// SPDX-License-Identifier: GPL-2.0
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <unistd.h>

#include "actions.h"
#include "trace.h"
#include "utils.h"

/*
 * actions_init - initialize struct actions
 */
void
actions_init(struct actions *self)
{
        self->size = action_default_size;
        self->list = calloc(self->size, sizeof(struct action));
        self->len = 0;
        self->continue_flag = false;

        /* This has to be set by the user */
        self->trace_output_inst = NULL;
}

/*
 * actions_destroy - destroy struct actions
 */
void
actions_destroy(struct actions *self)
{
        /* Free any action-specific data */
        struct action *action;

        for_each_action(self, action) {
                if (action->type == ACTION_SHELL)
                        free(action->command);
                if (action->type == ACTION_TRACE_OUTPUT)
                        free(action->trace_output);
        }

        /* Free action list */
        free(self->list);
}

/*
 * actions_new - Get pointer to new action
 */
static struct action *
actions_new(struct actions *self)
{
        if (self->len >= self->size) {
                self->size *= 2;
                self->list = realloc(self->list, self->size * sizeof(struct action));
        }

        return &self->list[self->len++];
}

/*
 * actions_add_trace_output - add an action to output trace
 */
int
actions_add_trace_output(struct actions *self, const char *trace_output)
{
        struct action *action = actions_new(self);

        self->present[ACTION_TRACE_OUTPUT] = true;
        action->type = ACTION_TRACE_OUTPUT;
        action->trace_output = calloc(strlen(trace_output) + 1, sizeof(char));
        if (!action->trace_output)
                return -1;
        strcpy(action->trace_output, trace_output);

        return 0;
}

/*
 * actions_add_trace_output - add an action to send signal to a process
 */
int
actions_add_signal(struct actions *self, int signal, int pid)
{
        struct action *action = actions_new(self);

        self->present[ACTION_SIGNAL] = true;
        action->type = ACTION_SIGNAL;
        action->signal = signal;
        action->pid = pid;

        return 0;
}

/*
 * actions_add_shell - add an action to execute a shell command
 */
int
actions_add_shell(struct actions *self, const char *command)
{
        struct action *action = actions_new(self);

        self->present[ACTION_SHELL] = true;
        action->type = ACTION_SHELL;
        action->command = calloc(strlen(command) + 1, sizeof(char));
        if (!action->command)
                return -1;
        strcpy(action->command, command);

        return 0;
}

/*
 * actions_add_continue - add an action to resume measurement
 */
int
actions_add_continue(struct actions *self)
{
        struct action *action = actions_new(self);

        self->present[ACTION_CONTINUE] = true;
        action->type = ACTION_CONTINUE;

        return 0;
}

/*
 * actions_parse - add an action based on text specification
 */
int
actions_parse(struct actions *self, const char *trigger, const char *tracefn)
{
        enum action_type type = ACTION_NONE;
        const char *token;
        char trigger_c[strlen(trigger) + 1];

        /* For ACTION_SIGNAL */
        int signal = 0, pid = 0;

        /* For ACTION_TRACE_OUTPUT */
        const char *trace_output;

        strcpy(trigger_c, trigger);
        token = strtok(trigger_c, ",");
        if (!token)
                return -1;

        if (strcmp(token, "trace") == 0)
                type = ACTION_TRACE_OUTPUT;
        else if (strcmp(token, "signal") == 0)
                type = ACTION_SIGNAL;
        else if (strcmp(token, "shell") == 0)
                type = ACTION_SHELL;
        else if (strcmp(token, "continue") == 0)
                type = ACTION_CONTINUE;
        else
                /* Invalid trigger type */
                return -1;

        token = strtok(NULL, ",");

        switch (type) {
        case ACTION_TRACE_OUTPUT:
                /* Takes no argument */
                if (token == NULL)
                        trace_output = tracefn;
                else {
                        if (strlen(token) > 5 && strncmp(token, "file=", 5) == 0) {
                                trace_output = token + 5;
                        } else {
                                /* Invalid argument */
                                return -1;
                        }

                        token = strtok(NULL, ",");
                        if (token != NULL)
                                /* Only one argument allowed */
                                return -1;
                }
                return actions_add_trace_output(self, trace_output);
        case ACTION_SIGNAL:
                /* Takes two arguments, num (signal) and pid */
                while (token != NULL) {
                        if (strlen(token) > 4 && strncmp(token, "num=", 4) == 0) {
                                if (strtoi(token + 4, &signal))
                                        return -1;
                        } else if (strlen(token) > 4 && strncmp(token, "pid=", 4) == 0) {
                                if (strncmp(token + 4, "parent", 7) == 0)
                                        pid = -1;
                                else if (strtoi(token + 4, &pid))
                                        return -1;
                        } else {
                                /* Invalid argument */
                                return -1;
                        }

                        token = strtok(NULL, ",");
                }

                if (!signal || !pid)
                        /* Missing argument */
                        return -1;

                return actions_add_signal(self, signal, pid);
        case ACTION_SHELL:
                if (token == NULL)
                        return -1;
                if (strlen(token) > 8 && strncmp(token, "command=", 8) == 0)
                        return actions_add_shell(self, token + 8);
                return -1;
        case ACTION_CONTINUE:
                /* Takes no argument */
                if (token != NULL)
                        return -1;
                return actions_add_continue(self);
        default:
                return -1;
        }
}

/*
 * actions_perform - perform all actions
 */
int
actions_perform(struct actions *self)
{
        int pid, retval;
        const struct action *action;

        for_each_action(self, action) {
                switch (action->type) {
                case ACTION_TRACE_OUTPUT:
                        retval = save_trace_to_file(self->trace_output_inst, action->trace_output);
                        if (retval) {
                                err_msg("Error saving trace\n");
                                return retval;
                        }
                        break;
                case ACTION_SIGNAL:
                        if (action->pid == -1)
                                pid = getppid();
                        else
                                pid = action->pid;
                        retval = kill(pid, action->signal);
                        if (retval) {
                                err_msg("Error sending signal\n");
                                return retval;
                        }
                        break;
                case ACTION_SHELL:
                        retval = system(action->command);
                        if (retval)
                                return retval;
                        break;
                case ACTION_CONTINUE:
                        self->continue_flag = true;
                        return 0;
                default:
                        break;
                }
        }

        return 0;
}