utrace: Deliver signals to traced processes

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

diff --git a/trace/trace.c b/trace/trace.c
index 35bc548..cad2d37 100644 (file)
--- a/trace/trace.c
+++ b/trace/trace.c
@@ -57,11 +57,15 @@
        fprintf(stderr, "utrace: "fmt, ## __VA_ARGS__); \
 } while (0)
 
-static struct uloop_process tracer;
+struct tracee {
+       struct uloop_process proc;
+       int in_syscall;
+};
+
+static struct tracee tracer;
 static int *syscall_count;
 static struct blob_buf b;
 static int syscall_max;
-static int in_syscall;
 static int debug;
 
 static int max_syscall = ARRAY_SIZE(syscall_names);
@@ -143,25 +147,53 @@ static void print_syscalls(int policy, const char *json)
 
 static void tracer_cb(struct uloop_process *c, int ret)
 {
-       if (WIFSTOPPED(ret) && WSTOPSIG(ret) & 0x80) {
-               if (!in_syscall) {
-                       int syscall = ptrace(PTRACE_PEEKUSER, c->pid, reg_syscall_nr);
-
-                       if (syscall < syscall_max) {
-                               syscall_count[syscall]++;
-                               if (debug)
-                                       fprintf(stderr, "%s()\n", syscall_names[syscall]);
-                       } else if (debug) {
-                               fprintf(stderr, "syscal(%d)\n", syscall);
+       struct tracee *tracee = container_of(c, struct tracee, proc);
+       int inject_signal = 0;
+
+       if (WIFSTOPPED(ret)) {
+               if (WSTOPSIG(ret) & 0x80) {
+                       if (!tracee->in_syscall) {
+                               int syscall = ptrace(PTRACE_PEEKUSER, c->pid, reg_syscall_nr);
+
+                               if (syscall < syscall_max) {
+                                       syscall_count[syscall]++;
+                                       if (debug)
+                                               fprintf(stderr, "%s()\n", syscall_names[syscall]);
+                               } else if (debug) {
+                                       fprintf(stderr, "syscal(%d)\n", syscall);
+                               }
                        }
+                       tracee->in_syscall = !tracee->in_syscall;
+               } 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);
+                       child->proc.cb = tracer_cb;
+                       ptrace(PTRACE_SYSCALL, child->proc.pid, 0, 0);
+                       uloop_process_add(&child->proc);
+                       if (debug)
+                               fprintf(stderr, "Tracing new child %d\n", child->proc.pid);
+               } 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) || (WIFSIGNALED(ret) && WTERMSIG(ret))) {
+               if (tracee == &tracer) {
+                       uloop_end(); /* Main process exit */
+               } else {
+                       if (debug)
+                               fprintf(stderr, "Child %d exited\n", tracee->proc.pid);
+                       free(tracee);
                }
-               in_syscall = !in_syscall;
-       } else if (WIFEXITED(ret)) {
-               uloop_end();
                return;
        }
-       ptrace(PTRACE_SYSCALL, c->pid, 0, 0);
-       uloop_process_add(&tracer);
+
+       ptrace(PTRACE_SYSCALL, c->pid, 0, inject_signal);
+       uloop_process_add(c);
 }
 
 int main(int argc, char **argv, char **envp)
@@ -228,13 +260,17 @@ int main(int argc, char **argv, char **envp)
                return -1;
        }
 
-       ptrace(PTRACE_SETOPTIONS, child, 0, PTRACE_O_TRACESYSGOOD);
+       ptrace(PTRACE_SETOPTIONS, child, 0,
+              PTRACE_O_TRACESYSGOOD |
+              PTRACE_O_TRACEFORK |
+              PTRACE_O_TRACEVFORK |
+              PTRACE_O_TRACECLONE);
        ptrace(PTRACE_SYSCALL, child, 0, 0);
 
        uloop_init();
-       tracer.pid = child;
-       tracer.cb = tracer_cb;
-       uloop_process_add(&tracer);
+       tracer.proc.pid = child;
+       tracer.proc.cb = tracer_cb;
+       uloop_process_add(&tracer.proc);
        uloop_run();
        uloop_done();