fdisk: introduce common fdisk_new_context_fd() helper

We do the same thing over and over again and it's a bit ugly, hence
let's unify the code for it at one common place.

5 files changed, 60 insertions, 40 deletions

diff --git a/src/home/homework-luks.c b/src/home/homework-luks.c
index 5e1d5bbd65..48e8cd1808 100644
--- a/src/home/homework-luks.c
+++ b/src/home/homework-luks.c
@@ -1837,7 +1837,7 @@ static int make_partition_table(
         _cleanup_(fdisk_unref_partitionp) struct fdisk_partition *p = NULL, *q = NULL;
         _cleanup_(fdisk_unref_parttypep) struct fdisk_parttype *t = NULL;
         _cleanup_(fdisk_unref_contextp) struct fdisk_context *c = NULL;
-        _cleanup_free_ char *path = NULL, *disk_uuid_as_string = NULL;
+        _cleanup_free_ char *disk_uuid_as_string = NULL;
         uint64_t offset, size, first_lba, start, last_lba, end;
         sd_id128_t disk_uuid;
         int r;
@@ -1855,14 +1855,7 @@ static int make_partition_table(
         if (r < 0)
                 return log_error_errno(r, "Failed to initialize partition type: %m");
 
-        c = fdisk_new_context();
-        if (!c)
-                return log_oom();
-
-        if (asprintf(&path, "/proc/self/fd/%i", fd) < 0)
-                return log_oom();
-
-        r = fdisk_assign_device(c, path, 0);
+        r = fdisk_new_context_fd(fd, /* read_only= */ false, &c);
         if (r < 0)
                 return log_error_errno(r, "Failed to open device: %m");
 
@@ -2645,7 +2638,7 @@ static int prepare_resize_partition(
 
         _cleanup_(fdisk_unref_contextp) struct fdisk_context *c = NULL;
         _cleanup_(fdisk_unref_tablep) struct fdisk_table *t = NULL;
-        _cleanup_free_ char *path = NULL, *disk_uuid_as_string = NULL;
+        _cleanup_free_ char *disk_uuid_as_string = NULL;
         struct fdisk_partition *found = NULL;
         sd_id128_t disk_uuid;
         size_t n_partitions;
@@ -2668,14 +2661,7 @@ static int prepare_resize_partition(
                 return 0;
         }
 
-        c = fdisk_new_context();
-        if (!c)
-                return log_oom();
-
-        if (asprintf(&path, "/proc/self/fd/%i", fd) < 0)
-                return log_oom();
-
-        r = fdisk_assign_device(c, path, 0);
+        r = fdisk_new_context_fd(fd, /* read_only= */ false, &c);
         if (r < 0)
                 return log_error_errno(r, "Failed to open device: %m");
 
@@ -2759,7 +2745,6 @@ static int apply_resize_partition(
 
         _cleanup_(fdisk_unref_contextp) struct fdisk_context *c = NULL;
         _cleanup_free_ void *two_zero_lbas = NULL;
-        _cleanup_free_ char *path = NULL;
         ssize_t n;
         int r;
 
@@ -2791,14 +2776,7 @@ static int apply_resize_partition(
         if (n != 1024)
                 return log_error_errno(SYNTHETIC_ERRNO(EIO), "Short write while wiping partition table.");
 
-        c = fdisk_new_context();
-        if (!c)
-                return log_oom();
-
-        if (asprintf(&path, "/proc/self/fd/%i", fd) < 0)
-                return log_oom();
-
-        r = fdisk_assign_device(c, path, 0);
+        r = fdisk_new_context_fd(fd, /* read_only= */ false, &c);
         if (r < 0)
                 return log_error_errno(r, "Failed to open device: %m");
 
diff --git a/src/partition/repart.c b/src/partition/repart.c
index 6951a1bf00..f6b8c9be65 100644
--- a/src/partition/repart.c
+++ b/src/partition/repart.c
@@ -1945,16 +1945,17 @@ static int context_load_partition_table(
         assert(context->end == UINT64_MAX);
         assert(context->total == UINT64_MAX);
 
