log: a bit clearer calls to dup()

diff --git a/logs.cc b/logs.cc
index 24937a88db6443cccbeb78b9fc35c0c9032aa11d..7cea49ac66906e25e90ac1654a7bfb59a559fa1d 100644 (file)
--- a/logs.cc
+++ b/logs.cc
@@ -45,12 +45,17 @@ static bool _log_fd_isatty = true;
 static enum llevel_t _log_level = INFO;
 static bool _log_set = false;
 
-int getDupLogFd(int fd) {
-       fd = fcntl(fd, F_DUPFD_CLOEXEC, 0);
-       if (fd >= 0) {
-               return fd;
+static void setDupLogFdOr(int fd, int orfd) {
+       int saved_errno = errno;
+       _log_fd = fcntl(fd, F_DUPFD_CLOEXEC, 0);
+       if (_log_fd == -1) {
+               _log_fd = fcntl(orfd, F_DUPFD_CLOEXEC, 0);
        }
-       return STDERR_FILENO;
+       if (_log_fd == -1) {
+               _log_fd = orfd;
+       }
+       _log_fd_isatty = (isatty(_log_fd) == 1);
+       errno = saved_errno;
 }
 
 /*
@@ -58,8 +63,7 @@ int getDupLogFd(int fd) {
  * connection socket with fd (0, 1, 2).
  */
 __attribute__((constructor)) static void log_init(void) {
-       _log_fd = getDupLogFd(STDERR_FILENO);
-       _log_fd_isatty = isatty(_log_fd);
+       setDupLogFdOr(STDERR_FILENO, STDERR_FILENO);
 }
 
 bool logSet() {
@@ -76,14 +80,14 @@ void logFile(const std::string& logfile) {
        if (_log_fd > STDERR_FILENO) {
                close(_log_fd);
        }
-       if (TEMP_FAILURE_RETRY(_log_fd = open(logfile.c_str(),
-                                  O_CREAT | O_RDWR | O_APPEND | O_CLOEXEC, 0640)) == -1) {
-               int saved_errno = errno;
-               _log_fd = getDupLogFd(STDERR_FILENO);
-               LOG_W(
-                   "Couldn't open logfile open('%s'): %s", logfile.c_str(), strerror(saved_errno));
+       int newlogfd = TEMP_FAILURE_RETRY(
+           open(logfile.c_str(), O_CREAT | O_RDWR | O_APPEND | O_CLOEXEC, 0640));
+       setDupLogFdOr(newlogfd, STDERR_FILENO);
+       if (newlogfd == -1) {
+               PLOG_W("Couldn't open logfile open('%s')", logfile.c_str());
+       } else {
+               close(newlogfd);
        }
-       _log_fd_isatty = (isatty(_log_fd) == 1);
 }
 
 void logMsg(enum llevel_t ll, const char* fn, int ln, bool perr, const char* fmt, ...) {