path: root/src/libsystemd/sd-bus/bus-error.c

/***
  This file is part of systemd.

  Copyright 2013 Lennart Poettering

  systemd is free software; you can redistribute it and/or modify it
  under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation; either version 2.1 of the License, or
  (at your option) any later version.

  systemd is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License
  along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/

#include <errno.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "sd-bus.h"

#include "alloc-util.h"
#include "bus-error.h"
#include "errno-list.h"
#include "string-util.h"
#include "util.h"

BUS_ERROR_MAP_ELF_REGISTER const sd_bus_error_map bus_standard_errors[] = {
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.Failed",                           EACCES),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.NoMemory",                         ENOMEM),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.ServiceUnknown",                   EHOSTUNREACH),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.NameHasNoOwner",                   ENXIO),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.NoReply",                          ETIMEDOUT),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.IOError",                          EIO),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.BadAddress",                       EADDRNOTAVAIL),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.NotSupported",                     EOPNOTSUPP),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.LimitsExceeded",                   ENOBUFS),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.AccessDenied",                     EACCES),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.AuthFailed",                       EACCES),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.InteractiveAuthorizationRequired", EACCES),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.NoServer",                         EHOSTDOWN),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.Timeout",                          ETIMEDOUT),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.NoNetwork",                        ENONET),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.AddressInUse",                     EADDRINUSE),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.Disconnected",                     ECONNRESET),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.InvalidArgs",                      EINVAL),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.FileNotFound",                     ENOENT),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.FileExists",                       EEXIST),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.UnknownMethod",                    EBADR),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.UnknownObject",                    EBADR),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.UnknownInterface",                 EBADR),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.UnknownProperty",                  EBADR),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.PropertyReadOnly",                 EROFS),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.UnixProcessIdUnknown",             ESRCH),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.InvalidSignature",                 EINVAL),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.InconsistentMessage",              EBADMSG),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.TimedOut",                         ETIMEDOUT),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.MatchRuleInvalid",                 EINVAL),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.InvalidFileContent",               EINVAL),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.MatchRuleNotFound",                ENOENT),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.SELinuxSecurityContextUnknown",    ESRCH),
        SD_BUS_ERROR_MAP("org.freedesktop.DBus.Error.ObjectPathInUse",                  EBUSY),
        SD_BUS_ERROR_MAP_END
};

/* GCC maps this magically to the beginning and end of the BUS_ERROR_MAP section */
extern const sd_bus_error_map __start_BUS_ERROR_MAP[];
extern const sd_bus_error_map __stop_BUS_ERROR_MAP[];

/* Additional maps registered with sd_bus_error_add_map() are in this
 * NULL terminated array */
static const sd_bus_error_map **additional_error_maps = NULL;

static int bus_error_name_to_errno(const char *name) {
        const sd_bus_error_map **map, *m;
        const char *p;
        int r;

        if (!name)
                return EINVAL;

        p = startswith(name, "System.Error.");
        if (p) {
                r = errno_from_name(p);
                if (r < 0)
                        return EIO;

                return r;
        }

        if (additional_error_maps)
                for (map = additional_error_maps; *map; map++)
                        for (m = *map;; m++) {
                                /* For additional error maps the end marker is actually the end marker */
                                if (m->code == BUS_ERROR_MAP_END_MARKER)
                                        break;

                                if (streq(m->name, name))
                                        return m->code;
                        }

        m = __start_BUS_ERROR_MAP;
        while (m < __stop_BUS_ERROR_MAP) {
                /* For magic ELF error maps, the end marker might
                 * appear in the middle of things, since multiple maps
                 * might appear in the same section. Hence, let's skip
                 * over it, but realign the pointer to the next 8 byte
                 * boundary, which is the selected alignment for the
                 * arrays. */
                if (m->code == BUS_ERROR_MAP_END_MARKER) {
                        m = ALIGN8_PTR(m+1);
                        continue;
                }

                if (streq(m->name, name))
                        return m->code;

                m++;
        }

        return EIO;
}

static sd_bus_error errno_to_bus_error_const(int error) {

        if (error < 0)
                error = -error;

        switch (error) {

        case ENOMEM:
                return BUS_ERROR_OOM;

        case EPERM:
        case EACCES:
                return SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_ACCESS_DENIED, "Access denied");

        case EINVAL:
                return SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_INVALID_ARGS, "Invalid argument");

        case ESRCH:
                return SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_UNIX_PROCESS_ID_UNKNOWN, "No such process");

        case ENOENT:
                return SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_FILE_NOT_FOUND, "File not found");

        case EEXIST:
                return SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_FILE_EXISTS, "File exists");

        case ETIMEDOUT:
        case ETIME:
                return SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_TIMEOUT, "Timed out");

        case EIO:
                return SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_IO_ERROR, "Input/output error");

        case ENETRESET:
        case ECONNABORTED:
        case ECONNRESET:
                return SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_DISCONNECTED, "Disconnected");

        case EOPNOTSUPP:
                return SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_NOT_SUPPORTED, "Not supported");

