From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sc8-sf-mx1-b.sourceforge.net ([10.3.1.91] helo=mail.sourceforge.net) by sc8-sf-list1-new.sourceforge.net with esmtp (Exim 4.43) id 1J0P1A-0005nO-8m for user-mode-linux-devel@lists.sourceforge.net; Thu, 06 Dec 2007 14:16:28 -0800 Received: from mx1.wp.pl ([212.77.101.5]) by mail.sourceforge.net with esmtps (TLSv1:AES256-SHA:256) (Exim 4.44) id 1J0P17-0004SR-P3 for user-mode-linux-devel@lists.sourceforge.net; Thu, 06 Dec 2007 14:16:26 -0800 From: Stanislaw Gruszka Date: Thu, 6 Dec 2007 23:21:24 +0100 References: <200712051853.45801.stf_xl@wp.pl> <20071206013920.GA10961@c2.user-mode-linux.org> In-Reply-To: <20071206013920.GA10961@c2.user-mode-linux.org> MIME-Version: 1.0 Content-Disposition: inline Message-Id: <200712062321.25013.stf_xl@wp.pl> Subject: Re: [uml-devel] [PATCH] Avoid not intended gdb breakpoints removal List-Id: The user-mode Linux development list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: user-mode-linux-devel-bounces@lists.sourceforge.net Errors-To: user-mode-linux-devel-bounces@lists.sourceforge.net To: Jeff Dike Cc: user-mode-linux-devel@lists.sourceforge.net On Thursday 06 December 2007 02:39, Jeff Dike wrote: > This has bugged me forever, and I was too scared to go into gdb to > figure out what its problem was. :-) I considered "debugging a debugger" as something strange but doable. > A couple of comments: > 1 - I think I would prefer to use __WCLONE instead of __WALL since > we know what type of process we are creating, and it seems clearer in > the code to say specifically what we want I removed __WALL where possible. Some functions still use it, because must wait for any kind of child. > 1a - I think I would like to stick all those waits under some API in > helper.c as we already have an interface for creating children, and as > it stands now, the callers have knowlege about the internal aspects of > child creation that they probably shouldn't. Ok, I changed a little helper_wait() function and use it for drivers. Signed-off-by: Stanislaw Gruszka --- diff --git a/arch/um/drivers/net_user.c b/arch/um/drivers/net_user.c index 90d7f2e..29185ca 100644 --- a/arch/um/drivers/net_user.c +++ b/arch/um/drivers/net_user.c @@ -201,7 +201,7 @@ static int change_tramp(char **argv, char *output, int output_len) close(fds[1]); if (pid > 0) - CATCH_EINTR(err = waitpid(pid, NULL, 0)); + helper_wait(pid, 0, "change_tramp"); return pid; } diff --git a/arch/um/drivers/slip_user.c b/arch/um/drivers/slip_user.c index 5f06204..a97d942 100644 --- a/arch/um/drivers/slip_user.c +++ b/arch/um/drivers/slip_user.c @@ -109,15 +109,7 @@ static int slip_tramp(char **argv, int fd) read_output(fds[0], output, output_len); printk("%s", output); - CATCH_EINTR(err = waitpid(pid, &status, 0)); - if (err < 0) - err = errno; - else if (!WIFEXITED(status) || (WEXITSTATUS(status) != 0)) { - printk(UM_KERN_ERR "'%s' didn't exit with status 0\n", argv[0]); - err = -EINVAL; - } - else err = 0; - + err = helper_wait(pid, 0, argv[0]); close(fds[0]); out_free: diff --git a/arch/um/drivers/slirp_user.c b/arch/um/drivers/slirp_user.c index 1865089..89c1be2 100644 --- a/arch/um/drivers/slirp_user.c +++ b/arch/um/drivers/slirp_user.c @@ -79,7 +79,7 @@ out: static void slirp_close(int fd, void *data) { struct slirp_data *pri = data; - int status,err; + int err; close(fd); close(pri->slave); @@ -98,18 +98,9 @@ static void slirp_close(int fd, void *data) "(%d)\n", pri->pid, errno); } #endif - - CATCH_EINTR(err = waitpid(pri->pid, &status, WNOHANG)); - if (err < 0) { - printk(UM_KERN_ERR "slirp_close: waitpid returned %d\n", errno); - return; - } - - if (err == 0) { - printk(UM_KERN_ERR "slirp_close: process %d has not exited\n", - pri->pid); + err = helper_wait(pri->pid, 1, "slirp_close"); + if (err < 0) return; - } pri->pid = -1; } diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c diff --git a/arch/um/drivers/ubd_user.c b/arch/um/drivers/ubd_user.c index 41d254b..48fc745 100644 --- a/arch/um/drivers/ubd_user.c +++ b/arch/um/drivers/ubd_user.c @@ -49,8 +49,7 @@ int start_io_thread(unsigned long sp, int *fd_out) goto out_close; } - pid = clone(io_thread, (void *) sp, CLONE_FILES | CLONE_VM | SIGCHLD, - NULL); + pid = clone(io_thread, (void *) sp, CLONE_FILES | CLONE_VM, NULL); if(pid < 0){ err = -errno; printk("start_io_thread - clone failed : errno = %d\n", errno); diff --git a/arch/um/include/os.h b/arch/um/include/os.h index fbf0a87..6f0d1c7 100644 --- a/arch/um/include/os.h +++ b/arch/um/include/os.h @@ -214,7 +214,7 @@ extern int execvp_noalloc(char *buf, const char *file, char *const argv[]); extern int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv); extern int run_helper_thread(int (*proc)(void *), void *arg, unsigned int flags, unsigned long *stack_out); -extern int helper_wait(int pid); +extern int helper_wait(int pid, int nohang, char *pname); /* tls.c */ diff --git a/arch/um/os-Linux/aio.c b/arch/um/os-Linux/aio.c index 4158118..93dc0c8 100644 --- a/arch/um/os-Linux/aio.c +++ b/arch/um/os-Linux/aio.c @@ -218,7 +218,7 @@ static int init_aio_24(void) goto out_close_pipe; err = run_helper_thread(not_aio_thread, NULL, - CLONE_FILES | CLONE_VM | SIGCHLD, &aio_stack); + CLONE_FILES | CLONE_VM, &aio_stack); if (err < 0) goto out_close_pipe; @@ -254,7 +254,7 @@ static int init_aio_26(void) } err = run_helper_thread(aio_thread, NULL, - CLONE_FILES | CLONE_VM | SIGCHLD, &aio_stack); + CLONE_FILES | CLONE_VM, &aio_stack); if (err < 0) return err; diff --git a/arch/um/os-Linux/drivers/ethertap_user.c b/arch/um/os-Linux/drivers/ethertap_user.c index 4ff5536..07ca0cb 100644 --- a/arch/um/os-Linux/drivers/ethertap_user.c +++ b/arch/um/os-Linux/drivers/ethertap_user.c @@ -94,7 +94,7 @@ static int etap_tramp(char *dev, char *gate, int control_me, int control_remote, int data_me, int data_remote) { struct etap_pre_exec_data pe_data; - int pid, status, err, n; + int pid, err, n; char version_buf[sizeof("nnnnn\0")]; char data_fd_buf[sizeof("nnnnnn\0")]; char gate_buf[sizeof("nnn.nnn.nnn.nnn\0")]; @@ -131,13 +131,7 @@ static int etap_tramp(char *dev, char *gate, int control_me, } if (c != 1) { printk(UM_KERN_ERR "etap_tramp : uml_net failed\n"); - err = -EINVAL; - CATCH_EINTR(n = waitpid(pid, &status, 0)); - if (n < 0) - err = -errno; - else if (!WIFEXITED(status) || (WEXITSTATUS(status) != 1)) - printk(UM_KERN_ERR "uml_net didn't exit with " - "status 1\n"); + err = helper_wait(pid, 0, "uml_net"); } return err; } diff --git a/arch/um/os-Linux/drivers/tuntap_user.c b/arch/um/os-Linux/drivers/tuntap_user.c index 6c55d3c..7b38289 100644 --- a/arch/um/os-Linux/drivers/tuntap_user.c +++ b/arch/um/os-Linux/drivers/tuntap_user.c @@ -107,7 +107,7 @@ static int tuntap_open_tramp(char *gate, int *fd_out, int me, int remote, "errno = %d\n", errno); return err; } - CATCH_EINTR(waitpid(pid, NULL, 0)); + helper_wait(pid, 0, "tuntap_open_tramp"); cmsg = CMSG_FIRSTHDR(&msg); if (cmsg == NULL) { diff --git a/arch/um/os-Linux/helper.c b/arch/um/os-Linux/helper.c index 7a72dbb..813b15d 100644 --- a/arch/um/os-Linux/helper.c +++ b/arch/um/os-Linux/helper.c @@ -76,7 +76,7 @@ int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv) data.fd = fds[1]; data.buf = __cant_sleep() ? kmalloc(PATH_MAX, UM_GFP_ATOMIC) : kmalloc(PATH_MAX, UM_GFP_KERNEL); - pid = clone(helper_child, (void *) sp, CLONE_VM | SIGCHLD, &data); + pid = clone(helper_child, (void *) sp, CLONE_VM, &data); if (pid < 0) { ret = -errno; printk("run_helper : clone failed, errno = %d\n", errno); @@ -101,7 +101,7 @@ int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv) ret = n; kill(pid, SIGKILL); } - CATCH_EINTR(waitpid(pid, NULL, 0)); + CATCH_EINTR(waitpid(pid, NULL, __WCLONE)); } out_free2: @@ -126,7 +126,7 @@ int run_helper_thread(int (*proc)(void *), void *arg, unsigned int flags, return -ENOMEM; sp = stack + UM_KERN_PAGE_SIZE - sizeof(void *); - pid = clone(proc, (void *) sp, flags | SIGCHLD, arg); + pid = clone(proc, (void *) sp, flags, arg); if (pid < 0) { err = -errno; printk("run_helper_thread : clone failed, errno = %d\n", @@ -134,7 +134,7 @@ int run_helper_thread(int (*proc)(void *), void *arg, unsigned int flags, return err; } if (stack_out == NULL) { - CATCH_EINTR(pid = waitpid(pid, &status, 0)); + CATCH_EINTR(pid = waitpid(pid, &status, __WCLONE)); if (pid < 0) { err = -errno; printk("run_helper_thread - wait