Handling ACL entries which match the POSIX permissions

doc/susp_aaip_0_2.txt

@@ -330,4 +330,9 @@ SUSP 1.12 ftp://ftp.ymi.com/pub/rockridge/susp112.ps
 RRIP 1.12 ftp://ftp.ymi.com/pub/rockridge/rrip112.ps
 (especially field SL)
 
+-------------------------------------------------------------------------------
+Pending considerations:
+
+- shall "AA" be fixely defined as signature ?
+
 

libisofs/aaip-os-freebsd.c

@@ -14,6 +14,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
+#include <sys/stat.h>
 
 #include <sys/acl.h>
 
@@ -27,6 +28,9 @@
                         with bit15 of flag.
    @param flag          Bitfield for control purposes
                         bit0=  obtain default ACL rather than access ACL
+                        bit4=  do not return entries which match the st_mode
+                               permissions. If no other ACL entries exist:
+                               set *text = NULL and return 2
                         bit15= free text and return 1
    @return              > 0 ok
                         -1  failure of system ACL service (see errno)
@@ -34,6 +38,8 @@
 int aaip_get_acl_text(char *path, char **text, int flag)
 {
  acl_t acl= NULL;
+ struct stat stbuf;
+ int ret;
 
  if(flag & (1 << 15)) {
    if(*text != NULL)
@@ -55,6 +61,16 @@ int aaip_get_acl_text(char *path, char **text, int flag)
  acl_free(acl);
  if(*text == NULL)
    return(-1);
+ if(flag & 16) {
+   ret= stat(path, &stbuf);
+   if(ret != -1)
+     aaip_cleanout_st_mode(*text, stbuf.st_mode, 0);
+   if((*text)[0] == 0 || strcmp(*text, "\n") == 0) {
+     acl_free(text);
+     *text= NULL;
+     return(2);
+   }
+ }
  return(1);
 }
 
@@ -74,6 +90,8 @@ int aaip_get_acl_text(char *path, char **text, int flag)
                         bit0=  obtain ACL (access and eventually default)
                         bit1=  use numeric ACL qualifiers rather than names
                         bit2=  do not encode attributes other than ACL
+                        bit3=  -reserved-
+                        bit4=  do not return st_mode permissions in ACL.
                         bit15= free memory of names, value_lengths, values
    @return              >0  ok
                         <=0 error
@@ -118,9 +136,11 @@ int aaip_get_attr_list(char *path, size_t *num_attrs, char ***names,
 
  if(flag & 1) { /* Obtain ACL */
    /* access-ACL */
-   ret= aaip_get_acl_text(path, &acl_text, 0);
+   ret= aaip_get_acl_text(path, &acl_text, flag & 16);
    if(ret <= 0)
      goto ex;
+   if(ret == 2)
+     {ret= 1; goto ex;} /* empty ACL / only st_mode info was found in ACL */
    ret= aaip_encode_acl(acl_text, &a_acl_len, &a_acl, flag & 2);
    if(ret <= 0)
      goto ex;

libisofs/aaip-os-linux.c

@@ -14,6 +14,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
+#include <sys/stat.h>
 
 #include <sys/acl.h>
 #include <attr/xattr.h>
@@ -30,6 +31,9 @@
                         with bit15 of flag.
    @param flag          Bitfield for control purposes
                         bit0=  obtain default ACL rather than access ACL
+                        bit4=  do not return entries which match the st_mode 
+                               permissions. If no other ACL entries exist:
+                               set *text = NULL and return 2
                         bit15= free text and return 1
    @return              > 0 ok
                         -1  failure of system ACL service (see errno)
@@ -37,6 +41,8 @@
 int aaip_get_acl_text(char *path, char **text, int flag)
 {
  acl_t acl= NULL;
+ struct stat stbuf;
+ int ret;
 
  if(flag & (1 << 15)) {
    if(*text != NULL)
@@ -52,6 +58,16 @@ int aaip_get_acl_text(char *path, char **text, int flag)
  acl_free(acl);
  if(*text == NULL)
    return(-1);
+ if(flag & 16) {
+   ret= stat(path, &stbuf);
+   if(ret != -1)
+     aaip_cleanout_st_mode(*text, stbuf.st_mode, 0);
+   if((*text)[0] == 0 || strcmp(*text, "\n") == 0) {
+     acl_free(text);
+     *text= NULL;
+     return(2);
+   }
+ }
  return(1);
 }
 
