[PATCH v4] Decode paths associated with file descriptors returned by syscalls

[zubin.mithra at gmail.com]

From: Zubin Mithra <zubin.mithra at gmail.com>

* defs.h (RVAL_FD): New macro.
* defs.h (RVAL_MASK, RVAL_STR, RVAL_NONE): Macro values modified.
* desc.c (sys_dup): New function.
* desc.c (sys_delete_module): New function.
* desc.c (do_dup2, decode_open, sys_creat): Modified to return
  RVAL_FD.
* linux/dummy.h (sys_delete_module, sys_dup): Macros removed.
* linux/syscall.h (sys_delete_module, sys_dup): New
  prototype.
* syscall.c (trace_syscall_exiting): Modified to handle RVAL_FD
  return value.

Signed-off-by: Zubin Mithra <zubin.mithra at gmail.com>
---
 defs.h          |  7 ++++---
 desc.c          | 11 ++++++++++-
 file.c          | 10 ++++++++--
 linux/dummy.h   |  2 --
 linux/syscall.h |  2 ++
 syscall.c       |  8 ++++++++
 6 files changed, 32 insertions(+), 8 deletions(-)

diff --git a/defs.h b/defs.h
index c862de5..99493b3 100644
--- a/defs.h
+++ b/defs.h
@@ -533,10 +533,11 @@ extern const struct xlat whence_codes[];
 # endif
 # define RVAL_LUDECIMAL	007	/* long unsigned decimal format */
 #endif
-#define RVAL_MASK	007	/* mask for these values */
+#define RVAL_FD 	010 	/* file descriptors */
+#define RVAL_MASK	017	/* mask for these values */
 
-#define RVAL_STR	010	/* Print `auxstr' field after return val */
-#define RVAL_NONE	020	/* Print nothing */
+#define RVAL_STR	020	/* Print `auxstr' field after return val */
+#define RVAL_NONE	040	/* Print nothing */
 
 #define TRACE_FILE	001	/* Trace file-related syscalls. */
 #define TRACE_IPC	002	/* Trace IPC-related syscalls. */
diff --git a/desc.c b/desc.c
index 0c9a817..5b8869b 100644
--- a/desc.c
+++ b/desc.c
@@ -265,6 +265,15 @@ sys_close(struct tcb *tcp)
 	return 0;
 }
 
+int
+sys_dup(struct tcb *tcp)
+{
+	if (entering(tcp)) {
+		printfd(tcp, tcp->u_arg[0]);
+	}
+	return RVAL_FD;
+}
+
 static int
 do_dup2(struct tcb *tcp, int flags_arg)
 {
@@ -277,7 +286,7 @@ do_dup2(struct tcb *tcp, int flags_arg)
 			printflags(open_mode_flags, tcp->u_arg[flags_arg], "O_???");
 		}
 	}
-	return 0;
+	return RVAL_FD;
 }
 
 int
diff --git a/file.c b/file.c
index c322242..f817182 100644
--- a/file.c
+++ b/file.c
@@ -303,7 +303,7 @@ decode_open(struct tcb *tcp, int offset)
 			tprintf(", %#lo", tcp->u_arg[offset + 2]);
 		}
 	}
-	return 0;
+	return RVAL_FD;
 }
 
 int
@@ -312,6 +312,12 @@ sys_open(struct tcb *tcp)
 	return decode_open(tcp, 0);
 }
 
+int sys_delete_module(struct tcb *tcp)
+{
+	decode_open(tcp, 0);
+	return RVAL_DECIMAL;
+}
+
 int
 sys_openat(struct tcb *tcp)
 {
@@ -348,7 +354,7 @@ sys_creat(struct tcb *tcp)
 		printpath(tcp, tcp->u_arg[0]);
 		tprintf(", %#lo", tcp->u_arg[1]);
 	}
-	return 0;
+	return RVAL_FD;
 }
 
 #include "xlat/access_flags.h"
diff --git a/linux/dummy.h b/linux/dummy.h
index 4f3e920..6068666 100644
--- a/linux/dummy.h
+++ b/linux/dummy.h
@@ -57,8 +57,6 @@
 #define	sys_acct		sys_chdir
 #define	sys_chroot		sys_chdir
 #define	sys_clock_getres	sys_clock_gettime
-#define	sys_delete_module	sys_open
-#define	sys_dup			sys_close
 #define	sys_fchdir		sys_close
 #define	sys_fdatasync		sys_close
 #define	sys_fsync		sys_close
diff --git a/linux/syscall.h b/linux/syscall.h
index 1943297..38aa4bd 100644
--- a/linux/syscall.h
+++ b/linux/syscall.h
@@ -52,6 +52,8 @@ int sys_close();
 int sys_connect();
 int sys_creat();
 int sys_create_module();
+int sys_delete_module();
+int sys_dup();
 int sys_dup2();
 int sys_dup3();
 int sys_epoll_create();
diff --git a/syscall.c b/syscall.c
index c95eb6c..b0ad47e 100644
--- a/syscall.c
+++ b/syscall.c
@@ -2688,6 +2688,14 @@ trace_syscall_exiting(struct tcb *tcp)
 			case RVAL_DECIMAL:
 				tprintf("= %ld", tcp->u_rval);
 				break;
+			case RVAL_FD:
+				if (show_fd_path) {
+					tprints("= ");
+					printfd(tcp, tcp->u_rval);
+				}
+				else
+					tprintf("= %ld", tcp->u_rval);
+				break;
 #if defined(LINUX_MIPSN32) || defined(X32)
 			/*
 			case RVAL_LHEX:
-- 
1.8.4