Bugfix: Use setsid() to avoid SIGINT for child processes

[i3/i3] / src / util.c

/*
 * vim:ts=8:expandtab
 *
 * i3 - an improved dynamic tiling window manager
 *
 * © 2009 Michael Stapelberg and contributors
 *
 * See file LICENSE for license information.
 *
 * util.c: Utility functions, which can be useful everywhere.
 *
 */
#include <sys/wait.h>
#include <stdarg.h>
#include <iconv.h>
#if defined(__OpenBSD__)
#include <sys/cdefs.h>
#endif

#include <fcntl.h>

#include "all.h"

static iconv_t conversion_descriptor = 0;

int min(int a, int b) {
        return (a < b ? a : b);
}

int max(int a, int b) {
        return (a > b ? a : b);
}

bool rect_contains(Rect rect, uint32_t x, uint32_t y) {
        return (x >= rect.x &&
                x <= (rect.x + rect.width) &&
                y >= rect.y &&
                y <= (rect.y + rect.height));
}

Rect rect_add(Rect a, Rect b) {
        return (Rect){a.x + b.x,
                      a.y + b.y,
                      a.width + b.width,
                      a.height + b.height};
}

/*
 * Updates *destination with new_value and returns true if it was changed or false
 * if it was the same
 *
 */
bool update_if_necessary(uint32_t *destination, const uint32_t new_value) {
        uint32_t old_value = *destination;

        return ((*destination = new_value) != old_value);
}

/*
 * The s* functions (safe) are wrappers around malloc, strdup, …, which exits if one of
 * the called functions returns NULL, meaning that there is no more memory available
 *
 */
void *smalloc(size_t size) {
        void *result = malloc(size);
        exit_if_null(result, "Error: out of memory (malloc(%zd))\n", size);
        return result;
}

void *scalloc(size_t size) {
        void *result = calloc(size, 1);
        exit_if_null(result, "Error: out of memory (calloc(%zd))\n", size);
        return result;
}

void *srealloc(void *ptr, size_t size) {
        void *result = realloc(ptr, size);
        exit_if_null(result, "Error: out memory (realloc(%zd))\n", size);
        return result;
}

char *sstrdup(const char *str) {
        char *result = strdup(str);
        exit_if_null(result, "Error: out of memory (strdup())\n");
        return result;
}

/*
 * Starts the given application by passing it through a shell. We use double fork
 * to avoid zombie processes. As the started application’s parent exits (immediately),
 * the application is reparented to init (process-id 1), which correctly handles
 * childs, so we don’t have to do it :-).
 *
 * The shell is determined by looking for the SHELL environment variable. If it
 * does not exist, /bin/sh is used.
 *
 */
void start_application(const char *command) {
        LOG("executing: %s\n", command);
        if (fork() == 0) {
                /* Child process */
                setsid();
                if (fork() == 0) {
                        /* Stores the path of the shell */
                        static const char *shell = NULL;

                        if (shell == NULL)
                                if ((shell = getenv("SHELL")) == NULL)
                                        shell = "/bin/sh";

                        /* This is the child */
                        execl(shell, shell, "-c", command, (void*)NULL);
                        /* not reached */
                }
                exit(0);
        }
        wait(0);
}

/*
 * Checks a generic cookie for errors and quits with the given message if there
 * was an error.
 *
 */
void check_error(xcb_connection_t *conn, xcb_void_cookie_t cookie, char *err_message) {
        xcb_generic_error_t *error = xcb_request_check(conn, cookie);
        if (error != NULL) {
                fprintf(stderr, "ERROR: %s (X error %d)\n", err_message , error->error_code);
                xcb_disconnect(conn);
                exit(-1);
        }
}

/*
 * Converts the given string to UCS-2 big endian for use with
 * xcb_image_text_16(). The amount of real glyphs is stored in real_strlen,
 * a buffer containing the UCS-2 encoded string (16 bit per glyph) is
 * returned. It has to be freed when done.
 *
 */
char *convert_utf8_to_ucs2(char *input, int *real_strlen) {
        size_t input_size = strlen(input) + 1;
        /* UCS-2 consumes exactly two bytes for each glyph */
        int buffer_size = input_size * 2;

        char *buffer = smalloc(buffer_size);
        size_t output_size = buffer_size;
        /* We need to use an additional pointer, because iconv() modifies it */
        char *output = buffer;

        /* We convert the input into UCS-2 big endian */
        if (conversion_descriptor == 0) {
                conversion_descriptor = iconv_open("UCS-2BE", "UTF-8");
                if (conversion_descriptor == 0) {
                        fprintf(stderr, "error opening the conversion context\n");
                        exit(1);
                }
        }

        /* Get the conversion descriptor back to original state */
        iconv(conversion_descriptor, NULL, NULL, NULL, NULL);

