/**
* 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/>.
*/
#ifndef PROGRAM_NAME
# define PROGRAM_NAME "scrotty"
#endif
#ifndef PROGRAM_VERSION
# define PROGRAM_VERSION "1.0"
#endif
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdio.h>
#include <alloca.h>
#include <time.h>
#ifndef PATH_MAX
# define PATH_MAX 4096
#endif
#ifndef DEVDIR
# define DEVDIR "/dev"
#endif
#ifndef SYSDIR
# define SYSDIR "/sys"
#endif
/**
* Stores a filename to `failure_file` and goes to the label `fail`.
*
* @param PATH:char * The file that could not be used.
* Must be accessible by `main`.
*/
#define FILE_FAILURE(PATH) \
do \
{ \
failure_file = PATH; \
goto fail; \
} \
while (0)
#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).
*/
static 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`.
*/
static const char *execname;
/**
* Arguments for `convert`,
* the output file should be printed into `convert_args[2]`.
* `NULL` is `convert` shall not be used.
*/
static char **convert_args = NULL;
/**
* If a function fails when it tries to
* open a file, it will set this variable
* point to the pathname of that file.
*/
static const char *failure_file = NULL;
/**
* Create an PNM-file that is sent to `convert` for convertion
* to a compressed format, 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 `convert`'s stdin
* @return Zero on success, -1 on error.
*/
static int
save_pnm (const char *fbpath, long width, long height, int fd)
{
char buf[PATH_MAX];
FILE *file = NULL;
int fbfd = 1;
int r, g, b;
ssize_t got, off;
uint32_t *pixel;
int saved_errno;
/* 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. */
for (off = 0; off < got; off += 4)
{
/* A pixel in the framebuffer is formatted as `%{blue}%{green}%{red}%{x}`
in big-endian binary, or `%{x}%{red}%{green}%{blue}` in little-endian binary. */
pixel = (uint32_t *)(buf + off);
r = (*pixel >> 16) & 255;
g = (*pixel >> 8) & 255;
b = (*pixel >> 0) & 255;
/* A pixel in the PNM image is formatted as `%{red} %{green} %{blue} ` in text. */
if (fprintf (file, "%s%s%s", inttable[r], inttable[g], inttable[b]) < 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 (off != got)
{
off -= 4;
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.
* @return Zero on success, -1 on error.
*/
static int
save (const char *fbpath, const char *imgpath, long width, long height)
{
int pipe_rw[2] = { -1, -1 };
pid_t pid;
int status;
int fd = -1;
int saved_errno;
if (convert_args == NULL)
goto no_convert;
/* Create a pipe that for sending data into the `convert` program. */
if (pipe (pipe_rw) < 0)
goto fail;
/* Fork the process, the child will exec. `convert`. */
pid = fork ();
if (pid == -1)
goto fail;
/* Child process: */
if (pid == 0)
{
/* Close the write-end of the pipe. */
close (pipe_rw[1]);
/* Turn the read-end of the into stdin. */
if (pipe_rw[0] != STDIN_FILENO)
{
close (STDIN_FILENO);
if (dup2 (pipe_rw[0], STDIN_FILENO) == -1)
goto child_fail;
close (pipe_rw[0]);
}
/* Exec. `convert` to convert the PNM-image we create to a compressed image. */
sprintf (convert_args[2], "%s", imgpath);
execvp ("convert", convert_args);
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 `convert` to exit. */
if (waitpid (pid, &status, 0) < 0)
goto fail;
/* Return successfully if and only if `convert` did. */
return status == 0 ? 0 : -1;
/* `convert` shall not be used: */
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;
}
/**
* Get the dimensions of the framebuffer.
*
* @param fbno The number of the framebuffer.
* @param width Output parameter for the width of the image.
* @param height Output parameter for the height of the image.
* @return Zero on success, -1 on error.
