public inbox for pve-devel@lists.proxmox.com
 help / color / mirror / Atom feed
From: Dominik Csapak <d.csapak@proxmox.com>
To: pve-devel@lists.proxmox.com
Subject: [pve-devel] [RFC PATCH mini-journalreader v2 2/2] include error in json output
Date: Mon,  2 Jun 2025 16:30:50 +0200	[thread overview]
Message-ID: <20250602143050.3732346-2-d.csapak@proxmox.com> (raw)
In-Reply-To: <20250602143050.3732346-1-d.csapak@proxmox.com>

by using json-c and printing the string into a variable via `vasprintf`.

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
---
changes from RFC v1:
* rebase on last patch and also use vfprintf in fallback case

 debian/control           |  2 +-
 src/Makefile             |  2 +-
 src/mini-journalreader.c | 31 +++++++++++++++++++++++++------
 3 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/debian/control b/debian/control
index 8280f6d..d03772e 100644
--- a/debian/control
+++ b/debian/control
@@ -2,7 +2,7 @@ Source: proxmox-mini-journalreader
 Section: admin
 Priority: optional
 Maintainer: Proxmox Support Team <support@proxmox.com>
-Build-Depends: debhelper-compat (= 13), libsystemd-dev, pkg-config, scdoc,
+Build-Depends: debhelper-compat (= 13), libsystemd-dev, pkg-config, scdoc, libjson-c-dev
 Standards-Version: 4.6.2
 
 Package: proxmox-mini-journalreader
diff --git a/src/Makefile b/src/Makefile
index 449004f..adb2782 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -4,7 +4,7 @@ SOURCES=mini-journalreader.c
 BIN_DIR ?= $(DESTDIR)/usr/bin
 MAN1_DIR ?= $(DESTDIR)/usr/share/man/man1
 
-LIBS := libsystemd
+LIBS := libsystemd json-c
 CFLAGS += -Werror -Wall -Wextra -Wl,-z,relro -g -O2 --std=gnu11
 CFLAGS += -fstack-protector-strong -D_FORTIFY_SOURCE=2
 CFLAGS += $(shell pkg-config --cflags $(LIBS))
diff --git a/src/mini-journalreader.c b/src/mini-journalreader.c
index 562b390..e3982ab 100644
--- a/src/mini-journalreader.c
+++ b/src/mini-journalreader.c
@@ -15,6 +15,10 @@
  * If not, see <https://www.gnu.org/licenses/>.
  */
 
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
 #include <errno.h>
 #include <stdbool.h>
 #include <stdio.h>
@@ -23,6 +27,7 @@
 #include <systemd/sd-journal.h>
 #include <time.h>
 #include <unistd.h>
+#include <json.h>
 
 #define BUFSIZE 4096
 
@@ -33,17 +38,31 @@ bool first_line = true;
 // helper to print errors on stderr
 // if we're in json mode, print closing json body if possible
 static void print_error_and_exit(const char *fmt, ...) {
+    fflush_unlocked(stdout);
+
     va_list args;
+    char *message;
     va_start(args, fmt);
-    vfprintf(stderr, fmt, args);
+    int r = vasprintf(&message, fmt, args);
+    if (r < 0) {
+        // could not allocate the string, so write it directly and don't
+        // include the error in the json output
+        vfprintf(stderr, fmt, args);
+        if (json) {
+            fprintf(stdout, "],\"success\":0}");
+        }
+        exit(1);
+    }
+    fprintf(stderr, "%s", message);
     va_end(args);
+
     if (json) {
-        size_t r = fwrite_unlocked("],\"success\":0}", 1, 14, stdout);
-        if (r < 14) {
-            fprintf(stderr, "Failed to write closing json\n");
-        }
-        fflush_unlocked(stdout);
+        struct json_object *obj = json_object_new_string(message);
+        const char *json_message = json_object_to_json_string(obj);
+        fprintf(stdout, "], \"error\":%s,\"success\":0}", json_message);
+        json_object_put(obj);
     }
+    free(message);
     exit(1);
 }
 
-- 
2.39.5



_______________________________________________
pve-devel mailing list
pve-devel@lists.proxmox.com
https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-devel


  reply	other threads:[~2025-06-02 14:30 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-06-02 14:30 [pve-devel] [PATCH mini-journalreader v2 1/2] fix #6410: properly close json output on error Dominik Csapak
2025-06-02 14:30 ` Dominik Csapak [this message]
2025-06-03  7:16   ` [pve-devel] [RFC PATCH mini-journalreader v2 2/2] include error in json output Dominik Csapak
2025-06-03  8:53 ` [pve-devel] [PATCH mini-journalreader v2 1/2] fix #6410: properly close json output on error Dominik Csapak

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20250602143050.3732346-2-d.csapak@proxmox.com \
    --to=d.csapak@proxmox.com \
    --cc=pve-devel@lists.proxmox.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
Service provided by Proxmox Server Solutions GmbH | Privacy | Legal