backsaver: Simple and efficient backlight saver daemon.

* Here comes the backsaver, ruthless ipaq-sleep killer.
* Work in progress.

1 files changed, 256 insertions, 0 deletions

diff --git a/packages/backsaver/files/backsaver.c b/packages/backsaver/files/backsaver.c
new file mode 100644
index 0000000000..3f030b9dd9
--- /dev/null
+++ b/packages/backsaver/files/backsaver.c
@@ -0,0 +1,256 @@
+/* 
+ *  backsaver - Small backlight power saver daemon
+ *
+ *  This app relies on contemporary Linux 2.6 intefaces, like
+ *  backlight class dev and generic input devices. Legacy interfaces
+ *  are not supported by design.
+ *
+ *  Copyright (C) 2007, 2008 Paul Sokolovsky <pmiscml@gmail.com>
+ *   
+ *  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 
+ *  2 of the License, or (at your option) any later version. 
+ */
+
+#include <getopt.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <dirent.h>
+#include <sys/stat.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+int opt_verbose;
+int opt_timeout = 2;
+int opt_power;
+int opt_brightness = -1;
+
+char readbuf[256];
+fd_set read_fds;
+fd_set work_fds;
+int fds[32];
+
+int bl_state = 1;
+
+#define BL_PATH "/sys/class/backlight/"
+
+/* Backlight device properties */
+char bldev_brightness_path[256] = BL_PATH;
+char bldev_power_path[256] = BL_PATH;
+int  bldev_max_brightness;
+int  bldev_saved_brightness;
+int  bldev_dim_brightness;
+
+void fatal(char *msg) 
+{
+    fprintf(stderr, "%s\n", msg);
+    exit(1);
+}
+
+int sysfs_get_value(char *fname)
+{
+    char buf[64];
+    int fd = open(fname, O_RDONLY);
+    int sz = read(fd, buf, sizeof(buf) - 1);
+    buf[sz] = 0;
+    close(fd);
+    return atoi(buf);
+}
+
+void sysfs_set_value(char *fname, int val)
+{
+    char buf[64];
+    int fd = open(fname, O_WRONLY);
+    int sz = sprintf(buf, "%d\n", val);
+    write(fd, buf, sz);
+    close(fd);
+}
+
+char *bldev_scan()
+{
+    static char name[256];
+    DIR *dir;
+    struct dirent *de;
+    int more_than_one = 0;
+    
+    dir = opendir(BL_PATH);
+    if (!dir)
+	fatal("Backlight device class does not seem to be support by kernel (" BL_PATH " is absent)");
+
+    *name = 0;
+    while (de = readdir(dir)) {
+	if (de->d_name[0] == '.')
+	    continue;
+	if (*name == 0) {
+	    strcpy(name, de->d_name);
+	} else {
+	    more_than_one = 1;
+	    break;
+	}
+    }
+
+    closedir(dir);
+    if (*name == 0)
+	fatal("There does not seem to be any backlight device available (" BL_PATH " is empty)");
+    if (more_than_one)
+	fatal("There seems to be several backlight devices available, use --device= option");
+
+    return name;
+}
+
+void bldev_init(char *bldev)
+{
+    strcat(bldev_brightness_path, bldev);
+    strcat(bldev_brightness_path, "/brightness");
+    strcat(bldev_power_path, bldev);
+    strcat(bldev_power_path, "/power");
+
+    char buf[PATH_MAX];
+    memcpy(buf, BL_PATH, sizeof(BL_PATH));
+    strcat(buf, bldev);
+    strcat(buf, "/max_brightness");
+    bldev_max_brightness = sysfs_get_value(buf);
+    
+    bldev_dim_brightness = bldev_max_brightness * opt_brightness / 100;
+}
+
+void set_backlight(int state) 
+{
+    if (!bl_state) {
+	if (opt_verbose)
+	    printf("BL off\n");
