util-lib: split shared/efivars into basic/efivars and shared/efi-loader

I want to use efivars.[ch] in proc-cmdline.c, but most of the efivars stuff is
not needed in basic/. Move the file from shared/ to basic/, but then move back
most of the higher-level functions to the new shared/efi-loader.c file.

1 files changed, 734 insertions, 0 deletions

diff --git a/src/shared/efi-loader.c b/src/shared/efi-loader.c
new file mode 100644
index 0000000000..46e187000f
--- /dev/null
+++ b/src/shared/efi-loader.c
@@ -0,0 +1,734 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "alloc-util.h"
+#include "dirent-util.h"
+#include "efi-loader.h"
+#include "efivars.h"
+#include "fd-util.h"
+#include "io-util.h"
+#include "parse-util.h"
+#include "sort-util.h"
+#include "stdio-util.h"
+#include "string-util.h"
+#include "utf8.h"
+#include "virt.h"
+
+#if ENABLE_EFI
+
+#define LOAD_OPTION_ACTIVE            0x00000001
+#define MEDIA_DEVICE_PATH                   0x04
+#define MEDIA_HARDDRIVE_DP                  0x01
+#define MEDIA_FILEPATH_DP                   0x04
+#define SIGNATURE_TYPE_GUID                 0x02
+#define MBR_TYPE_EFI_PARTITION_TABLE_HEADER 0x02
+#define END_DEVICE_PATH_TYPE                0x7f
+#define END_ENTIRE_DEVICE_PATH_SUBTYPE      0xff
+#define EFI_OS_INDICATIONS_BOOT_TO_FW_UI    0x0000000000000001
+
+#define boot_option__contents {                 \
+        uint32_t attr;                          \
+        uint16_t path_len;                      \
+        uint16_t title[];                       \
+        }
+
+struct boot_option boot_option__contents;
+struct boot_option__packed boot_option__contents _packed_;
+assert_cc(offsetof(struct boot_option, title) == offsetof(struct boot_option__packed, title));
+/* sizeof(struct boot_option) != sizeof(struct boot_option__packed), so
+ * the *size* of the structure should not be used anywhere below. */
+
+struct drive_path {
+        uint32_t part_nr;
+        uint64_t part_start;
+        uint64_t part_size;
+        char signature[16];
+        uint8_t mbr_type;
+        uint8_t signature_type;
+} _packed_;
+
+#define device_path__contents {                 \
+        uint8_t type;                           \
+        uint8_t sub_type;                       \
+        uint16_t length;                        \
+        union {                                 \
+                uint16_t path[0];               \
+                struct drive_path drive;        \
+        };                                      \
+        }
+
+struct device_path device_path__contents;
+struct device_path__packed device_path__contents _packed_;
+assert_cc(sizeof(struct device_path) == sizeof(struct device_path__packed));
+
+bool is_efi_boot(void) {
+        if (detect_container() > 0)
+                return false;
+
+        return access("/sys/firmware/efi/", F_OK) >= 0;
+}
+
+static int read_flag(const char *varname) {
+        _cleanup_free_ void *v = NULL;
+        uint8_t b;
+        size_t s;
+        int r;
+
+        if (!is_efi_boot()) /* If this is not an EFI boot, assume the queried flags are zero */
+                return 0;
+
+        r = efi_get_variable(EFI_VENDOR_GLOBAL, varname, NULL, &v, &s);
+        if (r < 0)
+                return r;
+
+        if (s != 1)
+                return -EINVAL;
+
+        b = *(uint8_t *)v;
+        return !!b;
+}
+
+bool is_efi_secure_boot(void) {
+        return read_flag("SecureBoot") > 0;
+}
+
+bool is_efi_secure_boot_setup_mode(void) {
+        return read_flag("SetupMode") > 0;
+}
+
+int efi_reboot_to_firmware_supported(void) {
+        _cleanup_free_ void *v = NULL;
+        uint64_t b;
+        size_t s;
+        int r;
+
+        if (!is_efi_boot())
+                return -EOPNOTSUPP;
+
+        r = efi_get_variable(EFI_VENDOR_GLOBAL, "OsIndicationsSupported", NULL, &v, &s);
+        if (r == -ENOENT) /* variable doesn't exist? it's not supported then */
+                return -EOPNOTSUPP;
