Rework the kernel environment subsystem. We now convert the static

environment needed at boot time to a dynamic subsystem when VM is
up.  The dynamic kernel environment is protected by an sx lock.

This adds some new functions to manipulate the kernel environment :
freeenv(), setenv(), unsetenv() and testenv().  freeenv() has to be
called after every getenv() when you have finished using the string.
testenv() only tests if an environment variable is present, and
doesn't require a freeenv() call. setenv() and unsetenv() are self
explanatory.

The kenv(2) syscall exports these new functionalities to userland,
mainly for kenv(1).

Reviewed by:	peter

3 files changed, 32 insertions, 8 deletions

diff --git a/sys/amd64/amd64/autoconf.c b/sys/amd64/amd64/autoconf.c
index d8d7b4f..60b3725 100644
--- a/sys/amd64/amd64/autoconf.c
+++ b/sys/amd64/amd64/autoconf.c
@@ -242,6 +242,7 @@ inaddr_to_sockaddr(char *ev, struct sockaddr_in *sa)
 {
 	u_int32_t	a[4];
 	char		*cp;
+	int		count;
 
 	bzero(sa, sizeof(*sa));
 	sa->sin_len = sizeof(*sa);
@@ -249,7 +250,9 @@ inaddr_to_sockaddr(char *ev, struct sockaddr_in *sa)
 
 	if ((cp = getenv(ev)) == NULL)
 		return(1);
-	if (sscanf(cp, "%d.%d.%d.%d", &a[0], &a[1], &a[2], &a[3]) != 4)
+	count = sscanf(cp, "%d.%d.%d.%d", &a[0], &a[1], &a[2], &a[3]);
+	freeenv(cp);
+	if (count != 4)
 		return(1);
 	/* XXX is this ordering correct? */
 	sa->sin_addr.s_addr = (a[3] << 24) + (a[2] << 16) + (a[1] << 8) + a[0];
@@ -261,6 +264,7 @@ hwaddr_to_sockaddr(char *ev, struct sockaddr_dl *sa)
 {
 	char		*cp;
 	u_int32_t	a[6];
+	int		count;
 
 	bzero(sa, sizeof(*sa));
 	sa->sdl_len = sizeof(*sa);
@@ -269,7 +273,10 @@ hwaddr_to_sockaddr(char *ev, struct sockaddr_dl *sa)
 	sa->sdl_alen = ETHER_ADDR_LEN;
 	if ((cp = getenv(ev)) == NULL)
 		return(1);
-	if (sscanf(cp, "%x:%x:%x:%x:%x:%x", &a[0], &a[1], &a[2], &a[3], &a[4], &a[5]) != 6)
+	count = sscanf(cp, "%x:%x:%x:%x:%x:%x",
+	    &a[0], &a[1], &a[2], &a[3], &a[4], &a[5]);
+	freeenv(cp);
+	if (count != 6)
 		return(1);
 	sa->sdl_data[0] = a[0];
 	sa->sdl_data[1] = a[1];
@@ -286,20 +293,30 @@ decode_nfshandle(char *ev, u_char *fh)
 	u_char	*cp;
 	int	len, val;
 
-	if (((cp = getenv(ev)) == NULL) || (strlen(cp) < 2) || (*cp != 'X'))
+	if ((cp = getenv(ev)) == NULL)
 		return(0);
+	if ((strlen(cp) < 2) || (*cp != 'X')) {
+		freeenv(cp);
+		return (0);
+	}
 	len = 0;
 	cp++;
 	for (;;) {
-		if (*cp == 'X')
+		if (*cp == 'X') {
+			freeenv(cp);
 			return(len);
-		if ((sscanf(cp, "%2x", &val) != 1) || (val > 0xff))
+		}
+		if ((sscanf(cp, "%2x", &val) != 1) || (val > 0xff)) {
+			freeenv(cp);
 			return(0);
+		}
 		*(fh++) = val;
 		len++;
 		cp += 2;
-		if (len > NFSX_V2FH)
+		if (len > NFSX_V2FH) {
+		    freeenv(cp);
 		    return(0);
+		}
 	}
 }
 
@@ -382,8 +399,10 @@ match_done:
 		printf("PXE: no NFS handle\n");
 		return;
 	}
-	if ((cp = getenv("boot.nfsroot.path")) != NULL)
+	if ((cp = getenv("boot.nfsroot.path")) != NULL) {
 		strncpy(nd->root_hostnam, cp, MNAMELEN - 1);
+		freeenv(cp);
+	}
 
 	nfs_diskless_valid = 1;
 }
diff --git a/sys/amd64/amd64/bios.c b/sys/amd64/amd64/bios.c
index 40696fb..bfd1afe 100644
--- a/sys/amd64/amd64/bios.c
+++ b/sys/amd64/amd64/bios.c
@@ -110,6 +110,8 @@ bios32_init(void *junk)
 		if (!bios32_SDlookup(&PCIbios) && bootverbose)
 		    printf("pcibios: PCI BIOS entry at 0x%x+0x%x\n", PCIbios.base, PCIbios.entry);
 	    }
+	    if (p != NULL)
+		    freeenv(p);
 	} else {
 	    printf("bios32: Bad BIOS32 Service Directory\n");
 	}
@@ -145,6 +147,8 @@ bios32_init(void *junk)
 	    printf("pnpbios: Bad PnP BIOS data checksum\n");
 	}
     }
+    if (p != NULL)
+	    freeenv(p);
     if (bootverbose) {
 	    /* look for other know signatures */
 	    printf("Other BIOS signatures found:\n");
diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c
index a3ad87b..8db2ab8 100644
--- a/sys/amd64/amd64/machdep.c
+++ b/sys/amd64/amd64/machdep.c
@@ -1238,7 +1238,7 @@ getmemsize(int first)
 	struct vm86context vmc;
 	vm_offset_t pa, physmap[PHYSMAP_SIZE];
 	pt_entry_t *pte;
-	const char *cp;
+	char *cp;
 	struct bios_smap *smap;
 
 	bzero(&vmf, sizeof(struct vm86frame));
@@ -1454,6 +1454,7 @@ physmap_done:
 			printf("Ignoring invalid memory size of '%s'\n", cp);
 		else
 			Maxmem = atop(AllowMem);
+		freeenv(cp);
 	}
 
 	if (atop(physmap[physmap_idx + 1]) != Maxmem &&