failed, errno = %d\n", @@ -150,14 +150,29 @@ int run_helper_thread(int (*proc)(void *), void *arg, unsigned int flags, return pid; } -int helper_wait(int pid) +int helper_wait(int pid, int nohang, char *pname) { - int ret; + int ret, status; + int wflags = __WCLONE; - CATCH_EINTR(ret = waitpid(pid, NULL, WNOHANG)); + if (nohang) + wflags |= WNOHANG; + + if (!pname) + pname = "helper_wait"; + + CATCH_EINTR(ret = waitpid(pid, &status, wflags)); if (ret < 0) { - ret = -errno; - printk("helper_wait : waitpid failed, errno = %d\n", errno); - } - return ret; + printk("%s : waitpid process %d failed, errno = %d\n", + pname, pid, errno); + return -errno; + } else if (nohang && ret == 0) { + printk("%s : process %d has not exited\n", pname, pid); + return -ECHILD; + } else if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) { + printk(UM_KERN_ERR "%s : process %d didn't exit with status 0\n", + pname, pid); + return -ECHILD; + } else + return 0; } diff --git a/arch/um/os-Linux/process.c b/arch/um/os-Linux/process.c index 37781db..bda5c31 100644 --- a/arch/um/os-Linux/process.c +++ b/arch/um/os-Linux/process.c @@ -101,7 +101,7 @@ void os_kill_process(int pid, int reap_child) { kill(pid, SIGKILL); if (reap_child) - CATCH_EINTR(waitpid(pid, NULL, 0)); + CATCH_EINTR(waitpid(pid, NULL, __WALL)); } /* This is here uniquely to have access to the userspace errno, i.e. the one @@ -130,7 +130,7 @@ void os_kill_ptraced_process(int pid, int reap_child) ptrace(PTRACE_KILL, pid); ptrace(PTRACE_CONT, pid); if (reap_child) - CATCH_EINTR(waitpid(pid, NULL, 0)); + CATCH_EINTR(waitpid(pid, NULL, __WALL)); } /* Don't use the glibc version, which caches the result in TLS. It misses some diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c index d77c81d..e8b7a97 100644 --- a/arch/um/os-Linux/skas/process.c +++ b/arch/um/os-Linux/skas/process.c @@ -64,7 +64,7 @@ void wait_stub_done(int pid) int n, status, err; while (1) { - CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED)); + CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED | __WALL)); if ((n < 0) || !WIFSTOPPED(status)) goto bad_wait; @@ -153,7 +153,7 @@ static void handle_trap(int pid, struct uml_pt_regs *regs, panic("handle_trap - continuing to end of syscall " "failed, errno = %d\n", errno); - CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED)); + CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED | __WALL)); if ((err < 0) || !WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP + 0x80)) { err = ptrace_dump_regs(pid); @@ -255,16 +255,18 @@ int start_userspace(unsigned long stub_stack) panic("start_userspace : mmap failed, errno = %d", errno); sp = (unsigned long) stack + UM_KERN_PAGE_SIZE - sizeof(void *); - flags = CLONE_FILES | SIGCHLD; + flags = CLONE_FILES; if (proc_mm) flags |= CLONE_VM; + else + flags |= SIGCHLD; pid = clone(userspace_tramp, (void *) sp, flags, (void *) stub_stack); if (pid < 0) panic("start_userspace : clone failed, errno = %d", errno); do { - CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED)); + CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED | __WALL)); if (n < 0) panic("start_userspace : wait failed, errno = %d", errno); @@ -314,7 +316,7 @@ void userspace(struct uml_pt_regs *regs) "pid=%d, ptrace operation = %d, errno = %d\n", pid, op, errno); - CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED)); + CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED | __WALL)); if (err < 0) panic("userspace - waitpid failed, errno = %d\n", errno); diff --git a/arch/um/os-Linux/start_up.c b/arch/um/os-Linux/start_up.c diff --git a/arch/um/os-Linux/util.c b/arch/um/os-Linux/util.c index ef09543..3e058ce 100644 --- a/arch/um/os-Linux/util.c +++ b/arch/um/os-Linux/util.c @@ -141,7 +141,7 @@ void os_dump_core(void) * nothing reasonable to do if that fails. */ - while ((pid = waitpid(-1, NULL, WNOHANG)) > 0) + while ((pid = waitpid(-1, NULL, WNOHANG | __WALL)) > 0) os_kill_ptraced_process(pid, 0); abort(); ------------------------------------------------------------------------- SF.Net email is sponsored by: Check out the new SourceForge.net Marketplace. 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