text: #include <ccan/take/take.h>
  #include <ccan/err/err.h>
  #include <ccan/noerr/noerr.h>
  #include <ccan/rbuf/rbuf.h>
  #include <ccan/read_write_all/read_write_all.h>
  #include <ccan/noerr/noerr.h>
  #include <ccan/time/time.h>
  #include <ccan/tal/path/path.h>
  #include <ccan/tal/grab_file/grab_file.h>
  #include <sys/stat.h>
  #include <sys/types.h>
  #include <sys/time.h>
  #include <sys/wait.h>
  #include <fcntl.h>
  #include <string.h>
  #include <unistd.h>
  #include <stdarg.h>
  #include <errno.h>
  #include <unistd.h>
  #include <assert.h>
  #include <signal.h>
  #include "tools.h"
  
  static const char *tmpdir = NULL;
  bool tools_verbose = false;
  
  /* Ten minutes. */
  const unsigned int default_timeout_ms = 10 * 60 * 1000;
  
  static void killme(int sig)
  {
  	kill(-getpid(), SIGKILL);
  }
  
  char *run_with_timeout(const void *ctx, const char *cmd,
  		       bool *ok, unsigned *timeout_ms)
  {
  	pid_t pid;
  	int p[2];
  	struct rbuf in;
  	int status, ms;
  	struct timeabs start;
  
  	*ok = false;
  	if (pipe(p) != 0)
  		return tal_fmt(ctx, "Failed to create pipe: %s",
  			       strerror(errno));
  
  	if (tools_verbose)
  		printf("Running: %s\n", cmd);
  
  	/* Always flush buffers before fork! */
  	fflush(stdout);
  	start = time_now();
  	pid = fork();
  	if (pid == -1) {
  		close_noerr(p[0]);
  		close_noerr(p[1]);
  		return tal_fmt(ctx, "Failed to fork: %s", strerror(errno));
  	}
  
  	if (pid == 0) {
  		struct itimerval itim;
  
  		if (dup2(p[1], STDOUT_FILENO) != STDOUT_FILENO
  		    || dup2(p[1], STDERR_FILENO) != STDERR_FILENO
  		    || close(p[0]) != 0
  		    || close(STDIN_FILENO) != 0
  		    || open("/dev/null", O_RDONLY) != STDIN_FILENO)
  			exit(128);
  
  		signal(SIGALRM, killme);
  		itim.it_interval.tv_sec = itim.it_interval.tv_usec = 0;
  		itim.it_value = timespec_to_timeval(time_from_msec(*timeout_ms).ts);
  		setitimer(ITIMER_REAL, &itim, NULL);
  
  		status = system(cmd);
  		if (WIFEXITED(status))
  			exit(WEXITSTATUS(status));
  		/* Here's a hint... */
  		exit(128 + WTERMSIG(status));
  	}
  
  	close(p[1]);
  	rbuf_init(&in, p[0], tal_arr(ctx, char, 4096), 4096);
  	if (!rbuf_read_str(&in, 0, do_tal_realloc) && errno)
  		in.buf = tal_free(in.buf);
  
  	/* This shouldn't fail... */
  	if (waitpid(pid, &status, 0) != pid)
  		err(1, "Failed to wait for child");
  
  	ms = time_to_msec(time_between(time_now(), start));
  	if (ms > *timeout_ms)
  		*timeout_ms = 0;
  	else
  		*timeout_ms -= ms;
  	close(p[0]);
  	if (tools_verbose) {
  		printf("%s", in.buf);
  		printf("Finished: %u ms, %s %u\n", ms,
  		       WIFEXITED(status) ? "exit status" : "killed by signal",
  		       WIFEXITED(status) ? WEXITSTATUS(status)
  		       : WTERMSIG(status));
  	}
  	*ok = (WIFEXITED(status) && WEXITSTATUS(status) == 0);
  	return in.buf;
  }
  
  /* Tals *output off ctx; return false if command fails. */
  bool run_command(const void *ctx, unsigned int *time_ms, char **output,
  		 const char *fmt, ...)
  {
  	va_list ap;
  	char *cmd;
  	bool ok;
  	unsigned int default_time = default_timeout_ms;
  
  	if (!time_ms)
  		time_ms = &default_time;
  	else if (*time_ms == 0) {
  		*output = tal_strdup(ctx, "\n== TIMED OUT ==\n");
  		return false;
  	}
  
  	va_start(ap, fmt);
  	cmd = tal_vfmt(ctx, fmt, ap);
  	va_end(ap);
  