@@ -69,6 +85,7 @@ int aaip_get_acl_text(char *path, char **text, int flag)
                         bit2=  do not obtain attributes other than ACL
                         bit3=  do not ignore eventual local ACL attribute
                                (e.g. system.posix_acl_access)
+                        bit4=  do not return st_mode permissions in ACL.
                         bit15= free memory of names, value_lengths, values
    @return              >0  ok
                         <=0 error
@@ -158,9 +175,11 @@ int aaip_get_attr_list(char *path, size_t *num_attrs, char ***names,
 
  if(flag & 1) { /* Obtain ACL */
    /* access-ACL */
-   ret= aaip_get_acl_text(path, &acl_text, 0);
+   ret= aaip_get_acl_text(path, &acl_text, flag & 16);
    if(ret <= 0)
      goto ex;
+   if(ret == 2)
+     {ret= 1; goto ex;} /* empty ACL / only st_mode info was found in ACL */
    ret= aaip_encode_acl(acl_text, &a_acl_len, &a_acl, flag & 2);
    if(ret <= 0)
      goto ex;

libisofs/aaip_0_2.c

@@ -17,6 +17,7 @@
 #include <stdio.h>
 #include <pwd.h>
 #include <grp.h>
+#include <sys/stat.h>
 
 /* <<<
 */
@@ -425,6 +426,121 @@ group_by_name:;
 }
 
 
+/* Remove the entries user::??? , group::??? , other::??? , other:??? 
+   from an ACL in long text form if they match the bits in st_mode.
+   @param flag       bit0= do not remove entries, only determine return value
+*/
+int aaip_cleanout_st_mode(char *acl_text, mode_t st_mode, int flag)
+{
+ char *rpt, *wpt, *npt, *cpt;
+ mode_t m;
+ int overriders= 0;
+
+ for(npt= wpt= rpt= acl_text; *npt != 0; rpt= npt + 1) {
+   npt= strchr(rpt, '\n');
+   if(npt == NULL)
+     npt= rpt + strlen(rpt);
+   if(strncmp(rpt, "user::", 6) == 0 && npt - rpt == 9) {
+     cpt= rpt + 6;
+     m= 0;
+     if(cpt[0] == 'r')
+       m|= S_IRUSR;
+     if(cpt[1] == 'w')
+       m|= S_IWUSR;
+     if(cpt[2] == 'x')
+       m|= S_IXUSR;
+     if((st_mode & S_IRWXU) == (m & S_IRWXU)) {
+       overriders|= 32;
+ continue;
+     }
+     overriders|= 4;
+   }
+   if(strncmp(rpt, "group::", 7) == 0 && npt - rpt == 10) {
+     cpt= rpt + 7;
+     m= 0;
+     if(cpt[0] == 'r')
+       m|= S_IRGRP;
+     if(cpt[1] == 'w')
+       m|= S_IWGRP;
+     if(cpt[2] == 'x')
+       m|= S_IXGRP;
+     if((st_mode & S_IRWXG) == (m & S_IRWXG)) {
+       overriders|= 16;
+ continue;
+     }
+     overriders|= 2;
+   }
+   if(strncmp(rpt, "other::", 7) == 0 && npt - rpt == 10) {
+     cpt= rpt + 7;
+others_st_mode:;
+     m= 0;
+     if(cpt[0] == 'r')
+       m|= S_IROTH;
+     if(cpt[1] == 'w')
+       m|= S_IWOTH;
+     if(cpt[2] == 'x')
+       m|= S_IXOTH;
+     if((st_mode & S_IRWXO) == (m & S_IRWXO)) {
+       overriders|= 8;
+ continue;
+     }
+     overriders|= 1;
+   }
+   if(strncmp(rpt, "other:", 6) == 0 && npt - rpt == 9) {
+     cpt= rpt + 7;
+     goto others_st_mode;
+   }
+   if(wpt == rpt) {
+     wpt= npt + 1;
+ continue;
+   }
+   if(!(flag & 1))
+     memmove(wpt, rpt, 1 + npt - rpt);
+   wpt+= 1 + npt - rpt;
+ }
+ if(!(flag & 1)) {
+   if(wpt == acl_text)
+     *wpt= 0;
+   else if(*(wpt - 1) != 0)
+     *wpt= 0;
+ }
+ return(overriders);
+}
+
+
+/* Important: acl_text must provide 32 bytes more than its current length !
+*/
+int aaip_add_acl_st_mode(char *acl_text, mode_t st_mode, int flag)
+{
+ char *wpt;
+ int overriders= 0;
+
+ overriders = aaip_cleanout_st_mode(acl_text, st_mode, 1);
+ if(!(overriders & (4 | 32))) {
+   wpt= acl_text + strlen(acl_text);
+   sprintf(wpt, "user::%c%c%c\n",
+           st_mode & S_IRUSR ? 'r' : '-',
+           st_mode & S_IWUSR ? 'w' : '-',
+           st_mode & S_IXUSR ? 'x' : '-');
+ }
+ if(!(overriders & (2 | 16))) {
+   wpt= acl_text + strlen(acl_text);
+   sprintf(wpt, "group::%c%c%c\n",
+         st_mode & S_IRGRP ? 'r' : '-',
+         st_mode & S_IWGRP ? 'w' : '-',
+         st_mode & S_IXGRP ? 'x' : '-');
+ }
+ if(!(overriders & (1 | 8))) {
+   wpt= acl_text + strlen(acl_text);
+   sprintf(wpt, "other::%c%c%c\n",
+         st_mode & S_IROTH ? 'r' : '-',
+         st_mode & S_IWOTH ? 'w' : '-',
+         st_mode & S_IXOTH ? 'x' : '-');
+ }
+ return(1); 
+}
+
+
 /* --------------------------------- Decoder ---------------------------- */
 
