Introduced unprivileged getsysinfo variant, to retrieve harmless data

in formats that don't change (or is upwards compatible).

include/minix/callnr.h

@@ -1,4 +1,4 @@
-#define NCALLS		  97	/* number of system calls allowed */
+#define NCALLS		  98	/* number of system calls allowed */
 
 #define EXIT		   1 
 #define FORK		   2 
@@ -77,6 +77,7 @@
 #define FTRUNCATE	  94	/* to FS */
 #define FCHMOD		  95	/* to FS */
 #define FCHOWN		  96	/* to FS */
+#define GETSYSINFO_UP	  97	/* to PM or FS */
 
 /* Calls provided by PM and FS that are not part of the API */
 #define EXEC_NEWMEM	100	/* from FS or RS to PM: new memory map for

include/minix/com.h

@@ -516,6 +516,11 @@
 #define SEL_ERRORFDS   m8_p3
 #define SEL_TIMEOUT    m8_p4
 
+/* Field names for GETSYSINFO_UP (PM). */
+#define SIU_WHAT	m2_i1
+#define SIU_LEN		m2_i2
+#define SIU_WHERE	m2_p1
+
 /* Message for SYS_READBIOS */
 #define RDB_SIZE	m2_i1
 #define RDB_ADDR	m2_l1

include/minix/sysinfo.h

@@ -0,0 +1,17 @@
+
+#ifndef _MINIX_SYSINFO_H
+#define _MINIX_SYSINFO_H
+
+#include <minix/endpoint.h>
+#include <minix/type.h>
+
+_PROTOTYPE( int getsysinfo, (endpoint_t who, int what, void *where)       );
+_PROTOTYPE( ssize_t getsysinfo_up, (endpoint_t who, int what, size_t size,
+	void *where));
+
+#define SIU_LOADINFO	1	/* retrieve load info data */
+
+/* Exported system parameters. */
+
+#endif
+

include/minix/type.h

@@ -116,10 +116,10 @@ struct kinfo {
 };
 
 /* Load data accounted every this no. of seconds. */
-#define _LOAD_UNIT_SECS		 6 
+#define _LOAD_UNIT_SECS		 6 	/* Changing this breaks ABI. */
 
 /* Load data history is kept for this long. */
-#define _LOAD_HISTORY_MINUTES	15
+#define _LOAD_HISTORY_MINUTES	15	/* Changing this breaks ABI. */
 #define _LOAD_HISTORY_SECONDS	(60*_LOAD_HISTORY_MINUTES)
 
 /* We need this many slots to store the load history. */

lib/other/_getsysinfo.c

@@ -1,10 +1,12 @@
 #include <lib.h>
+#include <minix/endpoint.h>
 #define getsysinfo	_getsysinfo
-#include <unistd.h>
+#define getsysinfo_up	_getsysinfo_up
+#include <minix/sysinfo.h>
 
 
 PUBLIC int getsysinfo(who, what, where)
-int who;			/* from whom to request info */
+endpoint_t who;			/* from whom to request info */
 int what;			/* what information is requested */
 void *where;			/* where to put it */
 {
@@ -15,3 +17,17 @@ void *where;			/* where to put it */
   return(0);
 }
 
+/* Unprivileged variant of getsysinfo. */
+PUBLIC ssize_t getsysinfo_up(who, what, size, where)
+endpoint_t who;			/* from whom to request info */
+int what;			/* what information is requested */
+size_t size;			/* input and output size */
+void *where;			/* where to put it */
+{
+  message m;
+  m.SIU_WHAT = what;
+  m.SIU_WHERE = where;
+  m.SIU_LEN = size;
+  return _syscall(who, GETSYSINFO_UP, &m);
+}
+

lib/posix/getloadavg.c

@@ -1,5 +1,6 @@
 
 #include <sys/types.h>
+#include <minix/sysinfo.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <lib.h>
@@ -11,12 +12,17 @@ int getloadavg(double *loadavg, int nelem)
   int h, p, unfilled_ticks;
 #define PERIODS 3
   int minutes[3] = { 1, 5, 15 };
+  size_t loadsize;
+  ssize_t l;
   if(nelem < 1) {
 	errno = ENOSPC;
 	return -1;
   }
 
