Simplify syscall_fixup[_on_sysexit]

* syscall.c (syscall_fixup): Remove checks for entering(tcp).
Remove code which executes if exiting(tcp).
(syscall_fixup_on_sysexit): Remove code which executes
if entering(tcp). Remove checks for exiting(tcp).

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

diff --git a/syscall.c b/syscall.c
index 521ca10b1c51366783d1685c7d247013d50ac789..57fd131972da83abe7db582752d8df1d7ea4cd27 100644 (file)
--- a/syscall.c
+++ b/syscall.c
@@ -1250,66 +1250,43 @@ syscall_fixup(struct tcb *tcp)
 #ifdef USE_PROCFS
        int scno = known_scno(tcp);
 
-       if (entering(tcp)) {
-               if (tcp->status.PR_WHY != PR_SYSENTRY) {
-                       if (
-                           scno == SYS_fork
+       if (tcp->status.PR_WHY != PR_SYSENTRY) {
+               if (
+                   scno == SYS_fork
 #ifdef SYS_vfork
-                           || scno == SYS_vfork
-#endif /* SYS_vfork */
+                   || scno == SYS_vfork
+#endif
 #ifdef SYS_fork1
-                           || scno == SYS_fork1
-#endif /* SYS_fork1 */
+                   || scno == SYS_fork1
+#endif
 #ifdef SYS_forkall
-                           || scno == SYS_forkall
-#endif /* SYS_forkall */
+                   || scno == SYS_forkall
+#endif
 #ifdef SYS_rfork1
-                           || scno == SYS_rfork1
-#endif /* SYS_fork1 */
+                   || scno == SYS_rfork1
+#endif
 #ifdef SYS_rforkall
-                           || scno == SYS_rforkall
-#endif /* SYS_rforkall */
-                           ) {
-                               /* We are returning in the child, fake it. */
-                               tcp->status.PR_WHY = PR_SYSENTRY;
-                               trace_syscall(tcp);
-                               tcp->status.PR_WHY = PR_SYSEXIT;
-                       }
-                       else {
-                               fprintf(stderr, "syscall: missing entry\n");
-                               tcp->flags |= TCB_INSYSCALL;
-                       }
+                   || scno == SYS_rforkall
+#endif
+                   ) {
+                       /* We are returning in the child, fake it. */
+                       tcp->status.PR_WHY = PR_SYSENTRY;
+                       trace_syscall(tcp);
+                       tcp->status.PR_WHY = PR_SYSEXIT;
                }
-       }
-       else {
-               if (tcp->status.PR_WHY != PR_SYSEXIT) {
-                       fprintf(stderr, "syscall: missing exit\n");
-                       tcp->flags &= ~TCB_INSYSCALL;
+               else {
+                       fprintf(stderr, "syscall: missing entry\n");
+                       tcp->flags |= TCB_INSYSCALL;
                }
        }
 #endif /* USE_PROCFS */
 
 #ifdef SUNOS4
-       if (entering(tcp)) {
-               if (scno == 0) {
-                       fprintf(stderr, "syscall: missing entry\n");
-                       tcp->flags |= TCB_INSYSCALL;
-               }
-       }
-       else {
-               if (scno != 0) {
-                       if (debug) {
-                               /*
-                                * This happens when a signal handler
-                                * for a signal which interrupted a
-                                * a system call makes another system call.
-                                */
-                               fprintf(stderr, "syscall: missing exit\n");
-                       }
-                       tcp->flags &= ~TCB_INSYSCALL;
-               }
+       if (scno == 0) {
+               fprintf(stderr, "syscall: missing entry\n");
+               tcp->flags |= TCB_INSYSCALL;
        }
-#endif /* SUNOS4 */
+#endif
 
