coredumpctl: use NULL outputs for COREDUMP existence checks

print_list() and print_info() used RETRIEVE() to strndup() the entire
COREDUMP field into a heap-allocated string, only to check whether it
exists.  With sd_journal_set_data_threshold(j, 0) in print_info(),
this copies the full coredump binary (potentially hundreds of MB) to
heap just to print "Storage: journal".

Now that sd_journal_get_data() accepts NULL output pointers, use a
direct NULL/NULL existence check instead.

Co-developed-by: Claude Opus 4.6 <noreply@anthropic.com>

diff --git a/src/coredump/coredumpctl.c b/src/coredump/coredumpctl.c
index 96724de12b6357f592c317070feb0949f76564a5..86d75bbdc9123098904393802645bd84e9b62309 100644 (file)
--- a/src/coredump/coredumpctl.c
+++ b/src/coredump/coredumpctl.c
@@ -552,14 +552,14 @@ static int print_list(FILE* file, sd_journal *j, Table *t) {
         _cleanup_free_ char
                 *mid = NULL, *pid = NULL, *uid = NULL, *gid = NULL,
                 *sgnl = NULL, *exe = NULL, *comm = NULL,
-                *filename = NULL, *truncated = NULL, *coredump = NULL;
+                *filename = NULL, *truncated = NULL;
         const void *d;
         size_t l;
         usec_t ts;
         int r, signal_as_int = 0;
         const char *present = NULL, *color = NULL;
         uint64_t size = UINT64_MAX;
-        bool normal_coredump;
+        bool normal_coredump, has_inline_coredump;
         uid_t uid_as_int = UID_INVALID;
         gid_t gid_as_int = GID_INVALID;
         pid_t pid_as_int = 0;
@@ -578,9 +578,11 @@ static int print_list(FILE* file, sd_journal *j, Table *t) {
                 RETRIEVE(d, l, "COREDUMP_COMM", comm);
                 RETRIEVE(d, l, "COREDUMP_FILENAME", filename);
                 RETRIEVE(d, l, "COREDUMP_TRUNCATED", truncated);
-                RETRIEVE(d, l, "COREDUMP", coredump);
         }
 
+        /* Check for an inline coredump without copying the (potentially large) payload to heap. */
+        has_inline_coredump = sd_journal_get_data(j, "COREDUMP", NULL, NULL) >= 0;
+
         if (!pid || !uid || !gid || !sgnl || !comm) {
                 log_warning("Found a coredump entry without mandatory fields (PID=%s, UID=%s, GID=%s, SIGNAL=%s, COMM=%s), ignoring.",
                             strna(pid), strna(uid), strna(gid), strna(sgnl), strna(comm));
@@ -604,7 +606,7 @@ static int print_list(FILE* file, sd_journal *j, Table *t) {
                         return r;
 
                 analyze_coredump_file(filename, &present, &color, &size);
-        } else if (coredump)
+        } else if (has_inline_coredump)
                 present = "journal";
         else if (normal_coredump) {
                 present = "none";
@@ -640,12 +642,12 @@ static int print_info(FILE *file, sd_journal *j, bool need_space) {
                 *boot_id = NULL, *machine_id = NULL, *hostname = NULL,
                 *slice = NULL, *cgroup = NULL, *owner_uid = NULL,
                 *message = NULL, *timestamp = NULL, *filename = NULL,
-                *truncated = NULL, *coredump = NULL,
+                *truncated = NULL,
                 *pkgmeta_name = NULL, *pkgmeta_version = NULL, *pkgmeta_json = NULL,
                 *tid = NULL, *thread_name = NULL;
         const void *d;
         size_t l;
-        bool normal_coredump;
+        bool normal_coredump, has_inline_coredump;
         int r;
 
         assert(file);
@@ -672,7 +674,6 @@ static int print_info(FILE *file, sd_journal *j, bool need_space) {
                 RETRIEVE(d, l, "COREDUMP_TIMESTAMP", timestamp);
                 RETRIEVE(d, l, "COREDUMP_FILENAME", filename);
                 RETRIEVE(d, l, "COREDUMP_TRUNCATED", truncated);
-                RETRIEVE(d, l, "COREDUMP", coredump);
                 RETRIEVE(d, l, "COREDUMP_PACKAGE_NAME", pkgmeta_name);
                 RETRIEVE(d, l, "COREDUMP_PACKAGE_VERSION", pkgmeta_version);
                 RETRIEVE(d, l, "COREDUMP_PACKAGE_JSON", pkgmeta_json);
@@ -683,6 +684,9 @@ static int print_info(FILE *file, sd_journal *j, bool need_space) {
                 RETRIEVE(d, l, "MESSAGE", message);
         }
 
+        /* Check for an inline coredump without copying the (potentially large) payload to heap. */
+        has_inline_coredump = sd_journal_get_data(j, "COREDUMP", NULL, NULL) >= 0;
+
         if (need_space)
                 fputs("\n", file);
 
@@ -820,7 +824,7 @@ static int print_info(FILE *file, sd_journal *j, bool need_space) {
                 if (size != UINT64_MAX)
                         fprintf(file, "  Size on Disk: %s\n", FORMAT_BYTES(size));
 
-        } else if (coredump)
+        } else if (has_inline_coredump)
                 fprintf(file, "       Storage: journal\n");
         else
                 fprintf(file, "       Storage: none\n");