*/
static int
measure (int fbno, long *width, long *height)
{
static char buf[PATH_MAX];
char *delim;
int sizefd = -1;
ssize_t got;
int saved_errno;
/* Open the file with the framebuffer's dimensions. */
sprintf (buf, SYSDIR "/class/graphics/fb%i/virtual_size", fbno);
sizefd = open (buf, O_RDONLY);
if (sizefd == -1)
FILE_FAILURE (buf);
/* Get the dimensions of the framebuffer. */
got = read (sizefd, buf, sizeof (buf) / sizeof (char) - 1);
if (got < 0)
goto fail;
close (sizefd);
/* The read content is formated as `%{width},%{height}\n`,
convert it to `%{width}\0%{height}\0` and parse it. */
buf[got] = '\0';
delim = strchr (buf, ',');
*delim++ = '\0';
*width = atol (buf);
*height = atol (delim);
return 0;
fail:
saved_errno = errno;
if (sizefd >= 0)
close (sizefd);
errno = saved_errno;
return -1;
}
/**
* Duplicate all '%':s in a buffer until the first occurrence of a zero byte.
*
* @param buf The buffer.
* @param n The size of the buffer.
* @return -1 if the buffer is too small, otherwise.
* the new position of the first zero byte.
*/
static ssize_t
duplicate_percents (char *restrict buf, size_t n)
{
size_t p = 0, pi, pc = 0, i;
/* Count number of '%':s. */
for (i = 0; buf[i]; i++)
if (buf[i] == '%')
pc++;
/* Check whether the string will overflow. */
if (i + pc > n)
return -1;
/* Duplicate all '%':s. */
for (pi = 0; pi < pc; pi++)
{
p = (size_t)(strchr (buf + p, '%') - buf);
memmove (buf + p + 1, buf + p, (i - (p - pi)) * sizeof (char));
p += 2;
}
return (ssize_t)(i + pi);
}
/**
* Parse and evaluate a --exec argument or filename pattern.
*
* If `path != NULL` than all non-escaped spaces in
* `pattern` will be stored as 255-bytes in `buf`.
*
* @param buf The output buffer.
* @param n The size of `buf`.
* @param pattern The pattern to evaluate.
* @param fbno The index of the framebuffer.
* @param width The width of the image/framebuffer.
* @param height The height of the image/framebuffer.
* @param path The filename of the saved image, `NULL` during the evaluation of the filename pattern.
* @return Zero on success, -1 on error.
*/
static int evaluate (char *restrict buf, size_t n, const char *restrict pattern,
int fbno, long width, long height, const char *restrict path)
{
#define P(format, value) r = snprintf (buf + i, n - i, format "%zn", value, &j)
size_t i = 0;
ssize_t j = 0;
int percent = 0, backslash = 0, dollar = 0, r;
char c;
char* fmt;
time_t t;
struct tm tm;
/* Expand '$' and '\'. */
while ((c = *pattern++))
{
if (dollar)
{
dollar = 0;
if (path == NULL)
if ((c == 'f') || (c == 'n'))
continue;
if (c == 'i') P ("%i", fbno);
else if (c == 'f') P ("%s", path);
else if (c == 'n') P ("%s", strrchr (path, '/') ? (strrchr (path, '/') + 1) : path);
else if (c == 'p') P ("%ju", (uintmax_t)width * (uintmax_t)height);
else if (c == 'w') P ("%li", width);
else if (c == 'h') P ("%li", height);
else if (c == '$') r = 0, j = 1, buf[i] = '$';
else
continue;
if ((r < 0) || (j <= 0))
return -1;
if ((c == 'f') || (c == 'n'))
if (j = duplicate_percents (buf + i, n - i), j < 0)
goto enametoolong;
i += (size_t)j;
}
else if (backslash) buf[i++] = (c == 'n' ? '\n' : c), backslash = 0;
else if (percent) buf[i++] = c, percent = 0;
else if (c == '%') buf[i++] = c, percent = 1;
else if (c == '\\') backslash = 1;
else if (c == '$') dollar = 1;
else if (c == ' ') buf[i++] = path == NULL ? ' ' : (char)255; /* 255 is not valid in UTF-8. */
else buf[i++] = c;
if (i >= n)
goto enametoolong;
}
buf[i] = '\0';
/* Check whether there are any '%' to expand. */
if (strchr (buf, '%') == NULL)
return 0;
/* Copy the buffer so we can reuse the buffer and use its old content for the format. */
fmt = alloca ((strlen (buf) + 1) * sizeof (char));
memcpy (fmt, buf, (strlen (buf) + 1) * sizeof (char));
/* Expand '%'. */
t = time (NULL);
localtime_r (&t, &tm);
#ifdef __GNUC__
# pragma GCC diagnostic push
# pragma GCC diagnostic ignored "-Wformat-nonliteral"
#endif
if (strftime (buf, n, fmt, &tm) == 0)
goto enametoolong; /* No errors are defined for `strftime`. */
#ifdef __GNUC__
# pragma GCC diagnostic pop
#endif
return 0;
enametoolong:
return errno = ENAMETOOLONG, -1;
#undef P
}
/**
* 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;
char *arg;
size_t i, arg_count = 1;
pid_t pid;
int status;
/* Count arguments. */
for (i = 0; flatten_args[i]; i++)
if ((unsigned char)(flatten_args[i]) == 255)
arg_count++;
/* Allocate argument array. */
args = alloca ((arg_count + 1) * sizeof (char*));
/* 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)
return -1;
/* 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)
return -1;
/* Return successfully if and only if `the child` did. */
return status == 0 ? 0 : -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 default.
