Removed some code duplication

main.c

@@ -26,6 +26,33 @@ size_t min_size_t(size_t a, size_t b)
   return a > b ? b : a;
 }
 
+/*Works simular to memcpy, but checks the sizes to avoid buffer overflows. If dest or src are NULL, returns 0, otherwise returns number of copied BYTES*/
+size_t copy_to_buf(void* dest, size_t dest_len, const void* src, size_t src_len)
+{
+  if(!dest || !src)
+  {
+    return 0;
+  }
+  size_t len = min_size_t(dest_len, src_len);
+  memcpy(dest, src, len);
+  return len;
+}
+
+/*Works simular to strcpy, but checks the sizes to avoid buffer overflows. If dest or src are NULL, returns 0, otherwise returns number of copied BYTES*/
+size_t copy_str_to_buf(void* dest, size_t dest_len, const char* src)
+{
+  if(!dest || !src)
+  {
+    return 0;
+  }
+  size_t len = copy_to_buf(dest, dest_len, src, strlen(src) + 1);
+  if(len != 0)
+  {
+    ((char*)dest)[len] = '\0';
+  }
+  return len;
+}
+
 void sigint_handler(int signo)
 {
   if(!jump_active)
@@ -910,39 +937,33 @@ int execute_pipeline(struct pipeline* pl, int capture, char** out)
 char* get_user()
 {
   static char buf[max_env_var_length] = {0};
-  char* result = getenv("USER");
+  size_t len = copy_str_to_buf(buf, sizeof(buf), getenv("USER"));
-  if(!result)
+  if(!len)
   {
     return "UNKNOWN";
   }
-  size_t length = min_size_t(sizeof(buf), strlen(result) + 1);
-  memcpy(buf, result, length);
   return buf;
 }
 
 char* get_home()
 {
   static char buf[max_length] = {0};
-  char* result = getenv("HOME");
+  size_t len = copy_str_to_buf(buf, sizeof(buf), getenv("HOME"));
-  if(!result)
+  if(!len)
   {
     return "UNKNOWN_HOME_PATH";
   }
-  size_t length = min_size_t(sizeof(buf), strlen(result) + 1);
-  memcpy(buf, result, length);
   return buf;
 }
 
 char* get_pwd()
 {
   static char buf[max_length] = {0};
-  char* result = getenv("PWD");
+  size_t len = copy_str_to_buf(buf, sizeof(buf), getenv("PWD"));
-  if(!result)
+  if(!len)
   {
     return "UNKNOWN";
   }
-  size_t length = min_size_t(sizeof(buf), strlen(result) + 1);
-  memcpy(buf, result, length);
   return buf;
 }
 
@@ -976,21 +997,14 @@ char* generate_ps1_prompt()
 {
   static char prompt_buf[max_length] = {0};
   char env_buf[max_env_var_length] = {0};
-  char* ps1 = getenv("PS1");
+  size_t ps1_len = copy_str_to_buf(env_buf, sizeof(env_buf), getenv("PS1"));
-  if(!ps1)
-  {
-    return default_prompt;
-  }
-  size_t ps1_len = min_size_t(sizeof(env_buf), strlen(ps1) + 1) - 1;
   if(ps1_len == 0)
   {
     return default_prompt;
   }
-  memcpy(env_buf, ps1, ps1_len);
-  env_buf[ps1_len + 1] = '\0';
   if(ps1_len < 2)
   {
-    memcpy(prompt_buf, env_buf, ps1_len + 1);
+    copy_str_to_buf(prompt_buf, sizeof(prompt_buf), getenv("PS1"));
     return prompt_buf;
   }
   size_t i = 1, j = 0;
@@ -1027,25 +1041,12 @@ char* generate_ps1_prompt()
       i++;
       continue;
     }
-    size_t len = strlen(data);
+    size_t start_len = copy_to_buf(prompt_buf + j, sizeof(prompt_buf) - j, env_buf + start, i - start - 1);
-    if(j + i - 1 - start + len >= sizeof(prompt_buf))
-    {
-      fprintf(stderr, "\nOut of memory(1) for prompt: %d >= %d\n", j + i - start + len, sizeof(prompt_buf));
-      break;
-    }
-    size_t start_len = min_size_t(sizeof(prompt_buf) - j, i - start - 1);
-    memcpy(prompt_buf + j, env_buf + start, start_len);
     j += start_len;
-    if(j + len >= sizeof(prompt_buf))
+    size_t len = copy_to_buf(prompt_buf + j, sizeof(prompt_buf) - j, data, strlen(data));
-    {
-      fprintf(stderr, "\nOut of memory(2) for prompt: %d >= %d\n", j + len, sizeof(prompt_buf));
-      break;
-    }
-    memcpy(prompt_buf + j, data, len);
     i += 1; start = i; j += len;
   }
-  size_t start_len = min_size_t(sizeof(prompt_buf) - j, i - start);
+  size_t start_len = copy_to_buf(prompt_buf + j, sizeof(prompt_buf) - j, env_buf + start, i - start);
-  memcpy(prompt_buf + j, env_buf + start, start_len);
   j += start_len;
   prompt_buf[j] = '\0';
   return prompt_buf;