[PATCH] untar: Make behavior similar to GNU or BSD tar

Christian Mauderer christian.mauderer at embedded-brains.de
Fri Dec 3 12:50:57 UTC 2021


RTEMS untar implementation had problems with overwriting or integrating
archives into existing directory structures. This patch adapts the
behavior to mimic that of a GNU tar or BSD tar and extends the tar01
test to check for the behavior. That is:

* If a directory structure exists, the files from the archive will be
  integrated. Existing files are overwritten.

* If a file exists and the archive contains a directory with the same
  name, the file is removed and a directory is created. In the above
  example: if l1/l2 is a file it will be overwritten with a new
  directory.

* If a directory exists and the archive contains a file with the same
  name, the directory will be replaced if it is empty. If it contains
  files, the result is an error.

* An archive also can contain only a file without the parent
  directories. If in that case one of the parent directories exists as a
  file extracting the archive results in an error. In the example: if
  l1/l2 is a file and the archive doesn't contain the directories but
  only the file l1/l2/x.txt that would be an error.

* In case of an error, it is possible that the archive has been
  partially extracted.

Closes #4552
---
 cpukit/libmisc/untar/untar.c        |  57 +++++---
 testsuites/libtests/tar01/init.c    | 199 +++++++++++++++++++++++++++-
 testsuites/libtests/tar01/tar01.doc |   1 +
 testsuites/libtests/tar01/tar01.scn |  54 ++++++--
 testsuites/libtests/tar01/tar01.tar | Bin 10240 -> 10240 bytes
 5 files changed, 282 insertions(+), 29 deletions(-)

diff --git a/cpukit/libmisc/untar/untar.c b/cpukit/libmisc/untar/untar.c
index a2f09fb99f..8888ab2c57 100644
--- a/cpukit/libmisc/untar/untar.c
+++ b/cpukit/libmisc/untar/untar.c
@@ -126,30 +126,25 @@ Make_Path(const rtems_printer *printer, char *path)
 
     *p = '\0';
     if (p[1] == '\0') {
-      /* Speculatively unlink the last component so that it can be re-created */
-      unlink(path);
       return 0;
     }
 
     if (mkdir(path, S_IRWXU | S_IRWXG | S_IRWXO) != 0) {
-      if (errno == EEXIST || errno == EISDIR) {
+      if (errno == EEXIST) {
+        /* If it exists already: Check whether it is a directory */
         struct stat sb;
-
-        if (stat(path, &sb) != 0) {
+        if (lstat(path, &sb) != 0) {
+          Print_Error(printer, "lstat", path);
+          return -1;
+        } else if (!S_ISDIR(sb.st_mode)) {
+          rtems_printf(printer,
+                       "untar: mkdir: %s: exists but is not a directory\n",
+                       path);
           return -1;
         }
-
-        if (!S_ISDIR(sb.st_mode)) {
-          if (unlink(path) != 0) {
-            Print_Error(printer, "unlink", path);
-            return -1;
-          }
-
-          if (mkdir(path, S_IRWXU | S_IRWXG | S_IRWXO) != 0) {
-            Print_Error(printer, "mkdir (unlink)", path);
-            return -1;
-          }
-        }
+      } else {
+        Print_Error(printer, "mkdir", path);
+        return -1;
       }
     }
 
@@ -206,6 +201,12 @@ Untar_ProcessHeader(
 
   if (Make_Path(ctx->printer, ctx->file_path) != 0) {
     retval = UNTAR_FAIL;
+  } else {
+    /*
+     * Speculatively unlink. This should unlink everything but non-empty
+     * directories or write protected stuff.
+     */
+    unlink(ctx->file_path);
   }
 