-        c = fdisk_new_context();
-        if (!c)
-                return log_oom();
-
         /* libfdisk doesn't have an API to operate on arbitrary fds, hence reopen the fd going via the
          * /proc/self/fd/ magic path if we have an existing fd. Open the original file otherwise. */
-        if (*backing_fd < 0)
+        if (*backing_fd < 0) {
+                c = fdisk_new_context();
+                if (!c)
+                        return log_oom();
+
                 r = fdisk_assign_device(c, node, arg_dry_run);
-        else
-                r = fdisk_assign_device(c, FORMAT_PROC_FD_PATH(*backing_fd), arg_dry_run);
+        } else
+                r = fdisk_new_context_fd(*backing_fd, arg_dry_run, &c);
+
         if (r == -EINVAL && arg_size_auto) {
                 struct stat st;
 
@@ -6065,11 +6066,7 @@ static int resize_pt(int fd) {
          * possession of the enlarged backing file. For this it suffices to open the device with libfdisk and
          * immediately write it again, with no changes. */
 
-        c = fdisk_new_context();
-        if (!c)
-                return log_oom();
-
-        r = fdisk_assign_device(c, FORMAT_PROC_FD_PATH(fd), 0);
+        r = fdisk_new_context_fd(fd, /* read_only= */ false, &c);
         if (r < 0)
                 return log_error_errno(r, "Failed to open device '%s': %m", FORMAT_PROC_FD_PATH(fd));
 
diff --git a/src/shared/fdisk-util.c b/src/shared/fdisk-util.c
new file mode 100644
index 0000000000..1cdf09b18d
--- /dev/null
+++ b/src/shared/fdisk-util.c
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "fd-util.h"
+#include "fdisk-util.h"
+
+#if HAVE_LIBFDISK
+
+int fdisk_new_context_fd(int fd, bool read_only, struct fdisk_context **ret) {
+        _cleanup_(fdisk_unref_contextp) struct fdisk_context *c = NULL;
+        int r;
+
+        assert(ret);
+
+        if (fd < 0)
+                return -EBADF;
+
+        c = fdisk_new_context();
+        if (!c)
+                return -ENOMEM;
+
+        r = fdisk_assign_device(c, FORMAT_PROC_FD_PATH(fd), read_only);
+        if (r < 0)
+                return r;
+
+        *ret = TAKE_PTR(c);
+        return 0;
+}
+
+#endif
diff --git a/src/shared/fdisk-util.h b/src/shared/fdisk-util.h
index 64c0c2f324..49cb840c33 100644
--- a/src/shared/fdisk-util.h
+++ b/src/shared/fdisk-util.h
@@ -12,4 +12,6 @@ DEFINE_TRIVIAL_CLEANUP_FUNC_FULL(struct fdisk_partition*, fdisk_unref_partition,
 DEFINE_TRIVIAL_CLEANUP_FUNC_FULL(struct fdisk_parttype*, fdisk_unref_parttype, NULL);
 DEFINE_TRIVIAL_CLEANUP_FUNC_FULL(struct fdisk_table*, fdisk_unref_table, NULL);
 
+int fdisk_new_context_fd(int fd, bool read_only, struct fdisk_context **ret);
+
 #endif
diff --git a/src/shared/meson.build b/src/shared/meson.build
index 5f66b865de..3be7ba17bf 100644
--- a/src/shared/meson.build
+++ b/src/shared/meson.build
@@ -125,7 +125,6 @@ shared_sources = files(
         'exit-status.h',
         'extension-release.c',
         'extension-release.h',
-        'fdisk-util.h',
         'fdset.c',
         'fdset.h',
         'fileio-label.c',
@@ -493,3 +492,18 @@ libshared = shared_library(
         dependencies : libshared_deps,
         install : true,
         install_dir : rootpkglibdir)
+
+shared_fdisk_sources = files(
+        'fdisk-util.h',
+        'fdisk-util.c',
+)
+
+if get_option('fdisk') != 'false'
+        libshared_fdisk = static_library(
+                'shared-fdisk',
+                shared_fdisk_sources,
+                include_directories : includes,
+                dependencies : [libfdisk],
+                c_args : ['-fvisibility=default'],
+                build_by_default : false)
+endif