lib/config: set default for primary user email

This is mainly copying code from the CLI into the lib. The CLI copy
will be deleted in a later commit.

lib/config.cc

@@ -23,6 +23,7 @@
 #include "database-private.h"
 
 #include <pwd.h>
+#include <netdb.h>
 
 static const std::string CONFIG_PREFIX = "C";
 
@@ -488,6 +489,63 @@ _get_name_from_passwd_file (void *ctx)
     return name;
 }
 
+static char *
+_get_username_from_passwd_file (void *ctx)
+{
+    long pw_buf_size;
+    char *pw_buf;
+    struct passwd passwd, *ignored;
+    char *name;
+    int e;
+
+    pw_buf_size = sysconf (_SC_GETPW_R_SIZE_MAX);
+    if (pw_buf_size == -1) pw_buf_size = 64;
+    pw_buf = (char *) talloc_zero_size (ctx, pw_buf_size);
+
+    while ((e = getpwuid_r (getuid (), &passwd, pw_buf,
+			    pw_buf_size, &ignored)) == ERANGE) {
+	pw_buf_size = pw_buf_size * 2;
+	pw_buf = (char *) talloc_zero_size (ctx, pw_buf_size);
+    }
+
+    if (e == 0)
+	name = talloc_strdup (ctx, passwd.pw_name);
+    else
+	name = talloc_strdup (ctx, "");
+
+    talloc_free (pw_buf);
+
+    return name;
+}
+
+static const char *
+_get_email_from_passwd_file (void *ctx)
+{
+
+    char hostname[256];
+    struct hostent *hostent;
+    const char *domainname;
+    char *email;
+
+    char *username = _get_username_from_passwd_file (ctx);
+
+    gethostname (hostname, 256);
+    hostname[255] = '\0';
+
+    hostent = gethostbyname (hostname);
+    if (hostent && (domainname = strchr (hostent->h_name, '.')))
+	domainname += 1;
+    else
+	domainname = "(none)";
+
+    email = talloc_asprintf (ctx, "%s@%s.%s",
+			     username, hostname, domainname);
+
+    talloc_free (username);
+    talloc_free (email);
+    return email;
+}
+
 static const char *
 _notmuch_config_key_to_string (notmuch_config_key_t key)
 {
@@ -523,7 +581,7 @@ static const char *
 _notmuch_config_default (notmuch_database_t *notmuch, notmuch_config_key_t key)
 {
     char *path;
-    const char *name;
+    const char *name, *email;
 
     switch (key) {
     case NOTMUCH_CONFIG_DATABASE_PATH:
@@ -549,13 +607,17 @@ _notmuch_config_default (notmuch_database_t *notmuch, notmuch_config_key_t key)
 	    name = talloc_strdup (notmuch, name);
 	else
 	    name = _get_name_from_passwd_file (notmuch);
-
 	return name;
-	break;
+    case NOTMUCH_CONFIG_PRIMARY_EMAIL:
+	email = getenv ("EMAIL");
+	if (email)
+	    email = talloc_strdup (notmuch, email);
+	else
+	    email = _get_email_from_passwd_file (notmuch);
+	return email;
     case NOTMUCH_CONFIG_HOOK_DIR:
     case NOTMUCH_CONFIG_BACKUP_DIR:
     case NOTMUCH_CONFIG_NEW_IGNORE:
-    case NOTMUCH_CONFIG_PRIMARY_EMAIL:
     case NOTMUCH_CONFIG_OTHER_EMAIL:
 	return NULL;
     default:

test/T590-libconfig.sh

@@ -397,7 +397,7 @@ MAIL_DIR/.notmuch/backups
 inbox;unread
 NULL
 true
-NULL
+USERNAME@FQDN
 NULL
 USER_FULL_NAME
 == stderr ==
@@ -626,9 +626,6 @@ EOF
 
 
 test_begin_subtest "notmuch_database_get_config (ndlc)"
-echo NOTMUCH_CONFIG=$NOTMUCH_CONFIG
-echo NOTMUCH_PROFILE=$NOTMUCH_PROFILE
-echo HOME=$HOME
 cat c_head2 - c_tail <<'EOF' | test_C ${MAIL_DIR} %NULL% %NULL%
 {
    EXPECT0(notmuch_database_get_config (db, "test.key1", &val));
@@ -742,7 +739,7 @@ MAIL_DIR/.notmuch/backups
 inbox;unread
 NULL
 true
-NULL
+USERNAME@FQDN
 NULL
 USER_FULL_NAME
 == stderr ==

test/test-lib.sh

@@ -107,6 +107,9 @@ unset GREP_OPTIONS
 # For emacsclient
 unset ALTERNATE_EDITOR
 
+# for reproducibility
+unset EMAIL
+
 add_gnupg_home ()
 {
     [ -e "${GNUPGHOME}/gpg.conf" ] && return
@@ -697,8 +700,9 @@ notmuch_built_with_sanitize ()
 notmuch_passwd_sanitize ()
 {
     local user=$(id -un)
+    local fqdn=$(hostname -f)
     local full_name=$(getent passwd $user | cut -d: -f 5 | cut -d, -f1)
-    sed "s/$full_name/USER_FULL_NAME/"
+    sed -e "s/$user/USERNAME/" -e "s/$fqdn/FQDN/" -e "s/$full_name/USER_FULL_NAME/"
 }
 
 notmuch_config_sanitize ()