X-Git-Url: http://git.hungrycats.org/cgi-bin/gitweb.cgi?p=xscreensaver;a=blobdiff_plain;f=driver%2Fsubprocs.c;h=88270d6ca0ad448ba55f374d1110faa3fb02ed5c;hp=527f379d4b5278ff1b3df095a7d2539e6a93bcd8;hb=6b1c86cf395f59389e4ece4ea8f4bea2c332745b;hpb=6cee540bdbb571485cd5e519f89f389faebd0495 diff --git a/driver/subprocs.c b/driver/subprocs.c index 527f379d..88270d6c 100644 --- a/driver/subprocs.c +++ b/driver/subprocs.c @@ -1,5 +1,5 @@ /* subprocs.c --- choosing, spawning, and killing screenhacks. - * xscreensaver, Copyright (c) 1991-2003 Jamie Zawinski + * xscreensaver, Copyright (c) 1991-2008 Jamie Zawinski * * Permission to use, copy, modify, distribute, and sell this software and its * documentation for any purpose is hereby granted without fee, provided that @@ -25,6 +25,7 @@ #endif #include /* sys/resource.h needs this for timeval */ +#include /* for PATH_MAX */ #ifdef HAVE_SYS_WAIT_H # include /* for waitpid() and associated macros */ @@ -65,12 +66,66 @@ extern int kill (pid_t, int); /* signal() is in sys/signal.h... */ #define Widget void* #include "xscreensaver.h" +#include "exec.h" #include "yarandom.h" #include "visual.h" /* for id_to_visual() */ extern saver_info *global_si_kludge; /* I hate C so much... */ +/* Used when printing error/debugging messages from signal handlers. + */ +static const char * +no_malloc_number_to_string (long num) +{ + static char string[128] = ""; + int num_digits; + Bool negative_p = False; + + num_digits = 0; + + if (num == 0) + return "0"; + + if (num < 0) + { + negative_p = True; + num = -num; + } + + while ((num > 0) && (num_digits < sizeof(string) - 1)) + { + int digit; + digit = (int) num % 10; + num_digits++; + string[sizeof(string) - 1 - num_digits] = digit + '0'; + num /= 10; + } + + if (negative_p) + { + num_digits++; + string[sizeof(string) - 1 - num_digits] = '-'; + } + + return string + sizeof(string) - 1 - num_digits; +} + +/* Like write(), but runs strlen() on the arg to get the length. */ +static int +write_string (int fd, const char *str) +{ + return write (fd, str, strlen (str)); +} + +static int +write_long (int fd, long n) +{ + const char *str = no_malloc_number_to_string (n); + return write_string (fd, str); +} + + /* RLIMIT_AS (called RLIMIT_VMEM on some systems) controls the maximum size of a process's address space, i.e., the maximal brk(2) and mmap(2) values. Setting this lets you put a cap on how much memory a process can allocate. @@ -163,7 +218,10 @@ struct screenhack_job { static struct screenhack_job *jobs = 0; -/* for debugging -- nothing calls this, but it's useful to invoke from gdb. */ +/* for debugging -- nothing calls this, but it's useful to invoke from gdb. + */ +void show_job_list (void); + void show_job_list (void) { @@ -294,28 +352,56 @@ static void describe_dead_child (saver_info *, pid_t, int wait_status); static int block_sigchld_handler = 0; -void +#ifdef HAVE_SIGACTION + sigset_t +#else /* !HAVE_SIGACTION */ + int +#endif /* !HAVE_SIGACTION */ block_sigchld (void) { #ifdef HAVE_SIGACTION + struct sigaction sa; sigset_t child_set; + + memset (&sa, 0, sizeof (sa)); + sa.sa_handler = SIG_IGN; + sigaction (SIGPIPE, &sa, NULL); + sigemptyset (&child_set); sigaddset (&child_set, SIGCHLD); sigprocmask (SIG_BLOCK, &child_set, 0); -#endif /* HAVE_SIGACTION */ + +#else /* !HAVE_SIGACTION */ + signal (SIGPIPE, SIG_IGN); +#endif /* !HAVE_SIGACTION */ block_sigchld_handler++; + +#ifdef HAVE_SIGACTION + return child_set; +#else /* !HAVE_SIGACTION */ + return 0; +#endif /* !HAVE_SIGACTION */ } void unblock_sigchld (void) { #ifdef HAVE_SIGACTION + struct sigaction sa; sigset_t child_set; + + memset(&sa, 0, sizeof (sa)); + sa.sa_handler = SIG_DFL; + sigaction(SIGPIPE, &sa, NULL); + sigemptyset(&child_set); sigaddset(&child_set, SIGCHLD); sigprocmask(SIG_UNBLOCK, &child_set, 0); -#endif /* HAVE_SIGACTION */ + +#else /* !HAVE_SIGACTION */ + signal(SIGPIPE, SIG_DFL); +#endif /* !HAVE_SIGACTION */ block_sigchld_handler--; } @@ -400,8 +486,19 @@ sigchld_handler (int sig) saver_info *si = global_si_kludge; /* I hate C so much... */ if (si->prefs.debug_p) - fprintf(stderr, "%s: got SIGCHLD%s\n", blurb(), + { + /* Don't call fprintf() from signal handlers, as it might malloc. + fprintf(stderr, "%s: got SIGCHLD%s\n", blurb(), (block_sigchld_handler ? " (blocked)" : "")); + */ + write_string (STDERR_FILENO, blurb()); + write_string (STDERR_FILENO, ": got SIGCHLD"); + + if (block_sigchld_handler) + write_string (STDERR_FILENO, " (blocked)\n"); + else + write_string (STDERR_FILENO, "\n"); + } if (block_sigchld_handler < 0) abort(); @@ -418,6 +515,7 @@ sigchld_handler (int sig) #ifndef VMS + static void await_dying_children (saver_info *si) { @@ -432,11 +530,29 @@ await_dying_children (saver_info *si) if (si->prefs.debug_p) { if (kid < 0 && errno) - fprintf (stderr, "%s: waitpid(-1) ==> %ld (%d)\n", blurb(), - (long) kid, errno); - else - fprintf (stderr, "%s: waitpid(-1) ==> %ld\n", blurb(), - (long) kid); + { + /* Don't call fprintf() from signal handlers, as it might malloc. + fprintf (stderr, "%s: waitpid(-1) ==> %ld (%d)\n", blurb(), + (long) kid, errno); + */ + write_string (STDERR_FILENO, blurb()); + write_string (STDERR_FILENO, ": waitpid(-1) ==> "); + write_long (STDERR_FILENO, (long) kid); + write_string (STDERR_FILENO, " ("); + write_long (STDERR_FILENO, (long) errno); + write_string (STDERR_FILENO, ")\n"); + } + else + { + /* Don't call fprintf() from signal handlers, as it might malloc. + fprintf (stderr, "%s: waitpid(-1) ==> %ld\n", blurb(), + (long) kid); + */ + write_string (STDERR_FILENO, blurb()); + write_string (STDERR_FILENO, ": waitpid(-1) ==> "); + write_long (STDERR_FILENO, (long) kid); + write_string (STDERR_FILENO, "\n"); + } } /* 0 means no more children to reap. @@ -476,12 +592,38 @@ describe_dead_child (saver_info *si, pid_t kid, int wait_status) if (!job || (exit_status != 0 && (p->verbose_p || job->status != job_killed))) - fprintf (stderr, - "%s: %d: child pid %lu (%s) exited abnormally (code %d).\n", - blurb(), screen_no, (unsigned long) kid, name, exit_status); + { + /* Don't call fprintf() from signal handlers, as it might malloc. + fprintf (stderr, + "%s: %d: child pid %lu (%s) exited abnormally (code %d).\n", + blurb(), screen_no, (unsigned long) kid, name, exit_status); + */ + write_string (STDERR_FILENO, blurb()); + write_string (STDERR_FILENO, ": "); + write_long (STDERR_FILENO, (long) screen_no); + write_string (STDERR_FILENO, ": child pid "); + write_long (STDERR_FILENO, (long) kid); + write_string (STDERR_FILENO, " ("); + write_string (STDERR_FILENO, name); + write_string (STDERR_FILENO, ") exited abnormally (code "); + write_long (STDERR_FILENO, (long) exit_status); + write_string (STDERR_FILENO, ").