        case EADDRNOTAVAIL:
                return SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_BAD_ADDRESS, "Address not available");

        case ENOBUFS:
                return SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_LIMITS_EXCEEDED, "Limits exceeded");

        case EADDRINUSE:
                return SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_ADDRESS_IN_USE, "Address in use");

        case EBADMSG:
                return SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_INCONSISTENT_MESSAGE, "Inconsistent message");
        }

        return SD_BUS_ERROR_NULL;
}

static int errno_to_bus_error_name_new(int error, char **ret) {
        const char *name;
        char *n;

        if (error < 0)
                error = -error;

        name = errno_to_name(error);
        if (!name)
                return 0;

        n = strappend("System.Error.", name);
        if (!n)
                return -ENOMEM;

        *ret = n;
        return 1;
}

bool bus_error_is_dirty(sd_bus_error *e) {
        if (!e)
                return false;

        return e->name || e->message || e->_need_free != 0;
}

_public_ void sd_bus_error_free(sd_bus_error *e) {
        if (!e)
                return;

        if (e->_need_free > 0) {
                free((void*) e->name);
                free((void*) e->message);
        }

        e->name = e->message = NULL;
        e->_need_free = 0;
}

_public_ int sd_bus_error_set(sd_bus_error *e, const char *name, const char *message) {

        if (!name)
                return 0;
        if (!e)
                goto finish;

        assert_return(!bus_error_is_dirty(e), -EINVAL);

        e->name = strdup(name);
        if (!e->name) {
                *e = BUS_ERROR_OOM;
                return -ENOMEM;
        }

        if (message)
                e->message = strdup(message);

        e->_need_free = 1;

finish:
        return -bus_error_name_to_errno(name);
}

int bus_error_setfv(sd_bus_error *e, const char *name, const char *format, va_list ap) {

        if (!name)
                return 0;

        if (e) {
                assert_return(!bus_error_is_dirty(e), -EINVAL);

                e->name = strdup(name);
                if (!e->name) {
                        *e = BUS_ERROR_OOM;
                        return -ENOMEM;
                }

                /* If we hit OOM on formatting the pretty message, we ignore
                 * this, since we at least managed to write the error name */
                if (format)
                        (void) vasprintf((char**) &e->message, format, ap);

                e->_need_free = 1;
        }

        return -bus_error_name_to_errno(name);
}

_public_ int sd_bus_error_setf(sd_bus_error *e, const char *name, const char *format, ...) {

        if (format) {
                int r;
                va_list ap;

                va_start(ap, format);
                r = bus_error_setfv(e, name, format, ap);
                va_end(ap);

                return r;
        }

        return sd_bus_error_set(e, name, NULL);
}

_public_ int sd_bus_error_copy(sd_bus_error *dest, const sd_bus_error *e) {

        if (!sd_bus_error_is_set(e))
                return 0;
        if (!dest)
                goto finish;

        assert_return(!bus_error_is_dirty(dest), -EINVAL);

        /*
         * _need_free  < 0 indicates that the error is temporarily const, needs deep copying
         * _need_free == 0 indicates that the error is perpetually const, needs no deep copying
         * _need_free  > 0 indicates that the error is fully dynamic, needs deep copying
         */

        if (e->_need_free == 0)
                *dest = *e;
        else {
                dest->name = strdup(e->name);
                if (!dest->name) {
                        *dest = BUS_ERROR_OOM;
                        return -ENOMEM;
                }

                if (e->message)
                        dest->message = strdup(e->message);

                dest->_need_free = 1;
        }

finish:
        return -bus_error_name_to_errno(e->name);
}

_public_ int sd_bus_error_set_const(sd_bus_error *e, const char *name, const char *message) {
        if (!name)
                return 0;
        if (!e)
                goto finish;

        assert_return(!bus_error_is_dirty(e), -EINVAL);

        *e = SD_BUS_ERROR_MAKE_CONST(name, message);

finish:
        return -bus_error_name_to_errno(name);
}

_public_ int sd_bus_error_is_set(const sd_bus_error *e) {
        if (!e)
                return 0;

        return !!e->name;
}

_public_ int sd_bus_error_has_name(const sd_bus_error *e, const char *name) {
        if (!e)
                return 0;

        return streq_ptr(e->name, name);
}

_public_ int sd_bus_error_get_errno(const sd_bus_error* e) {
        if (!e)
                return 0;

        if (!e->name)
                return 0;

        return bus_error_name_to_errno(e->name);
}

static void bus_error_strerror(sd_bus_error *e, int error) {
        size_t k = 64;
        char *m;

        assert(e);

        for (;;) {
                char *x;

                m = new(char, k);
                if (!m)
                        return;

                errno = 0;
                x = strerror_r(error, m, k);
                if (errno == ERANGE || strlen(x) >= k - 1) {
                        free(m);
                        k *= 2;
                        continue;
                }

                if (errno) {
                        free(m);
                        return;
                }

                if (x == m) {
                        if (e->_need_free > 0) {
                                /* Error is already dynamic, let's just update the message */
                                free((char*) e->message);
                                e->message = x;

