno == EINTR || errno == ERRNO_BLOCK)); + if (res < 1) { errno = EPIPE; errln = __LINE__; goto child_error; } + DEBUG_PRINT("Set cwd to: '%s'",cwd); + + if (chdir(cwd) < 0) { + /* This is not good, it probably means that the cwd of + beam is invalid. We ignore it and try anyways as + the child might now need a cwd or the chdir below + could take us to a valid directory. + */ + } + DEBUG_PRINT("Set wd to: '%s'",wd); if (wd && chdir(wd) < 0) { - errln = __LINE__; - goto child_error; + int err = errno; + fprintf(stderr,"spawn: Could not cd to %s\r\n", wd); + _exit(err); } DEBUG_PRINT("Do that forking business: '%s'",cmd); -- cgit v1.2.3