From 0f280de9e63e0ba71dd826b0e62b65e5a94df6d5 Mon Sep 17 00:00:00 2001
From: Joe Orton <jorton@redhat.com>
Date: Thu, 27 Mar 2025 14:10:05 +0000
Subject: [PATCH] Add %pg printf format string converter to print a pool tag:

* strings/apr_snprintf.c (apr_vformatter): Add %pg support.

* test/testfmt.c (test_tag_fmt): New test case.
---
 include/apr_lib.h      |  3 +++
 strings/apr_snprintf.c | 19 +++++++++++++++++++
 test/testfmt.c         | 22 ++++++++++++++++++++++
 3 files changed, 44 insertions(+)

diff --git a/include/apr_lib.h b/include/apr_lib.h
index 9f4cb2b3397..cfdd2516b01 100644
--- a/include/apr_lib.h
+++ b/include/apr_lib.h
@@ -120,6 +120,8 @@ APR_DECLARE(const char *) apr_filepath_name_get(const char *pathname);
  * ('0' is printed if !APR_HAS_THREADS)
  * - %%pm takes an apr_status_t * and prints the appropriate error
  * string (from apr_strerror) corresponding to that error code.
+ * - %%pg takes an apr_pool_t * and prints the pool tag,
+ * or '(untagged)' if no pool tag is set
  * - %%pp takes a void * and outputs it in hex
  * - %%pB takes a apr_uint32_t * as bytes and outputs it's apr_strfsize
  * - %%pF same as above, but takes a apr_off_t *
@@ -128,6 +130,7 @@ APR_DECLARE(const char *) apr_filepath_name_get(const char *pathname);
  * %%pA, %%pI, %%pT, %%pp are available from APR 1.0.0 onwards (and in 0.9.x).
  * %%pt is only available from APR 1.2.0 onwards.
  * %%pm, %%pB, %%pF and %%pS are only available from APR 1.3.0 onwards.
+ * %%pg is only available from APR 2.0.0 onwards.
  *
  * The %%p hacks are to force gcc's printf warning code to skip
  * over a pointer argument without complaining.  This does
diff --git a/strings/apr_snprintf.c b/strings/apr_snprintf.c
index 6c2549f4289..b483d309e9b 100644
--- a/strings/apr_snprintf.c
+++ b/strings/apr_snprintf.c
@@ -1191,6 +1191,25 @@ APR_DECLARE(int) apr_vformatter(int (*flush_func)(apr_vformatter_buff_t *),
                 }
                 break;
 
+                /* print the tag for an apr_pool_t */
+                case 'g':
+                {
+                    apr_pool_t *prv;
+
+                    prv = va_arg(ap, apr_pool_t *);
+                    if (prv != NULL) {
+                        s = (char *)apr_pool_get_tag(prv);
+                        if (!s) s = "(untagged)";
+                        s_len = strlen(s);
+                    }
+                    else {
+                        s = S_NULL;
+                        s_len = S_NULL_LEN;
+                    }
+                    pad_char = ' ';
+                }
+                break;
+
                 case 'T':
 #if APR_HAS_THREADS
                 {
diff --git a/test/testfmt.c b/test/testfmt.c
index 5b066ddb439..fe2fc93cf51 100644
--- a/test/testfmt.c
+++ b/test/testfmt.c
@@ -146,6 +146,27 @@ static void error_fmt(abts_case *tc, void *data)
     ABTS_STR_EQUAL(tc, sbuf, s);
 }
 
+#define TEST_TAG "pool_tag_fmt_tag"
+
+static void pool_tag_fmt(abts_case *tc, void *data)
+{
+    char sbuf[150];
+    apr_pool_t *testp;
+
+    APR_ASSERT_SUCCESS(tc, "Create test pool", apr_pool_create(&testp, NULL));
+
+#if !APR_POOL_DEBUG
+    apr_snprintf(sbuf, sizeof sbuf, "tag-%pg-end", testp);
+    ABTS_STR_EQUAL(tc, "tag-(untagged)-end", sbuf);
+#endif
+
+    apr_pool_tag(testp, TEST_TAG);
+    apr_snprintf(sbuf, sizeof sbuf, "tag-%pg-end", testp);
+    ABTS_STR_EQUAL(tc, "tag-" TEST_TAG "-end", sbuf);
+
+    apr_pool_destroy(testp);
+}
+
 abts_suite *testfmt(abts_suite *suite)
 {
     suite = ADD_SUITE(suite)
@@ -160,6 +181,7 @@ abts_suite *testfmt(abts_suite *suite)
     abts_run_test(suite, uint64_t_hex_fmt, NULL);
     abts_run_test(suite, more_int64_fmts, NULL);
     abts_run_test(suite, error_fmt, NULL);
+    abts_run_test(suite, pool_tag_fmt, NULL);
 
     return suite;
 }