  	*output = run_with_timeout(ctx, cmd, &ok, time_ms);
  	if (ok)
  		return true;
  	if (!*output)
  		err(1, "Problem running child");
  	if (*time_ms == 0)
  		*output = tal_strcat(ctx, take(*output), "\n== TIMED OUT ==\n");
  	return false;
  }
  
  static void unlink_all(const char *dir)
  {
  	char cmd[strlen(dir) + sizeof("rm -rf ")];
  	sprintf(cmd, "rm -rf %s", dir);
  	if (tools_verbose)
  		printf("Running: %s\n", cmd);
  	if (system(cmd) != 0)
  		warn("Could not remove temporary work in %s", dir);
  }
  
  static pid_t *afree;
  static void free_autofree(void)
  {
  	if (*afree == getpid())
  		tal_free(afree);
  }
  
  tal_t *autofree(void)
  {
  	if (!afree) {
  		afree = tal(NULL, pid_t);
  		*afree = getpid();
  		atexit(free_autofree);
  	}
  	return afree;
  }
  
  const char *temp_dir(void)
  {
  	/* For first call, create dir. */
  	while (!tmpdir) {
  		tmpdir = getenv("TMPDIR");
  		if (!tmpdir)
  			tmpdir = "/tmp";
  		tmpdir = tal_fmt(autofree(), "%s/ccanlint-%u.%lu",
  				 tmpdir, getpid(), random());
  		if (mkdir(tmpdir, 0700) != 0) {
  			if (errno == EEXIST) {
  				tal_free(tmpdir);
  				tmpdir = NULL;
  				continue;
  			}
  			err(1, "mkdir %s failed", tmpdir);
  		}
  		tal_add_destructor(tmpdir, unlink_all);
  		if (tools_verbose)
  			printf("Created temporary directory %s\n", tmpdir);
  	}
  	return tmpdir;
  }
  
  void keep_temp_dir(void)
  {
  	tal_del_destructor(temp_dir(), unlink_all);
  }
  
  char *temp_file(const void *ctx, const char *extension, const char *srcname)
  {
  	char *f, *base, *suffix;
  	struct stat st;
  	unsigned int count = 0;
  
  	base = path_join(ctx, temp_dir(), take(path_basename(ctx, srcname)));
  	/* Trim extension. */
  	base[path_ext_off(base)] = '\0';
  	suffix = tal_strdup(ctx, extension);
  
  	do {
  		f = tal_strcat(ctx, base, suffix);
  		suffix = tal_fmt(base, "-%u%s", ++count, extension);
  	} while (lstat(f, &st) == 0);
  
  	if (tools_verbose)
  		printf("Creating file %s\n", f);
  
  	tal_free(base);
  	return f;
  }
  
  bool move_file(const char *oldname, const char *newname)
  {
  	char *contents;
  	int fd;
  	bool ret;
  
  	if (tools_verbose)
  		printf("Moving file %s to %s: ", oldname, newname);
  
  	/* Simple case: rename works. */
  	if (rename(oldname, newname) == 0) {
  		if (tools_verbose)
  			printf("rename worked\n");
  		return true;
  	}
  
  	/* Try copy and delete: not atomic! */
  	contents = grab_file(NULL, oldname);
  	if (!contents) {
  		if (tools_verbose)
  			printf("read failed: %s\n", strerror(errno));
  		return false;
  	}
  
  	fd = open(newname, O_WRONLY|O_CREAT|O_TRUNC, 0666);
  	if (fd < 0) {
  		if (tools_verbose)
  			printf("output open failed: %s\n", strerror(errno));
  		ret = false;
  		goto free;
  	}
  
  	ret = write_all(fd, contents, tal_count(contents)-1);
  	if (close(fd) != 0)
  		ret = false;
  
  	if (ret) {
  		if (tools_verbose)
  			printf("copy worked\n");
  		unlink(oldname);
  	} else {
  		if (tools_verbose)
  			printf("write/close failed\n");
  		unlink(newname);
  	}
  
  free:
  	tal_free(contents);
  	return ret;
  }
  
  void *do_tal_realloc(void *p, size_t size)
  {
  	tal_resize((char **)&p, size);
  	return p;
  }
  