process_event.c

#if HAVE_CONFIG_H
#include "config.h"
#endif

#define _GNU_SOURCE
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <signal.h>
#include <assert.h>
#include <sys/time.h>

#include "ltrace.h"
#include "output.h"
#include "options.h"
#include "elf.h"
#include "debug.h"

#ifdef __powerpc__
#include <sys/ptrace.h>
#endif

static void process_signal(struct event *event);
static void process_exit(struct event *event);
static void process_exit_signal(struct event *event);
static void process_syscall(struct event *event);
static void process_sysret(struct event *event);
static void process_breakpoint(struct event *event);
static void remove_proc(struct process *proc);

static void callstack_push_syscall(struct process *proc, int sysnum);
static void callstack_push_symfunc(struct process *proc,
				   struct library_symbol *sym);
static void callstack_pop(struct process *proc);

static char *shortsignal(int signum)
{
	static char *signalent0[] = {
#include "signalent.h"
	};
	int nsignals0 = sizeof signalent0 / sizeof signalent0[0];

	if (signum < 0 || signum >= nsignals0) {
		return "UNKNOWN_SIGNAL";
	} else {
		return signalent0[signum];
	}
}

static char *sysname(int sysnum)
{
	static char result[128];
	static char *syscalent0[] = {
#include "syscallent.h"
	};
	int nsyscals0 = sizeof syscalent0 / sizeof syscalent0[0];

	if (sysnum < 0 || sysnum >= nsyscals0) {
		sprintf(result, "SYS_%d", sysnum);
		return result;
	} else {
		sprintf(result, "SYS_%s", syscalent0[sysnum]);
		return result;
	}
}

void process_event(struct event *event)
{
	switch (event->thing) {
	case LT_EV_NONE:
		debug(1, "event: none");
		return;
	case LT_EV_SIGNAL:
		debug(1, "event: signal (%s [%d])",
		      shortsignal(event->e_un.signum), event->e_un.signum);
		process_signal(event);
		return;
	case LT_EV_EXIT:
		debug(1, "event: exit (%d)", event->e_un.ret_val);
		process_exit(event);
		return;
	case LT_EV_EXIT_SIGNAL:
		debug(1, "event: exit signal (%s [%d])",
		      shortsignal(event->e_un.signum), event->e_un.signum);
		process_exit_signal(event);
		return;
	case LT_EV_SYSCALL:
		debug(1, "event: syscall (%s [%d])",
		      sysname(event->e_un.sysnum), event->e_un.sysnum);
		process_syscall(event);
		return;
	case LT_EV_SYSRET:
		debug(1, "event: sysret (%s [%d])", sysname(event->e_un.sysnum),
		      event->e_un.sysnum);
		process_sysret(event);
		return;
	case LT_EV_BREAKPOINT:
		debug(1, "event: breakpoint");
		process_breakpoint(event);
		return;
	default:
		fprintf(stderr, "Error! unknown event?\n");
		exit(1);
	}
}

static void process_signal(struct event *event)
{
	if (exiting && event->e_un.signum == SIGSTOP) {
		pid_t pid = event->proc->pid;
		disable_all_breakpoints(event->proc);
		untrace_pid(pid);
		remove_proc(event->proc);
		continue_after_signal(pid, event->e_un.signum);
		return;
	}
	output_line(event->proc, "--- %s (%s) ---",
		    shortsignal(event->e_un.signum),
		    strsignal(event->e_un.signum));
	continue_after_signal(event->proc->pid, event->e_un.signum);
}

static void process_exit(struct event *event)
{
	output_line(event->proc, "+++ exited (status %d) +++",
		    event->e_un.ret_val);
	remove_proc(event->proc);
}

static void process_exit_signal(struct event *event)
{
	output_line(event->proc, "+++ killed by %s +++",
		    shortsignal(event->e_un.signum));
	remove_proc(event->proc);
}

static void remove_proc(struct process *proc)
{
	struct process *tmp, *tmp2;

	debug(1, "Removing pid %u\n", proc->pid);

	if (list_of_processes == proc) {
		tmp = list_of_processes;
		list_of_processes = list_of_processes->next;
		free(tmp);
		return;
	}
	tmp = list_of_processes;
	while (tmp->next) {
		if (tmp->next == proc) {
			tmp2 = tmp->next;
			tmp->next = tmp->next->next;
			free(tmp2);
			continue;
		}
		tmp = tmp->next;
	}
}

static void process_syscall(struct event *event)
{
	if (opt_S) {
		output_left(LT_TOF_SYSCALL, event->proc,
			    sysname(event->e_un.sysnum));
	}
	if (fork_p(event->e_un.sysnum)) {
		disable_all_breakpoints(event->proc);
	} else if (!event->proc->breakpoints_enabled) {
		enable_all_breakpoints(event->proc);
	}
	callstack_push_syscall(event->proc, event->e_un.sysnum);
	continue_process(event->proc->pid);
}

struct timeval current_time_spent;

static void calc_time_spent(struct process *proc)
{
	struct timeval tv;
	struct timezone tz;
	struct timeval diff;
	struct callstack_element *elem;

	elem = &proc->callstack[proc->callstack_depth - 1];

	gettimeofday(&tv, &tz);

	diff.tv_sec = tv.tv_sec - elem->time_spent.tv_sec;
	if (tv.tv_usec >= elem->time_spent.tv_usec) {
		diff.tv_usec = tv.tv_usec - elem->time_spent.tv_usec;
	} else {
		diff.tv_sec++;
		diff.tv_usec = 1000000 + tv.tv_usec - elem->time_spent.tv_usec;
	}
	current_time_spent = diff;
}

