partx: add update command

Update the kernel partition table to match what is on disk.  Remove any
extra partitions and add any missing ones.

Signed-off-by: Phillip Susi <psusi@ubuntu.com>

diff --git a/disk-utils/partx.8 b/disk-utils/partx.8
index 6142bd09f4964b3492e871fa9e292033626baf10..d5de3d938c710ce40f838286d4aae256df2aa332 100644 (file)
--- a/disk-utils/partx.8
+++ b/disk-utils/partx.8
@@ -8,9 +8,9 @@
 partx \- tell the Linux kernel about the presence and numbering of
 on-disk partitions
 .SH SYNOPSIS
-partx [\-a|\-d|\-s] [\-t TYPE] [\-n M:N] [\-] disk
+partx [\-a|\-d|\-s|\-u] [\-t TYPE] [\-n M:N] [\-] disk
 .br
-partx [\-a|\-d|\-s] [\-t TYPE] partition [disk]
+partx [\-a|\-d|\-s|\-u] [\-t TYPE] partition [disk]
 .SH DESCRIPTION
 Given a device or disk-image,
 .B partx
@@ -43,6 +43,8 @@ Add the specified partitions, or read the disk and add all partitions.
 Print the SIZE column in bytes rather than in human-readable format.
 .IP "\fB\-d\fR, \fB\-\-delete\fP"
 Delete the specified partitions or all partitions.
+.IP "\fB\-u\fR, \fB\-\-update\fP"
+Update the specified partitions.
 .IP "\fB\-g\fR, \fB\-\-noheadings\fP"
 Do not print a header line.
 .IP "\fB\-h\fR, \fB\-\-help\fP"

diff --git a/disk-utils/partx.c b/disk-utils/partx.c
index 909157902c9302cef8cb4ea50a4c92d7b0623d36..45bf7739f4dc1d050bc5d240e651e36df8317438 100644 (file)
--- a/disk-utils/partx.c
+++ b/disk-utils/partx.c
@@ -59,6 +59,7 @@ enum {
        ACT_LIST,
        ACT_SHOW,
        ACT_ADD,
+       ACT_UPD,
        ACT_DELETE
 };
 
@@ -402,6 +403,105 @@ static int add_parts(int fd, const char *device,
        return rc;
 }
 
+static void upd_parts_warnx(const char *device, int first, int last)
+{
+       if (first == last)
+               warnx(_("%s: error updating partition %d"), device, first);
+       else
+               warnx(_("%s: error updating partitions %d-%d"),
+                               device, first, last);
+}
+
+static int upd_parts(int fd, const char *device, dev_t devno,
+                    blkid_partlist ls, int lower, int upper)
+{
+       int i, n, an, nparts, rc = 0, errfirst = 0, errlast = 0, err;
+       blkid_partition par;
+       uintmax_t start, size;
+
+       assert(fd >= 0);
+       assert(device);
+       assert(ls);
+
+       nparts = blkid_partlist_numof_partitions(ls);
+       if (!lower)
+               lower = 1;
+       if (!upper || lower < 0 || upper < 0) {
+               n = get_max_partno(device, devno);
+               if (!upper)
+                       upper = n > nparts ? n : nparts;
+               else if (upper < 0)
+                       upper = n + upper + 1;
+               if (lower < 0)
+                       lower = n + lower + 1;
+       }
+       if (lower > upper) {
+               warnx(_("specified range <%d:%d> "
+                       "does not make sense"), lower, upper);
+               return -1;
+       }
+
+       for (i = 0, n = lower; n <= upper; n++) {
+               par = blkid_partlist_get_partition(ls, i);
+               an = blkid_partition_get_partno(par);
+
+               if (lower && n < lower)
+                       continue;
+               if (upper && n > upper)
+                       continue;
+
+               start = blkid_partition_get_start(par);
+               size =  blkid_partition_get_size(par);
+
+               if (blkid_partition_is_extended(par))
+                       /*
+                        * Let's follow the Linux kernel and reduce
+                        * DOS extended partition to 1 or 2 sectors.
+                        */
+                       size = min(size, (uintmax_t) 2);
+
+               err = partx_del_partition(fd, n);
+               if (err == -1 && errno == ENXIO)
+                       err = 0; /* good, it already doesn't exist */
+               if (an == n)
+               {
+                       if (i < nparts)
+                               i++;
+                       if (err == -1 && errno == EBUSY)
+                       {
+                               /* try to resize */
+                               err = partx_resize_partition(fd, n, start, size);
+                               if (verbose)
+                                       printf(_("%s: partition #%d resized\n"), device, n);
+                               if (err == 0)
+                                       continue;
+                       }
+                       if (err == 0 && partx_add_partition(fd, n, start, size) == 0) {
+                               if (verbose)
+                                       printf(_("%s: partition #%d added\n"), device, n);
+                               continue;
+                       }
+               }
+               if (err == 0)
+                       continue;
+               rc = -1;
+               if (verbose)
+                       warn(_("%s: updating partition #%d failed"), device, n);
+               if (!errfirst)
+                       errlast = errfirst = n;
+               else if (errlast + 1 == n)
+                       errlast++;
+               else {
+                       upd_parts_warnx(device, errfirst, errlast);
+                       errlast = errfirst = n;
+               }
+       }
+
+       if (errfirst)
+               upd_parts_warnx(device, errfirst, errlast);
+       return rc;
+}
+
 static int list_parts(blkid_partlist ls, int lower, int upper)
 {
        int i, nparts;
@@ -600,7 +700,7 @@ static void __attribute__((__noreturn__)) usage(FILE *out)
 
