utrace: Use PTHREAD_SEIZE instead of PTHREAD_TRACEME

[project/procd.git] / trace / trace.c

diff --git a/trace/trace.c b/trace/trace.c
index f882c2e..9d3cd0a 100644 (file)
--- a/trace/trace.c
+++ b/trace/trace.c
@@ -24,6 +24,12 @@
 #include <string.h>
 #include <syslog.h>
 
+#ifndef PTRACE_EVENT_STOP
+/* PTRACE_EVENT_STOP is defined in linux/ptrace.h, but this header
+ * collides with musl's sys/ptrace.h */
+#define PTRACE_EVENT_STOP 128
+#endif
+
 #include <libubox/uloop.h>
 #include <libubox/blobmsg.h>
 #include <libubox/blobmsg_json.h>
@@ -148,8 +154,12 @@ static void print_syscalls(int policy, const char *json)
 static void tracer_cb(struct uloop_process *c, int ret)
 {
        struct tracee *tracee = container_of(c, struct tracee, proc);
+       int inject_signal = 0;
 
-       if (WIFSTOPPED(ret)) {
+       /* We explicitely check for events in upper 16 bits, because
+        * musl (as opposed to glibc) does not report
+        * PTRACE_EVENT_STOP as WIFSTOPPED */
+       if (WIFSTOPPED(ret) || (ret >> 16)) {
                if (WSTOPSIG(ret) & 0x80) {
                        if (!tracee->in_syscall) {
                                int syscall = ptrace(PTRACE_PEEKUSER, c->pid, reg_syscall_nr);
@@ -163,7 +173,9 @@ static void tracer_cb(struct uloop_process *c, int ret)
                                }
                        }
                        tracee->in_syscall = !tracee->in_syscall;
-               } else if ((ret >> 8) == (SIGTRAP | (PTRACE_EVENT_FORK << 8))) {
+               } else if ((ret >> 8) == (SIGTRAP | (PTRACE_EVENT_FORK << 8)) ||
+                          (ret >> 8) == (SIGTRAP | (PTRACE_EVENT_VFORK << 8)) ||
+                          (ret >> 8) == (SIGTRAP | (PTRACE_EVENT_CLONE << 8))) {
                        struct tracee *child = calloc(1, sizeof(struct tracee));
 
                        ptrace(PTRACE_GETEVENTMSG, c->pid, 0, &child->proc.pid);
@@ -172,8 +184,15 @@ static void tracer_cb(struct uloop_process *c, int ret)
                        uloop_process_add(&child->proc);
                        if (debug)
                                fprintf(stderr, "Tracing new child %d\n", child->proc.pid);
+               } else if ((ret >> 16) == PTRACE_EVENT_STOP) {
+                       /* Nothing special to do here */
+               } else {
+                       inject_signal = WSTOPSIG(ret);
+                       if (debug)
+                               fprintf(stderr, "Injecting signal %d into pid %d\n",
+                                       inject_signal, tracee->proc.pid);
                }
-       } else if (WIFEXITED(ret)) {
+       } else if (WIFEXITED(ret) || (WIFSIGNALED(ret) && WTERMSIG(ret))) {
                if (tracee == &tracer) {
                        uloop_end(); /* Main process exit */
                } else {
@@ -184,7 +203,7 @@ static void tracer_cb(struct uloop_process *c, int ret)
                return;
        }
 
-       ptrace(PTRACE_SYSCALL, c->pid, 0, 0);
+       ptrace(PTRACE_SYSCALL, c->pid, 0, inject_signal);
        uloop_process_add(c);
 }
 
@@ -246,16 +265,18 @@ int main(int argc, char **argv, char **envp)
 
        syscall_max = ARRAY_SIZE(syscall_names);
        syscall_count = calloc(syscall_max, sizeof(int));
-       waitpid(child, &status, 0);
+       waitpid(child, &status, WUNTRACED);
        if (!WIFSTOPPED(status)) {
                ERROR("failed to start %s\n", *argv);
                return -1;
        }
 
-       ptrace(PTRACE_SETOPTIONS, child, 0,
+       ptrace(PTRACE_SEIZE, child, 0,
               PTRACE_O_TRACESYSGOOD |
-              PTRACE_O_TRACEFORK);
-       ptrace(PTRACE_SYSCALL, child, 0, 0);
+              PTRACE_O_TRACEFORK |
+              PTRACE_O_TRACEVFORK |
+              PTRACE_O_TRACECLONE);
+       ptrace(PTRACE_SYSCALL, child, 0, SIGCONT);
 
        uloop_init();
        tracer.proc.pid = child;