\n"); + } else if (p->verbose_p) - fprintf (stderr, "%s: %d: child pid %lu (%s) exited normally.\n", - blurb(), screen_no, (unsigned long) kid, name); + { + /* Don't call fprintf() from signal handlers, as it might malloc. + fprintf (stderr, "%s: %d: child pid %lu (%s) exited normally.\n", + blurb(), screen_no, (unsigned long) kid, name); + */ + write_string (STDERR_FILENO, blurb()); + write_string (STDERR_FILENO, ": "); + write_long (STDERR_FILENO, (long) screen_no); + write_string (STDERR_FILENO, ": child pid "); + write_long (STDERR_FILENO, (long) kid); + write_string (STDERR_FILENO, " ("); + write_string (STDERR_FILENO, name); + write_string (STDERR_FILENO, ") exited normally.\n"); + } if (job) job->status = job_dead; @@ -492,9 +634,23 @@ describe_dead_child (saver_info *si, pid_t kid, int wait_status) !job || job->status != job_killed || WTERMSIG (wait_status) != SIGTERM) - fprintf (stderr, "%s: %d: child pid %lu (%s) terminated with %s.\n", - blurb(), screen_no, (unsigned long) kid, name, - signal_name (WTERMSIG(wait_status))); + { + /* Don't call fprintf() from signal handlers, as it might malloc. + fprintf (stderr, "%s: %d: child pid %lu (%s) terminated with %s.\n", + blurb(), screen_no, (unsigned long) kid, name, + signal_name (WTERMSIG(wait_status))); + */ + write_string (STDERR_FILENO, blurb()); + write_string (STDERR_FILENO, ": "); + write_long (STDERR_FILENO, (long) screen_no); + write_string (STDERR_FILENO, ": child pid "); + write_long (STDERR_FILENO, (long) kid); + write_string (STDERR_FILENO, " ("); + write_string (STDERR_FILENO, name); + write_string (STDERR_FILENO, ") terminated with signal "); + write_long (STDERR_FILENO, WTERMSIG(wait_status)); + write_string (STDERR_FILENO, ".\n"); + } if (job) job->status = job_dead; @@ -502,17 +658,41 @@ describe_dead_child (saver_info *si, pid_t kid, int wait_status) else if (WIFSTOPPED (wait_status)) { if (p->verbose_p) - fprintf (stderr, "%s: child pid %lu (%s) stopped with %s.\n", - blurb(), (unsigned long) kid, name, - signal_name (WSTOPSIG (wait_status))); + { + /* Don't call fprintf() from signal handlers, as it might malloc. + fprintf (stderr, "%s: child pid %lu (%s) stopped with %s.\n", + blurb(), (unsigned long) kid, name, + signal_name (WSTOPSIG (wait_status))); + */ + write_string (STDERR_FILENO, blurb()); + write_string (STDERR_FILENO, ": "); + write_long (STDERR_FILENO, (long) screen_no); + write_string (STDERR_FILENO, ": child pid "); + write_long (STDERR_FILENO, (long) kid); + write_string (STDERR_FILENO, " ("); + write_string (STDERR_FILENO, name); + write_string (STDERR_FILENO, ") stopped with signal "); + write_long (STDERR_FILENO, WSTOPSIG(wait_status)); + write_string (STDERR_FILENO, ".