Merge pull request #25563 from vespa-engine/arnej/make-dup-of-logging-fd

make a duplicate of the file descriptor in target

3 files changed, 17 insertions, 15 deletions

diff --git a/vespalog/src/vespa/log/log-target-fd.cpp b/vespalog/src/vespa/log/log-target-fd.cpp
index cb1b2e792b4..bb7590a9908 100644
--- a/vespalog/src/vespa/log/log-target-fd.cpp
+++ b/vespalog/src/vespa/log/log-target-fd.cpp
@@ -1,6 +1,7 @@
 // Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 #include <sys/types.h>
 #include <unistd.h>
+#include <fcntl.h>
 #include <cstring>
 #include <cstdlib>
 
@@ -11,22 +12,23 @@ LOG_SETUP(".log");
 
 namespace ns_log {
 
-LogTargetFd::LogTargetFd(const char *target)
+LogTargetFd::LogTargetFd(int fd_spec, const char *target)
     : LogTarget(target),
       _fd(-1), _istty(false)
 {
-    if (strncmp(target, "fd:", 3) != 0) {
+    _fd = dup(fd_spec);
+    if (_fd == -1) {
         throwInvalid("Bad target for LogTargetFd: '%s'", target);
     }
-    _fd = strtol(target + 3, NULL, 0);
     if (isatty(_fd) == 1) {
         _istty = true;
     }
+    fcntl(_fd, F_SETFD, FD_CLOEXEC);
 }
 
 LogTargetFd::~LogTargetFd()
 {
-    // Must not close _fd, we did not open it!
+    close(_fd);
 }
 
 
diff --git a/vespalog/src/vespa/log/log-target-fd.h b/vespalog/src/vespa/log/log-target-fd.h
index fa8df8ce8ed..85857c206b5 100644
--- a/vespalog/src/vespa/log/log-target-fd.h
+++ b/vespalog/src/vespa/log/log-target-fd.h
@@ -9,12 +9,12 @@ class LogTargetFd : public LogTarget {
 private:
     int _fd;
     bool _istty;
-    LogTargetFd();
-    LogTargetFd(const LogTargetFd&);
-    LogTargetFd& operator = (const LogTargetFd);
+    LogTargetFd() = delete;
+    LogTargetFd(const LogTargetFd&) = delete;
+    LogTargetFd& operator= (const LogTargetFd) = delete;
 
 public:
-    explicit LogTargetFd(const char *target);
+    LogTargetFd(int fd_spec, const char *target);
     int write(const char *buf, int len) override;
     ~LogTargetFd();
     bool makeHumanReadable() const override { return _istty; }
diff --git a/vespalog/src/vespa/log/log-target.cpp b/vespalog/src/vespa/log/log-target.cpp
index 4ac037354e1..26f064634ca 100644
--- a/vespalog/src/vespa/log/log-target.cpp
+++ b/vespalog/src/vespa/log/log-target.cpp
@@ -25,21 +25,21 @@ LogTarget *
 LogTarget::defaultTarget()
 {
     // Note! This function cannot LOG().
-    return new LogTargetFd("fd:2");
+    return new LogTargetFd(2, "fd:2");
 }
 
 LogTarget *
 LogTarget::makeTarget(const char *const target)
 {
-    LogTarget *res = NULL;
     if (strncmp(target, "fd:", 3) == 0) {
-        res = new LogTargetFd(target);
+        int fd_spec = strtol(target + 3, NULL, 0);
+        if (fd_spec > 0) {
+            return new LogTargetFd(fd_spec, target);
+        }
     } else if (strncmp(target, "file:", 5) == 0) {
-        res = new LogTargetFile(target);
-    } else {
-        throwInvalid("Log target '%s' is invalid.", target);
+        return new LogTargetFile(target);
     }
-    return res;
+    throwInvalid("Log target '%s' is invalid.", target);
 }