static void process_sysret(struct event *event)
{
	if (opt_T || opt_c) {
		calc_time_spent(event->proc);
	}
	if (fork_p(event->e_un.sysnum)) {
		if (opt_f) {
			pid_t child =
			    gimme_arg(LT_TOF_SYSCALLR, event->proc, -1);
			if (child > 0) {
				open_pid(child, 0);
			}
		}
		enable_all_breakpoints(event->proc);
	}
	callstack_pop(event->proc);
	if (opt_S) {
		output_right(LT_TOF_SYSCALLR, event->proc,
			     sysname(event->e_un.sysnum));
	}
	if (exec_p(event->e_un.sysnum)) {
		if (gimme_arg(LT_TOF_SYSCALLR, event->proc, -1) == 0) {
			event->proc->filename = pid2name(event->proc->pid);
			breakpoints_init(event->proc);
		}
	}
	continue_process(event->proc->pid);
}

static void process_breakpoint(struct event *event)
{
	struct library_symbol *tmp;
	int i, j;

	debug(2, "event: breakpoint (%p)", event->e_un.brk_addr);
	if (event->proc->breakpoint_being_enabled) {
		/* Reinsert breakpoint */
		continue_enabling_breakpoint(event->proc->pid,
					     event->proc->
					     breakpoint_being_enabled);
		event->proc->breakpoint_being_enabled = NULL;
		return;
	}

	for (i = event->proc->callstack_depth - 1; i >= 0; i--) {
		if (event->e_un.brk_addr ==
		    event->proc->callstack[i].return_addr) {
#ifdef __powerpc__
			unsigned long a;
			unsigned long addr =
			    event->proc->callstack[i].c_un.libfunc->enter_addr;
			struct breakpoint *sbp =
			    address2bpstruct(event->proc, addr);
			unsigned char break_insn[] = BREAKPOINT_VALUE;

			/*
			 * PPC HACK! (XXX FIXME TODO)
			 * The PLT gets modified during the first call,
			 * so be sure to re-enable the breakpoint.
			 */
			a = ptrace(PTRACE_PEEKTEXT, event->proc->pid, addr);

			if (memcmp(&a, break_insn, 4)) {
				sbp->enabled--;
				insert_breakpoint(event->proc, addr);
			}
#endif
			for (j = event->proc->callstack_depth - 1; j > i; j--) {
				callstack_pop(event->proc);
			}
			if (opt_T || opt_c) {
				calc_time_spent(event->proc);
			}
			callstack_pop(event->proc);
			event->proc->return_addr = event->e_un.brk_addr;
			output_right(LT_TOF_FUNCTIONR, event->proc,
				     event->proc->callstack[i].c_un.libfunc->
				     name);
			continue_after_breakpoint(event->proc,
						  address2bpstruct(event->proc,
								   event->e_un.
								   brk_addr));
			return;
		}
	}

	tmp = event->proc->list_of_symbols;
	while (tmp) {
		if (event->e_un.brk_addr == tmp->enter_addr) {
			event->proc->stack_pointer =
			    get_stack_pointer(event->proc);
			event->proc->return_addr =
			    get_return_addr(event->proc,
					    event->proc->stack_pointer);
			output_left(LT_TOF_FUNCTION, event->proc, tmp->name);
			callstack_push_symfunc(event->proc, tmp);
			continue_after_breakpoint(event->proc,
						  address2bpstruct(event->proc,
								   tmp->
								   enter_addr));
			return;
		}
		tmp = tmp->next;
	}
	output_line(event->proc, "breakpointed at %p (?)",
		    (void *)event->e_un.brk_addr);
	continue_process(event->proc->pid);
}

static void callstack_push_syscall(struct process *proc, int sysnum)
{
	struct callstack_element *elem;

	/* FIXME: not good -- should use dynamic allocation. 19990703 mortene. */
	if (proc->callstack_depth == MAX_CALLDEPTH - 1) {
		fprintf(stderr, "Error: call nesting too deep!\n");
		return;
	}

	elem = &proc->callstack[proc->callstack_depth];
	elem->is_syscall = 1;
	elem->c_un.syscall = sysnum;
	elem->return_addr = NULL;

	proc->callstack_depth++;
	if (opt_T || opt_c) {
		struct timezone tz;
		gettimeofday(&elem->time_spent, &tz);
	}
}

static void
callstack_push_symfunc(struct process *proc, struct library_symbol *sym)
{
	struct callstack_element *elem;

	/* FIXME: not good -- should use dynamic allocation. 19990703 mortene. */
	if (proc->callstack_depth == MAX_CALLDEPTH - 1) {
		fprintf(stderr, "Error: call nesting too deep!\n");
		return;
	}

	elem = &proc->callstack[proc->callstack_depth];
	elem->is_syscall = 0;
	elem->c_un.libfunc = sym;

	elem->return_addr = proc->return_addr;
	insert_breakpoint(proc, elem->return_addr);

	proc->callstack_depth++;
	if (opt_T || opt_c) {
		struct timezone tz;
		gettimeofday(&elem->time_spent, &tz);
	}
}

static void callstack_pop(struct process *proc)
{
	struct callstack_element *elem;
	assert(proc->callstack_depth > 0);

	elem = &proc->callstack[proc->callstack_depth - 1];
	if (!elem->is_syscall) {
		delete_breakpoint(proc, elem->return_addr);
	}
	proc->callstack_depth--;
}