From: Dmitry V. Levin <ldv@altlinux.org>
Date: Sat, 18 Nov 2017 01:35:20 +0000 (+0000)
Subject: ipc_shm: decode hugetlb page size in shmget flags
X-Git-Tag: v4.21~303
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=f34045326262ff82fb8959d6dee22237424600ac;p=strace

ipc_shm: decode hugetlb page size in shmget flags

Decode alternative hugetlb page sizes introduced by kernel commit
v3.8-rc1~175^2~36.

* ipc_shm.c [!SHM_HUGE_SHIFT] (SHM_HUGE_SHIFT): New macro.
[!SHM_HUGE_MASK] (SHM_HUGE_MASK): Likewise.
(SYS_FUNC(shmget)): Print hugetlb page size.
* tests/ipc_shm.c: Check it.
---

diff --git a/ipc_shm.c b/ipc_shm.c
index 7284b183..b358fc69 100644
--- a/ipc_shm.c
+++ b/ipc_shm.c
@@ -39,6 +39,14 @@
 # include <linux/shm.h>
 #endif
 
+#ifndef SHM_HUGE_SHIFT
+# define SHM_HUGE_SHIFT 26
+#endif
+
+#ifndef SHM_HUGE_MASK
+# define SHM_HUGE_MASK 0x3f
+#endif
+
 #include "xlat/shm_resource_flags.h"
 #include "xlat/shm_flags.h"
 
@@ -50,9 +58,24 @@ SYS_FUNC(shmget)
 	else
 		tprints("IPC_PRIVATE");
 	tprintf(", %" PRI_klu ", ", tcp->u_arg[1]);
-	if (printflags(shm_resource_flags, tcp->u_arg[2] & ~0777, NULL) != 0)
+
+	unsigned int flags = tcp->u_arg[2] & ~0777;
+	const unsigned int mask = SHM_HUGE_MASK << SHM_HUGE_SHIFT;
+	const unsigned int hugetlb_value = flags & mask;
+
+	flags &= ~mask;
+	if (flags || !hugetlb_value)
+		printflags(shm_resource_flags, flags, NULL);
+
+	if (hugetlb_value)
+		tprintf("%s%u<<SHM_HUGE_SHIFT",
+			flags ? "|" : "",
+			hugetlb_value >> SHM_HUGE_SHIFT);
+
+	if (flags || hugetlb_value)
 		tprints("|");
 	print_numeric_umode_t(tcp->u_arg[2] & 0777);
+
 	return RVAL_DECODED;
 }
 
diff --git a/tests/ipc_shm.c b/tests/ipc_shm.c
index 9e9c5609..fd700f8f 100644
--- a/tests/ipc_shm.c
+++ b/tests/ipc_shm.c
@@ -32,6 +32,14 @@
 #include <stdlib.h>
 #include <sys/shm.h>
 
+#ifndef SHM_HUGE_SHIFT
+# define SHM_HUGE_SHIFT 26
+#endif
+
+#ifndef SHM_HUGE_MASK
+# define SHM_HUGE_MASK 0x3f
+#endif
+
 #include "xlat.h"
 #include "xlat/shm_resource_flags.h"
 
@@ -64,20 +72,54 @@ main(void)
 	#else
 		(size_t) 0x1e55c0de5dec0dedULL;
 	#endif
-	static const int bogus_flags = 0xface1e55;
-
+	static const unsigned int bogus_ipc_shm_flags =
+		IPC_CREAT | IPC_EXCL | SHM_HUGETLB | SHM_NORESERVE;
+	static const unsigned int huge_mask = SHM_HUGE_MASK << SHM_HUGE_SHIFT;
+	static const unsigned int huge_flags = 21 << SHM_HUGE_SHIFT;
+	int bogus_flags;
 	int rc;
 	struct shmid_ds ds;
 
+	rc = shmget(bogus_key, bogus_size, 0);
+	printf("shmget\\(%#llx, %zu, 000\\) += %s\n",
+	       zero_extend_signed_to_ull(bogus_key), bogus_size,
+	       sprintrc_grep(rc));
+
+	rc = shmget(bogus_key, bogus_size, huge_flags);
+	printf("shmget\\(%#llx, %zu, %s\\|%#03o\\) += %s\n",
+	       zero_extend_signed_to_ull(bogus_key), bogus_size,
+	       "21<<SHM_HUGE_SHIFT", 0, sprintrc_grep(rc));
+
+	bogus_flags = 0xface1e55 & ~(bogus_ipc_shm_flags | huge_mask);
+	rc = shmget(bogus_key, bogus_size, bogus_flags);
+	printf("shmget\\(%#llx, %zu, %#x\\|%#03o\\) += %s\n",
+	       zero_extend_signed_to_ull(bogus_key), bogus_size,
+	       bogus_flags & ~0777,
+	       bogus_flags & 0777, sprintrc_grep(rc));
+
+	bogus_flags |= bogus_ipc_shm_flags;
+	rc = shmget(bogus_key, bogus_size, bogus_flags);
+	printf("shmget\\(%#llx, %zu, %s\\|%#x\\|%#03o\\) += %s\n",
+	       zero_extend_signed_to_ull(bogus_key), bogus_size,
+	       "IPC_CREAT\\|IPC_EXCL\\|SHM_HUGETLB\\|SHM_NORESERVE",
+	       bogus_flags & ~(0777 | bogus_ipc_shm_flags),
+	       bogus_flags & 0777, sprintrc_grep(rc));
+
+	bogus_flags |= huge_flags;
+	rc = shmget(bogus_key, bogus_size, bogus_flags);
+	printf("shmget\\(%#llx, %zu, %s\\|%#x\\|%s\\|%#03o\\) += %s\n",
+	       zero_extend_signed_to_ull(bogus_key), bogus_size,
+	       "IPC_CREAT\\|IPC_EXCL\\|SHM_HUGETLB\\|SHM_NORESERVE",
+	       bogus_flags & ~(0777 | bogus_ipc_shm_flags | huge_mask),
+	       "21<<SHM_HUGE_SHIFT",
+	       bogus_flags & 0777, sprintrc_grep(rc));
+
+	bogus_flags &= ~bogus_ipc_shm_flags;
 	rc = shmget(bogus_key, bogus_size, bogus_flags);
-	printf("shmget\\(%#llx, %zu, %s%s%s%s%#x\\|%#04o\\) += %s\n",
+	printf("shmget\\(%#llx, %zu, %#x\\|%s\\|%#03o\\) += %s\n",
 	       zero_extend_signed_to_ull(bogus_key), bogus_size,
-	       IPC_CREAT & bogus_flags ? "IPC_CREAT\\|" : "",
-	       IPC_EXCL & bogus_flags ? "IPC_EXCL\\|" : "",
-	       SHM_HUGETLB & bogus_flags ? "SHM_HUGETLB\\|" : "",
-	       SHM_NORESERVE & bogus_flags ? "SHM_NORESERVE\\|" : "",
-	       bogus_flags & ~(0777 | IPC_CREAT | IPC_EXCL
-				    | SHM_HUGETLB | SHM_NORESERVE),
+	       bogus_flags & ~(0777 | huge_mask),
+	       "21<<SHM_HUGE_SHIFT",
 	       bogus_flags & 0777, sprintrc_grep(rc));
 
 	id = shmget(private_key, 1, 0600);