\n"); + } if (job) job->status = job_stopped; } else { + /* Don't call fprintf() from signal handlers, as it might malloc. fprintf (stderr, "%s: child pid %lu (%s) died in a mysterious way!", blurb(), (unsigned long) kid, name); + */ + write_string (STDERR_FILENO, blurb()); + write_string (STDERR_FILENO, ": "); + write_long (STDERR_FILENO, (long) screen_no); + write_string (STDERR_FILENO, ": child pid "); + write_long (STDERR_FILENO, (long) kid); + write_string (STDERR_FILENO, " ("); + write_string (STDERR_FILENO, name); + write_string (STDERR_FILENO, ") died in a mysterious way!"); if (job) job->status = job_dead; } @@ -625,7 +805,8 @@ print_path_error (const char *program) fprintf (stderr, "\n"); *path = 0; # if defined(HAVE_GETCWD) - getcwd (path, sizeof(path)); + if (! getcwd (path, sizeof(path))) + *path = 0; # elif defined(HAVE_GETWD) getwd (path); # endif @@ -643,6 +824,60 @@ print_path_error (const char *program) } +/* Executes the command in another process. + Command may be any single command acceptable to /bin/sh. + It may include wildcards, but no semicolons. + If successful, the pid of the other process is returned. + Otherwise, -1 is returned and an error may have been + printed to stderr. + */ +pid_t +fork_and_exec (saver_screen_info *ssi, const char *command) +{ + saver_info *si = ssi->global; + saver_preferences *p = &si->prefs; + pid_t forked; + + switch ((int) (forked = fork ())) + { + case -1: + { + char buf [255]; + sprintf (buf, "%s: couldn't fork", blurb()); + perror (buf); + break; + } + + case 0: + close (ConnectionNumber (si->dpy)); /* close display fd */ + limit_subproc_memory (p->inferior_memory_limit, p->verbose_p); + hack_subproc_environment (ssi); /* set $DISPLAY */ + + if (p->verbose_p) + fprintf (stderr, "%s: %d: spawning \"%s\" in pid %lu.\n", + blurb(), ssi->number, command, + (unsigned long) getpid ()); + + exec_command (p->shell, command, p->nice_inferior); + + /* If that returned, we were unable to exec the subprocess. + Print an error message, if desired. + */ + if (! p->ignore_uninstalled_p) + print_path_error (command); + + exit (1); /* exits child fork */ + break; + + default: /* parent */ + (void) make_job (forked, ssi->number, command); + break; + } + + return forked; +} + + static void spawn_screenhack_1 (saver_screen_info *ssi, Bool first_time_p) { @@ -656,7 +891,7 @@ spawn_screenhack_1 (saver_screen_info *ssi, Bool first_time_p) screenhack *hack; pid_t forked; char buf [255]; - int new_hack; + int new_hack = -1; int retry_count = 0; Bool force = False; @@ -703,6 +938,14 @@ spawn_screenhack_1 (saver_screen_info *ssi, Bool first_time_p) { new_hack = -1; } + else if (p->mode == RANDOM_HACKS_SAME && + ssi->number != 0) + { + /* Use the same hack that's running on screen 0. + (Assumes this function was called on screen 0 first.) + */ + new_hack = si->screens[0].current_hack; + } else /* (p->mode == RANDOM_HACKS) */ { /* Select a random hack (but not the one we just ran.) */ @@ -732,6 +975,7 @@ spawn_screenhack_1 (saver_screen_info *ssi, Bool first_time_p) if (!force && (!hack->enabled_p || + !on_path_p (hack->command) || !select_visual_of_hack (ssi, hack))) { if (++retry_count > (p->screenhacks_count*4)) @@ -757,38 +1001,19 @@ spawn_screenhack_1 (saver_screen_info *ssi, Bool first_time_p) if (si->selection_mode < 0) si->selection_mode = 0; - switch ((int) (forked = fork ())) + forked = fork_and_exec (ssi, hack->command); + switch ((int) forked) { - case -1: + case -1: /* fork failed */ + case 0: /* child fork (can't happen) */ sprintf (buf, "%s: couldn't fork", blurb()); perror (buf); restore_real_vroot (si); - saver_exit (si, 1, 0); - - case 0: - close (ConnectionNumber (si->dpy)); /* close display fd */ - limit_subproc_memory (p->inferior_memory_limit, p->verbose_p); - hack_subproc_environment (ssi); /* set $DISPLAY */ - - if (p->verbose_p) - fprintf (stderr, "%s: %d: spawning \"%s\" in pid %lu.