/**
* scrotty — Screenshot program for Linux's TTY
*
* Copyright © 2014, 2015 Mattias Andrée (maandree@member.fsf.org)
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#define _GNU_SOURCE /* For getopt_long. */
#include "common.h"
#include "kern.h"
#include "info.h"
#include "pnm.h"
#include "png.h"
#include "pattern.h"
#include <getopt.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/stat.h>
#ifdef USE_GETTEXT
# include <locale.h>
#endif
/**
* X-macro that lists all environment variables
* that indicate that the program is running
* inside a display server.
*/
#define LIST_DISPLAY_VARS X(DISPLAY) X(MDS_DISPLAY) X(MIR_DISPLAY) X(WAYLAND_DISPLAY) X(PREFERRED_DISPLAY)
#define LIST_0_9(P) P"0\n", P"1\n", P"2\n", P"3\n", P"4\n", P"5\n", P"6\n", P"7\n", P"8\n", P"9\n"
/**
* [0, 255]-integer-to-text convertion lookup table for faster conversion from
* raw framebuffer data to the PNM format. The values have a whitespace at the
* end for even faster conversion.
* Lines should not be longer than 70 (although most programs will probably
* work even if there are longer lines), therefore the selected whitespace
* is LF (new line).
*
* ASCII has wider support than binary, and is create for version control,
* especifially with one datum per line.
*/
const char* inttable[] =
{
LIST_0_9(""), LIST_0_9("1"), LIST_0_9("2"), LIST_0_9("3"), LIST_0_9("4"),
LIST_0_9("5"), LIST_0_9("6"), LIST_0_9("7"), LIST_0_9("8"), LIST_0_9("9"),
LIST_0_9("10"), LIST_0_9("11"), LIST_0_9("12"), LIST_0_9("13"), LIST_0_9("14"),
LIST_0_9("15"), LIST_0_9("16"), LIST_0_9("17"), LIST_0_9("18"), LIST_0_9("19"),
LIST_0_9("20"), LIST_0_9("21"), LIST_0_9("22"), LIST_0_9("23"), LIST_0_9("24"),
"250\n", "251\n", "252\n", "253\n", "254\n", "255\n"
};
/**
* `argv[0]` from `main`.
*/
const char *execname;
/**
* If a function fails when it tries to
* open a file, it will set this variable
* point to the pathname of that file.
*/
const char *failure_file = NULL;
/**
* The index of the alternative path-pattern,
* for the framebuffers, to try.
*/
static int try_alt_fbpath = 0;
/**
* Create an PNM-file that is sent to a conversion process,
* or directly to a file.
*
* @param fbname The framebuffer device.
* @param width The width of the image.
* @param height The height of the image.
* @param fd The file descriptor connected to conversion process's stdin.
* @return Zero on success, -1 on error.
*/
static int
save_pnm (const char *fbpath, long width, long height, int fd)
{
char buf[8 << 10];
FILE *file = NULL;
int fbfd = 1;
ssize_t got, off;
int saved_errno;
size_t adjustment;
/* Open the framebuffer device for reading. */
fbfd = open (fbpath, O_RDONLY);
if (fbfd == -1)
goto fail;
/* Create a FILE *, for writing, for the image file. */
file = fdopen (fd, "w");
if (file == NULL)
goto fail;
/* The PNM image should begin with `P3\n%{width} %{height}\n%{colour max=255}\n`.
('\n' and ' ' can be exchanged at will.) */
if (fprintf (file, "P3\n%li %li\n255\n", width, height) < 0)
goto fail;
/* Convert raw framebuffer data into an PNM image. */
for (off = 0;;)
{
/* Read data from the framebuffer, we may have up to 3 bytes buffered. */
got = read (fbfd, buf + off, sizeof (buf) - (size_t)off * sizeof (char));
if (got < 0)
goto fail;
if (got == 0)
break;
got += off;
/* Convert read pixels. */
if (convert_fb (file, buf, (size_t)got, &adjustment) < 0)
goto fail;
/* If we read a whole number of pixels, reset the buffer, otherwise,
move the unconverted bytes to the beginning of the buffer. */
if (adjustment)
{
off -= (ssize_t)adjustment;
memcpy (buf, buf + off, (size_t)(got - off) * sizeof (char));
off = got - off;
}
else
off = 0;
}
/* Close files and return successfully. */
fflush (file);
fclose (file);
close (fbfd);
return 0;
fail:
saved_errno = errno;
if (file != NULL)
fclose (file);
if (fbfd >= 0)
close (fbfd);
errno = saved_errno;
return -1;
}
/**
* Create an image of a framebuffer.
*
* @param fbname The framebuffer device.
* @param imgname The pathname of the output image.
* @param width The width of the image.
* @param height The height of the image.
* @param raw Save in PNM?
* @return Zero on success, -1 on error.