   if (ctx->linkflag == SYMTYPE) {
@@ -225,8 +226,22 @@ Untar_ProcessHeader(
     rtems_printf(ctx->printer, "untar: dir: %s\n", ctx->file_path);
     r = mkdir(ctx->file_path, ctx->mode);
     if (r != 0) {
-      Print_Error(ctx->printer, "mkdir", ctx->file_path);
-      retval = UNTAR_FAIL;
+      if (errno == EEXIST) {
+        /* If it exists already: Check whether it is a directory */
+        struct stat sb;
+        if (lstat(ctx->file_path, &sb) != 0) {
+          Print_Error(ctx->printer, "lstat", ctx->file_path);
+          retval = UNTAR_FAIL;
+        } else if (!S_ISDIR(sb.st_mode)) {
+          rtems_printf(ctx->printer,
+                       "untar: mkdir: %s: exists but is not a directory\n",
+                       ctx->file_path);
+          retval = UNTAR_FAIL;
+        }
+      } else {
+        Print_Error(ctx->printer, "mkdir", ctx->file_path);
+        retval = UNTAR_FAIL;
+      }
     }
   }
 
@@ -426,7 +441,9 @@ Untar_FromFile_Print(
        */
 
       if ((out_fd = creat(ctx.file_path, ctx.mode)) == -1) {
-        (void) lseek(fd, SEEK_CUR, 512UL * ctx.nblocks);
+        /* Couldn't create that file. Abort. */
+        retval = UNTAR_FAIL;
+        break;
       } else {
         for (i = 0; i < ctx.nblocks; i++) {
           n = read(fd, bufr, 512);
diff --git a/testsuites/libtests/tar01/init.c b/testsuites/libtests/tar01/init.c
index 4cad67a6ae..2deff3a482 100644
--- a/testsuites/libtests/tar01/init.c
+++ b/testsuites/libtests/tar01/init.c
@@ -7,6 +7,33 @@
  *  http://www.rtems.org/license/LICENSE.
  */
 
+/*
+ * Note on the used tar file: Generate the file on a system that supports
+ * symlinks with the following commands (tested on Linux - you might have to
+ * adapt on other systems):
+ *
+ * export WORK=some_work_directory
+ * rm -r ${WORK}
+ * mkdir -p ${WORK}/home/abc/def
+ * mkdir -p ${WORK}/home/dir
+ * cd ${WORK}
+ * echo "#! joel" > home/abc/def/test_script
+ * echo "ls -las /dev" >> home/abc/def/test_script
+ * chmod 755 home/abc/def/test_script
+ * echo "This is a test of loading an RTEMS filesystem from an" > home/test_file
+ * echo "initial tar image." >> home/test_file
+ * echo "Hello world" >> home/dir/file
+ * ln -s home/test_file symlink
+ * tar cf tar01.tar --format=ustar \
+ *     symlink \
+ *     home/test_file \
+ *     home/abc/def/test_script \
+ *     home/dir
+ *
+ * Note that "home/dir" is in the archive as separate directory. "home/abc" is
+ * only in the archive as a parent of the file "test_script".
+ */
+
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
@@ -95,6 +122,84 @@ void test_untar_from_memory(void)
 
 }
 
+static void assert_file_content(
+    const char *name,
+    const char *expected_content,
+    ssize_t expected_size
+)
+{
+  char buf[16];
+  int fd;
+  int rd;
+
+  fd = open(name, O_RDONLY);
+  rtems_test_assert( fd >= 0 );
+  do {
+    rd = read(fd, buf, sizeof(buf));
+    rtems_test_assert( rd >= 0 );
+    if (rd > 0) {
+      rtems_test_assert( expected_size - rd >= 0 );
+      rtems_test_assert( memcmp(buf, expected_content, rd) == 0 );
+      expected_content += rd;
+      expected_size -= rd;
+    }
+  } while(rd > 0);
+  rtems_test_assert( expected_size == 0 );
+  close(fd);
+}
+
+static void assert_content_like_expected(void)
+{
+  const char *directories[] = {
+    "home",
+    "home/abc",
+    "home/abc/def",
+    "home/dir",
+  };
+  const char *symlinks[] = {
+    "symlink",
+  };
+  const struct {
+    const char *name;
+    const char *content;
+  } files[] = {
+    {
+      .name = "home/abc/def/test_script",
+      .content = "#! joel\nls -las /dev\n",
+    }, {
+      .name = "home/test_file",
+      .content = "This is a test of loading an RTEMS filesystem from an\n"
+                 "initial tar image.\n",
+    }, {
+      .name = "home/dir/file",
+      .content = "Hello world\n",
+    }
+  };
+  size_t i;
+  struct stat st;
+
+  for(i = 0; i < RTEMS_ARRAY_SIZE(directories); ++i) {
+    lstat(directories[i], &st);
+    rtems_test_assert( S_ISDIR(st.st_mode) );
+  }
+
+  for(i = 0; i < RTEMS_ARRAY_SIZE(symlinks); ++i) {
+    lstat(symlinks[i], &st);
+    rtems_test_assert( S_ISLNK(st.st_mode) );
+  }
+
+  for(i = 0; i < RTEMS_ARRAY_SIZE(files); ++i) {
+    lstat(files[i].name, &st);
+    rtems_test_assert( S_ISREG(st.st_mode) );
+
+    assert_file_content(
+        files[i].name,
+        files[i].content,
+        strlen(files[i].content)
+        );
+  }
+}
+
 void test_untar_from_file(void)
 {
   int                fd;
@@ -119,13 +224,105 @@ void test_untar_from_file(void)
   rv = chdir( "/dest" );
   rtems_test_assert( rv == 0 );
 