* @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)
{
static char imgpath[PATH_MAX];
char fbpath[PATH_MAX];
char *execargs = NULL;
void *new;
long width, height;
size_t size = PATH_MAX;
int i, saved_errno;
/* Get pathname for framebuffer, and stop if we have read all existing ones. */
sprintf (fbpath, DEVDIR "/fb%i", fbno);
if (access (fbpath, F_OK))
return 1;
/* Get the size of the framebuffer. */
if (measure (fbno, &width, &height) < 0)
goto fail;
/* Get output pathname. */
if (filepattern == NULL)
{
sprintf (imgpath, "fb%i.%s", fbno, (raw ? "pnm" : "png"));
if (access (imgpath, F_OK) == 0)
for (i = 2;; i++)
{
sprintf (imgpath, "fb%i.%s.%i", fbno, (raw ? "pnm" : "png"), i);
if (access (imgpath, F_OK))
break;
}
}
else
if (evaluate (imgpath, (size_t)PATH_MAX, filepattern, fbno, width, height, NULL) < 0)
return -1;
/* Take a screenshot of the current framebuffer. */
if (save (fbpath, imgpath, width, height) < 0)
goto fail;
fprintf (stderr, "Saved framebuffer %i to %s\n", fbno, imgpath);
/* Should we run a command over the image? */
if (execpattern == NULL)
return 0;
/* Get execute arguments. */
retry:
new = realloc (execargs, size * sizeof (char));
if (execargs == NULL)
goto fail;
execargs = new;
if (evaluate (execargs, size, execpattern, fbno, width, height, imgpath) < 0)
{
if ((errno != ENAMETOOLONG) || ((size >> 8) <= PATH_MAX))
goto fail;
size <<= 1;
goto retry;
}
/* Run command over image. */
if (exec_image (execargs) < 0)
goto fail;
free (execargs);
return 0;
fail:
saved_errno = errno;
free (execargs);
errno = saved_errno;
return -1;
}
/**
* Print usage information.
*
* @return Zero on success, -1 on error.
*/
static int
print_help(void)
{
return printf ("SYNOPSIS\n"
"\t%s [options...] [filename-pattern] [-- options-for-convert...]\n"
"\n"
"OPTIONS\n"
"\t--help Print usage information.\n"
"\t--version Print program name and version.\n"
"\t--copyright Print copyright information.\n"
"\t--raw Save in PNM rather than in PNG.\n"
"\t--exec CMD Command to run for each saved image.\n"
"\n"
"SPECIAL STRINGS\n"
"\tBoth the --exec and filename-pattern parameters can take format specifiers\n"
"\tthat are expanded by scrotty when encountered. There are two types of format\n"
"\tspecifier. Characters preceded by a '%%' are interpretted by strftime(3).\n"
"\tSee `man strftime` for examples. These options may be used to refer to the\n"
"\tcurrent date and time. The second kind are internal to scrotty and are prefixed\n"
"\tby '$' or '\\'. The following specifiers are recognised:\n"
"\n"
"\t\n"
"\t$i framebuffer index\n"
"\t$f image filename/pathname (ignored when used in filename-pattern)\n"
"\t$n image filename (ignored when used in filename-pattern)\n"
"\t$p image width multiplied by image height\n"
"\t$w image width\n"
"\t$h image height\n"
"\t$$ expands to a literal '$'\n"
"\t\\n expands to a new line\n"
"\t\\\\ expands to a literal '\\'\n"
"\t\\ expands to a literal ' ' (the string is a backslash followed by a space)\n"
"\n"
"\tA space that is not prefixed by a backslash in --exec is interpreted as an\n"
"\targument delimiter. This is the case even at the beginning and end of the\n"
"\tstring and if a space was the previous character in the string.\n"
"\n",
execname) < 0 ? -1 : 0;
}
/**
* Print program name and version.
