From 519f9d415fba66b58572cf39b4cf5e2596a29e9f Mon Sep 17 00:00:00 2001
From: Hippolyte Chauvin <hchauvin38@outlook.fr>
Date: Mon, 4 Dec 2023 23:07:42 +0100
Subject: [PATCH] first-free-port : meilleure gestion des erreurs

---
 src/first-free-port.c | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/src/first-free-port.c b/src/first-free-port.c
index 1e246cd..62fe88f 100644
--- a/src/first-free-port.c
+++ b/src/first-free-port.c
@@ -3,6 +3,7 @@
 #include <fcntl.h>
 #include <sysexits.h>
 #include <string.h>
+#include <errno.h>
 
 #define MIN_TCP_PORT 1
 #define TCP_TABLE "/proc/net/tcp"
@@ -12,6 +13,13 @@
 #define LISTENING_HEX "0A"
 #define PORTS_BLOCKS_TO_ALLOW 4
 
+/**
+ * Print a nice error message
+ */
+static void print_error(char *name, const char *message) {
+    fprintf(stderr, "%s: %s\n", name, message);
+}
+
 /**
  * Get all the listening TCP ports
  */
@@ -81,20 +89,25 @@ int main(int argc, char *argv[]) {
     }
 
     if (!is_valid_tcp_port(current_port)) {
-        fprintf(stderr, "%s: provide a valid TCP port number as first argument.\n", argv[0]);
+        print_error(argv[0], "provide a valid TCP port number as first argument.");
         return EX_USAGE;
     }
 
     // Open TCP table
     FILE *tcp_table_fptr = fopen(TCP_TABLE, "r");
     if (tcp_table_fptr == NULL) {
-        fprintf(stderr, "%s: error opening the TCP table.\n", argv[0]);
-        return EX_OSFILE;
+        print_error(argv[0], "error opening the TCP table.");
+        return errno;
     }
 
     unsigned short *listening_ports = malloc(PORTS_BLOCKS_TO_ALLOW * sizeof(unsigned short));
     listening_ports = get_listening_ports(listening_ports, tcp_table_fptr);
 
+    if (fclose(tcp_table_fptr) != 0) {
+        print_error(argv[0], "can't close the TCP table.");
+        return errno;
+    }
+
     // Check if the current port is available, add
     while (!is_port_available(current_port, listening_ports)) {
         current_port++;
@@ -106,7 +119,7 @@ int main(int argc, char *argv[]) {
         printf("%d\n", current_port);
         return EXIT_SUCCESS;
     } else {
-        fprintf(stderr, "%s: no more ports available; how did you fuck up that bad ???\n", argv[0]);
+        print_error(argv[0], "no more ports available; how did you fuck up that bad ???");
         return EX_TEMPFAIL;
     }
 }