-  /* Untar it */
+  /* Case 1: Untar it into empty directory */
   rv = Untar_FromFile( "/test.tar" );
   printf("Untaring from file - ");
   if (rv != UNTAR_SUCCESSFUL) {
     printf ("error: untar failed: %i\n", rv);
     exit(1);
   }
+  assert_content_like_expected();
+  printf ("successful\n");
+
+  /* Case 2: Most files exist */
+  rv = unlink("/dest/home/test_file");
+  rtems_test_assert( rv == 0 );
+
+  rv = Untar_FromFile( "/test.tar" );
+  printf("Untar from file into existing structure with one missing file - ");
+  if (rv != UNTAR_SUCCESSFUL) {
+    printf ("error: untar failed: %i\n", rv);
+    exit(1);
+  }
+  assert_content_like_expected();
+  printf ("successful\n");
+
+  /* Case 3: An empty directory exists where a file should be */
+  rv = unlink("/dest/home/test_file");
+  rtems_test_assert( rv == 0 );
+  rv = mkdir("/dest/home/test_file", S_IRWXU | S_IRWXG | S_IROTH | S_IXOTH);
+  rtems_test_assert( rv == 0 );
+
+  rv = Untar_FromFile( "/test.tar" );
+  printf("Untar from file; overwrite empty directory with file - ");
+  if (rv != UNTAR_SUCCESSFUL) {
+    printf ("error: untar failed: %i\n", rv);
+    exit(1);
+  }
+  assert_content_like_expected();
+  printf ("successful\n");
+
+  /* Case 4: A file exists where a parent directory should be created */
+  rv = unlink("/dest/home/abc/def/test_script");
+  rtems_test_assert( rv == 0 );
+  rv = unlink("/dest/home/abc/def");
+  rtems_test_assert( rv == 0 );
+  rv = unlink("/dest/home/abc");
+  rtems_test_assert( rv == 0 );
+  fd = creat("/dest/home/abc", S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
+  rtems_test_assert( fd >= 0 );
+  close(fd);
+
+  rv = Untar_FromFile( "/test.tar" );
+  printf("Untar from file; file exists where parent dir should be created - ");
+  if (rv != UNTAR_FAIL) {
+    printf ("error: untar didn't fail like expected: %i\n", rv);
+    exit(1);
+  }
+  printf ("expected fail\n");
+  /* cleanup so that the next one works */
+  rv = unlink("/dest/home/abc");
+  rtems_test_assert( rv == 0 );
+
+  /* Case 5: A non-empty directory exists where a file should be created */
+  rv = unlink("/dest/home/test_file");
+  rtems_test_assert( rv == 0 );
+  rv = mkdir("/dest/home/test_file", S_IRWXU | S_IRWXG | S_IROTH | S_IXOTH);
+  rtems_test_assert( rv == 0 );
+  fd = creat("/dest/home/test_file/file",
+      S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
+  rtems_test_assert( fd >= 0 );
+  close(fd);
+
+  rv = Untar_FromFile( "/test.tar" );
+  printf("Untar from file; non-empty dir where file should be created - ");
+  if (rv != UNTAR_FAIL) {
+    printf ("error: untar didn't fail like expected: %i\n", rv);
+    exit(1);
+  }
+  printf ("expected fail\n");
+  /* cleanup so that the next one works */
+  rv = unlink("/dest/home/test_file/file");
+  rtems_test_assert( rv == 0 );
+  rv = unlink("/dest/home/test_file");
+  rtems_test_assert( rv == 0 );
+
+  /* Case 6: A file exists where a directory is explicitly in the archive */
+  rv = unlink("/dest/home/dir/file");
+  rtems_test_assert( rv == 0 );
+  rv = unlink("/dest/home/dir");
+  rtems_test_assert( rv == 0 );
+  fd = creat("/dest/home/dir", S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
+  rtems_test_assert( fd >= 0 );
+  close(fd);
+
+  rv = Untar_FromFile( "/test.tar" );
+  printf("Untar from file; overwrite file with explicit directory - ");
+  if (rv != UNTAR_SUCCESSFUL) {
+    printf ("error: untar failed: %i\n", rv);
+    exit(1);
+  }
+  assert_content_like_expected();
   printf ("successful\n");
 