        /* Convert our text */
        int rc = iconv(conversion_descriptor, (void*)&input, &input_size, &output, &output_size);
        if (rc == (size_t)-1) {
                perror("Converting to UCS-2 failed");
                if (real_strlen != NULL)
                        *real_strlen = 0;
                return NULL;
        }

        if (real_strlen != NULL)
                *real_strlen = ((buffer_size - output_size) / 2) - 1;

        return buffer;
}
#if 0

/*
 * Returns the client which comes next in focus stack (= was selected before) for
 * the given container, optionally excluding the given client.
 *
 */
Client *get_last_focused_client(xcb_connection_t *conn, Container *container, Client *exclude) {
        Client *current;
        SLIST_FOREACH(current, &(container->workspace->focus_stack), focus_clients)
                if ((current->container == container) && ((exclude == NULL) || (current != exclude)))
                        return current;
        return NULL;
}


/*
 * Sets the given client as focused by updating the data structures correctly,
 * updating the X input focus and finally re-decorating both windows (to signalize
 * the user the new focus situation)
 *
 */
void set_focus(xcb_connection_t *conn, Client *client, bool set_anyways) {
        /* The dock window cannot be focused, but enter notifies are still handled correctly */
        if (client->dock)
                return;

        /* Store the old client */
        Client *old_client = SLIST_FIRST(&(c_ws->focus_stack));

        /* Check if the focus needs to be changed at all */
        if (!set_anyways && (old_client == client))
                return;

        /* Store current_row/current_col */
        c_ws->current_row = current_row;
        c_ws->current_col = current_col;
        c_ws = client->workspace;
        ewmh_update_current_desktop();
        /* Load current_col/current_row if we switch to a client without a container */
        current_col = c_ws->current_col;
        current_row = c_ws->current_row;

        /* Update container */
        if (client->container != NULL) {
                client->container->currently_focused = client;

                current_col = client->container->col;
                current_row = client->container->row;
        }

        CLIENT_LOG(client);
        /* Set focus to the entered window, and flush xcb buffer immediately */
        xcb_set_input_focus(conn, XCB_INPUT_FOCUS_POINTER_ROOT, client->child, XCB_CURRENT_TIME);
        ewmh_update_active_window(client->child);
        //xcb_warp_pointer(conn, XCB_NONE, client->child, 0, 0, 0, 0, 10, 10);

        if (client->container != NULL) {
                /* Get the client which was last focused in this particular container, it may be a different
                   one than old_client */
                Client *last_focused = get_last_focused_client(conn, client->container, NULL);

                /* In stacking containers, raise the client in respect to the one which was focused before */
                if ((client->container->mode == MODE_STACK || client->container->mode == MODE_TABBED) &&
                    client->container->workspace->fullscreen_client == NULL) {
                        /* We need to get the client again, this time excluding the current client, because
                         * we might have just gone into stacking mode and need to raise */
                        Client *last_focused = get_last_focused_client(conn, client->container, client);

                        if (last_focused != NULL) {
                                DLOG("raising above frame %p / child %p\n", last_focused->frame, last_focused->child);
                                uint32_t values[] = { last_focused->frame, XCB_STACK_MODE_ABOVE };
                                xcb_configure_window(conn, client->frame, XCB_CONFIG_WINDOW_SIBLING | XCB_CONFIG_WINDOW_STACK_MODE, values);
                        }
                }

                /* If it is the same one as old_client, we save us the unnecessary redecorate */
                if ((last_focused != NULL) && (last_focused != old_client))
                        redecorate_window(conn, last_focused);
        }

        /* If the last client was a floating client, we need to go to the next
         * tiling client in stack and re-decorate it. */
        if (old_client != NULL && client_is_floating(old_client)) {
                DLOG("Coming from floating client, searching next tiling...\n");
                Client *current;
                SLIST_FOREACH(current, &(client->workspace->focus_stack), focus_clients) {
                        if (client_is_floating(current))
                                continue;

                        DLOG("Found window: %p / child %p\n", current->frame, current->child);
                        redecorate_window(conn, current);
                        break;
                }
        }

        SLIST_REMOVE(&(client->workspace->focus_stack), client, Client, focus_clients);
        SLIST_INSERT_HEAD(&(client->workspace->focus_stack), client, focus_clients);

        /* Clear the urgency flag if set (necessary when i3 sets the flag, for
         * example when automatically putting windows on the workspace of their
         * leader) */
        client->urgent = false;
        workspace_update_urgent_flag(client->workspace);

        /* If we’re in stacking mode, this renders the container to update changes in the title
           bars and to raise the focused client */
        if ((old_client != NULL) && (old_client != client) && !old_client->dock)
                redecorate_window(conn, old_client);

        /* redecorate_window flushes, so we don’t need to */
        redecorate_window(conn, client);
}