 /* --- private --- */

libisofs/aaip_0_2.h

@@ -58,6 +58,44 @@ int aaip_encode_acl(char *acl_text,
                     size_t *result_len, unsigned char **result, int flag);
 
 
+/* Remove the entries of type "user::" , "group::" , "other::" , "other:"
+   from an ACL in long text form if they match the bits in st_mode.
+   @param acl_text   The text to be shortened
+   @param st_mode    The component of struct stat which shall take the
+                     removed information. The caller should submit the st_mode
+                     variable which holds permissions as indicated by ECMA-119
+                     and RRIP data.
+   @param flag       bit0= do not remove entries, only determine return value
+   @return           <0  failure
+                     >=0 tells in six bits which tag types are present.
+                         The first three tell which types deviate from the
+                         corresponding st_mode settings:
+                         bit0= "other::" overrides S_IRWXO
+                         bit1= "group::" overrides S_IRWXG
+                         bit2= "user::"  overrides S_IRWXU       
+                         The second three tell which types comply with st_mode:
+                         bit3= "other::" matches S_IRWXO
+                         bit4= "group::" matches S_IRWXG
+                         bit5= "user::"  matches S_IRWXU       
+                         Given the nature of ACLs all 64 combinations are
+                         possible although some show inner contradictions.
+*/
+int aaip_cleanout_st_mode(char *acl_text, mode_t st_mode, int flag);
+
+
+/* Append entries of type "user::" , "group::" , "other::" representing the
+   permission bits in st_mode if those tag types are not present in the ACL
+   text.
+   @param acl_text   The text to be made longer. It must offer 33 bytes more
+                     storage space than its length when it is submitted.
+   @param st_mode    The component of struct stat which shall provide the
+                     permission information.
+   @param flag       Unused yet. Submit 0.
+   @return           <0 failure
+*/
+int aaip_add_acl_st_mode(char *acl_text, mode_t st_mode, int flag);
+
+
 /* ------ OS interface ------ */
 
