diff options
Diffstat (limited to 'runtime/staprun/mainloop.c')
| -rw-r--r-- | runtime/staprun/mainloop.c | 628 |
1 files changed, 330 insertions, 298 deletions
diff --git a/runtime/staprun/mainloop.c b/runtime/staprun/mainloop.c index a7b919cb..6fc061ae 100644 --- a/runtime/staprun/mainloop.c +++ b/runtime/staprun/mainloop.c @@ -12,6 +12,9 @@ #include "staprun.h" #include <sys/utsname.h> +#include <sys/ptrace.h> +#include <wordexp.h> + /* globals */ int ncpus; @@ -22,172 +25,192 @@ static int use_old_transport = 0; static void *signal_thread(void *arg) { - sigset_t *s = (sigset_t *) arg; - int signum, rc, btype = STP_EXIT; - - while (1) { - if (sigwait(s, &signum) < 0) { - _perr("sigwait"); - continue; - } - dbug(2, "sigproc %d (%s)\n", signum, strsignal(signum)); - if (signum == SIGQUIT) - cleanup_and_exit(1); - else if (signum == SIGINT || signum == SIGHUP || signum == SIGTERM) { - // send STP_EXIT - rc = write(control_channel, &btype, sizeof(btype)); - break; - } - } - return NULL; + sigset_t *s = (sigset_t *) arg; + int signum, rc, btype = STP_EXIT; + + while (1) { + if (sigwait(s, &signum) < 0) { + _perr("sigwait"); + continue; + } + dbug(2, "sigproc %d (%s)\n", signum, strsignal(signum)); + if (signum == SIGQUIT) + cleanup_and_exit(1); + else if (signum == SIGINT || signum == SIGHUP || signum == SIGTERM) { + // send STP_EXIT + rc = write(control_channel, &btype, sizeof(btype)); + break; + } + } + return NULL; } static void chld_proc(int signum) { - int32_t rc, btype = STP_EXIT; - dbug(2, "chld_proc %d (%s)\n", signum, strsignal(signum)); - pid_t pid = waitpid(-1, NULL, WNOHANG); - if (pid != target_pid) - return; - // send STP_EXIT - rc = write(control_channel, &btype, sizeof(btype)); + int32_t rc, btype = STP_EXIT; + dbug(2, "chld_proc %d (%s)\n", signum, strsignal(signum)); + pid_t pid = waitpid(-1, NULL, WNOHANG); + if (pid != target_pid) + return; + // send STP_EXIT + rc = write(control_channel, &btype, sizeof(btype)); } static void setup_main_signals(void) { - pthread_t tid; - struct sigaction sa; - sigset_t *s = malloc(sizeof(*s)); - if (!s) { - _perr("malloc failed"); - exit(1); - } - sigfillset(s); - pthread_sigmask(SIG_SETMASK, s, NULL); - memset(&sa, 0, sizeof(sa)); - sigfillset(&sa.sa_mask); - sa.sa_handler = SIG_IGN; - sigaction(SIGINT, &sa, NULL); - sigaction(SIGTERM, &sa, NULL); - sigaction(SIGHUP, &sa, NULL); - sigaction(SIGQUIT, &sa, NULL); - - sa.sa_handler = chld_proc; - sigaction(SIGCHLD, &sa, NULL); - - sigemptyset(s); - sigaddset(s, SIGINT); - sigaddset(s, SIGTERM); - sigaddset(s, SIGHUP); - sigaddset(s, SIGQUIT); - pthread_sigmask(SIG_SETMASK, s, NULL); - if (pthread_create(&tid, NULL, signal_thread, s) < 0) { - _perr("failed to create thread"); - exit(1); - } + pthread_t tid; + struct sigaction sa; + sigset_t *s = malloc(sizeof(*s)); + if (!s) { + _perr("malloc failed"); + exit(1); + } + sigfillset(s); + pthread_sigmask(SIG_SETMASK, s, NULL); + memset(&sa, 0, sizeof(sa)); + sigfillset(&sa.sa_mask); + sa.sa_handler = SIG_IGN; + sigaction(SIGINT, &sa, NULL); + sigaction(SIGTERM, &sa, NULL); + sigaction(SIGHUP, &sa, NULL); + sigaction(SIGQUIT, &sa, NULL); + + sa.sa_handler = chld_proc; + sigaction(SIGCHLD, &sa, NULL); + + sigemptyset(s); + sigaddset(s, SIGINT); + sigaddset(s, SIGTERM); + sigaddset(s, SIGHUP); + sigaddset(s, SIGQUIT); + pthread_sigmask(SIG_SETMASK, s, NULL); + if (pthread_create(&tid, NULL, signal_thread, s) < 0) { + _perr("failed to create thread"); + exit(1); + } } -/* - * start_cmd forks the command given on the command line - * with the "-c" option. It will not exec that command - * until it received signal SIGUSR1. We do it this way because - * we must have the pid of the forked command so it can be set to - * the module and made available internally as _stp_target. - * SIGUSR1 is sent from stp_main_loop() below when it receives - * STP_START from the module. +/* + * start_cmd forks the command given on the command line with the "-c" + * option. It will wait just at the cusp of the exec until we get the + * signal from the kernel to let it run. We do it this way because we + * must have the pid of the forked command so it can be set to the + * module and made available internally as _stp_target. PTRACE_DETACH + * is sent from stp_main_loop() below when it receives STP_START from + * the module. */ void start_cmd(void) { - pid_t pid; - sigset_t usrset; - struct sigaction a; - - sigemptyset(&usrset); - sigaddset(&usrset, SIGUSR1); - pthread_sigmask(SIG_BLOCK, &usrset, NULL); - - /* if we are execing a target cmd, ignore ^C in stapio */ - /* and let the target cmd get it. */ - sigemptyset(&a.sa_mask); - a.sa_flags = 0; - a.sa_handler = SIG_IGN; - sigaction(SIGINT, &a, NULL); - - dbug(1, "execing target_cmd %s\n", target_cmd); - if ((pid = fork()) < 0) { - _perr("fork"); - exit(1); - } else if (pid == 0) { - int signum; - - a.sa_handler = SIG_DFL; - sigaction(SIGINT, &a, NULL); - - /* commands we fork need to run at normal priority */ - setpriority(PRIO_PROCESS, 0, 0); - - /* wait here until signaled */ - sigwait(&usrset, &signum); - - if (execl("/bin/sh", "sh", "-c", target_cmd, NULL) < 0) - perror(target_cmd); - _exit(1); - } - target_pid = pid; + pid_t pid; + struct sigaction a; + + /* if we are execing a target cmd, ignore ^C in stapio */ + /* and let the target cmd get it. */ + sigemptyset(&a.sa_mask); + a.sa_flags = 0; + a.sa_handler = SIG_IGN; + sigaction(SIGINT, &a, NULL); + + if ((pid = fork()) < 0) { + _perr("fork"); + exit(1); + } else if (pid == 0) { + /* We're in the target process. Let's start the execve of target_cmd, */ + int rc; + wordexp_t words; + + a.sa_handler = SIG_DFL; + sigaction(SIGINT, &a, NULL); + + /* Formerly, we just execl'd(sh,-c,$target_cmd). But this does't + work well if target_cmd is a shell builtin. We really want to + probe a new child process, not a mishmash of shell-interpreted + stuff. */ + rc = wordexp (target_cmd, & words, WRDE_NOCMD); + if (rc != 0) { _perr ("wordexp parsing error"); _exit (1); } + if (words.we_wordc < 1) { _perr ("empty target_cmd"); _exit (1); } + + rc = ptrace (PTRACE_TRACEME, 0, 0, 0); + if (rc < 0) perror ("ptrace me"); + +#if 0 + dbug(1, "blocking briefly\n"); + raise (SIGCONT); /* Harmless; just passes control to parent. */ +#endif + + dbug(1, "execing target_cmd %s\n", target_cmd); + + /* Note that execvp() is not a direct system call; it does a $PATH + search in glibc. We would like to filter out these dummy syscalls + from the utrace