 #ifdef LINUX
        /* A common case of "not a syscall entry" is post-execve SIGTRAP */
@@ -1318,7 +1295,7 @@ syscall_fixup(struct tcb *tcp)
         * Every extra ptrace call is expensive, so check EAX
         * on syscall entry only if PTRACE_O_TRACEEXEC is not enabled:
         */
-       if (entering(tcp) && !(ptrace_setoptions & PTRACE_O_TRACEEXEC)) {
+       if (!(ptrace_setoptions & PTRACE_O_TRACEEXEC)) {
                if (upeek(tcp, 4*EAX, &eax) < 0)
                        return -1;
                if (eax != -ENOSYS) {
@@ -1328,7 +1305,7 @@ syscall_fixup(struct tcb *tcp)
                }
        }
 #elif defined (X86_64)
-       if (entering(tcp) && !(ptrace_setoptions & PTRACE_O_TRACEEXEC)) {
+       if (!(ptrace_setoptions & PTRACE_O_TRACEEXEC)) {
                if (upeek(tcp, 8*RAX, &rax) < 0)
                        return -1;
                if (current_personality == 1)
@@ -1344,21 +1321,11 @@ syscall_fixup(struct tcb *tcp)
                return -1;
        if (syscall_mode != -ENOSYS)
                syscall_mode = tcp->scno;
-       if (gpr2 != syscall_mode && entering(tcp)) {
+       if (gpr2 != syscall_mode) {
                if (debug)
                        fprintf(stderr, "not a syscall entry (gpr2 = %ld)\n", gpr2);
                return 0;
        }
-       else if (((tcp->flags & (TCB_INSYSCALL|TCB_WAITEXECVE))
-                 == (TCB_INSYSCALL|TCB_WAITEXECVE))
-                && (gpr2 == -ENOSYS || gpr2 == tcp->scno)) {
-               /*
-                * Return from execve.
-                * Fake a return value of zero.  We leave the TCB_WAITEXECVE
-                * flag set for the post-execve SIGTRAP to see and reset.
-                */
-               gpr2 = 0;
-       }
 #elif defined (POWERPC)
 # define SO_MASK 0x10000000
        if (upeek(tcp, sizeof(unsigned long)*PT_CCR, &flags) < 0)
@@ -1370,15 +1337,13 @@ syscall_fixup(struct tcb *tcp)
 #elif defined (M68K)
        if (upeek(tcp, 4*PT_D0, &d0) < 0)
                return -1;
-       if (d0 != -ENOSYS && entering(tcp)) {
+       if (d0 != -ENOSYS) {
                if (debug)
                        fprintf(stderr, "not a syscall entry (d0 = %ld)\n", d0);
                return 0;
        }
 #elif defined (ARM)
-       /*
-        * Nothing required
-        */
+       /* Nothing required */
 #elif defined(BFIN)
        if (upeek(tcp, PT_R0, &r0) < 0)
                return -1;
@@ -1390,7 +1355,7 @@ syscall_fixup(struct tcb *tcp)
                return -1;
        if (upeek(tcp, PT_R8, &r8) < 0)
                return -1;
-       if (ia32 && r8 != -ENOSYS && entering(tcp)) {
+       if (ia32 && r8 != -ENOSYS) {
                if (debug)
                        fprintf(stderr, "not a syscall entry (r8 = %ld)\n", r8);
                return 0;
@@ -1398,7 +1363,7 @@ syscall_fixup(struct tcb *tcp)
 #elif defined(CRISV10) || defined(CRISV32)
        if (upeek(tcp, 4*PT_R10, &r10) < 0)
                return -1;
-       if (r10 != -ENOSYS && entering(tcp)) {
+       if (r10 != -ENOSYS) {
                if (debug)
                        fprintf(stderr, "not a syscall entry (r10 = %ld)\n", r10);
                return 0;
@@ -1406,7 +1371,7 @@ syscall_fixup(struct tcb *tcp)
 #elif defined(MICROBLAZE)
        if (upeek(tcp, 3 * 4, &r3) < 0)
                return -1;
-       if (r3 != -ENOSYS && entering(tcp)) {
+       if (r3 != -ENOSYS) {
                if (debug)
                        fprintf(stderr, "not a syscall entry (r3 = %ld)\n", r3);
                return 0;
@@ -1998,55 +1963,15 @@ static int
 syscall_fixup_on_sysexit(struct tcb *tcp)
 {
 #ifdef USE_PROCFS
-       int scno = known_scno(tcp);
-
-       if (entering(tcp)) {
-               if (tcp->status.PR_WHY != PR_SYSENTRY) {
-                       if (
-                           scno == SYS_fork
-#ifdef SYS_vfork
-                           || scno == SYS_vfork
-#endif /* SYS_vfork */
-#ifdef SYS_fork1
-                           || scno == SYS_fork1
-#endif /* SYS_fork1 */
-#ifdef SYS_forkall
-                           || scno == SYS_forkall
-#endif /* SYS_forkall */
-#ifdef SYS_rfork1
-                           || scno == SYS_rfork1
-#endif /* SYS_fork1 */
-#ifdef SYS_rforkall
-                           || scno == SYS_rforkall
-#endif /* SYS_rforkall */
-                           ) {
-                               /* We are returning in the child, fake it. */
-                               tcp->status.PR_WHY = PR_SYSENTRY;
-                               trace_syscall(tcp);
-                               tcp->status.PR_WHY = PR_SYSEXIT;
-                       }
-                       else {
-                               fprintf(stderr, "syscall: missing entry\n");
-                               tcp->flags |= TCB_INSYSCALL;
-                       }
-               }
-       }
-       else {
-               if (tcp->status.PR_WHY != PR_SYSEXIT) {
-                       fprintf(stderr, "syscall: missing exit\n");
-                       tcp->flags &= ~TCB_INSYSCALL;
-               }
+       if (tcp->status.PR_WHY != PR_SYSEXIT) {
+               fprintf(stderr, "syscall: missing exit\n");
+               tcp->flags &= ~TCB_INSYSCALL;
        }
 #endif /* USE_PROCFS */
 
