From 278ec70925695a7b767e2b628c67319d218c3d03 Mon Sep 17 00:00:00 2001
From: Carson Fleming <cflems@cflems.net>
Date: Mon, 19 Oct 2020 22:04:09 +0200
Subject: Added logging support (incomplete unless using noclose)

---
 daemonize.c | 104 ++++++++++++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 83 insertions(+), 21 deletions(-)

(limited to 'daemonize.c')

diff --git a/daemonize.c b/daemonize.c
index 94662d6..c9c925f 100644
--- a/daemonize.c
+++ b/daemonize.c
@@ -1,16 +1,37 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <unistd.h>
+#include <getopt.h>
 #include <ctype.h>
 #include <string.h>
+#include <stdbool.h>
+
+const struct option longopts[] = {
+  {"chdir", no_argument, NULL, 'd'},
+  {"noclose", no_argument, NULL, 'n'},
+  {"log-stdout", required_argument, NULL, '1'},
+  {"log-stderr", required_argument, NULL, '2'},
+  {0, 0, 0, 0}
+};
+const char* optstring = "dn1:2:";
 
 void q (char* m) {
     fprintf(stderr, "%s\n", m);
     exit(1);
 }
 
+void qusage () {
+    q("[daemonize] Usage: daemonize [-d|--chdir] [-n|--noclose] [-1|--log-stdout /path/to/log] [-2|--log-stderr /path/to/log] <command>");
+}
+
 void qtoofewargs () {
-    q("[daemonize] Too few arguments.\nUsage: daemonize [--chdir] [--noclose] <command>");
+    fprintf(stderr, "[daemonize] Too few arguments.\n");
+    qusage();
+}
+
+void qinvalidarg (char* arg) {
+    fprintf(stderr, "[daemonize] Unrecognized argument: %s\n", arg);
+    qusage();
 }
 
 char* lowerdup (char* a) {
@@ -22,32 +43,73 @@ char* lowerdup (char* a) {
     return b;
 }
 
-int main (int argc, char** argv) {
+struct opts {
+    int nochdir;
+    int noclose;
+    FILE* stdlog;
+    FILE* errlog;
+};
+
+void parseargs(int argc, char** argv, struct opts* savedopts) {
     if (argc < 2) qtoofewargs();
-    int i, cmdlen = 0, buff_size = 256, nochdir = 1, noclose = 0;
+    int c;
+
+    while ((c = getopt_long(argc, argv, optstring, longopts, NULL)) != -1) {
+        switch (c) {
+            case 'd':
+                savedopts->nochdir = false;
+                break;
+            case 'n':
+                savedopts->noclose = true;
+                break;
+            case '1':
+                savedopts->stdlog = fopen(optarg, "a");
+                if (!savedopts->stdlog) q("[daemonize] Unable to open stdout log, quitting.");
+                break;
+            case '2':
+                savedopts->errlog = fopen(optarg, "a");
+                if (!savedopts->errlog) q("[daemonize] Unable to open stderr log, quitting.");
+                break;
+            default:
+                // just let getopt print the error
+                break;
+    }
+  }
+}
+
+int main (int argc, char** argv) {
+    struct opts options = {true, false, NULL, NULL};
+    parseargs(argc, argv, &options);
+
+    int cmdlen = 0, buff_size = 256;
     char* buffer = malloc(buff_size);
-    
-    for (i = 1; i < argc; i++) {
-        char* cmp = lowerdup(argv[i]);
-        if (strcmp(cmp, "--chdir") == 0) nochdir = 0;
-        else if (strcmp(cmp, "--noclose") == 0) noclose = 1;
-        else {
-            int arglen = strlen(argv[i]);
-            if (cmdlen+arglen+1 > buff_size) {
-                buff_size *= 2;
-                buffer = realloc(buffer, buff_size);
-                if (buffer == NULL) q("[daemonize] Out of memory parsing arguments.");
-            }
-            strncpy(&buffer[cmdlen], argv[i], arglen);
-            cmdlen += arglen+1;
-            buffer[cmdlen-1] = ' ';
+
+    while (optind < argc) {
+        int arglen = strlen(argv[optind]);
+        if (cmdlen+arglen+1 > buff_size) {
+            buff_size *= 2;
+            buffer = realloc(buffer, buff_size);
+            if (buffer == NULL) q("[daemonize] Out of memory parsing arguments.");
         }
-        free(cmp);
+        strncpy(&buffer[cmdlen], argv[optind++], arglen);
+        cmdlen += arglen+1;
+        buffer[cmdlen-1] = ' ';
     }
     buffer[cmdlen-1] = 0;
-    
+
     if (cmdlen < 1) qtoofewargs();
 
-    daemon(nochdir, noclose);
+    // Set up logs as appropriate
+    int logs = options.stdlog || options.errlog;
+    if (options.stdlog) {
+        dup2(fileno(options.stdlog), fileno(stdout));
+        fclose(options.stdlog);
+    }
+    if (options.errlog) {
+        dup2(fileno(options.errlog), fileno(stderr));
+        fclose(options.errlog);
+    }
+    // TODO: close stdin, stderr, stdout and redirect to /dev/null if logging
+    daemon(options.nochdir, options.noclose | logs);
     system(buffer);
 }
-- 
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