+        if (r < 0)
+                return r;
+        if (s != sizeof(uint64_t))
+                return -EINVAL;
+
+        b = *(uint64_t*) v;
+        if (!(b & EFI_OS_INDICATIONS_BOOT_TO_FW_UI))
+                return -EOPNOTSUPP; /* bit unset? it's not supported then */
+
+        return 0;
+}
+
+static int get_os_indications(uint64_t *os_indication) {
+        _cleanup_free_ void *v = NULL;
+        size_t s;
+        int r;
+
+        /* Let's verify general support first */
+        r = efi_reboot_to_firmware_supported();
+        if (r < 0)
+                return r;
+
+        r = efi_get_variable(EFI_VENDOR_GLOBAL, "OsIndications", NULL, &v, &s);
+        if (r == -ENOENT) {
+                /* Some firmware implementations that do support OsIndications and report that with
+                 * OsIndicationsSupported will remove the OsIndications variable when it is unset. Let's pretend it's 0
+                 * then, to hide this implementation detail. Note that this call will return -ENOENT then only if the
+                 * support for OsIndications is missing entirely, as determined by efi_reboot_to_firmware_supported()
+                 * above. */
+                *os_indication = 0;
+                return 0;
+        } else if (r < 0)
+                return r;
+        else if (s != sizeof(uint64_t))
+                return -EINVAL;
+
+        *os_indication = *(uint64_t *)v;
+        return 0;
+}
+
+int efi_get_reboot_to_firmware(void) {
+        int r;
+        uint64_t b;
+
+        r = get_os_indications(&b);
+        if (r < 0)
+                return r;
+
+        return !!(b & EFI_OS_INDICATIONS_BOOT_TO_FW_UI);
+}
+
+int efi_set_reboot_to_firmware(bool value) {
+        int r;
+        uint64_t b, b_new;
+
+        r = get_os_indications(&b);
+        if (r < 0)
+                return r;
+
+        if (value)
+                b_new = b | EFI_OS_INDICATIONS_BOOT_TO_FW_UI;
+        else
+                b_new = b & ~EFI_OS_INDICATIONS_BOOT_TO_FW_UI;
+
+        /* Avoid writing to efi vars store if we can due to firmware bugs. */
+        if (b != b_new)
+                return efi_set_variable(EFI_VENDOR_GLOBAL, "OsIndications", &b_new, sizeof(uint64_t));
+
+        return 0;
+}
+
+
+static ssize_t utf16_size(const uint16_t *s, size_t buf_len_bytes) {
+        size_t l = 0;
+
+        /* Returns the size of the string in bytes without the terminating two zero bytes */
+
+        if (buf_len_bytes % sizeof(uint16_t) != 0)
+                return -EINVAL;
+
+        while (l < buf_len_bytes / sizeof(uint16_t)) {
+                if (s[l] == 0)
+                        return (l + 1) * sizeof(uint16_t);
+                l++;
+        }
+
+        return -EINVAL; /* The terminator was not found */
+}
+
+struct guid {
+        uint32_t u1;
+        uint16_t u2;
+        uint16_t u3;
+        uint8_t u4[8];
+} _packed_;
+
+static void efi_guid_to_id128(const void *guid, sd_id128_t *id128) {
+        uint32_t u1;
+        uint16_t u2, u3;
+        const struct guid *uuid = guid;
+
+        memcpy(&u1, &uuid->u1, sizeof(uint32_t));
+        id128->bytes[0] = (u1 >> 24) & 0xff;
+        id128->bytes[1] = (u1 >> 16) & 0xff;
+        id128->bytes[2] = (u1 >> 8) & 0xff;
+        id128->bytes[3] = u1 & 0xff;
+        memcpy(&u2, &uuid->u2, sizeof(uint16_t));
+        id128->bytes[4] = (u2 >> 8) & 0xff;
+        id128->bytes[5] = u2 & 0xff;
+        memcpy(&u3, &uuid->u3, sizeof(uint16_t));
+        id128->bytes[6] = (u3 >> 8) & 0xff;
+        id128->bytes[7] = u3 & 0xff;
+        memcpy(&id128->bytes[8], uuid->u4, sizeof(uuid->u4));
+}
+
+int efi_get_boot_option(
+                uint16_t id,
+                char **title,
+                sd_id128_t *part_uuid,
+                char **path,
+                bool *active) {
+
+        char boot_id[9];
+        _cleanup_free_ uint8_t *buf = NULL;
+        size_t l;
+        struct boot_option *header;
+        ssize_t title_size;