 /* Obtain the ACL of the given file in long text form.
@@ -67,8 +105,12 @@ int aaip_encode_acl(char *acl_text,
                         with bit15 of flag.
    @param flag          Bitfield for control purposes
                         bit0=  obtain default ACL rather than access ACL
+                        bit4=  do not return entries which match the st_mode 
+                               permissions. If no other ACL entries exist:
+                               set *text = NULL and return 2
                         bit15= free text and return 1
-   @return              > 0 ok
+   @return               1 ok
+                         2 only st_mode permissions exist and bit 4 is set
                         -1 failure of system ACL service (see errno)
 */
 int aaip_get_acl_text(char *path, char **text, int flag);
@@ -89,6 +131,7 @@ int aaip_get_acl_text(char *path, char **text, int flag);
                         bit2=  do not obtain attributes other than ACLs
                         bit3=  do not ignore eventual ACL attribute
                                (e.g. system.posix_acl_access)
+                        bit4=  do not return st_mode permissions in ACL.
                         bit15= free memory of names, value_lengths, values
    @return              >0  ok
                         <=0 error

libisofs/fs_local.c

@@ -489,11 +489,13 @@ int lfs_get_aa_string(IsoFileSource *src, unsigned char **aa_string, int flag)
 
     *aa_string = NULL;
     /* Obtain EAs and ACLs ("access" and "default"). ACLs encoded according
-       to AAIP ACL representation.
+       to AAIP ACL representation. Clean out st_mode ACL entries.
     */ 
     path = iso_file_source_get_path(src);
+
+    /* >>> make adjustable: bit4 = ignoring of st_mode ACL entries */
     ret = aaip_get_attr_list(path, &num_attrs, &names,
-                             &value_lengths, &values, 1 | 2);
+                             &value_lengths, &values, 1 | 2 | 16);
     if (ret <= 0) {
         ret = ISO_FILE_ERROR;
         goto ex;

libisofs/libisofs.h

@@ -4141,9 +4141,12 @@ int aaip_xinfo_func(void *data, int flag);
  *      bit0=  obtain "default" ACL rather than "access" ACL
  *             (Linux directories can have a "default" ACL which influences
  *              the permissions of newly created files.)
+ *      bit4=  if no ACL available: return *text == NULL
+               else: produce ACL from PROSIX permissions
  *      bit15= free memory and return 1
  * @return
- *      1 on success,
+ *      2 ACL produced from POSIX permissions
+ *      1 ACL was read from node
  *      0 if the desire ACL type is not available
  *      < 0 on error
  *

libisofs/node.c

@@ -1421,7 +1421,8 @@ int iso_node_get_acl_text(IsoNode *node, char **text, int flag)
     size_t v_len;
     char **names = NULL, **values = NULL;
     unsigned char *v_data;
-    int ret;
+    int ret, from_posix= 0;
+    mode_t st_mode;
 
     if (flag & (1 << 15)) {
         if (*text != NULL)
@@ -1468,7 +1469,7 @@ int iso_node_get_acl_text(IsoNode *node, char **text, int flag)
             ret = 0;
             goto ex;
         }
-        *text = calloc(text_fill, 1);
+        *text = calloc(text_fill + 32, 1); /* 32 for aaip_update_acl_st_mode */
         if (*text == NULL) {
             ret = ISO_OUT_OF_MEM;
             goto ex;
@@ -1480,7 +1481,20 @@ int iso_node_get_acl_text(IsoNode *node, char **text, int flag)
         break;
     }
     
-    ret = (*text != NULL);
+    if (*text == NULL && !(flag & 16)) {
+        from_posix = 1;
+        *text = calloc(32, 1); /* 32 for aaip_update_acl_st_mode */
+    }
+    if (*text != NULL) {
+        st_mode = iso_node_get_permissions(node);
+        aaip_add_acl_st_mode(*text, st_mode, 0);
+        text_fill = strlen(*text);
+    }
+
+    if (text == NULL)
+        ret = 0;
+    else
+        ret = 1 + from_posix;
 ex:;
     iso_node_get_attrs(node, &num_attrs, &names,
                        &value_lengths, &values, 1 << 15); /* free memory */