-  if(getsysinfo(PM_PROC_NR, SI_LOADINFO, &loadinfo) < 0)
+  loadsize = sizeof(loadinfo);
+  if((l=getsysinfo_up(PM_PROC_NR, SIU_LOADINFO, loadsize, &loadinfo)) < 0)
+	return -1;
+  if(l != sizeof(loadinfo))
 	return -1;
   if(nelem > PERIODS)
 	nelem = PERIODS;

lib/syscall/getsysinfo.s

@@ -1,7 +1,11 @@
 .sect .text
 .extern	__getsysinfo
 .define	_getsysinfo
+.extern	__getsysinfo_up
+.define	_getsysinfo_up
 .align 2
 
 _getsysinfo:
 	jmp	__getsysinfo
+_getsysinfo_up:
+	jmp	__getsysinfo_up

servers/fs/table.c

@@ -114,6 +114,7 @@ PUBLIC _PROTOTYPE (int (*call_vec[]), (void) ) = {
 	do_ftruncate,	/* 94 = truncate */
 	do_chmod,	/* 95 = fchmod */
 	do_chown,	/* 96 = fchown */
+	no_sys,		/* 97 = (getsysinfo_up) */
 };
 /* This should not fail with "array size is negative": */
 extern int dummy[sizeof(call_vec) == NCALLS * sizeof(call_vec[0]) ? 1 : -1];

servers/pm/misc.c

@@ -21,6 +21,7 @@
 #include <sys/utsname.h>
 #include <minix/com.h>
 #include <minix/config.h>
+#include <minix/sysinfo.h>
 #include <minix/type.h>
 #include <string.h>
 #include <lib.h>
@@ -276,6 +277,37 @@ PUBLIC int do_getsysinfo()
   return(OK);
 }
 
+/*===========================================================================*
+ *				do_getsysinfo_up		       	     *
+ *===========================================================================*/
+PUBLIC int do_getsysinfo_up()
+{
+  vir_bytes src_addr, dst_addr;
+  struct loadinfo loadinfo;
+  size_t len, real_len;
+  int s, r;
+
+  switch(m_in.SIU_WHAT) {
+  case SIU_LOADINFO:			/* loadinfo is obtained via PM */
+        sys_getloadinfo(&loadinfo);
+        src_addr = (vir_bytes) &loadinfo;
+        real_len = sizeof(struct loadinfo);
+        break;
+  default:
+  	return(EINVAL);
+  }
+
+  /* Let application know what the length was. */
+  len = real_len;
+  if(len > m_in.SIU_LEN)
+	len = m_in.SIU_LEN;
+
+  dst_addr = (vir_bytes) m_in.SIU_WHERE;
+  if (OK != (s=sys_datacopy(SELF, src_addr, who_e, dst_addr, len)))
+  	return(s);
+  return(real_len);
+}
+
 /*===========================================================================*
  *				do_getprocnr			             *
  *===========================================================================*/

servers/pm/proto.h

@@ -66,6 +66,7 @@ _PROTOTYPE( int do_reboot, (void)					);
 _PROTOTYPE( int do_procstat, (void)					);
 _PROTOTYPE( int do_sysuname, (void)					);
 _PROTOTYPE( int do_getsysinfo, (void)					);
+_PROTOTYPE( int do_getsysinfo_up, (void)					);
 _PROTOTYPE( int do_getprocnr, (void)					);
 _PROTOTYPE( int do_svrctl, (void)					);
 _PROTOTYPE( int do_allocmem, (void)					);

servers/pm/table.c

@@ -112,6 +112,7 @@ _PROTOTYPE (int (*call_vec[NCALLS]), (void) ) = {
 	no_sys,		/* 94 = (ftruncate) */
 	no_sys,		/* 95 = (fchmod) */
 	no_sys,		/* 96 = (fchown) */
+	do_getsysinfo_up,/* 97 = getsysinfo_up */
 };
 /* This should not fail with "array size is negative": */
 extern int dummy[sizeof(call_vec) == NCALLS * sizeof(call_vec[0]) ? 1 : -1];