+        _cleanup_free_ char *s = NULL, *p = NULL;
+        sd_id128_t p_uuid = SD_ID128_NULL;
+        int r;
+
+        if (!is_efi_boot())
+                return -EOPNOTSUPP;
+
+        xsprintf(boot_id, "Boot%04X", id);
+        r = efi_get_variable(EFI_VENDOR_GLOBAL, boot_id, NULL, (void **)&buf, &l);
+        if (r < 0)
+                return r;
+        if (l < offsetof(struct boot_option, title))
+                return -ENOENT;
+
+        header = (struct boot_option *)buf;
+        title_size = utf16_size(header->title, l - offsetof(struct boot_option, title));
+        if (title_size < 0)
+                return title_size;
+
+        if (title) {
+                s = utf16_to_utf8(header->title, title_size);
+                if (!s)
+                        return -ENOMEM;
+        }
+
+        if (header->path_len > 0) {
+                uint8_t *dbuf;
+                size_t dnext, doff;
+
+                doff = offsetof(struct boot_option, title) + title_size;
+                dbuf = buf + doff;
+                if (header->path_len > l - doff)
+                        return -EINVAL;
+
+                dnext = 0;
+                while (dnext < header->path_len) {
+                        struct device_path *dpath;
+
+                        dpath = (struct device_path *)(dbuf + dnext);
+                        if (dpath->length < 4)
+                                break;
+
+                        /* Type 0x7F – End of Hardware Device Path, Sub-Type 0xFF – End Entire Device Path */
+                        if (dpath->type == END_DEVICE_PATH_TYPE && dpath->sub_type == END_ENTIRE_DEVICE_PATH_SUBTYPE)
+                                break;
+
+                        dnext += dpath->length;
+
+                        /* Type 0x04 – Media Device Path */
+                        if (dpath->type != MEDIA_DEVICE_PATH)
+                                continue;
+
+                        /* Sub-Type 1 – Hard Drive */
+                        if (dpath->sub_type == MEDIA_HARDDRIVE_DP) {
+                                /* 0x02 – GUID Partition Table */
+                                if (dpath->drive.mbr_type != MBR_TYPE_EFI_PARTITION_TABLE_HEADER)
+                                        continue;
+
+                                /* 0x02 – GUID signature */
+                                if (dpath->drive.signature_type != SIGNATURE_TYPE_GUID)
+                                        continue;
+
+                                if (part_uuid)
+                                        efi_guid_to_id128(dpath->drive.signature, &p_uuid);
+                                continue;
+                        }
+
+                        /* Sub-Type 4 – File Path */
+                        if (dpath->sub_type == MEDIA_FILEPATH_DP && !p && path) {
+                                p = utf16_to_utf8(dpath->path, dpath->length-4);
+                                if (!p)
+                                        return  -ENOMEM;
+
+                                efi_tilt_backslashes(p);
+                                continue;
+                        }
+                }
+        }
+
+        if (title)
+                *title = TAKE_PTR(s);
+        if (part_uuid)
+                *part_uuid = p_uuid;
+        if (path)
+                *path = TAKE_PTR(p);
+        if (active)
+                *active = header->attr & LOAD_OPTION_ACTIVE;
+
+        return 0;
+}
+
+static void to_utf16(uint16_t *dest, const char *src) {
+        int i;
+
+        for (i = 0; src[i] != '\0'; i++)
+                dest[i] = src[i];
+        dest[i] = '\0';
+}
+
+static void id128_to_efi_guid(sd_id128_t id, void *guid) {
+        struct guid uuid = {
+                .u1 = id.bytes[0] << 24 | id.bytes[1] << 16 | id.bytes[2] << 8 | id.bytes[3],
+                .u2 = id.bytes[4] << 8 | id.bytes[5],
+                .u3 = id.bytes[6] << 8 | id.bytes[7],
+        };
+        memcpy(uuid.u4, id.bytes+8, sizeof(uuid.u4));
