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Diffstat (limited to '')
| -rw-r--r-- | src/kern-linux.c | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/src/kern-linux.c b/src/kern-linux.c new file mode 100644 index 0000000..af17822 --- /dev/null +++ b/src/kern-linux.c @@ -0,0 +1,151 @@ +/** + * 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/>. + */ +#include "common.h" +#include "kern.h" +#include "pnm.h" + + + +/** + * Stop when `try_alt_fbpath` (in scrotty.c) reaches this value. + */ +const int alt_fbpath_limit = 2; + + + +/** + * This is called if no framebuffer is found. + * + * It prints a message describing this condition + * and suggests how to resolve it. + */ +void +print_not_found_help (void) +{ + fprintf (stderr, _("%s: Unable to find a framebuffer. " + "If you have a file named %s/MAKEDEV, " + "run it with '-d /dev/fb' as root, " + "or try running '%s'.\n"), + execname, DEVDIR, "mknod /dev/fb0 c 29 0 && chgrp video /dev/fb0"); +} + + +/** + * Construct the path to a framebuffer device. + * + * @param pathbuf Ouput buffer for the path. + * @param altpath The index of the alternative path-pattern to use. + * @param fbno The index of the framebuffer. + */ +void +get_fbpath (char *pathbuf, int altpath, int fbno) +{ + sprintf (pathbuf, "%s/fb%s%i", DEVDIR, (altpath ? "/" : ""), fbno); +} + + +/** + * Get the dimensions of a framebuffer. + * + * @param fbno The number of the framebuffer. + * @param fbpath The path to the framebuffer device.. + * @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. + */ +int +measure (int fbno, char *fbpath, 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, "%s/class/graphics/fb%i/virtual_size", SYSDIR, 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; + + (void) fbpath; +} + + +/** + * Convert read data from a framebuffer to PNM pixel data. + * + * @param file The output image file. + * @param buf Buffer with read data. + * @param n The number of read characters. + * @param adjustment Set to zero if all bytes were converted + * (a whole number of pixels where available,) + * otherwise, set to the number of bytes a + * pixel is encoded. + * @return Zero on success, -1 on error. + */ +int +convert_fb (FILE *file, char *buf, size_t n, size_t *adjustment) +{ + uint32_t *pixel; + int r, g, b; + size_t off; + + for (off = 0; off < n; 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; + + if (SAVE_PIXEL(file, r, g, b) < 0) + goto fail; + } + + *adjustment = (off != n ? 4 : 0); + return 0; + fail: + return -1; +} + |