shared: introduce mkfs-util.c/.h

Let's move the "mkfs" code from homed there, plus other related code.

This way we can easily reuse it from other places.

1 files changed, 114 insertions, 0 deletions

diff --git a/src/shared/mkfs-util.c b/src/shared/mkfs-util.c
new file mode 100644
index 0000000000..a78f68e398
--- /dev/null
+++ b/src/shared/mkfs-util.c
@@ -0,0 +1,114 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include "id128-util.h"
+#include "mkfs-util.h"
+#include "path-util.h"
+#include "process-util.h"
+#include "string-util.h"
+
+int mkfs_exists(const char *fstype) {
+        const char *mkfs;
+        int r;
+
+        assert(fstype);
+
+        if (STR_IN_SET(fstype, "auto", "swap")) /* these aren't real file system types, refuse early */
+                return -EINVAL;
+
+        mkfs = strjoina("mkfs.", fstype);
+        if (!filename_is_valid(mkfs)) /* refuse file system types with slashes and similar */
+                return -EINVAL;
+
+        r = find_binary(mkfs, NULL);
+        if (r == -ENOENT)
+                return false;
+        if (r < 0)
+                return r;
+
+        return true;
+}
+
+int make_filesystem(
+                const char *node,
+                const char *fstype,
+                const char *label,
+                sd_id128_t uuid,
+                bool discard) {
+
+        _cleanup_free_ char *mkfs = NULL;
+        int r;
+
+        assert(node);
+        assert(fstype);
+        assert(label);
+
+        if (streq(fstype, "swap")) {
+                r = find_binary("mkswap", &mkfs);
+                if (r == -ENOENT)
+                        return log_error_errno(SYNTHETIC_ERRNO(EPROTONOSUPPORT), "mkswap binary not available.");
+                if (r < 0)
+                        return log_error_errno(r, "Failed to determine whether mkswap binary exists: %m");
+        } else {
+                r = mkfs_exists(fstype);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to determine whether mkfs binary for %s exists: %m", fstype);
+                if (r == 0)
+                        return log_error_errno(SYNTHETIC_ERRNO(EPROTONOSUPPORT), "mkfs binary for %s is not available.", fstype);
+
+                mkfs = strjoin("mkfs.", fstype);
+                if (!mkfs)
+                        return log_oom();
+        }
+
+        r = safe_fork("(mkfs)", FORK_RESET_SIGNALS|FORK_RLIMIT_NOFILE_SAFE|FORK_DEATHSIG|FORK_LOG|FORK_WAIT|FORK_STDOUT_TO_STDERR, NULL);
+        if (r < 0)
+                return r;
+        if (r == 0) {
+                char suuid[ID128_UUID_STRING_MAX];
+
+                /* Child */
+                id128_to_uuid_string(uuid, suuid);
+
+                if (streq(fstype, "ext4"))
+                        (void) execlp(mkfs, mkfs,
+                               "-L", label,
+                               "-U", suuid,
+                               "-I", "256",
+                               "-O", "has_journal",
+                               "-m", "0",
+                               "-E", discard ? "lazy_itable_init=1,discard" : "lazy_itable_init=1,nodiscard",
+                               node, NULL);
+
+                else if (streq(fstype, "btrfs")) {
+                        if (discard)
+                                (void) execlp(mkfs, mkfs, "-L", label, "-U", suuid, node, NULL);
+                        else
+                                (void) execlp(mkfs, mkfs, "-L", label, "-U", suuid, "--nodiscard", node, NULL);
+
+                } else if (streq(fstype, "xfs")) {
+                        const char *j;
+
+                        j = strjoina("uuid=", suuid);
+                        if (discard)
+                                (void) execlp(mkfs, mkfs, "-L", label, "-m", j, "-m", "reflink=1", node, NULL);
+                        else
+                                (void) execlp(mkfs, mkfs, "-L", label, "-m", j, "-m", "reflink=1", "-K", node, NULL);
+
+                } else if (streq(fstype, "swap")) {
+
+                        (void) execlp(mkfs, mkfs,
+                               "-L", label,
+                               "-U", suuid,
+                               node, NULL);
+
+                } else
+                        /* Generic fallback for all other file systems */
+                        (void) execlp(mkfs, mkfs, node, NULL);
+
+                log_error_errno(errno, "Failed to execute %s: %m", mkfs);
+
+                _exit(EXIT_FAILURE);
+        }
+
+        return 0;
+}