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[PATCH 4/9] bsd-user: Two helper routines oidfmt and sysctl_oldcvt
From: |
Warner Losh |
Subject: |
[PATCH 4/9] bsd-user: Two helper routines oidfmt and sysctl_oldcvt |
Date: |
Fri, 10 Feb 2023 16:18:24 -0700 |
From: Stacey Son <sson@FreeBSD.org>
oidfmt uses undocumented system call to get the type of the sysctl.
sysctl_oldcvt does the byte swapping in the data to return it to the
target.
Co-Authored-by: Sean Bruno <sbruno@FreeBSD.org>
Signed-off-by: Sean Bruno <sbruno@FreeBSD.org>
Co-Authored-by: Juergen Lock <nox@jelal.kn-bremen.de>
Signed-off-by: Juergen Lock <nox@jelal.kn-bremen.de>
Co-Authored-by: Raphael Kubo da Costa <rakuco@FreeBSD.org>
Signed-off-by: Raphael Kubo da Costa <rakuco@FreeBSD.org>
Signed-off-by: Stacey Son <sson@FreeBSD.org>
Signed-off-by: Warner Losh <imp@bsdimp.com>
---
bsd-user/freebsd/os-sys.c | 94 +++++++++++++++++++++++++++++++++++++++
1 file changed, 94 insertions(+)
diff --git a/bsd-user/freebsd/os-sys.c b/bsd-user/freebsd/os-sys.c
index 1676ec10f83..e3b9f168a2b 100644
--- a/bsd-user/freebsd/os-sys.c
+++ b/bsd-user/freebsd/os-sys.c
@@ -21,6 +21,100 @@
#include "qemu.h"
#include "target_arch_sysarch.h"
+#include <sys/sysctl.h>
+
+/*
+ * This uses the undocumented oidfmt interface to find the kind of a requested
+ * sysctl, see /sys/kern/kern_sysctl.c:sysctl_sysctl_oidfmt() (compare to
+ * src/sbin/sysctl/sysctl.c)
+ */
+static int oidfmt(int *oid, int len, char *fmt, uint32_t *kind)
+{
+ int qoid[CTL_MAXNAME + 2];
+ uint8_t buf[BUFSIZ];
+ int i;
+ size_t j;
+
+ qoid[0] = 0;
+ qoid[1] = 4;
+ memcpy(qoid + 2, oid, len * sizeof(int));
+
+ j = sizeof(buf);
+ i = sysctl(qoid, len + 2, buf, &j, 0, 0);
+ if (i) {
+ return i;
+ }
+
+ if (kind) {
+ *kind = *(uint32_t *)buf;
+ }
+
+ if (fmt) {
+ strcpy(fmt, (char *)(buf + sizeof(uint32_t)));
+ }
+ return 0;
+}
+
+/*
+ * try and convert sysctl return data for the target.
+ * Note: doesn't handle CTLTYPE_OPAQUE and CTLTYPE_STRUCT.
+ */
+static int sysctl_oldcvt(void *holdp, size_t *holdlen, uint32_t kind)
+{
+ switch (kind & CTLTYPE) {
+ case CTLTYPE_INT:
+ case CTLTYPE_UINT:
+ *(uint32_t *)holdp = tswap32(*(uint32_t *)holdp);
+ break;
+
+#ifdef TARGET_ABI32
+ case CTLTYPE_LONG:
+ case CTLTYPE_ULONG:
+ /*
+ * If the sysctl has a type of long/ulong but seems to be bigger than
+ * these data types, its probably an array. Double check that its
+ * evenly divisible by the size of long and convert holdp to a series
of
+ * 32bit elements instead, adjusting holdlen to the new size.
+ */
+ if ((*holdlen > sizeof(abi_ulong)) &&
+ ((*holdlen % sizeof(abi_ulong)) == 0)) {
+ int array_size = *holdlen / sizeof(long);
+ int i;
+ if (holdp) {
+ for (i = 0; i < array_size; i++) {
+ ((uint32_t *)holdp)[i] = tswap32(((long *)holdp)[i]);
+ }
+ *holdlen = array_size * sizeof(abi_ulong);
+ } else {
+ *holdlen = sizeof(abi_ulong);
+ }
+ } else {
+ *(uint32_t *)holdp = tswap32(*(long *)holdp);
+ *holdlen = sizeof(uint32_t);
+ }
+ break;
+#else
+ case CTLTYPE_LONG:
+ *(uint64_t *)holdp = tswap64(*(long *)holdp);
+ break;
+ case CTLTYPE_ULONG:
+ *(uint64_t *)holdp = tswap64(*(unsigned long *)holdp);
+ break;
+#endif
+ case CTLTYPE_U64:
+ case CTLTYPE_S64:
+ *(uint64_t *)holdp = tswap64(*(uint64_t *)holdp);
+ break;
+
+ case CTLTYPE_STRING:
+ break;
+
+ default:
+ return -1;
+ }
+ return 0;
+}
+
/* sysarch() is architecture dependent. */
abi_long do_freebsd_sysarch(void *cpu_env, abi_long arg1, abi_long arg2)
{
--
2.39.1
[PATCH 5/9] bsd-user: sysctl helper funtions: sysctl_name2oid and sysctl_oidfmt, Warner Losh, 2023/02/10
[PATCH 3/9] bsd-user: Add sysarch syscall, Warner Losh, 2023/02/10
[PATCH 6/9] bsd-user: common routine do_freebsd_sysctl_oid for all sysctl variants, Warner Losh, 2023/02/10