Make use of ptrace(2) instead of procfs in truss(1), eliminating

yet another need of an available /proc/ mount.

Tested with:	make universe
Submitted by:	howardsu
Reviewed by:	alfred

1 files changed, 17 insertions, 32 deletions

diff --git a/usr.bin/truss/amd64-fbsd.c b/usr.bin/truss/amd64-fbsd.c
index 7c7a82e..dd00f59 100644
--- a/usr.bin/truss/amd64-fbsd.c
+++ b/usr.bin/truss/amd64-fbsd.c
@@ -43,8 +43,7 @@ static const char rcsid[] =
  */
 
 #include <sys/types.h>
-#include <sys/ioctl.h>
-#include <sys/pioctl.h>
+#include <sys/ptrace.h>
 #include <sys/syscall.h>
 
 #include <machine/reg.h>
@@ -63,7 +62,6 @@ static const char rcsid[] =
 #include "syscall.h"
 #include "extern.h"
 
-static int fd = -1;
 static int cpid = -1;
 
 #include "syscalls.h"
@@ -113,25 +111,16 @@ clear_fsc(void) {
 
 void
 amd64_syscall_entry(struct trussinfo *trussinfo, int nargs) {
-  char buf[32];
   struct reg regs;
   int syscall_num;
   int i, reg;
   struct syscall *sc;
 
-  if (fd == -1 || trussinfo->pid != cpid) {
-    sprintf(buf, "/proc/%d/regs", trussinfo->pid);
-    fd = open(buf, O_RDWR);
-    if (fd == -1) {
-      fprintf(trussinfo->outfile, "-- CANNOT OPEN REGISTERS --\n");
-      return;
-    }
-    cpid = trussinfo->pid;
-  }
+  cpid = trussinfo->curthread->tid;
 
   clear_fsc();
-  lseek(fd, 0L, 0);
-  if (read(fd, &regs, sizeof(regs)) != sizeof(regs)) {
+  if (ptrace(PT_GETREGS, cpid, (caddr_t)&regs, 0) < 0)
+  {
     fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
     return;
   }
@@ -163,7 +152,7 @@ amd64_syscall_entry(struct trussinfo *trussinfo, int nargs) {
     || !strcmp(fsc.name, "rfork")
     || !strcmp(fsc.name, "vfork"))))
   {
-    trussinfo->in_fork = 1;
+    trussinfo->curthread->in_fork = 1;
   }
 
   if (nargs == 0)
@@ -181,8 +170,13 @@ amd64_syscall_entry(struct trussinfo *trussinfo, int nargs) {
     }
   }
   if (nargs > i) {
-    lseek(Procfd, regs.r_rsp + sizeof(register_t), SEEK_SET);
-    if (read(Procfd, &fsc.args[i], (nargs-i) * sizeof(register_t)) == -1)
+    struct ptrace_io_desc iorequest;
+    iorequest.piod_op = PIOD_READ_D;
+    iorequest.piod_offs = (void *)(regs.r_rsp + sizeof(register_t));
+    iorequest.piod_addr = &fsc.args[i];
+    iorequest.piod_len = (nargs - i) * sizeof(register_t);
+    ptrace(PT_IO, cpid, (caddr_t)&iorequest, 0);
+    if (iorequest.piod_len == 0)
       return;
   }
 
@@ -223,7 +217,7 @@ amd64_syscall_entry(struct trussinfo *trussinfo, int nargs) {
 	      i < (fsc.nargs - 1) ? "," : "");
 #endif
       if (sc && !(sc->args[i].type & OUT)) {
-	fsc.s_args[i] = print_arg(Procfd, &sc->args[i], fsc.args, 0, trussinfo);
+	fsc.s_args[i] = print_arg(&sc->args[i], fsc.args, 0, trussinfo);
       }
     }
 #if DEBUG
@@ -279,25 +273,16 @@ amd64_syscall_entry(struct trussinfo *trussinfo, int nargs) {
 long
 amd64_syscall_exit(struct trussinfo *trussinfo, int syscall_num __unused)
 {
-  char buf[32];
   struct reg regs;
   long retval;
   int i;
   int errorp;
   struct syscall *sc;
 
-  if (fd == -1 || trussinfo->pid != cpid) {
-    sprintf(buf, "/proc/%d/regs", trussinfo->pid);
-    fd = open(buf, O_RDONLY);
-    if (fd == -1) {
-      fprintf(trussinfo->outfile, "-- CANNOT OPEN REGISTERS --\n");
-      return (-1);
-    }
-    cpid = trussinfo->pid;
-  }
+  cpid = trussinfo->curthread->tid;
 
-  lseek(fd, 0L, 0);
-  if (read(fd, &regs, sizeof(regs)) != sizeof(regs)) {
+  if (ptrace(PT_GETREGS, cpid, (caddr_t)&regs, 0) < 0)
+  {
     fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
     return (-1);
   }
@@ -328,7 +313,7 @@ amd64_syscall_exit(struct trussinfo *trussinfo, int syscall_num __unused)
 	if (errorp)
 	  asprintf(&temp, "0x%lx", fsc.args[sc->args[i].offset]);
 	else
-	  temp = print_arg(Procfd, &sc->args[i], fsc.args, retval, trussinfo);
+	  temp = print_arg(&sc->args[i], fsc.args, retval, trussinfo);
 	fsc.s_args[i] = temp;
       }
     }