/**
* scrotty — Screenshot program for Linux's TTY
* Copyright © 2014 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>
#ifndef PATH_MAX
# define PATH_MAX 4096
#endif
#ifndef DEVDIR
# define DEVDIR "/dev"
#endif
#ifndef SYSDIR
# define SYSDIR "/sys"
#endif
#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]`.
*/
static char** convert_args;
/**
* Create an PNM-file that is sent to `convert` for convertion to a compressed format
*
* @param fbname The framebuffer device
* @param fbno The number of the framebuffer
* @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, int fbno, long width, long height, int fd)
{
char buf[PATH_MAX];
FILE* file;
int saved_errno, fbfd, r, g, b;
ssize_t got, off;
/* Open the framebuffer device for reading. */
if (fbfd = open(fbpath, O_RDONLY), fbfd < 0)
return -1;
/* Create a FILE*, for writing, for the image file. */
file = fdopen(fd, "w");
if (file == NULL)
return saved_errno = errno, close(fbfd), errno = saved_errno, -1;
/* The PNM image should begin with `P3\n%{width} %{height}\n%{colour max=255}\n`.
('\n' and ' ' can be exchanged at will.) */
fprintf(file, "P3\n%li %li\n255\n", width, height);
/* 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) - off * sizeof(char));
if (got < 0)
return saved_errno = errno, fclose(file), close(fbfd), errno = saved_errno, -1;
if (got += off, got == 0)
break;
/* 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. */
uint32_t* 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. */
fprintf(file, "%s%s%s", inttable[r], inttable[g], inttable[b]);
}
/* 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, (got - off) * sizeof(char));
off = got - off;
}
else
off = 0;
}
/* Close files and return successfully. */
fflush(file);
fclose(file);
close(fbfd);
return 0;
}
/**
* Create an image of a framebuffer
*
* @param fbname The framebuffer device
* @param imgname The pathname of the output image
* @param fbno The number of the framebuffer
* @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, int fbno, long width, long height)
{
int pipe_rw[2];
pid_t pid, reaped;
int saved_errno, status;
/* Create a pipe that for sending data into the `convert` program. */
if (pipe(pipe_rw) < 0)
return -1;
/* Fork the process, the child will exec. `convert`. */
if (pid = fork(), pid == -1)
return saved_errno = errno, close(pipe_rw[0]), close(pipe_rw[1]), errno = saved_errno, -1;
/* 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);
dup2(pipe_rw[0], STDIN_FILENO);
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);
perror(execname);
exit(1);
}
/* Parent process: */
/* Close the read-end of the pipe. */
close(pipe_rw[0]);
/* Create a PNM-image of the framebuffer. */
if (save_pnm(fbpath, fbno, width, height, pipe_rw[1]) < 0)
return saved_errno = errno, close(pipe_rw[1]), errno = saved_errno, -1;
/* Close the write-end of the pipe. */
close(pipe_rw[1]);
/* Wait for `convert` to exit. */
for (reaped = 0; reaped != pid;)
if (reaped = waitpid(pid, &status, 0), reaped < 0)
return -1;
/* Return successfully if and only if `convert` did. */
return status == 0 ? 0 : -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)
{
char buf[PATH_MAX];
char* delim;
int sizefd, saved_errno;
ssize_t got;
/* Open the file with the framebuffer's dimensions. */
sprintf(buf, SYSDIR "/class/graphics/fb%i/virtual_size", fbno);
if (sizefd = open(buf, O_RDONLY), sizefd < 0)
return -1;
/* Get the dimensions of the framebuffer. */
if (got = read(sizefd, buf, sizeof(buf) / sizeof(char) - 1), got < 0)
return saved_errno = errno, close(sizefd), errno = saved_errno, -1;
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;
}
/**
* Take a screenshot of a framebuffer
*
* @param fbno The number of the framebuffer
* @return Zero on success, -1 on error, 1 if the framebuffer does not exist
*/
static int save_fb(int fbno)
{
char fbpath[PATH_MAX];
char imgpath[PATH_MAX];
long width, height;
int i;
/* 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)
return -1;
/* Get output pathname. */
sprintf(imgpath, "fb%i.png", fbno);
if (access(imgpath, F_OK) == 0)
for (i = 2;; i++)
{
sprintf(imgpath, "fb%i.png.%i", fbno, i);
if (access(imgpath, F_OK))