*/
static int
save (const char *fbpath, const char *imgpath, long width, long height, int raw)
{
int pipe_rw[2] = { -1, -1 };
pid_t pid;
int status;
int fd = -1;
int saved_errno;
if (raw)
goto no_convert;
/* Create a pipe that for sending data into the conversion process program. */
if (pipe (pipe_rw) < 0)
goto fail;
/* Fork the process, the child will become the conversion process. */
pid = fork ();
if (pid == -1)
goto fail;
/* Child process: */
if (pid == 0)
{
/* Close the write-end of the pipe. */
close (pipe_rw[1]);
/* Open file descriptor for the output image. */
fd = open (imgpath, O_WRONLY | O_CREAT | O_TRUNC,
S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
if (fd == -1)
goto child_fail;
/* Convert the PNM-image we create to a compressed image, namely in PNG. */
if (convert (pipe_rw[0], fd) < 0)
goto child_fail;
_exit(0);
child_fail:
perror(execname);
_exit(1);
}
/* Parent process: */
/* Close the read-end of the pipe. */
close (pipe_rw[0]), pipe_rw[0] = -1;
/* Create a PNM-image of the framebuffer. */
if (save_pnm (fbpath, width, height, pipe_rw[1]) < 0)
goto fail;
/* Close the write-end of the pipe. */
close (pipe_rw[1]), pipe_rw[1] = -1;
/* Wait for conversion process to exit. */
if (waitpid (pid, &status, 0) < 0)
goto fail;
/* Return successfully if and only if conversion did. */
return status == 0 ? 0 : -1;
/* Conversion shall not take place: */
no_convert:
/* Open output file. */
if (fd = open (imgpath, O_WRONLY | O_CREAT | O_TRUNC,
S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH), fd == -1)
FILE_FAILURE (imgpath);
/* Save image. */
if (save_pnm (fbpath, width, height, fd) < 0)
goto fail;
close (fd);
return 0;
fail:
saved_errno = errno;
if (pipe_rw[0] >= 0)
close (pipe_rw[0]);
if (pipe_rw[1] >= 0)
close (pipe_rw[1]);
if (fd >= 0)
close (fd);
errno = saved_errno;
return -1;
}
/**
* Run a command for an image
*
* @param flatten_args The arguments to run, 255 delimits the arguments
* @return Zero on success -1 on error
*/
static int
exec_image (char *flatten_args)
{
char **args = NULL;
char *arg;
size_t i, arg_count = 1;
pid_t pid;
int status, saved_errno;
/* Count arguments. */
for (i = 0; flatten_args[i]; i++)
if ((unsigned char)(flatten_args[i]) == 255)
arg_count++;
/* Allocate argument array. */
args = malloc ((arg_count + 1) * sizeof (char*));
if (args == NULL)
goto fail;
/* Unflatten argument array. */
for (arg = flatten_args, i = 0;;)
{
args[i++] = arg;
arg = strchr (arg, 255);
if (arg == NULL)
break;
*arg++ = '\0';
}
args[i] = NULL;
/* Fork process. */
pid = fork ();
if (pid == -1)
goto fail;
/* Child process: */
if (pid == 0)
{
execvp (*args, args);
perror (execname);
_exit (1);
}
/* Parent process: */
/* Wait for child to exit. */
if (waitpid (pid, &status, 0) < 0)
goto fail;
/* Return successfully if and only if `the child` did. */
free (args);
return status == 0 ? 0 : -1;
fail:
saved_errno = errno;
free (args);
errno = saved_errno;
return -1;
}
/**
* Take a screenshot of a framebuffer.
*
* @param fbno The number of the framebuffer.
* @param raw Save in PNM rather than in PNG?.
* @param filepattern The pattern for the filename, `NULL` for default.
* @param execpattern The pattern for the command to run to
* process the image, `NULL` for none.
* @return Zero on success, -1 on error, 1 if the framebuffer does not exist.