events seen by scripts. */ + if (execvp (words.we_wordv[0], words.we_wordv) < 0) + perror(target_cmd); + + /* (There is no need to wordfree() words; they are or will be gone.) */ + + _exit(1); + } else { + /* We're in the parent. The child will parse target_cmd and execv() + the result. It will be stopped thereabouts and send us a SIGTRAP. */ + target_pid = pid; + int status; + waitpid (target_pid, &status, 0); + dbug(1, "waited for target_cmd %s pid %d status %x\n", target_cmd, target_pid, (unsigned) status); + } } -/** +/** * system_cmd() executes system commands in response * to an STP_SYSTEM message from the module. These * messages are sent by the system() systemtap function. */ void system_cmd(char *cmd) { - pid_t pid; - - dbug(2, "system %s\n", cmd); - if ((pid = fork()) < 0) { - _perr("fork"); - } else if (pid == 0) { - setpriority(PRIO_PROCESS, 0, 0); - if (execl("/bin/sh", "sh", "-c", cmd, NULL) < 0) - perr("%s", cmd); - _exit(1); - } + pid_t pid; + + dbug(2, "system %s\n", cmd); + if ((pid = fork()) < 0) { + _perr("fork"); + } else if (pid == 0) { + setpriority(PRIO_PROCESS, 0, 0); + if (execl("/bin/sh", "sh", "-c", cmd, NULL) < 0) + perr("%s", cmd); + _exit(1); + } } /* This is only used in the old relayfs code */ static void read_buffer_info(void) { - char buf[PATH_MAX]; - struct statfs st; - int fd, len, ret; - - if (!use_old_transport) - return; - - if (statfs("/sys/kernel/debug", &st) == 0 && (int)st.f_type == (int)DEBUGFS_MAGIC) - return; - - if (sprintf_chk(buf, "/proc/systemtap/%s/bufsize", modname)) - return; - fd = open(buf, O_RDONLY); - if (fd < 0) - return; - - len = read(fd, buf, sizeof(buf)); - if (len <= 0) { - perr("Couldn't read bufsize"); - close(fd); - return; - } - ret = sscanf(buf, "%u,%u", &n_subbufs, &subbuf_size); - if (ret != 2) - perr("Couldn't read bufsize"); - - dbug(2, "n_subbufs= %u, size=%u\n", n_subbufs, subbuf_size); - close(fd); - return; + char buf[PATH_MAX]; + struct statfs st; + int fd, len, ret; + + if (!use_old_transport) + return; + + if (statfs("/sys/kernel/debug", &st) == 0 && (int)st.f_type == (int)DEBUGFS_MAGIC) + return; + + if (sprintf_chk(buf, "/proc/systemtap/%s/bufsize", modname)) + return; + fd = open(buf, O_RDONLY); + if (fd < 0) + return; + + len = read(fd, buf, sizeof(buf)); + if (len <= 0) { + perr("Couldn't read bufsize"); + close(fd); + return; + } + ret = sscanf(buf, "%u,%u", &n_subbufs, &subbuf_size); + if (ret != 2) + perr("Couldn't read bufsize"); + + dbug(2, "n_subbufs= %u, size=%u\n", n_subbufs, subbuf_size); + close(fd); + return; } /** @@ -198,79 +221,79 @@ static void read_buffer_info(void) */ int init_stapio(void) { - dbug(2, "init_stapio\n"); - - /* create control channel */ - use_old_transport = init_ctl_channel(modname, 1); - if (use_old_transport < 0) { - err("Failed to initialize control channel.\n"); - return -1; - } - read_buffer_info(); - - if (attach_mod) { - dbug(2, "Attaching\n"); - if (use_old_transport) { - if (init_oldrelayfs() < 0) { - close_ctl_channel(); - return -1; - } - } else { - if (init_relayfs() < 0) { - close_ctl_channel(); - return -1; - } - } - return 0; - } - - /* fork target_cmd if requested. */ - /* It will not actually exec until signalled. */ - if (target_cmd) - start_cmd(); - - return 0; + dbug(2, "init_stapio\n"); + + /* create control channel */ + use_old_transport = init_ctl_channel(modname, 1); + if (use_old_transport < 0) { + err("Failed to initialize control channel.