*
* @return Zero on success, -1 on error.
*/
static int
print_version (void)
{
return printf ("%s %s\n", PROGRAM_NAME, PROGRAM_VERSION) < 0 ? -1 : 0;
}
/**
* Print copyright information
*
* @return Zero on success, -1 on error
*/
static int
print_copyright (void)
{
return printf ("scrotty -- Screenshot program for Linux's TTY\n"
"Copyright (C) 2014, 2015 Mattias Andrée (maandree@member.fsf.org)\n"
"\n"
"This program is free software: you can redistribute it and/or modify\n"
"it under the terms of the GNU General Public License as published by\n"
"the Free Software Foundation, either version 3 of the License, or\n"
"(at your option) any later version.\n"
"\n"
"This program is distributed in the hope that it will be useful,\n"
"but WITHOUT ANY WARRANTY; without even the implied warranty of\n"
"MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the\n"
"GNU General Public License for more details.\n"
"\n"
"You should have received a copy of the GNU General Public License\n"
"along with this program. If not, see <http://www.gnu.org/licenses/>.\n"
) < 0 ? -1 : 0;
}
/**
* Take a screenshot of all framebuffers
*
* @param argc The number of elements in `argv`
* @param argv Command line arguments
* @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), 1
int fbno, r, i, dash = argc, exec = -1, help = 0;
int raw = 0, version = 0, copyright = 0, filepattern = -1;
static char convert_args_0[] = "convert";
static char convert_args_1[] = DEVDIR "/stdin";
static char convert_args_2[PATH_MAX];
execname = argc ? *argv : "scrotty";
/* Parse command line. */
for (i = 1; i < argc; i++)
{
if (!strcmp (argv[i], "--help")) help = 1;
else if (!strcmp (argv[i], "--version")) version = 1;
else if (!strcmp (argv[i], "--copyright")) copyright = 1;
else if (!strcmp (argv[i], "--raw")) raw = 1;
else if (!strcmp (argv[i], "--exec")) exec = ++i;
else if (!strcmp (argv[i], "--"))
{
dash = i + 1;
break;
}
else if ((argv[i][0] == '-') || (filepattern != -1))
EXIT_USAGE ("Unrecognised option.");
else
filepattern = i;
}
/* Check that --exec is valid. */
if (exec == argc)
EXIT_USAGE ("--exec has no argument.");
/* Was --help, --version, or --copyright used? */
if (help) return -(print_help ());
if (version) return -(print_version ());
if (copyright) return -(print_copyright ());
/* Create arguments for `convert`. */
if ((!raw) || (dash < argc))
{
convert_args = alloca ((size_t)(4 + (argc - dash)) * sizeof (char*));
convert_args[0] = convert_args_0;
convert_args[1] = convert_args_1;
convert_args[2] = convert_args_2;
for (i = dash; i < argc; i++)
convert_args[i - dash + 2] = argv[i];
convert_args[3 + (argc - dash)] = NULL;
}
/* Take a screenshot of each framebuffer. */
for (fbno = 0;; fbno++)
{
r = save_fb (fbno, raw,
(filepattern < 0 ? NULL : argv[filepattern]),
(exec < 0 ? NULL : argv[exec]));
if (r < 0)
goto fail;
if (r > 0)
break;
}
return 0;
fail:
if (failure_file == NULL)
perror (execname);
else
fprintf (stderr, "%s: %s: %s\n",
execname, strerror (errno), failure_file);
return 1;
#undef EXIT_USAGE
}
