From 3660c07f5ad83e0f1b26a8ccd1e3244189165ba6 Mon Sep 17 00:00:00 2001
From: Matthias Baesken <mbaesken@openjdk.org>
Date: Wed, 23 Oct 2024 08:10:45 +0000
Subject: [PATCH] 8339487: ProcessHandleImpl os_getChildren sysctl call - retry
in case of ENOMEM and enhance exception message
Backport-of: 4ff72dc57e65e99b129f0ba28196994edf402018
---
.../native/libjava/ProcessHandleImpl_macosx.c | 44 ++++++++++++-------
.../native/libjava/ProcessHandleImpl_unix.c | 2 +-
2 files changed, 28 insertions(+), 18 deletions(-)
diff --git a/src/java.base/macosx/native/libjava/ProcessHandleImpl_macosx.c b/src/java.base/macosx/native/libjava/ProcessHandleImpl_macosx.c
index 30fa8eea206..b9f3428c1fa 100644
--- a/src/java.base/macosx/native/libjava/ProcessHandleImpl_macosx.c
+++ b/src/java.base/macosx/native/libjava/ProcessHandleImpl_macosx.c
@@ -89,25 +89,35 @@ jint os_getChildren(JNIEnv *env, jlong jpid, jlongArray jarray,
}
}
- // Get buffer size needed to read all processes
- int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_ALL, 0};
- if (sysctl(mib, 4, NULL, &bufSize, NULL, 0) < 0) {
- JNU_ThrowByNameWithLastError(env,
- "java/lang/RuntimeException", "sysctl failed");
- return -1;
- }
+ int errsysctl;
+ int maxRetries = 100;
+ void *buffer = NULL;
+ do {
+ int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_ALL, 0};
+ if (buffer != NULL) free(buffer);
+ // Get buffer size needed to read all processes
+ if (sysctl(mib, 4, NULL, &bufSize, NULL, 0) < 0) {
+ JNU_ThrowByNameWithMessageAndLastError(env,
+ "java/lang/RuntimeException", "sysctl failed");
+ return -1;
+ }
- // Allocate buffer big enough for all processes
- void *buffer = malloc(bufSize);
- if (buffer == NULL) {
- JNU_ThrowOutOfMemoryError(env, "malloc failed");
- return -1;
- }
+ // Allocate buffer big enough for all processes; add a little
+ // bit of space to be able to hold a few more proc infos
+ // for processes started right after the first sysctl call
+ buffer = malloc(bufSize + 4 * sizeof(struct kinfo_proc));
+ if (buffer == NULL) {
+ JNU_ThrowOutOfMemoryError(env, "malloc failed");
+ return -1;
+ }
- // Read process info for all processes
- if (sysctl(mib, 4, buffer, &bufSize, NULL, 0) < 0) {
- JNU_ThrowByNameWithLastError(env,
- "java/lang/RuntimeException", "sysctl failed");
+ // Read process info for all processes
+ errsysctl = sysctl(mib, 4, buffer, &bufSize, NULL, 0);
+ } while (errsysctl < 0 && errno == ENOMEM && maxRetries-- > 0);
+
+ if (errsysctl < 0) {
+ JNU_ThrowByNameWithMessageAndLastError(env,
+ "java/lang/RuntimeException", "sysctl failed to get info about all processes");
free(buffer);
return -1;
}
diff --git a/src/java.base/unix/native/libjava/ProcessHandleImpl_unix.c b/src/java.base/unix/native/libjava/ProcessHandleImpl_unix.c
index d53e88764c5..8b900dcf6f6 100644
--- a/src/java.base/unix/native/libjava/ProcessHandleImpl_unix.c
+++ b/src/java.base/unix/native/libjava/ProcessHandleImpl_unix.c
@@ -537,7 +537,7 @@ jint unix_getChildren(JNIEnv *env, jlong jpid, jlongArray jarray,
* position integer as a filename.
*/
if ((dir = opendir("/proc")) == NULL) {
- JNU_ThrowByNameWithLastError(env,
+ JNU_ThrowByNameWithMessageAndLastError(env,
"java/lang/RuntimeException", "Unable to open /proc");
return -1;
}
--
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