\n"); + return -1; + } + read_buffer_info(); + + if (attach_mod) { + dbug(2, "Attaching\n"); + if (use_old_transport) { + if (init_oldrelayfs() < 0) { + close_ctl_channel(); + return -1; + } + } else { + if (init_relayfs() < 0) { + close_ctl_channel(); + return -1; + } + } + return 0; + } + + /* fork target_cmd if requested. */ + /* It will not actually exec until signalled. */ + if (target_cmd) + start_cmd(); + + return 0; } /* cleanup_and_exit() closed channels, frees memory, * removes the module (if necessary) and exits. */ void cleanup_and_exit(int detach) { - pid_t err; - static int exiting = 0; - - if (exiting) - return; - exiting = 1; - - setup_main_signals(); - - dbug(1, "detach=%d\n", detach); - - /* what about child processes? we will wait for them here. */ - err = waitpid(-1, NULL, WNOHANG); - if (err >= 0) - err("\nWaiting for processes to exit\n"); - while (wait(NULL) > 0) ; - - if (use_old_transport) - close_oldrelayfs(detach); - else - close_relayfs(); - - dbug(1, "closing control channel\n"); - close_ctl_channel(); - - if (detach) { - err("\nDisconnecting from systemtap module.\n" "To reconnect, type \"staprun -A %s\"\n", modname); - } else { - dbug(2, "removing %s\n", modname); - if (execl(BINDIR "/staprun", "staprun", "-d", modname, NULL) < 0) { - perror(modname); - _exit(1); - } - } - _exit(0); + pid_t err; + static int exiting = 0; + + if (exiting) + return; + exiting = 1; + + setup_main_signals(); + + dbug(1, "detach=%d\n", detach); + + /* what about child processes? we will wait for them here. */ + err = waitpid(-1, NULL, WNOHANG); + if (err >= 0) + err("\nWaiting for processes to exit\n"); + while (wait(NULL) > 0) ; + + if (use_old_transport) + close_oldrelayfs(detach); + else + close_relayfs(); + + dbug(1, "closing control channel\n"); + close_ctl_channel(); + + if (detach) { + err("\nDisconnecting from systemtap module.\n" "To reconnect, type \"staprun -A %s\"\n", modname); + } else { + dbug(2, "removing %s\n", modname); + if (execl(BINDIR "/staprun", "staprun", "-d", modname, NULL) < 0) { + perror(modname); + _exit(1); + } + } + _exit(0); } /** @@ -279,97 +302,106 @@ void cleanup_and_exit(int detach) int stp_main_loop(void) { - ssize_t nb; - void *data; - uint32_t type; - FILE *ofp = stdout; - char recvbuf[8196]; - - setvbuf(ofp, (char *)NULL, _IOLBF, 0); - setup_main_signals(); - dbug(2, "in main loop\n"); - - send_request(STP_READY, NULL, 0); - - /* handle messages from control channel */ - while (1) { - nb = read(control_channel, recvbuf, sizeof(recvbuf)); - dbug(2, "nb=%d\n", (int)nb); - if (nb <= 0) { - if (errno != EINTR) - _perr("Unexpected EOF in read (nb=%ld)", (long)nb); - continue; - } - - type = *(uint32_t *) recvbuf; - data = (void *)(recvbuf + sizeof(uint32_t)); - nb -= sizeof(uint32_t); - - switch (type) { + ssize_t nb; + void *data; + uint32_t type; + FILE *ofp = stdout; + char recvbuf[8196]; + + setvbuf(ofp, (char *)NULL, _IOLBF, 0); + setup_main_signals(); + dbug(2, "in main loop\n"); + + send_request(STP_READY, NULL, 0); + + /* handle