break;
}
/* Take a screenshot of the current framebuffer. */
if (save(fbpath, imgpath, fbno, width, height) < 0)
return -1;
fprintf(stderr, "Saved framebuffer %i to %s\n", fbno, imgpath);
return 0;
}
#define p(...) if (printf(__VA_ARGS__) < 0) return -1;
/**
* Print usage information
*
* @return Zero on success, -1 on error
*/
static int print_help(void)
{
p("SYNOPSIS\n");
p("\t%s [options...] [filename-pattern] [-- options-for-convert...]\n", execname);
p("\n");
p("OPTIONS\n");
p("\t--help Print usage information.\n");
p("\t--version Print program name and version.\n");
p("\t--copyright Print copyright information.\n");
p("\t--exec CMD Command to run for each saved image.\n");
p("\n");
p("SPECIAL STRINGS\n");
p("\tBoth the --exec and filename-pattern parameters can take format specifiers\n");
p("\tthat are expanded by scrotty when encountered. There are two types of format\n");
p("\tspecifier. Characters preceded by a '%%' are interpretted by strftime(2).\n");
p("\tSee `man strftime` for examples. These options may be used to refer to the\n");
p("\tcurrent date and time. The second kind are internal to scrotty and are prefixed\n");
p("\tby '$'. The following specifiers are recognised:\n");
p("\n");
p("\t\n");
p("\t$i framebuffer index\n");
p("\t$f image filename/pathname (ignored when used in filename-pattern)\n");
p("\t$n image filename (ignored when used in filename-pattern)\n");
p("\t$p image width multiplied by image height\n");
p("\t$w image width\n");
p("\t$h image height\n");
p("\t$$ expands to a literal '$'\n");
p("\t\\n expands to a new line\n");
p("\t\\\\ expands to a literal '\\'\n");
p("\t\\ expands to a literal ' ' (the string is a backslash followed by a space)\n");
p("\n");
p("\tA space that is not prefixed by a backslash in --exec is interpreted as an\n");
p("\targument delimiter. This is the case even at the beginning and end of the\n");
p("\tstring and if the a space was the previous character in the string.\n");
p("\n");
return 0;
}
/**
* Print program name and version
*
* @return Zero on success, -1 on error
*/
static int print_version(void)
{
p("%s %s\n", PROGRAM_NAME, PROGRAM_VERSION);
return 0;
}
/**
* Print copyright information
*
* @return Zero on success, -1 on error
*/
static int print_copyright(void)
{
p("scrotty -- Screenshot program for Linux's TTY\n");
p("Copyright (C) 2014 Mattias Andrée (maandree@member.fsf.org)\n");
p("\n");
p("This program is free software: you can redistribute it and/or modify\n");
p("it under the terms of the GNU General Public License as published by\n");
p("the Free Software Foundation, either version 3 of the License, or\n");
p("(at your option) any later version.\n");
p("\n");
p("This program is distributed in the hope that it will be useful,\n");
p("but WITHOUT ANY WARRANTY; without even the implied warranty of\n");
p("MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the\n");
p("GNU General Public License for more details.\n");
p("\n");
p("You should have received a copy of the GNU General Public License\n");
p("along with this program. If not, see <http://www.gnu.org/licenses/>.\n");
return 0;
}
#undef p
/**
* 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[])
{
int fbno, r, i, dash = argc, exec = -1, help = 0, version = 0, copyright = 0, filepattern = -1;
static char convert_args_2[PATH_MAX];
execname = *argv;
/* 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], "--exec")) exec = ++i; /* TODO use this */
else if (!strcmp(argv[i], "--"))
{
dash = i + 1;
break;
}
else if ((argv[i][0] == '-') || (filepattern != -1))
return fprintf(stderr, "Unrecognised option. Type `%s --help` for help.\n", execname), 1;
else
filepattern = i; /* TODO use this */
}
/* Check that --exec is valid. */
if (exec == argc)
return fprintf(stderr, "--exec has no argument. Type `%s --help` for help.\n", execname), 1;
/* 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`. */
convert_args = alloca((4 + (argc - dash)) * sizeof(char*));
convert_args[0] = "convert";
convert_args[1] = DEVDIR "/stdin";
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);
if (r < 0) return perror(execname), 1;
if (r > 0) break;
}
return 0;
}