                        } else {
                                char *t;
                                /* Error was const so far, let's make it dynamic, if we can */

                                t = strdup(e->name);
                                if (!t) {
                                        free(m);
                                        return;
                                }

                                e->_need_free = 1;
                                e->name = t;
                                e->message = x;
                        }
                } else {
                        free(m);

                        if (e->_need_free > 0) {
                                char *t;

                                /* Error is dynamic, let's hence make the message also dynamic */
                                t = strdup(x);
                                if (!t)
                                        return;

                                free((char*) e->message);
                                e->message = t;
                        } else {
                                /* Error is const, hence we can just override */
                                e->message = x;
                        }
                }

                return;
        }
}

_public_ int sd_bus_error_set_errno(sd_bus_error *e, int error) {

        if (error < 0)
                error = -error;

        if (!e)
                return -error;
        if (error == 0)
                return -error;

        assert_return(!bus_error_is_dirty(e), -EINVAL);

        /* First, try a const translation */
        *e = errno_to_bus_error_const(error);

        if (!sd_bus_error_is_set(e)) {
                int k;

                /* If that didn't work, try a dynamic one. */

                k = errno_to_bus_error_name_new(error, (char**) &e->name);
                if (k > 0)
                        e->_need_free = 1;
                else if (k < 0) {
                        *e = BUS_ERROR_OOM;
                        return -error;
                } else
                        *e = BUS_ERROR_FAILED;
        }

        /* Now, fill in the message from strerror() if we can */
        bus_error_strerror(e, error);
        return -error;
}

_public_ int sd_bus_error_set_errnofv(sd_bus_error *e, int error, const char *format, va_list ap) {
        PROTECT_ERRNO;
        int r;

        if (error < 0)
                error = -error;

        if (!e)
                return -error;
        if (error == 0)
                return 0;

        assert_return(!bus_error_is_dirty(e), -EINVAL);

        /* First, try a const translation */
        *e = errno_to_bus_error_const(error);

        if (!sd_bus_error_is_set(e)) {
                int k;

                /* If that didn't work, try a dynamic one */

                k = errno_to_bus_error_name_new(error, (char**) &e->name);
                if (k > 0)
                        e->_need_free = 1;
                else if (k < 0) {
                        *e = BUS_ERROR_OOM;
                        return -ENOMEM;
                } else
                        *e = BUS_ERROR_FAILED;
        }

        if (format) {
                char *m;

                /* Then, let's try to fill in the supplied message */

                errno = error; /* Make sure that %m resolves to the specified error */
                r = vasprintf(&m, format, ap);
                if (r >= 0) {

                        if (e->_need_free <= 0) {
                                char *t;

                                t = strdup(e->name);
                                if (t) {
                                        e->_need_free = 1;
                                        e->name = t;
                                        e->message = m;
                                        return -error;
                                }

                                free(m);
                        } else {
                                free((char*) e->message);
                                e->message = m;
                                return -error;
                        }
                }
        }

        /* If that didn't work, use strerror() for the message */
        bus_error_strerror(e, error);
        return -error;
}

_public_ int sd_bus_error_set_errnof(sd_bus_error *e, int error, const char *format, ...) {
        int r;

        if (error < 0)
                error = -error;

        if (!e)
                return -error;
        if (error == 0)
                return 0;

        assert_return(!bus_error_is_dirty(e), -EINVAL);

        if (format) {
                va_list ap;

                va_start(ap, format);
                r = sd_bus_error_set_errnofv(e, error, format, ap);
                va_end(ap);

                return r;
        }

        return sd_bus_error_set_errno(e, error);
}

const char *bus_error_message(const sd_bus_error *e, int error) {

        if (e) {
                /* Sometimes, the D-Bus server is a little bit too verbose with
                 * its error messages, so let's override them here */
                if (sd_bus_error_has_name(e, SD_BUS_ERROR_ACCESS_DENIED))
                        return "Access denied";

                if (e->message)
                        return e->message;
        }

        if (error < 0)
                error = -error;

        return strerror(error);
}

static bool map_ok(const sd_bus_error_map *map) {
        for (; map->code != BUS_ERROR_MAP_END_MARKER; map++)
                if (!map->name || map->code <=0)
                        return false;
        return true;
}

_public_ int sd_bus_error_add_map(const sd_bus_error_map *map) {
        const sd_bus_error_map **maps = NULL;
        unsigned n = 0;

        assert_return(map, -EINVAL);
        assert_return(map_ok(map), -EINVAL);

        if (additional_error_maps)
                for (; additional_error_maps[n] != NULL; n++)
                        if (additional_error_maps[n] == map)
                                return 0;

        maps = realloc_multiply(additional_error_maps, sizeof(struct sd_bus_error_map*), n + 2);
        if (!maps)
                return -ENOMEM;

        maps[n] = map;
        maps[n+1] = NULL;

        additional_error_maps = maps;
        return 1;
}