\n", - blurb(), ssi->number, hack->command, - (unsigned long) getpid ()); - - exec_command (p->shell, hack->command, p->nice_inferior); - - /* If that returned, we were unable to exec the subprocess. - Print an error message, if desired. - */ - if (! p->ignore_uninstalled_p) - print_path_error (hack->command); - - exit (1); /* exits child fork */ + saver_exit (si, 1, "couldn't fork"); break; default: ssi->pid = forked; - (void) make_job (forked, ssi->number, hack->command); break; } } @@ -922,29 +1147,46 @@ hack_subproc_environment (saver_screen_info *ssi) be the screen on which this particular hack is running -- not the display specification which the driver itself is using, since the driver ignores its screen number and manages all existing screens. + + Likewise, store a window ID in $XSCREENSAVER_WINDOW -- this will allow + us to (eventually) run multiple hacks in Xinerama mode, where each hack + has the same $DISPLAY but a different piece of glass. */ saver_info *si = ssi->global; const char *odpy = DisplayString (si->dpy); - char *ndpy = (char *) malloc(strlen(odpy) + 20); - char *s; + char *ndpy = (char *) malloc (strlen(odpy) + 20); + char *nssw = (char *) malloc (40); + char *s, *c; strcpy (ndpy, "DISPLAY="); s = ndpy + strlen(ndpy); strcpy (s, odpy); - while (*s && *s != ':') s++; /* skip to colon */ - while (*s == ':') s++; /* skip over colons */ + /* We have to find the last colon since it is the boundary between + hostname & screen - IPv6 numeric format addresses may have many + colons before that point, and DECnet addresses always have two colons */ + c = strrchr(s,':'); /* skip to last colon */ + if (c != NULL) s = c+1; while (isdigit(*s)) s++; /* skip over dpy number */ while (*s == '.') s++; /* skip over dot */ if (s[-1] != '.') *s++ = '.'; /* put on a dot */ - sprintf(s, "%d", ssi->number); /* put on screen number */ + sprintf(s, "%d", ssi->real_screen_number); /* put on screen number */ + + sprintf (nssw, "XSCREENSAVER_WINDOW=0x%lX", + (unsigned long) ssi->screensaver_window); /* Allegedly, BSD 4.3 didn't have putenv(), but nobody runs such systems any more, right? It's not Posix, but everyone seems to have it. */ #ifdef HAVE_PUTENV if (putenv (ndpy)) abort (); - /* do not free(ndpy) -- see above. */ + if (putenv (nssw)) + abort (); + + /* don't free ndpy/nssw -- some implementations of putenv (BSD 4.4, + glibc 2.0) copy the argument, but some (libc4,5, glibc 2.1.2) + do not. So we must leak it (and/or the previous setting). Yay. + */ #endif /* HAVE_PUTENV */ } @@ -999,9 +1241,9 @@ get_best_gl_visual (saver_screen_info *ssi) execvp (av[0], av); /* shouldn't return. */ - if (errno != ENOENT || si->prefs.verbose_p) + if (errno != ENOENT /* || si->prefs.verbose_p */ ) { - /* Ignore "no such file or directory" errors, unless verbose. + /* Ignore "no such file or directory" errors. Issue all other exec errors, though. */ sprintf (buf, "%s: running %s", blurb(), av[0]); perror (buf); @@ -1021,7 +1263,8 @@ get_best_gl_visual (saver_screen_info *ssi) close (out); /* don't need this one */ *buf = 0; - fgets (buf, sizeof(buf)-1, f); + if (! fgets (buf, sizeof(buf)-1, f)) + *buf = 0; fclose (f); /* Wait for the child to die. */