+	if (opt_power) {
+	    sysfs_set_value(bldev_power_path, 4);
+	} else {
+	    bldev_saved_brightness = sysfs_get_value(bldev_brightness_path);
+	    sysfs_set_value(bldev_brightness_path, bldev_dim_brightness);
+	}
+    } else {
+	if (opt_verbose)
+	    printf("BL on\n");
+	if (opt_power) {
+	    sysfs_set_value(bldev_power_path, 0);
+	} else {
+	    sysfs_set_value(bldev_brightness_path, bldev_saved_brightness);
+	}
+    }
+}
+
+#define INPUT_PATH "/dev/input/"
+
+int main_loop(int argc, char *argv[], int argstart) 
+{
+    fd_set read_fds;
+    struct timeval timeout;
+    int i, maxfd = 0, numfd = 0;
+    
+    FD_ZERO(&read_fds);
+    
+    if (argstart == argc) {
+	static char path[256] = INPUT_PATH;
+        DIR *dir;
+	struct dirent *de;
+	struct stat stat;
+    
+	dir = opendir(INPUT_PATH);
+	if (!dir)
+	    fatal("Cannot open generic input device directory (" INPUT_PATH " is absent)");
+
+	while (de = readdir(dir)) {
+	    if (de->d_name[0] == '.')
+		continue;
+	    strcpy(path + sizeof(INPUT_PATH) - 1, de->d_name);
+	    
+	    if (lstat(path, &stat))
+		fatal("Cannot stat input device to monitor");
+	    if (S_ISLNK(stat.st_mode)) {
+		if (opt_verbose)
+		    printf("Skipping symlink %s\n", path);
+		continue;
+	    }
+	    if (opt_verbose)
+		printf("Using %s\n", path);
+
+    	    int fd = open(path, O_RDONLY);
+	    if (fd == -1)
+		fatal("Cannot open input device to monitor");
+	    if (fd > maxfd)
+		maxfd = fd;
+	    fds[numfd++] = fd;
+	    FD_SET(fd, &read_fds);
+	}
+
+	closedir(dir);
+    } else {
+        for (i = argstart; i < argc; i++) {
+	    if (opt_verbose)
+		printf("Using: %s\n", argv[i]);
+    	    int fd = open(argv[i], O_RDONLY);
+	    if (fd == -1)
+		fatal("Cannot open input device to monitor");
+	    if (fd > maxfd)
+		maxfd = fd;
+	    fds[numfd++] = fd;
+	    FD_SET(fd, &read_fds);
+        }
+    }
+
+    timeout.tv_usec = 0;
+
+    while (1) {
+	memcpy(&work_fds, &read_fds, sizeof(read_fds));
+	timeout.tv_sec = opt_timeout;
+	i = select(maxfd + 1, &work_fds, NULL, NULL, &timeout);
+	if (opt_verbose)
+    	    printf("Select returned: %d\n", i);
+	if (i > 0) {
+	    if (!bl_state) {
+		bl_state = 1;
+		set_backlight(bl_state);
+	    }
+	    for (i = 0; i < numfd; i++) {
+		if (FD_ISSET(fds[i], &work_fds)) {
+		    int sz = read(fds[i], readbuf, sizeof(readbuf));
+		    if (opt_verbose)
+			printf("Discarded %d bytes from fd %d\n", sz, fds[i]);
+		}
+	    }
+	} else {
+	    if (bl_state) {
+		bl_state = 0;
+		set_backlight(bl_state);
+	    }
+	}
+	    
+    }
+}
+
+struct option options[] = {
+    { "verbose", no_argument, &opt_verbose, 1 },
+    { "timeout", required_argument, NULL, 't' },
+    { "power", no_argument, &opt_power, 1 },
+    { "brightness", required_argument, NULL, 'b' },
+    NULL
+}; 
+int main(int argc, char *argv[])
+{
+    int opt;
+    while ((opt = getopt_long(argc, argv, "?h", options, NULL)) != -1) {
+	switch (opt) {
+	case 't':
+	    opt_timeout = atoi(optarg);
+	    break;
+	case 'b':
+	    opt_brightness = atoi(optarg);
+	    break;
+	}
+    }
+    printf("%d\n", optind);
+    
+    char *bldev = bldev_scan();
+    bldev_init(bldev);
+    
+    return main_loop(argc, argv, optind);
+}