cpio: add support for --renumber-inodes like GNU cpio

The --renumber-inodes option renumbers the inodes starting from 1,
so that the sequence of inodes is always stable.  This helps with
reproducibility.

function                                             old     new   delta
cpio_o                                               961    1045     +84
.rodata                                            78422   78440     +18
bbconfig_config_bz2                                 6168    6164      -4
packed_usage                                       25764   25756      -8
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/2 up/down: 102/-12)            Total: 90 bytes

Signed-off-by: Ariadne Conill <ariadne@dereferenced.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 32 insertions, 0 deletions

diff --git a/archival/cpio.c b/archival/cpio.c
index daf6cffc9..7149782d7 100644
--- a/archival/cpio.c
+++ b/archival/cpio.c
@@ -45,6 +45,13 @@
 //config:       depends on FEATURE_CPIO_O && LONG_OPTS
 //config:       help
 //config:       Optionally ignore device numbers when creating archives.
+//config:
+//config:config FEATURE_CPIO_RENUMBER_INODES
+//config:       bool "Support --renumber-inodes like GNU cpio"
+//config:       default y
+//config:       depends on FEATURE_CPIO_O && LONG_OPTS
+//config:       help
+//config:       Optionally renumber inodes when creating archives.
 
 //applet:IF_CPIO(APPLET(cpio, BB_DIR_BIN, BB_SUID_DROP))
 
@@ -85,6 +92,9 @@
 //usage:        IF_FEATURE_CPIO_IGNORE_DEVNO(
 //usage:     "\n        --ignore-devno"
 //usage:        )
+//usage:        IF_FEATURE_CPIO_RENUMBER_INODES(
+//usage:     "\n        --renumber-inodes"
+//usage:        )
 
 /* GNU cpio 2.9 --help (abridged):
 
@@ -173,18 +183,21 @@ enum {
         IF_LONG_OPTS(     OPTBIT_QUIET      ,)
         IF_LONG_OPTS(     OPTBIT_2STDOUT    ,)
         IF_FEATURE_CPIO_IGNORE_DEVNO(OPTBIT_IGNORE_DEVNO,)
+        IF_FEATURE_CPIO_RENUMBER_INODES(OPTBIT_RENUMBER_INODES,)
         OPT_CREATE             = IF_FEATURE_CPIO_O((1 << OPTBIT_CREATE     )) + 0,
         OPT_FORMAT             = IF_FEATURE_CPIO_O((1 << OPTBIT_FORMAT     )) + 0,
         OPT_PASSTHROUGH        = IF_FEATURE_CPIO_P((1 << OPTBIT_PASSTHROUGH)) + 0,
         OPT_QUIET              = IF_LONG_OPTS(     (1 << OPTBIT_QUIET      )) + 0,
         OPT_2STDOUT            = IF_LONG_OPTS(     (1 << OPTBIT_2STDOUT    )) + 0,
         OPT_IGNORE_DEVNO       = IF_FEATURE_CPIO_IGNORE_DEVNO((1 << OPTBIT_IGNORE_DEVNO)) + 0,
+        OPT_RENUMBER_INODES    = IF_FEATURE_CPIO_RENUMBER_INODES((1 << OPTBIT_RENUMBER_INODES)) + 0,
 };
 
 #define OPTION_STR "it0uvdmLF:R:"
 
 struct globals {
         struct bb_uidgid_t owner_ugid;
+        ino_t next_inode;
 } FIX_ALIASING;
 #define G (*(struct globals*)bb_common_bufsiz1)
 void BUG_cpio_globals_too_big(void);
@@ -218,6 +231,9 @@ static NOINLINE int cpio_o(void)
                 struct inodes_s *next;
                 struct name_s *names;
                 struct stat st;
+#if ENABLE_FEATURE_CPIO_RENUMBER_INODES
+                ino_t mapped_inode;
+#endif
         };
 
         struct inodes_s *links = NULL;
@@ -272,6 +288,10 @@ static NOINLINE int cpio_o(void)
                                                 l = xzalloc(sizeof(*l));
                                                 l->st = st;
                                                 l->next = links;
+#if ENABLE_FEATURE_CPIO_RENUMBER_INODES
+                                                if (option_mask32 & OPT_RENUMBER_INODES)
+                                                        l->mapped_inode = ++G.next_inode;
+#endif
                                                 links = l;
                                                 break;
                                         }
@@ -290,6 +310,11 @@ static NOINLINE int cpio_o(void)
                                 free(line);
                                 continue;
                         }
+#if ENABLE_FEATURE_CPIO_RENUMBER_INODES
+                        else if (option_mask32 & OPT_RENUMBER_INODES) {
+                                st.st_ino = ++G.next_inode;
+                        }
+#endif
                 } else { /* line == NULL: EOF */
  next_link:
                         if (links) {
@@ -297,6 +322,10 @@ static NOINLINE int cpio_o(void)
                                 st = links->st;
                                 name = links->names->name;
                                 links->names = links->names->next;
+#if ENABLE_FEATURE_CPIO_RENUMBER_INODES
+                                if (links->mapped_inode)
+                                        st.st_ino = links->mapped_inode;
+#endif
                                 /* GNU cpio is reported to emit file data
                                  * only for the last instance. Mimic that. */
                                 if (links->names == NULL)
@@ -399,6 +428,9 @@ int cpio_main(int argc UNUSED_PARAM, char **argv)
 #if ENABLE_FEATURE_CPIO_IGNORE_DEVNO
                 "ignore-devno\0" No_argument       "\xfd"
 #endif
+#if ENABLE_FEATURE_CPIO_RENUMBER_INODES
+                "renumber-inodes\0" No_argument    "\xfc"
+#endif
                 ;
 #endif