From 32985c59782202b9c1471316f2a9a0e0895696af Mon Sep 17 00:00:00 2001
From: JGZYES <JGZYES@users.noreply.github.com>
Date: Tue, 1 Sep 2026 19:10:28 +0800
Subject: [PATCH] diag: log errno when popen/malloc fails in run_capture (Linux
 mirror lookup)

---
 src/http.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/http.c b/src/http.c
index 2bf50ed..d54cd05 100644
--- a/src/http.c
+++ b/src/http.c
@@ -3,6 +3,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <errno.h>
 
 #ifdef _WIN32
 #include <io.h>
@@ -29,10 +30,18 @@
 /* Read all output of `cmd` into a malloc'd buffer. */
 static char *run_capture(const char *cmd, size_t *out_len) {
     FILE *f = PMM_POPEN(cmd, "rb");
-    if (!f) return NULL;
+    if (!f) {
+        if (getenv("PMM_DEBUG"))
+            fprintf(stderr, "[http] popen(cmd) failed: errno=%d %s\n", errno, strerror(errno));
+        return NULL;
+    }
     size_t cap = 64 * 1024, len = 0;
     char *buf = malloc(cap);
-    if (!buf) { PMM_PCLOSE(f); return NULL; }
+    if (!buf) {
+        if (getenv("PMM_DEBUG"))
+            fprintf(stderr, "[http] malloc(%zu) failed: errno=%d %s\n", cap, errno, strerror(errno));
+        PMM_PCLOSE(f); return NULL;
+    }
     for (;;) {
         if (len + 4096 > cap) {
             cap *= 2;