+        memcpy(guid, &uuid, sizeof(uuid));
+}
+
+static uint16_t *tilt_slashes(uint16_t *s) {
+        uint16_t *p;
+
+        for (p = s; *p; p++)
+                if (*p == '/')
+                        *p = '\\';
+
+        return s;
+}
+
+int efi_add_boot_option(
+                uint16_t id,
+                const char *title,
+                uint32_t part,
+                uint64_t pstart,
+                uint64_t psize,
+                sd_id128_t part_uuid,
+                const char *path) {
+
+        size_t size, title_len, path_len;
+        _cleanup_free_ char *buf = NULL;
+        struct boot_option *option;
+        struct device_path *devicep;
+        char boot_id[9];
+
+        if (!is_efi_boot())
+                return -EOPNOTSUPP;
+
+        title_len = (strlen(title)+1) * 2;
+        path_len = (strlen(path)+1) * 2;
+
+        buf = malloc0(offsetof(struct boot_option, title) + title_len +
+                      sizeof(struct drive_path) +
+                      sizeof(struct device_path) + path_len);
+        if (!buf)
+                return -ENOMEM;
+
+        /* header */
+        option = (struct boot_option *)buf;
+        option->attr = LOAD_OPTION_ACTIVE;
+        option->path_len = offsetof(struct device_path, drive) + sizeof(struct drive_path) +
+                           offsetof(struct device_path, path) + path_len +
+                           offsetof(struct device_path, path);
+        to_utf16(option->title, title);
+        size = offsetof(struct boot_option, title) + title_len;
+
+        /* partition info */
+        devicep = (struct device_path *)(buf + size);
+        devicep->type = MEDIA_DEVICE_PATH;
+        devicep->sub_type = MEDIA_HARDDRIVE_DP;
+        devicep->length = offsetof(struct device_path, drive) + sizeof(struct drive_path);
+        memcpy(&devicep->drive.part_nr, &part, sizeof(uint32_t));
+        memcpy(&devicep->drive.part_start, &pstart, sizeof(uint64_t));
+        memcpy(&devicep->drive.part_size, &psize, sizeof(uint64_t));
+        id128_to_efi_guid(part_uuid, devicep->drive.signature);
+        devicep->drive.mbr_type = MBR_TYPE_EFI_PARTITION_TABLE_HEADER;
+        devicep->drive.signature_type = SIGNATURE_TYPE_GUID;
+        size += devicep->length;
+
+        /* path to loader */
+        devicep = (struct device_path *)(buf + size);
+        devicep->type = MEDIA_DEVICE_PATH;
+        devicep->sub_type = MEDIA_FILEPATH_DP;
+        devicep->length = offsetof(struct device_path, path) + path_len;
+        to_utf16(devicep->path, path);
+        tilt_slashes(devicep->path);
+        size += devicep->length;
+
+        /* end of path */
+        devicep = (struct device_path *)(buf + size);
+        devicep->type = END_DEVICE_PATH_TYPE;
+        devicep->sub_type = END_ENTIRE_DEVICE_PATH_SUBTYPE;
+        devicep->length = offsetof(struct device_path, path);
+        size += devicep->length;
+
+        xsprintf(boot_id, "Boot%04X", id);
+        return efi_set_variable(EFI_VENDOR_GLOBAL, boot_id, buf, size);
+}
+
+int efi_remove_boot_option(uint16_t id) {
+        char boot_id[9];
+
+        if (!is_efi_boot())
+                return -EOPNOTSUPP;
+
+        xsprintf(boot_id, "Boot%04X", id);
+        return efi_set_variable(EFI_VENDOR_GLOBAL, boot_id, NULL, 0);
+}
+
+int efi_get_boot_order(uint16_t **order) {
+        _cleanup_free_ void *buf = NULL;
+        size_t l;
+        int r;
+
+        if (!is_efi_boot())
+                return -EOPNOTSUPP;
+
+        r = efi_get_variable(EFI_VENDOR_GLOBAL, "BootOrder", NULL, &buf, &l);
+        if (r < 0)
+                return r;
+
+        if (l <= 0)
+                return -ENOENT;
+
+        if (l % sizeof(uint16_t) > 0 ||
+            l / sizeof(uint16_t) > INT_MAX)
+                return -EINVAL;
+
+        *order = TAKE_PTR(buf);
+        return (int) (l / sizeof(uint16_t));
+}
+
+int efi_set_boot_order(uint16_t *order, size_t n) {
+
+        if (!is_efi_boot())
