X-Git-Url: https://git.jankratochvil.net/?p=nethome.git;a=blobdiff_plain;f=src%2Forphanripper.c;h=ffccabfcff621f075a47ba37ccb6b14e54b0b1c7;hp=f60651a7733393ec063cfee3a9416d8b7941db81;hb=eb1ec4bc2438b6ced53aa11d69b41720547b87d1;hpb=82079b22573dc1ba5dda12325c584c2f7d5ceae7 diff --git a/src/orphanripper.c b/src/orphanripper.c index f60651a..ffccabf 100644 --- a/src/orphanripper.c +++ b/src/orphanripper.c @@ -41,50 +41,129 @@ #include #include #include +#include #define LENGTH(x) (sizeof (x) / sizeof (*(x))) static const char *progname; -static volatile int signal_child_hit = 0; +static volatile pid_t child; -/* We use it to race-safely emulate ppoll(2) by poll(2). */ -static int pipefd[2]; - -static void signal_child (int signo) +static void signal_chld (int signo) { - int i; +} - signal_child_hit = 1; +static volatile int signal_alrm_hit = 0; - assert (pipefd[1] != -1); - i = close (pipefd[1]); - assert (i == 0); - pipefd[1] = -1; +static void signal_alrm (int signo) +{ + signal_alrm_hit = 1; } static char childptyname[LINE_MAX]; -static pid_t child; -static int spawn (char **argv) +static void print_child_error (const char *reason, char **argv) +{ + char **sp; + + fprintf (stderr, "%s: %d %s:", progname, (int) child, reason); + for (sp = argv; *sp != NULL; sp++) + { + fputc (' ', stderr); + fputs (*sp, stderr); + } + fputc ('\n', stderr); +} + +static int read_out (int amaster) +{ + char buf[LINE_MAX]; + ssize_t buf_got; + + buf_got = read (amaster, buf, sizeof buf); + if (buf_got == 0) + return 0; + /* Weird but at least after POLLHUP we get EIO instead of just EOF. */ + if (buf_got == -1 && errno == EIO) + return 0; + if (buf_got == -1 && errno == EAGAIN) + return 0; + if (buf_got < 0) + { + perror ("read (amaster)"); + exit (EXIT_FAILURE); + } + if (write (STDOUT_FILENO, buf, buf_got) != buf_got) + { + perror ("write(2)"); + exit (EXIT_FAILURE); + } + return 1; +} + +/* kill (child, 0) ==0 sometimes even when CHILD's state is already Z. */ + +static int child_exited (void) +{ + char buf[200]; + int fd, i, retval; + ssize_t got; + char *state; + + snprintf (buf, sizeof (buf), "/proc/%ld/stat", (long) child); + fd = open (buf, O_RDONLY); + if (fd == -1) + { + perror ("open (/proc/CHILD/stat)"); + exit (EXIT_FAILURE); + } + got = read (fd, buf, sizeof(buf)); + if (got <= 0) + { + perror ("read (/proc/CHILD/stat)"); + exit (EXIT_FAILURE); + } + if (close (fd) != 0) + { + perror ("close (/proc/CHILD/stat)"); + exit (EXIT_FAILURE); + } + i = sscanf (buf, "%*d%*s%ms", &state); + if (i != 1) + { + perror ("sscanf (/proc/CHILD/stat)"); + exit (EXIT_FAILURE); + } + retval = strcmp (state, "Z") == 0; + free (state); + return retval; +} + +static int spawn (char **argv, int timeout) { pid_t child_got; - int status, amaster, i; + int status, amaster, i, rc; struct sigaction act; + sigset_t set; struct termios termios; + unsigned alarm_orig; - i = pipe (pipefd); - assert (i == 0); - - /* We do not use signal(2) to be sure we have SA_RESTART set. */ + /* We do not use signal(2) to be sure we do not have SA_RESTART. */ memset (&act, 0, sizeof (act)); - act.sa_handler = signal_child; + act.sa_handler = signal_chld; i = sigemptyset (&act.sa_mask); assert (i == 0); - act.sa_flags = SA_RESTART; + act.sa_flags = 0; /* !SA_RESTART */ i = sigaction (SIGCHLD, &act, NULL); assert (i == 0); + i = sigemptyset (&set); + assert (i == 0); + i = sigaddset (&set, SIGCHLD); + assert (i == 0); + i = sigprocmask (SIG_SETMASK, &set, NULL); + assert (i == 0); + /* With TERMP passed as NULL we get "\n" -> "\r\n". */ termios.c_iflag = IGNBRK | IGNPAR; termios.c_oflag = 0; @@ -105,11 +184,6 @@ static int spawn (char **argv) perror ("forkpty(3)"); exit (EXIT_FAILURE); case 0: - i = close (pipefd[0]); - assert (i == 0); - i = close (pipefd[1]); - assert (i == 0); - /* Do not replace STDIN as inferiors query its termios. */ #if 0 i = close (STDIN_FILENO); @@ -118,6 +192,11 @@ static int spawn (char **argv) assert (i == STDIN_FILENO); #endif + i = sigemptyset (&set); + assert (i == 0); + i = sigprocmask (SIG_SETMASK, &set, NULL); + assert (i == 0); + /* Do not setpgrp(2) in the parent process as the process-group is shared for the whole sh(1) pipeline we could be a part of. The process-group is set according to PID of the first @@ -134,7 +213,7 @@ static int spawn (char **argv) perror ("getpgrp(2)"); exit (EXIT_FAILURE); } - execvp (argv[1], argv + 1); + execvp (argv[0], argv); perror ("execvp(2)"); exit (EXIT_FAILURE); default: @@ -146,51 +225,63 @@ static int spawn (char **argv) perror ("fcntl (amaster, F_SETFL, O_NONBLOCK)"); exit (EXIT_FAILURE); } - for (;;) + + /* We do not use signal(2) to be sure we do not have SA_RESTART. */ + act.sa_handler = signal_alrm; + i = sigaction (SIGALRM, &act, NULL); + assert (i == 0); + + alarm_orig = alarm (timeout); + assert (alarm_orig == 0); + + i = sigemptyset (&set); + assert (i == 0); + + while (!signal_alrm_hit) { - struct pollfd pollfd[2]; - char buf[LINE_MAX]; - ssize_t buf_got; + struct pollfd pollfd; - pollfd[0].fd = amaster; - pollfd[0].events = POLLIN; - pollfd[1].fd = pipefd[0]; - pollfd[1].events = POLLIN; - i = poll (pollfd, LENGTH (pollfd), -1); + pollfd.fd = amaster; + pollfd.events = POLLIN; + i = ppoll (&pollfd, 1, NULL, &set); if (i == -1 && errno == EINTR) - { - /* Weird but SA_RESTART sometimes does not work. */ + { + if (child_exited ()) + break; + /* Non-CHILD child may have exited. */ continue; } - assert (i >= 1); + assert (i == 1); /* Data available? Process it first. */ - if (pollfd[0].revents & POLLIN) + if (pollfd.revents & POLLIN) { - buf_got = read (amaster, buf, sizeof buf); - if (buf_got <= 0) + if (!read_out (amaster)) { - perror ("read (amaster)"); - exit (EXIT_FAILURE); - } - if (write (STDOUT_FILENO, buf, buf_got) != buf_got) - { - perror ("write(2)"); + fprintf (stderr, "%s: Unexpected EOF\n", progname); exit (EXIT_FAILURE); } } - if (pollfd[0].revents & POLLHUP) + if (pollfd.revents & POLLHUP) break; - if ((pollfd[0].revents &= ~POLLIN) != 0) + if ((pollfd.revents &= ~POLLIN) != 0) { fprintf (stderr, "%s: ppoll(2): revents 0x%x\n", progname, - (unsigned) pollfd[0].revents); + (unsigned) pollfd.revents); exit (EXIT_FAILURE); } /* Child exited? */ - if (pollfd[1].revents & POLLHUP) + if (child_exited ()) break; - assert (pollfd[1].revents == 0); } + + if (signal_alrm_hit) + { + i = kill (child, SIGKILL); + assert (i == 0); + } + else + alarm (0); + /* WNOHANG still could fail. */ child_got = waitpid (child, &status, 0); if (child != child_got) @@ -198,17 +289,53 @@ static int spawn (char **argv) fprintf (stderr, "waitpid (%d) = %d: %m\n", (int) child, (int) child_got); exit (EXIT_FAILURE); } - if (!WIFEXITED (status)) + if (signal_alrm_hit) + { + char *buf; + + if (asprintf (&buf, "Timed out after %d seconds", timeout) != -1) + { + print_child_error (buf, argv); + free (buf); + } + rc = 128 + SIGALRM; + } + else if (WIFEXITED (status)) + rc = WEXITSTATUS (status); + else if (WIFSIGNALED (status)) + { + print_child_error (strsignal (WTERMSIG (status)), argv); + rc = 128 + WTERMSIG (status); + } + else if (WIFSTOPPED (status)) + { + fprintf (stderr, "waitpid (%d): WIFSTOPPED - WSTOPSIG is %d\n", + (int) child, WSTOPSIG (status)); + exit (EXIT_FAILURE); + } + else { fprintf (stderr, "waitpid (%d): !WIFEXITED (%d)\n", (int) child, status); exit (EXIT_FAILURE); } - assert (signal_child_hit != 0); - assert (pipefd[1] == -1); - i = close (pipefd[0]); + /* Not used in fact. */ + i = sigprocmask (SIG_SETMASK, &set, NULL); assert (i == 0); + /* Do not unset O_NONBLOCK as a stale child (the whole purpose of this + program) having open its output pty would block us in read_out. */ +#if 0 + i = fcntl (amaster, F_SETFL, O_RDONLY /* !O_NONBLOCK */); + if (i != 0) + { + perror ("fcntl (amaster, F_SETFL, O_RDONLY /* !O_NONBLOCK */)"); + exit (EXIT_FAILURE); + } +#endif + + while (read_out (amaster)); + /* Do not close the master FD as the child would have `/dev/pts/23 (deleted)' entries which are not expected (and expecting ` (deleted)' would be a race. */ @@ -221,7 +348,7 @@ static int spawn (char **argv) } #endif - return WEXITSTATUS (status); + return rc; } /* Detected commandline may look weird due to a race: @@ -296,7 +423,7 @@ static int dir_scan (const char *dirname, pathname_len = snprintf (pathname, sizeof pathname, "%s/%s", dirname, dirent->d_name); - if (pathname_len <= 0 || pathname_len >= sizeof pathname) + if (pathname_len <= 0 || pathname_len >= (int) sizeof pathname) { fprintf (stderr, "entry file name too long: `%s' / `%s'\n", dirname, dirent->d_name); @@ -372,7 +499,7 @@ static int fd_fs_scan (pid_t pid, int (*func) (pid_t pid, const char *link)) if (dirent->d_type == DT_DIR) return 0; buf_len = readlink (pathname, buf, sizeof buf - 1); - if (buf_len <= 0 || buf_len >= sizeof buf - 1) + if (buf_len <= 0 || buf_len >= (ssize_t) sizeof buf - 1) { if (errno != ENOENT && errno != EACCES) fprintf (stderr, "Error reading link \"%s\": %m\n", pathname); @@ -582,16 +709,44 @@ static void rip (void) int main (int argc, char **argv) { + int timeout = 0; int rc; - if (argc < 2 || strcmp (argv[1], "-h") == 0 - || strcmp (argv[1], "--help") == 0) + progname = *argv++; + argc--; + + if (argc < 1 || strcmp (*argv, "-h") == 0 + || strcmp (*argv, "--help") == 0) { - fputs ("Syntax: orphanripper \n", stdout); + puts ("Syntax: orphanripper [-t ] "); exit (EXIT_FAILURE); } - progname = argv[0]; - rc = spawn (argv); + if ((*argv)[0] == '-' && (*argv)[1] == 't') + { + char *timeout_s = NULL; + + if ((*argv)[2] == 0) + timeout_s = *++argv; + else if (isdigit ((*argv)[2])) + timeout_s = (*argv) + 2; + if (timeout_s != NULL) + { + long l; + char *endptr; + + argv++; + l = strtol (timeout_s, &endptr, 0); + timeout = l; + if ((endptr != NULL && *endptr != 0) || timeout < 0 || timeout != l) + { + fprintf (stderr, "%s: Invalid timeout value: %s\n", progname, + timeout_s); + exit (EXIT_FAILURE); + } + } + } + + rc = spawn (argv, timeout); rip (); return rc; }