/*
 * Gets the first matching client for the given window class/window title.
 * If the paramater specific is set to a specific client, only this one
 * will be checked.
 *
 */
Client *get_matching_client(xcb_connection_t *conn, const char *window_classtitle,
                            Client *specific) {
        char *to_class, *to_title, *to_title_ucs = NULL;
        int to_title_ucs_len = 0;
        Client *matching = NULL;

        to_class = sstrdup(window_classtitle);

        /* If a title was specified, split both strings at the slash */
        if ((to_title = strstr(to_class, "/")) != NULL) {
                *(to_title++) = '\0';
                /* Convert to UCS-2 */
                to_title_ucs = convert_utf8_to_ucs2(to_title, &to_title_ucs_len);
        }

        /* If we were given a specific client we only check if that one matches */
        if (specific != NULL) {
                if (client_matches_class_name(specific, to_class, to_title, to_title_ucs, to_title_ucs_len))
                        matching = specific;
                goto done;
        }

        DLOG("Getting clients for class \"%s\" / title \"%s\"\n", to_class, to_title);
        Workspace *ws;
        TAILQ_FOREACH(ws, workspaces, workspaces) {
                if (ws->output == NULL)
                        continue;

                Client *client;
                SLIST_FOREACH(client, &(ws->focus_stack), focus_clients) {
                        DLOG("Checking client with class=%s / %s, name=%s\n", client->window_class_instance,
                             client->window_class_class, client->name);
                        if (!client_matches_class_name(client, to_class, to_title, to_title_ucs, to_title_ucs_len))
                                continue;

                        matching = client;
                        goto done;
                }
        }

done:
        free(to_class);
        FREE(to_title_ucs);
        return matching;
}
#endif

/*
 * Goes through the list of arguments (for exec()) and checks if the given argument
 * is present. If not, it copies the arguments (because we cannot realloc it) and
 * appends the given argument.
 *
 */
static char **append_argument(char **original, char *argument) {
        int num_args;
        for (num_args = 0; original[num_args] != NULL; num_args++) {
                DLOG("original argument: \"%s\"\n", original[num_args]);
                /* If the argument is already present we return the original pointer */
                if (strcmp(original[num_args], argument) == 0)
                        return original;
        }
        /* Copy the original array */
        char **result = smalloc((num_args+2) * sizeof(char*));
        memcpy(result, original, num_args * sizeof(char*));
        result[num_args] = argument;
        result[num_args+1] = NULL;

        return result;
}

#define y(x, ...) yajl_gen_ ## x (gen, ##__VA_ARGS__)
#define ystr(str) yajl_gen_string(gen, (unsigned char*)str, strlen(str))

void store_restart_layout() {
        yajl_gen gen = yajl_gen_alloc(NULL, NULL);

        dump_node(gen, croot, true);

        const unsigned char *payload;
        unsigned int length;
        y(get_buf, &payload, &length);

        char *globbed = resolve_tilde(config.restart_state_path);
        int fd = open(globbed, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR);
        free(globbed);
        if (fd == -1) {
                perror("open()");
                return;
        }

        int written = 0;
        while (written < length) {
                int n = write(fd, payload + written, length - written);
                /* TODO: correct error-handling */
                if (n == -1) {
                        perror("write()");
                        return;
                }
                if (n == 0) {
                        printf("write == 0?\n");
                        return;
                }
                written += n;
                printf("written: %d of %d\n", written, length);
        }
        close(fd);

        printf("layout: %.*s\n", length, payload);

        y(free);
}

/*
 * Restart i3 in-place
 * appends -a to argument list to disable autostart
 *
 */
void i3_restart() {
        store_restart_layout();
        restore_geometry();

        //ipc_shutdown();

        LOG("restarting \"%s\"...\n", start_argv[0]);
        /* make sure -a is in the argument list or append it */
        start_argv = append_argument(start_argv, "-a");

        execvp(start_argv[0], start_argv);
        /* not reached */
}

#if 0

#if defined(__OpenBSD__)

/*
 * Taken from FreeBSD
 * Find the first occurrence of the byte string s in byte string l.
 *
 */
void *memmem(const void *l, size_t l_len, const void *s, size_t s_len) {
        register char *cur, *last;
        const char *cl = (const char *)l;
        const char *cs = (const char *)s;

        /* we need something to compare */
        if (l_len == 0 || s_len == 0)
                return NULL;

        /* "s" must be smaller or equal to "l" */
        if (l_len < s_len)
                return NULL;

        /* special case where s_len == 1 */
        if (s_len == 1)
                return memchr(l, (int)*cs, l_len);

        /* the last position where its possible to find "s" in "l" */
        last = (char *)cl + l_len - s_len;

        for (cur = (char *)cl; cur <= last; cur++)
                if (cur[0] == cs[0] && memcmp(cur, cs, s_len) == 0)
                        return cur;

        return NULL;
}

#endif
#endif