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-rw-r--r--libfdisk/src/utils.c214
1 files changed, 214 insertions, 0 deletions
diff --git a/libfdisk/src/utils.c b/libfdisk/src/utils.c
new file mode 100644
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--- /dev/null
+++ b/libfdisk/src/utils.c
@@ -0,0 +1,214 @@
+
+#include "fdiskP.h"
+#include "pathnames.h"
+#include "canonicalize.h"
+
+#include <ctype.h>
+
+/**
+ * SECTION: utils
+ * @title: Utils
+ * @short_description: misc fdisk functions
+ */
+
+static int read_from_device(struct fdisk_context *cxt,
+ unsigned char *buf,
+ uintmax_t start, size_t size)
+{
+ ssize_t r;
+
+ assert(cxt);
+
+ DBG(CXT, ul_debugobj(cxt, "reading: offset=%ju, size=%zu",
+ start, size));
+
+ r = lseek(cxt->dev_fd, start, SEEK_SET);
+ if (r == -1)
+ {
+ DBG(CXT, ul_debugobj(cxt, "failed to seek to offset %ju: %m", start));
+ return -errno;
+ }
+
+ errno = 0;
+ r = read(cxt->dev_fd, buf, size);
+ if (r < 0 || (size_t)r != size) {
+ if (!errno)
+ errno = EINVAL; /* probably too small file/device */
+ DBG(CXT, ul_debugobj(cxt, "failed to read %zu from offset %ju: %m",
+ size, start));
+ return -errno;
+ }
+
+ return 0;
+}
+
+
+/*
+ * Zeros in-memory first sector buffer
+ */
+int fdisk_init_firstsector_buffer(struct fdisk_context *cxt,
+ unsigned int protect_off,
+ unsigned int protect_size)
+{
+ if (!cxt)
+ return -EINVAL;
+
+ assert(protect_off + protect_size <= cxt->sector_size);
+
+ if (!cxt->firstsector || cxt->firstsector_bufsz != cxt->sector_size) {
+ /* Let's allocate a new buffer if no allocated yet, or the
+ * current buffer has incorrect size */
+ if (!cxt->parent || cxt->parent->firstsector != cxt->firstsector)
+ free(cxt->firstsector);
+
+ DBG(CXT, ul_debugobj(cxt, "initialize in-memory first sector "
+ "buffer [sector_size=%lu]", cxt->sector_size));
+ cxt->firstsector = calloc(1, cxt->sector_size);
+ if (!cxt->firstsector)
+ return -ENOMEM;
+
+ cxt->firstsector_bufsz = cxt->sector_size;
+ return 0;
+ }
+
+ DBG(CXT, ul_debugobj(cxt, "zeroize in-memory first sector buffer"));
+ memset(cxt->firstsector, 0, cxt->firstsector_bufsz);
+
+ if (protect_size) {
+ /*
+ * It would be possible to reuse data from cxt->firstsector
+ * (call memset() for non-protected area only) and avoid one
+ * read() from the device, but it seems like a too fragile
+ * solution as we have no clue about stuff in the buffer --
+ * maybe it was already modified. Let's re-read from the device
+ * to be sure. -- kzak 13-Apr-2015
+ */
+ DBG(CXT, ul_debugobj(cxt, "first sector protection enabled -- re-reading"));
+ read_from_device(cxt, cxt->firstsector, protect_off, protect_size);
+ }
+ return 0;
+}
+
+int fdisk_read_firstsector(struct fdisk_context *cxt)
+{
+ int rc;
+
+ assert(cxt);
+ assert(cxt->sector_size);
+
+ rc = fdisk_init_firstsector_buffer(cxt, 0, 0);
+ if (rc)
+ return rc;
+
+ assert(cxt->sector_size == cxt->firstsector_bufsz);
+
+
+ return read_from_device(cxt, cxt->firstsector, 0, cxt->sector_size);
+}
+
+/**
+ * fdisk_partname:
+ * @dev: device name
+ * @partno: partition name
+ *
+ * Return: allocated buffer with partition name, use free() to deallocate.
+ */
+char *fdisk_partname(const char *dev, size_t partno)
+{
+ char *res = NULL;
+ const char *p = "";
+ char *dev_mapped = NULL;
+ int w = 0;
+
+ if (!dev || !*dev) {
+ if (asprintf(&res, "%zd", partno) > 0)
+ return res;
+ return NULL;
+ }
+
+ /* It is impossible to predict /dev/dm-N partition names. */
+ if (strncmp(dev, "/dev/dm-", sizeof("/dev/dm-") - 1) == 0) {
+ dev_mapped = canonicalize_dm_name (dev + 5);
+ if (dev_mapped)
+ dev = dev_mapped;
+ }
+
+ w = strlen(dev);
+ if (isdigit(dev[w - 1]))
+#ifdef __GNU__
+ p = "s";
+#else
+ p = "p";
+#endif
+
+ /* devfs kludge - note: fdisk partition names are not supposed
+ to equal kernel names, so there is no reason to do this */
+ if (endswith(dev, "disc")) {
+ w -= 4;
+ p = "part";
+ }
+
+ /* udev names partitions by appending -partN
+ e.g. ata-SAMSUNG_SV8004H_0357J1FT712448-part1
+ multipath-tools kpartx.rules also append -partN */
+ if ((strncmp(dev, _PATH_DEV_BYID, sizeof(_PATH_DEV_BYID) - 1) == 0) ||
+ strncmp(dev, _PATH_DEV_BYPATH, sizeof(_PATH_DEV_BYPATH) - 1) == 0 ||
+ strncmp(dev, "/dev/mapper", sizeof("/dev/mapper") - 1) == 0) {
+
+ /* check for <name><partno>, e.g. mpatha1 */
+ if (asprintf(&res, "%.*s%zu", w, dev, partno) <= 0)
+ res = NULL;
+ if (res && access(res, F_OK) == 0)
+ goto done;
+
+ free(res);
+
+ /* check for partition separator "p" */
+ if (asprintf(&res, "%.*sp%zu", w, dev, partno) <= 0)
+ res = NULL;
+ if (res && access(res, F_OK) == 0)
+ goto done;
+
+ free(res);
+
+ /* otherwise, default to "-path" */
+ p = "-part";
+ }
+
+ if (asprintf(&res, "%.*s%s%zu", w, dev, p, partno) <= 0)
+ res = NULL;
+done:
+ free(dev_mapped);
+ return res;
+}
+
+#ifdef TEST_PROGRAM
+struct fdisk_label *fdisk_new_dos_label(struct fdisk_context *cxt) { return NULL; }
+struct fdisk_label *fdisk_new_bsd_label(struct fdisk_context *cxt) { return NULL; }
+
+static int test_partnames(struct fdisk_test *ts, int argc, char *argv[])
+{
+ size_t i;
+ const char *disk = argv[1];
+
+ for (i = 0; i < 5; i++) {
+ char *p = fdisk_partname(disk, i + 1);
+ if (p)
+ printf("%zu: '%s'\n", i + 1, p);
+ free(p);
+ }
+
+ return 0;
+}
+
+int main(int argc, char *argv[])
+{
+ struct fdisk_test tss[] = {
+ { "--partnames", test_partnames, "<diskname>" },
+ { NULL }
+ };
+
+ return fdisk_run_test(tss, argc, argv);
+}
+
+#endif