+                return -EOPNOTSUPP;
+
+        return efi_set_variable(EFI_VENDOR_GLOBAL, "BootOrder", order, n * sizeof(uint16_t));
+}
+
+static int boot_id_hex(const char s[static 4]) {
+        int id = 0, i;
+
+        assert(s);
+
+        for (i = 0; i < 4; i++)
+                if (s[i] >= '0' && s[i] <= '9')
+                        id |= (s[i] - '0') << (3 - i) * 4;
+                else if (s[i] >= 'A' && s[i] <= 'F')
+                        id |= (s[i] - 'A' + 10) << (3 - i) * 4;
+                else
+                        return -EINVAL;
+
+        return id;
+}
+
+static int cmp_uint16(const uint16_t *a, const uint16_t *b) {
+        return CMP(*a, *b);
+}
+
+int efi_get_boot_options(uint16_t **options) {
+        _cleanup_closedir_ DIR *dir = NULL;
+        _cleanup_free_ uint16_t *list = NULL;
+        struct dirent *de;
+        size_t alloc = 0;
+        int count = 0;
+
+        assert(options);
+
+        if (!is_efi_boot())
+                return -EOPNOTSUPP;
+
+        dir = opendir("/sys/firmware/efi/efivars/");
+        if (!dir)
+                return -errno;
+
+        FOREACH_DIRENT(de, dir, return -errno) {
+                int id;
+
+                if (strncmp(de->d_name, "Boot", 4) != 0)
+                        continue;
+
+                if (strlen(de->d_name) != 45)
+                        continue;
+
+                if (strcmp(de->d_name + 8, "-8be4df61-93ca-11d2-aa0d-00e098032b8c") != 0)
+                        continue;
+
+                id = boot_id_hex(de->d_name + 4);
+                if (id < 0)
+                        continue;
+
+                if (!GREEDY_REALLOC(list, alloc, count + 1))
+                        return -ENOMEM;
+
+                list[count++] = id;
+        }
+
+        typesafe_qsort(list, count, cmp_uint16);
+
+        *options = TAKE_PTR(list);
+
+        return count;
+}
+
+static int read_usec(sd_id128_t vendor, const char *name, usec_t *u) {
+        _cleanup_free_ char *j = NULL;
+        int r;
+        uint64_t x = 0;
+
+        assert(name);
+        assert(u);
+
+        r = efi_get_variable_string(EFI_VENDOR_LOADER, name, &j);
+        if (r < 0)
+                return r;
+
+        r = safe_atou64(j, &x);
+        if (r < 0)
+                return r;
+
+        *u = x;
+        return 0;
+}
+
+int efi_loader_get_boot_usec(usec_t *firmware, usec_t *loader) {
+        uint64_t x, y;
+        int r;
+
+        assert(firmware);
+        assert(loader);
+
+        if (!is_efi_boot())
+                return -EOPNOTSUPP;
+
+        r = read_usec(EFI_VENDOR_LOADER, "LoaderTimeInitUSec", &x);
+        if (r < 0)
+                return r;
+
+        r = read_usec(EFI_VENDOR_LOADER, "LoaderTimeExecUSec", &y);
+        if (r < 0)
+                return r;
+
+        if (y == 0 || y < x)
+                return -EIO;
+
+        if (y > USEC_PER_HOUR)
+                return -EIO;
+
+        *firmware = x;
+        *loader = y;
+
+        return 0;
+}
+
+int efi_loader_get_device_part_uuid(sd_id128_t *u) {
+        _cleanup_free_ char *p = NULL;
+        int r, parsed[16];
+
+        if (!is_efi_boot())
+                return -EOPNOTSUPP;
+
+        r = efi_get_variable_string(EFI_VENDOR_LOADER, "LoaderDevicePartUUID", &p);
+        if (r < 0)
+                return r;
+
+        if (sscanf(p, SD_ID128_UUID_FORMAT_STR,
+                   &parsed[0], &parsed[1], &parsed[2], &parsed[3],
+                   &parsed[4], &parsed[5], &parsed[6], &parsed[7],
+                   &parsed[8], &parsed[9], &parsed[10], &parsed[11],
+                   &parsed[12], &parsed[13], &parsed[14], &parsed[15]) != 16)
+                return -EIO;
+
+        if (u) {
+                unsigned i;
+
+                for (i = 0; i < ELEMENTSOF(parsed); i++)
+                        u->bytes[i] = parsed[i];
+        }
+
+        return 0;
+}
+
+int efi_loader_get_entries(char ***ret) {
+        _cleanup_free_ char16_t *entries = NULL;
