gluon-packages/net/batman-adv-visdata/src/batman-adv-visdata.c

100 lines
2.5 KiB
C

#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
/*
* batadv-vis updates its originators every 10s
* We choose a bigger interval to make reboots even more unlikely,
* and make our interval coprime with batadv-vis's
*/
#define UPDATE_INTERVAL 19
#define INPUT_DIR "/sys/kernel/debug/batman_adv"
#define OUTPUT_DIR "/tmp/batman-adv-visdata"
#define ORIGINATORS "originators"
#define TRANSTABLE_GLOBAL "transtable_global"
static bool copy_file(const char *src, const char *dst) {
FILE *input = NULL, *output = NULL;
input = fopen(src, "r");
if (!input)
goto error;
output = fopen(dst, "w");
if (!output)
goto error;
while (!feof(input)) {
if (ferror(input))
goto error;
char buf[1024];
size_t r = fread(buf, 1, sizeof(buf), input);
if (!r)
continue;
if (!fwrite(buf, r, 1, output))
goto error;
}
fclose(input);
fclose(output);
return true;
error:
if (input)
fclose(input);
if (output)
fclose(output);
unlink(dst);
return false;
}
static void handle_file(const char *mesh, const char *file) {
char src[strlen(INPUT_DIR) + 1 + strlen(mesh) + 1 + strlen(file) + 1];
char dst[strlen(OUTPUT_DIR) + 1 + strlen(mesh) + 1 + strlen(file) + 1];
char tmp[sizeof(dst) + 4];
snprintf(src, sizeof(src), "%s/%s/%s", INPUT_DIR, mesh, file);
snprintf(dst, sizeof(dst), "%s/%s/%s", OUTPUT_DIR, mesh, file);
snprintf(tmp, sizeof(tmp), "%s.new", dst);
if (copy_file(src, tmp))
rename(tmp, dst);
else
unlink(dst);
}
static void handle_mesh(const char *mesh) {
char dir[strlen(OUTPUT_DIR) + 1 + strlen(mesh) + 1];
snprintf(dir, sizeof(dir), "%s/%s", OUTPUT_DIR, mesh);
mkdir(dir, 0777);
handle_file(mesh, ORIGINATORS);
handle_file(mesh, TRANSTABLE_GLOBAL);
}
int main(int argc, char *argv[]) {
system("rm -rf " OUTPUT_DIR "; mkdir -p " OUTPUT_DIR);
while (true) {
int i;
for (i = 1; i < argc; i++)
handle_mesh(argv[i]);
sleep(UPDATE_INTERVAL);
}
}