   /******************/
diff --git a/testsuites/libtests/tar01/tar01.doc b/testsuites/libtests/tar01/tar01.doc
index 060f98a813..adffdca291 100644
--- a/testsuites/libtests/tar01/tar01.doc
+++ b/testsuites/libtests/tar01/tar01.doc
@@ -20,3 +20,4 @@ directives:
 concepts:
 
 + exercise these routines
++ check whether existing files are overwritten or not overwritten like expected
diff --git a/testsuites/libtests/tar01/tar01.scn b/testsuites/libtests/tar01/tar01.scn
index 68fa951881..dd72f9517b 100644
--- a/testsuites/libtests/tar01/tar01.scn
+++ b/testsuites/libtests/tar01/tar01.scn
@@ -1,9 +1,24 @@
-*** TAR01 TEST ***
-Untaring from memory - successful
+*** BEGIN OF TEST TAR 1 ***
+*** TEST VERSION: 6.0.0.e1efb4eb8a9d6dd5f6f37dafc9feb0a9e6a888f1
+*** TEST STATE: EXPECTED_PASS
+*** TEST BUILD: RTEMS_POSIX_API
+*** TEST TOOLS: 10.3.1 20210409 (RTEMS 6, RSB ad54d1dd3cf8249d9d39deb1dd28b2f294df062d-modified, Newlib eb03ac1)
+Untaring from memory - untar: memory at 0x11ece8 (10240)
+untar: symlink: home/test_file -> symlink
+untar: file: home/test_file (s:73,m:0644)
+untar: file: home/abc/def/test_script (s:21,m:0755)
+untar: dir: home/dir
+untar: file: home/dir/file (s:12,m:0644)
+successful
 ========= /home/test_file =========
 (0)This is a test of loading an RTEMS filesystem from an
 initial tar image.
 
+========= /home/abc/def/test_script =========
+(0)#! joel
+ls -las /dev
+
+ /home/abc/def/test_script: mode: 0755 want: 0755
 ========= /symlink =========
 (0)This is a test of loading an RTEMS filesystem from an
 initial tar image.
@@ -11,35 +26,58 @@ initial tar image.
 
 Copy tar image to test.tar
 Untaring from file - successful
+Untar from file into existing structure with one missing file - successful
+Untar from file; overwrite empty directory with file - successful
+Untar from file; file exists where parent dir should be created - expected fail
+Untar from file; non-empty dir where file should be created - expected fail
+Untar from file; overwrite file with explicit directory - successful
 ========= /dest/home/test_file =========
 (0)This is a test of loading an RTEMS filesystem from an
 initial tar image.
 
+========= /dest/home/abc/def/test_script =========
+(0)#! joel
+ls -las /dev
+
+ /dest/home/abc/def/test_script: mode: 0755 want: 0755
 ========= /dest/symlink =========
 (0)This is a test of loading an RTEMS filesystem from an
 initial tar image.
 