 #ifdef SUNOS4
-       if (entering(tcp)) {
-               if (scno == 0) {
-                       fprintf(stderr, "syscall: missing entry\n");
-                       tcp->flags |= TCB_INSYSCALL;
-               }
-       }
-       else {
+       {
+               int scno = known_scno(tcp);
                if (scno != 0) {
                        if (debug) {
                                /*
@@ -2062,45 +1987,12 @@ syscall_fixup_on_sysexit(struct tcb *tcp)
 #endif /* SUNOS4 */
 
 #ifdef LINUX
-       /* A common case of "not a syscall entry" is post-execve SIGTRAP */
-#if defined (I386)
-       /* With PTRACE_O_TRACEEXEC, post-execve SIGTRAP is disabled.
-        * Every extra ptrace call is expensive, so check EAX
-        * on syscall entry only if PTRACE_O_TRACEEXEC is not enabled:
-        */
-       if (entering(tcp) && !(ptrace_setoptions & PTRACE_O_TRACEEXEC)) {
-               if (upeek(tcp, 4*EAX, &eax) < 0)
-                       return -1;
-               if (eax != -ENOSYS) {
-                       if (debug)
-                               fprintf(stderr, "not a syscall entry (eax = %ld)\n", eax);
-                       return 0;
-               }
-       }
-#elif defined (X86_64)
-       if (entering(tcp) && !(ptrace_setoptions & PTRACE_O_TRACEEXEC)) {
-               if (upeek(tcp, 8*RAX, &rax) < 0)
-                       return -1;
-               if (current_personality == 1)
-                       rax = (long int)(int)rax; /* sign extend from 32 bits */
-               if (rax != -ENOSYS && entering(tcp)) {
-                       if (debug)
-                               fprintf(stderr, "not a syscall entry (rax = %ld)\n", rax);
-                       return 0;
-               }
-       }
-#elif defined (S390) || defined (S390X)
+#if defined (S390) || defined (S390X)
        if (upeek(tcp, PT_GPR2, &gpr2) < 0)
                return -1;
        if (syscall_mode != -ENOSYS)
                syscall_mode = tcp->scno;
-       if (gpr2 != syscall_mode && entering(tcp)) {
-               if (debug)
-                       fprintf(stderr, "not a syscall entry (gpr2 = %ld)\n", gpr2);
-               return 0;
-       }
-       else if (((tcp->flags & (TCB_INSYSCALL|TCB_WAITEXECVE))
-                 == (TCB_INSYSCALL|TCB_WAITEXECVE))
+       if ((tcp->flags & TCB_WAITEXECVE)
                 && (gpr2 == -ENOSYS || gpr2 == tcp->scno)) {
                /*
                 * Return from execve.
@@ -2120,15 +2012,8 @@ syscall_fixup_on_sysexit(struct tcb *tcp)
 #elif defined (M68K)
        if (upeek(tcp, 4*PT_D0, &d0) < 0)
                return -1;
-       if (d0 != -ENOSYS && entering(tcp)) {
-               if (debug)
-                       fprintf(stderr, "not a syscall entry (d0 = %ld)\n", d0);
-               return 0;
-       }
 #elif defined (ARM)
-       /*
-        * Nothing required
-        */
+       /* Nothing required */
 #elif defined(BFIN)
        if (upeek(tcp, PT_R0, &r0) < 0)
                return -1;
@@ -2140,27 +2025,12 @@ syscall_fixup_on_sysexit(struct tcb *tcp)
                return -1;
        if (upeek(tcp, PT_R8, &r8) < 0)
                return -1;
-       if (ia32 && r8 != -ENOSYS && entering(tcp)) {
-               if (debug)
-                       fprintf(stderr, "not a syscall entry (r8 = %ld)\n", r8);
-               return 0;
-       }
 #elif defined(CRISV10) || defined(CRISV32)
        if (upeek(tcp, 4*PT_R10, &r10) < 0)
                return -1;
-       if (r10 != -ENOSYS && entering(tcp)) {
-               if (debug)
-                       fprintf(stderr, "not a syscall entry (r10 = %ld)\n", r10);
-               return 0;
-       }
 #elif defined(MICROBLAZE)
        if (upeek(tcp, 3 * 4, &r3) < 0)
                return -1;
-       if (r3 != -ENOSYS && entering(tcp)) {
-               if (debug)
-                       fprintf(stderr, "not a syscall entry (r3 = %ld)\n", r3);
-               return 0;
-       }
 #endif
 #endif /* LINUX */
        return 1;