From 5b20475c7faf89bbabc9eab43c7e5622317a18fc Mon Sep 17 00:00:00 2001
From: dec05eba <dec05eba@protonmail.com>
Date: Tue, 14 Jul 2020 07:49:07 +0200
Subject: Implement first part of command_sync

---
 src/main.c | 87 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 83 insertions(+), 4 deletions(-)

diff --git a/src/main.c b/src/main.c
index bc554b5..11fdc54 100644
--- a/src/main.c
+++ b/src/main.c
@@ -14,6 +14,10 @@
 
 #include <dirent.h>
 #include <libgen.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <signal.h>
+#include <unistd.h>
 
 #define NAME_MAX_LEN 250
 
@@ -261,11 +265,86 @@ static void command_add(int argc, char **argv, char *rss_config_dir, char *html_
     }
 }
 
-static void command_sync(int argc, char **argv) {
-    if(argc < 2)
+static void sync_rss_html(char *rss_config_dir, char *html_config_dir, const char *download_dir, int sync_rate_sec) {
+    (void)rss_config_dir;
+    (void)html_config_dir;
+    (void)download_dir;
+    (void)sync_rate_sec;
+}
+
+static int cmdline_contains_str(const char *cmdline, const char *str) {
+    for(;;) {
+        int arg_len = strlen(cmdline);
+        if(arg_len == 0)
+            return -1;
+
+        if(strstr(cmdline, str))
+            return 0;
+
+        cmdline += arg_len;
+    }
+}
+
+static void automedia_pid_signal_handler(int signum) {
+    (void)signum;
+    unlink("/tmp/automedia.pid");
+    exit(1);
+}
+
+static void command_sync(int argc, char **argv, char *rss_config_dir, char *html_config_dir) {
+    if(argc < 1)
         usage_sync();
 
-    (void)argv;
+    const char *download_dir = argv[0];
+    const char automedia_pid_path[] = "/tmp/automedia.pid";
+    
+    int pid_file = open(automedia_pid_path, O_CREAT | O_EXCL | O_RDWR);
+    if(pid_file == -1 && errno == EEXIST) {
+        char *running_automedia_pid;
+        long running_automedia_pid_size;
+        if(file_get_content(automedia_pid_path, &running_automedia_pid, &running_automedia_pid_size) == 0) {
+            char cmdline_file_path[128];
+            sprintf(cmdline_file_path, "/proc/%s/cmdline", running_automedia_pid);
+            free(running_automedia_pid);
+
+            char *cmdline;
+            long cmdline_size;
+            if(file_get_content(cmdline_file_path, &cmdline, &cmdline_size) == 0
+                    && cmdline_contains_str(cmdline, "automedia") == 0
+                    && cmdline_contains_str(cmdline, "sync") == 0) {
+                fprintf(stderr, "Automedia is already running with sync");
+                free(cmdline);
+                exit(0);
+            }
+            free(cmdline);
+        } else {
+            free(running_automedia_pid);
+        }
+
+        remove(automedia_pid_path);
+        pid_file = open(automedia_pid_path, O_CREAT | O_EXCL | O_RDWR);
+    }
+
+    if(pid_file == -1 && errno != EEXIST) {
+        fprintf(stderr, "Failed to create %s\n", automedia_pid_path);
+        exit(1);
+    }
+
+    signal(SIGINT, automedia_pid_signal_handler);
+
+    char process_pid_str[32];
+    sprintf(process_pid_str, "%d", getpid());
+    int process_pid_str_len = strlen(process_pid_str);
+    if(write(pid_file, process_pid_str, process_pid_str_len) != process_pid_str_len) {
+        fprintf(stderr, "Failed to write pid to %s\n", automedia_pid_path);
+        unlink(automedia_pid_path);
+        exit(1);
+    }
+
+    close(pid_file);
+    const int sync_rate_sec = 15 * 60; /* every 15 min */
+    sync_rss_html(rss_config_dir, html_config_dir, download_dir, sync_rate_sec);
+    unlink(automedia_pid_path);
 }
 
 static void command_downloaded(const char *rss_config_dir, const char *html_config_dir) {
@@ -317,7 +396,7 @@ int main(int argc, char **argv) {
     if(strcmp(command, "add") == 0) {
         command_add(argc - 2, argv + 2, rss_config_dir, html_config_dir, dirname(argv[0]));
     } else if(strcmp(command, "sync") == 0) {
-        command_sync(argc - 2, argv + 2);
+        command_sync(argc - 2, argv + 2, rss_config_dir, html_config_dir);
     } else if(strcmp(command, "downloaded") == 0) {
         command_downloaded(rss_config_dir, html_config_dir);
     } else {
-- 
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