*/
static int
save_fb (int fbno, int raw, const char *filepattern, const char *execpattern)
{
char imgpath_[sizeof ("fb.xyz.") + 2 * 3 * sizeof (int)];
char *imgpath = imgpath_;
char *fbpath; /* Statically allocate string is returned. */
char *execargs = NULL;
long width, height;
int i, rc = 0, saved_errno = 0;
/* Get pathname for framebuffer, and stop if we have read all existing ones. */
fbpath = get_fbpath (try_alt_fbpath, fbno);
if (access (fbpath, F_OK))
return 1;
/* Get the size of the framebuffer. */
if (measure (fbno, fbpath, &width, &height) < 0)
goto fail;
/* Get output pathname. */
if (filepattern == NULL)
{
sprintf (imgpath, "fb%i.%s", fbno, (raw ? "pnm" : "png"));
for (i = 2; access (imgpath, F_OK) == 0; i++)
sprintf (imgpath, "fb%i.%s.%i", fbno, (raw ? "pnm" : "png"), i);
}
else
{
imgpath = evaluate (filepattern, fbno, width, height, NULL);
if (imgpath == NULL)
goto fail;
}
/* Take a screenshot of the current framebuffer. */
if (save (fbpath, imgpath, width, height, raw) < 0)
goto fail;
fprintf (stderr, _("Saved framebuffer %i to %s.\n"), fbno, imgpath);
/* Should we run a command over the image? */
if (execpattern == NULL)
goto done;
/* Get execute arguments. */
execargs = evaluate (execpattern, fbno, width, height, imgpath);
if (execargs == NULL)
goto fail;
/* Run command over image. */
if (exec_image (execargs) < 0)
goto fail;
goto done;
fail:
saved_errno = errno;
rc = -1;
done:
free (execargs);
if (imgpath != imgpath_)
free (imgpath);
return errno = saved_errno, rc;
}
/**
* Take a screenshot of all framebuffers.
*
* @param raw Save in PNM rather than in PNG?.
* @param filepattern The pattern for the filename, `NULL` for default.
* @param execpattern The pattern for the command to run to
* process thes image, `NULL` for none.
* @return Zero on success, -1 on error, 1 if no framebuffer exists.
*/
static
int save_fbs (int raw, const char *filepattern, const char *exec)
{
int r, fbno, found = 0;
retry:
/* Take a screenshot of each framebuffer. */
for (fbno = 0;; fbno++)
{
r = save_fb (fbno, raw, filepattern, exec);
if (r < 0)
goto fail;
else if (r == 0)
found = 1;
else if (fbno > 0)
break;
else
continue; /* Perhaps framebuffer 1 is the first. */
}
/* Did not find any framebuffer? */
if (found == 0)
{
if (try_alt_fbpath++ < alt_fbpath_limit)
goto retry;
return 1;
}
return 0;
fail:
return -1;
}
/**
* Figure out whether the user is in a display server.
* We will print a warning in `main` if so.
*/
static int
have_display (void)
{
char *env;
#define X(VAR) env = getenv(#VAR); if (env && *env) return 1;
LIST_DISPLAY_VARS
return 0;
}
/**
* Take a screenshot of all framebuffers.
*
* @param argc The number of elements in `argv`.
* @param argv Command line arguments, run with `--help` for more information.
* @return Zero on and only on success.
*/
int
main (int argc, char *argv[])
{
#define EXIT_USAGE(MSG) \
return fprintf (stderr, _("%s: %s. Type '%s --help' for help.\n"), execname, MSG, execname), 2
#define USAGE_ASSERT(ASSERTION, MSG) \
do { if (!(ASSERTION)) EXIT_USAGE (MSG); } while (0)
int r, raw = 0;
char *exec = NULL;
char *filepattern = NULL;
struct option long_options[] =
{
{"help", no_argument, NULL, 'h'},
{"version", no_argument, NULL, 'v'},
{"copyright", no_argument, NULL, 'c'},
{"raw", no_argument, NULL, 'r'},
{"exec", required_argument, NULL, 'e'},
{NULL, 0, NULL, 0 }
};
/* Set up for internationalisation. */
#if defined(USE_GETTEXT) && defined(PACKAGE) && defined(LOCALEDIR)
setlocale (LC_ALL, "");
bindtextdomain (PACKAGE, LOCALEDIR);
textdomain (PACKAGE);
#endif
/* Parse command line. */
execname = argc ? *argv : "scrotty";
for (;;)
{
r = getopt_long (argc, argv, "hvcre:", long_options, NULL);
if (r == -1) break;
else if (r == 'h') return -(print_help ());
else if (r == 'v') return -(print_version ());
else if (r == 'c') return -(print_copyright ());
else if (r == 'r') raw = 1;
else if (r == 'e')
{
USAGE_ASSERT (exec == NULL, _("--exec is used twice."));
exec = optarg;
}
else if (r == '?')
EXIT_USAGE (_("Invalid input."));
else
abort ();
}
while (optind < argc)
{
USAGE_ASSERT (filepattern == NULL, _("FILENAME-PATTERN is used twice."));
filepattern = argv[optind++];
}
/* Take a screenshot of each framebuffer. */
r = save_fbs (raw, filepattern, exec);
if (r < 0)
goto fail;
if (r > 0)
goto no_fb;
/* Warn about being inside a display server. */
if (have_display ())
fprintf (stderr, _("%s: It looks like you are inside a display server. "
"If this is correct, what you see is probably not "
"what you get.\n"), execname);
return 0;
fail:
if (failure_file == NULL)
perror (execname);
else
fprintf (stderr, _("%s: %s: %s\n"),
execname, strerror (errno), failure_file);
return 1;
no_fb:
print_not_found_help ();
return 1;
}