 
-Untaring chunks from memory - untar: dir: home
-untar: file: home/test_file (73)
+Untaring chunks from memory - untar: symlink: home/test_file -> symlink
+untar: file: home/test_file (s:73,m:0644)
+untar: file: home/abc/def/test_script (s:21,m:0755)
+untar: dir: home/dir
+untar: file: home/dir/file (s:12,m:0644)
 successful
 ========= /dest2/home/test_file =========
 (0)This is a test of loading an RTEMS filesystem from an
 initial tar image.
 
+========= /dest2/home/abc/def/test_script =========
+(0)#! joel
+ls -las /dev
+
+ /dest2/home/abc/def/test_script: mode: 0755 want: 0755
 ========= /dest2/symlink =========
 (0)This is a test of loading an RTEMS filesystem from an
 initial tar image.
 
 
-Untaring chunks from tgz- untar: dir: home
-untar: file: home/test_file (73)
-successful
+Untaring chunks from tgz - successful
 ========= /dest3/home/test_file =========
 (0)This is a test of loading an RTEMS filesystem from an
 initial tar image.
 
+========= /dest3/home/abc/def/test_script =========
+(0)#! joel
+ls -las /dev
+
+ /dest3/home/abc/def/test_script: mode: 0755 want: 0755
 ========= /dest3/symlink =========
 (0)This is a test of loading an RTEMS filesystem from an
 initial tar image.
-*** END OF TAR01 TEST ***
+
+
+*** END OF TEST TAR 1 ***
diff --git a/testsuites/libtests/tar01/tar01.tar b/testsuites/libtests/tar01/tar01.tar
index 6c6952ef183d51a9635c6ebbc8ed0443e8da1725..9874f426d15eb817f270af7dab48fce1f36be848 100644
GIT binary patch
literal 10240
zcmeH}-%i6I6vlhKr#QxI9dtmSz{DGGboUFc)S*yJ=`?$L>C6^qR=rsp<Gzz7G(h<C
z`}hvTjd!+w$%YJ;q9}@tv3w?S_NDAvwvlncWzL0CN at Ofg9c4!ODtI$(O>7sHb!M0)
zu4Aj4w4~*#v9YzfUihOEmBDLUucK+=(e~X&cIDAdf3I>3#2pePlCC}abIuR-=Srnx
zLTn6NXRiNzWh13eQ|B`Z6}g~GTR)Mm>3)85_duQZ;wHAnQ`H2Y8YZ^3$tsSLb;x at C
zWUeP;XoWdWPGIYQ{kWW#rus~^aoO0{_LLKK{x78L^*_tyq5pFx(scp<pHhULu`Vy@
zIT$x_k*=JMl+M8$yxarpA69SuU)p9m;NE`qKVygf=Tb6}ksNSM`=QVL{@?3A+zUJ9
z{h!}|jEisjtC`@)|NApK;LojbF3@{uT#2+lAZH8>0w4eaAOHd&00JNY0w4eaAOHd&
V00JNY0w4eaAOHd&00LtX_yCHOyx{-<

literal 10240
zcmeI!-)h1z6b5jw`xIyFdh?`zpJ11}*}Ru%Q=2VqM^7F2_Dfp^QXGoV;n)`hsW~ah
z&wOdirZUUUNVhJmGmBXo`<BKrF^5qc^3iwS!>p7d6{RW-lY}|){VG$LubX8ylbi0P
z)9r#;%tlLRb-gYp72{>zRNB_G7t_kAf^jMR;)X`2YHskiRcVF%M^nEEs42)bI=A(X
zbWJa-r{`DdH-;RfGZhtWQ~8d-*49%w@^oY?y)%!&4XzDSIxkT6`PZB6GB?F|4#>8(
zAKm$pmsj+G$dcqJ_uuEhm=z9_N&Z8{afbX~PJDIc{T;nE#syC3!D%7C4?dCQt2zJN
zKsi*-*6*{<d&qz0^Zdi}-}g`R&nYJq4u{jsFDL)}`9JF)kDEgP0uX=z1Rwwb2tWV=
g5P$##AOHafKmY;|fB*y_009U<00Izzz^@5>0Tj at K8~^|S

-- 
2.31.1



More information about the devel mailing list