+        _cleanup_strv_free_ char **l = NULL;
+        size_t size, i, start;
+        int r;
+
+        assert(ret);
+
+        if (!is_efi_boot())
+                return -EOPNOTSUPP;
+
+        r = efi_get_variable(EFI_VENDOR_LOADER, "LoaderEntries", NULL, (void**) &entries, &size);
+        if (r < 0)
+                return r;
+
+        /* The variable contains a series of individually NUL terminated UTF-16 strings. */
+
+        for (i = 0, start = 0;; i++) {
+                _cleanup_free_ char *decoded = NULL;
+                bool end;
+
+                /* Is this the end of the variable's data? */
+                end = i * sizeof(char16_t) >= size;
+
+                /* Are we in the middle of a string? (i.e. not at the end of the variable, nor at a NUL terminator?) If
+                 * so, let's go to the next entry. */
+                if (!end && entries[i] != 0)
+                        continue;
+
+                /* We reached the end of a string, let's decode it into UTF-8 */
+                decoded = utf16_to_utf8(entries + start, (i - start) * sizeof(char16_t));
+                if (!decoded)
+                        return -ENOMEM;
+
+                if (efi_loader_entry_name_valid(decoded)) {
+                        r = strv_consume(&l, TAKE_PTR(decoded));
+                        if (r < 0)
+                                return r;
+                } else
+                        log_debug("Ignoring invalid loader entry '%s'.", decoded);
+
+                /* We reached the end of the variable */
+                if (end)
+                        break;
+
+                /* Continue after the NUL byte */
+                start = i + 1;
+        }
+
+        *ret = TAKE_PTR(l);
+        return 0;
+}
+
+int efi_loader_get_features(uint64_t *ret) {
+        _cleanup_free_ void *v = NULL;
+        size_t s;
+        int r;
+
+        if (!is_efi_boot()) {
+                *ret = 0;
+                return 0;
+        }
+
+        r = efi_get_variable(EFI_VENDOR_LOADER, "LoaderFeatures", NULL, &v, &s);
+        if (r == -ENOENT) {
+                _cleanup_free_ char *info = NULL;
+
+                /* The new (v240+) LoaderFeatures variable is not supported, let's see if it's systemd-boot at all */
+                r = efi_get_variable_string(EFI_VENDOR_LOADER, "LoaderInfo", &info);
+                if (r < 0) {
+                        if (r != -ENOENT)
+                                return r;
+
+                        /* Variable not set, definitely means not systemd-boot */
+
+                } else if (first_word(info, "systemd-boot")) {
+
+                        /* An older systemd-boot version. Let's hardcode the feature set, since it was pretty
+                         * static in all its versions. */
+
+                        *ret = EFI_LOADER_FEATURE_CONFIG_TIMEOUT |
+                                EFI_LOADER_FEATURE_ENTRY_DEFAULT |
+                                EFI_LOADER_FEATURE_ENTRY_ONESHOT;
+
+                        return 0;
+                }
+
+                /* No features supported */
+                *ret = 0;
+                return 0;
+        }
+        if (r < 0)
+                return r;
+
+        if (s != sizeof(uint64_t))
+                return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
+                                       "LoaderFeatures EFI variable doesn't have the right size.");
+
+        memcpy(ret, v, sizeof(uint64_t));
+        return 0;
+}
+
+#endif
+
+bool efi_loader_entry_name_valid(const char *s) {
+        if (isempty(s))
+                return false;
+
+        if (strlen(s) > FILENAME_MAX) /* Make sure entry names fit in filenames */
+                return false;
+
+        return in_charset(s, ALPHANUMERICAL "+-_.");
+}
+
+char *efi_tilt_backslashes(char *s) {
+        char *p;
+
+        for (p = s; *p; p++)
+                if (*p == '\\')
+                        *p = '/';
+
+        return s;
+}