        fputs(USAGE_HEADER, out);
        fprintf(out,
-             _(" %s [-a|-d|-s] [--nr <n:m> | <partition>] <disk>\n"),
+             _(" %s [-a|-d|-s|-u] [--nr <n:m> | <partition>] <disk>\n"),
                program_invocation_short_name);
 
        fputs(USAGE_OPTIONS, out);
@@ -608,7 +708,7 @@ static void __attribute__((__noreturn__)) usage(FILE *out)
                " -d, --delete         delete specified partitions or all of them\n"
                " -l, --list           list partitions (DEPRECATED)\n"
                " -s, --show           list partitions\n\n"
-
+               " -u, --update         update specified partitions or all of them\n"
                " -b, --bytes          print SIZE in bytes rather than in human readable format\n"
                " -g, --noheadings     don't print headings for --show\n"
                " -n, --nr <n:m>       specify the range of partitions (e.g. --nr 2:4)\n"
@@ -650,6 +750,7 @@ int main(int argc, char **argv)
                { "show",       no_argument,       NULL, 's' },
                { "add",        no_argument,       NULL, 'a' },
                { "delete",     no_argument,       NULL, 'd' },
+               { "update",     no_argument,       NULL, 'u' },
                { "type",       required_argument, NULL, 't' },
                { "nr",         required_argument, NULL, 'n' },
                { "output",     required_argument, NULL, 'o' },
@@ -672,7 +773,7 @@ int main(int argc, char **argv)
        atexit(close_stdout);
 
        while ((c = getopt_long(argc, argv,
-                               "abdglrsvn:t:o:PhV", long_opts, NULL)) != -1) {
+                               "abdglrsuvn:t:o:PhV", long_opts, NULL)) != -1) {
 
                err_exclusive_options(c, long_opts, excl, excl_st);
 
@@ -713,6 +814,9 @@ int main(int argc, char **argv)
                case 't':
                        type = optarg;
                        break;
+               case 'u':
+                       what = ACT_UPD;
+                       break;
                case 'v':
                        verbose = 1;
                        break;
@@ -870,6 +974,8 @@ int main(int argc, char **argv)
                        case ACT_ADD:
                                rc = add_parts(fd, wholedisk, ls, lower, upper);
                                break;
+                       case ACT_UPD:
+                               rc = upd_parts(fd, wholedisk, disk_devno, ls, lower, upper);
                        case ACT_NONE:
                                break;
                        default: