From: Andre Noll <maan@tuebingen.mpg.de>
Date: Mon, 19 Jun 2023 19:24:29 +0000 (+0200)
Subject: string.c: Don't fall back to /tmp in para_homedir().
X-Git-Tag: v0.7.3~4
X-Git-Url: http://git.tue.mpg.de/?a=commitdiff_plain;h=3e0b33d1daabc885c6fb9a8f9efca307a724bc40;p=paraslash.git

string.c: Don't fall back to /tmp in para_homedir().

This can only lead to trouble. If we can't get the path to the home
directory, something is deeply wrong and we really should abort.
---

diff --git a/string.c b/string.c
index 423fd296..d8bd027b 100644
--- a/string.c
+++ b/string.c
@@ -308,15 +308,32 @@ __must_check __malloc char *para_logname(void)
 }
 
 /**
- * Get the home directory of the current user.
+ * Get the home directory of the calling user.
  *
  * \return A dynamically allocated string that must be freed by the caller. If
- * the home directory could not be found, this function returns "/tmp".
+ * no entry is found which matches the UID of the calling process, or any other
+ * error occurs, the function prints an error message and aborts.
+ *
+ * \sa getpwuid(3), getuid(2).
  */
 __must_check __malloc char *para_homedir(void)
 {
-	struct passwd *pw = getpwuid(getuid());
-	return para_strdup(pw? pw->pw_dir : "/tmp");
+	struct passwd *pw;
+
+	/*
+	 * To distinguish between the error case and the "not found" case we
+	 * have to check errno after getpwuid(3). The manual page recommends to
+	 * set it to zero before the call.
+	 */
+	errno = 0;
+	pw = getpwuid(getuid());
+	if (pw)
+		return para_strdup(pw->pw_dir);
+	if (errno != 0)
+		PARA_EMERG_LOG("getpwuid error: %s\n", strerror(errno));
+	else
+		PARA_EMERG_LOG("no pw entry for uid %u\n", (unsigned)getuid());
+	exit(EXIT_FAILURE);
 }
 
 /**