messages from control channel */ + while (1) { + nb = read(control_channel, recvbuf, sizeof(recvbuf)); + dbug(2, "nb=%d\n", (int)nb); + if (nb <= 0) { + if (errno != EINTR) + _perr("Unexpected EOF in read (nb=%ld)", (long)nb); + continue; + } + + type = *(uint32_t *) recvbuf; + data = (void *)(recvbuf + sizeof(uint32_t)); + nb -= sizeof(uint32_t); + + switch (type) { #ifdef STP_OLD_TRANSPORT - case STP_REALTIME_DATA: - { - ssize_t bw = write(out_fd[0], data, nb); - if (bw >= 0 && bw != nb) { - nb = nb - bw; - bw = write(out_fd[0], data, nb); - } - if (bw != nb) { - _perr("write error (nb=%ld)", (long)nb); - cleanup_and_exit(0); - } - break; - } + case STP_REALTIME_DATA: + { + ssize_t bw = write(out_fd[0], data, nb); + if (bw >= 0 && bw != nb) { + nb = nb - bw; + bw = write(out_fd[0], data, nb); + } + if (bw != nb) { + _perr("write error (nb=%ld)", (long)nb); + cleanup_and_exit(0); + } + break; + } #endif - case STP_OOB_DATA: - fputs((char *)data, stderr); - break; - case STP_EXIT: - { - /* module asks us to unload it and exit */ - dbug(2, "got STP_EXIT\n"); - cleanup_and_exit(0); - break; - } - case STP_START: - { - struct _stp_msg_start *t = (struct _stp_msg_start *)data; - dbug(2, "probe_start() returned %d\n", t->res); - if (t->res < 0) { - if (target_cmd) - kill(target_pid, SIGKILL); - cleanup_and_exit(0); - } else if (target_cmd) - kill(target_pid, SIGUSR1); - break; - } - case STP_SYSTEM: - { - struct _stp_msg_cmd *c = (struct _stp_msg_cmd *)data; - dbug(2, "STP_SYSTEM: %s\n", c->cmd); - system_cmd(c->cmd); - break; - } - case STP_TRANSPORT: - { - struct _stp_msg_start ts; - if (use_old_transport) { - if (init_oldrelayfs() < 0) - cleanup_and_exit(0); - } else { - if (init_relayfs() < 0) - cleanup_and_exit(0); - } - ts.target = target_pid; - send_request(STP_START, &ts, sizeof(ts)); - if (load_only) - cleanup_and_exit(1); - break; - } - default: - err("WARNING: ignored message of type %d\n", (type)); - } - } - fclose(ofp); - return 0; + case STP_OOB_DATA: + fputs((char *)data, stderr); + break; + case STP_EXIT: + { + /* module asks us to unload it and exit */ + dbug(2, "got STP_EXIT\n"); + cleanup_and_exit(0); + break; + } + case STP_START: + { + struct _stp_msg_start *t = (struct _stp_msg_start *)data; + dbug(2, "probe_start() returned %d\n", t->res); + if (t->res < 0) { + if (target_cmd) + kill(target_pid, SIGKILL); + cleanup_and_exit(0); + } else if (target_cmd) { + dbug(1, "detaching pid %d\n", target_pid); + int rc = ptrace (PTRACE_DETACH, target_pid, 0, 0); + if (rc < 0) + { + perror ("ptrace detach"); + if (target_cmd) + kill(target_pid, SIGKILL); + cleanup_and_exit(0); + } + } + break; + } + case STP_SYSTEM: + { + struct _stp_msg_cmd *c = (struct _stp_msg_cmd *)data; + dbug(2, "STP_SYSTEM: %s\n", c->cmd); + system_cmd(c->cmd); + break; + } + case STP_TRANSPORT: + { + struct _stp_msg_start ts; + if (use_old_transport) { + if (init_oldrelayfs() < 0) + cleanup_and_exit(0); + } else { + if (init_relayfs() < 0) + cleanup_and_exit(0); + } + ts.target = target_pid; + send_request(STP_START, &ts, sizeof(ts)); + if (load_only) + cleanup_and_exit(1); + break; + } + default: + err("WARNING: ignored message of type %d\n", (type)); + } + } + fclose(ofp); + return 0; } |