From: Denys Vlasenko <dvlasenk@redhat.com>
Date: Wed, 26 Jun 2013 12:14:29 +0000 (+0200)
Subject: Get rid of TCB_INUSE and TCB_STRACE_CHILD
X-Git-Tag: v4.9~225
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=fadbf6679cb52d4265a771cbb8635a2ff472e869;p=strace

Get rid of TCB_INUSE and TCB_STRACE_CHILD

We can use tcb::pid == 0 as an indicator of free tcb,
and we already have strace_child variable which holds
pid of our child, if any.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
---

diff --git a/defs.h b/defs.h
index fbbe48cf..1f1602a2 100644
--- a/defs.h
+++ b/defs.h
@@ -393,7 +393,7 @@ typedef struct ioctlent {
 /* Trace Control Block */
 struct tcb {
 	int flags;		/* See below for TCB_ values */
-	int pid;		/* Process Id of this entry */
+	int pid;		/* If 0, this tcb is free */
 	int qual_flg;		/* qual_flags[scno] or DEFAULT_QUAL_FLAGS + RAW */
 	int u_error;		/* Error code */
 	long scno;		/* System call number */
@@ -418,10 +418,9 @@ struct tcb {
 };
 
 /* TCB flags */
-#define TCB_INUSE		00001	/* This table entry is in use */
 /* We have attached to this process, but did not see it stopping yet */
-#define TCB_STARTUP		00002
-#define TCB_IGNORE_ONE_SIGSTOP	00004	/* Next SIGSTOP is to be ignored */
+#define TCB_STARTUP		0x01
+#define TCB_IGNORE_ONE_SIGSTOP	0x02	/* Next SIGSTOP is to be ignored */
 /*
  * Are we in system call entry or in syscall exit?
  *
@@ -440,14 +439,13 @@ struct tcb {
  *
  * Use entering(tcp) / exiting(tcp) to check this bit to make code more readable.
  */
-#define TCB_INSYSCALL	00010
-#define TCB_ATTACHED	00020   /* It is attached already */
-/* Are we PROG from "strace PROG [ARGS]" invocation? */
-#define TCB_STRACE_CHILD 0040
-#define TCB_BPTSET	00100	/* "Breakpoint" set after fork(2) */
-#define TCB_REPRINT	00200	/* We should reprint this syscall on exit */
-#define TCB_FILTERED	00400	/* This system call has been filtered out */
-/* x86 does not need TCB_WAITEXECVE.
+#define TCB_INSYSCALL	0x04
+#define TCB_ATTACHED	0x08	/* We attached to it already */
+#define TCB_BPTSET	0x10	/* "Breakpoint" set after fork(2) */
+#define TCB_REPRINT	0x20	/* We should reprint this syscall on exit */
+#define TCB_FILTERED	0x40	/* This system call has been filtered out */
+/*
+ * x86 does not need TCB_WAITEXECVE.
  * It can detect post-execve SIGTRAP by looking at eax/rax.
  * See "not a syscall entry (eax = %ld)\n" message.
  *
@@ -468,7 +466,7 @@ struct tcb {
 /* This tracee has entered into execve syscall. Expect post-execve SIGTRAP
  * to happen. (When it is detected, tracee is continued and this bit is cleared.)
  */
-# define TCB_WAITEXECVE	01000
+# define TCB_WAITEXECVE	0x80
 #endif
 
 /* qualifier flags */
diff --git a/strace.c b/strace.c
index 3fd35d92..1415aab3 100644
--- a/strace.c
+++ b/strace.c
@@ -678,10 +678,9 @@ alloctcb(int pid)
 
 	for (i = 0; i < tcbtabsize; i++) {
 		tcp = tcbtab[i];
-		if ((tcp->flags & TCB_INUSE) == 0) {
+		if (!tcp->pid) {
 			memset(tcp, 0, sizeof(*tcp));
 			tcp->pid = pid;
-			tcp->flags = TCB_INUSE;
 #if SUPPORTED_PERSONALITIES > 1
 			tcp->currpers = current_personality;
 #endif
@@ -959,7 +958,7 @@ startup_attach(void)
 	for (tcbi = 0; tcbi < tcbtabsize; tcbi++) {
 		tcp = tcbtab[tcbi];
 
-		if (!(tcp->flags & TCB_INUSE))
+		if (!tcp->pid)
 			continue;
 
 		/* Is this a process we should attach to, but not yet attached? */
@@ -1252,9 +1251,9 @@ startup_child(char **argv)
 		}
 		tcp = alloctcb(pid);
 		if (!NOMMU_SYSTEM)
-			tcp->flags |= TCB_ATTACHED | TCB_STRACE_CHILD | TCB_STARTUP | post_attach_sigstop;
+			tcp->flags |= TCB_ATTACHED | TCB_STARTUP | post_attach_sigstop;
 		else
-			tcp->flags |= TCB_ATTACHED | TCB_STRACE_CHILD | TCB_STARTUP;
+			tcp->flags |= TCB_ATTACHED | TCB_STARTUP;
 		newoutf(tcp);
 	}
 	else {
@@ -1916,7 +1915,7 @@ pid2tcb(int pid)
 
 	for (i = 0; i < tcbtabsize; i++) {
 		struct tcb *tcp = tcbtab[i];
-		if (tcp->pid == pid && (tcp->flags & TCB_INUSE))
+		if (tcp->pid == pid)
 			return tcp;
 	}
 
@@ -1937,12 +1936,12 @@ cleanup(void)
 
 	for (i = 0; i < tcbtabsize; i++) {
 		tcp = tcbtab[i];
-		if (!(tcp->flags & TCB_INUSE))
+		if (!tcp->pid)
 			continue;
 		if (debug_flag)
 			fprintf(stderr,
 				"cleanup: looking at pid %u\n", tcp->pid);
-		if (tcp->flags & TCB_STRACE_CHILD) {
+		if (tcp->pid == strace_child) {
 			kill(tcp->pid, SIGCONT);
 			kill(tcp->pid, fatal_sig);
 		}