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libisofs/libisofs/aaip-os-linux.c

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/*
aaip-os-linux.c
Arbitrary Attribute Interchange Protocol , system adapter for getting and
setting of ACLs and xattr.
To be included by aaip_0_2.c
Copyright (c) 2009 Thomas Schmitt, libburnia project, GPLv2+
*/
#ifdef HAVE_CONFIG_H
#include "../config.h"
#endif
#include <ctype.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <sys/stat.h>
#include <errno.h>
#ifdef Libisofs_with_aaip_acL
#include <sys/acl.h>
#endif
#ifdef Libisofs_with_aaip_xattR
#include <attr/xattr.h>
#endif
/* ------------------------------ Getters --------------------------------- */
/* Obtain the ACL of the given file in long text form.
@param path Path to the file
@param text Will hold the result. This is a managed object which
finally has to be freed by a call to this function
with bit15 of flag.
@param flag Bitfield for control purposes
bit0= obtain default ACL rather than access ACL
behave like bit4 if ACL is empty
bit4= set *text = NULL and return 2
if the ACL matches st_mode permissions.
bit5= in case of symbolic link: inquire link target
bit15= free text and return 1
@return 1 ok
2 only st_mode permissions exist and bit 4 is set
or empty ACL and bit0 is set
0 ACL support not enabled at compile time
or filesystem does not support ACL
-1 failure of system ACL service (see errno)
-2 attempt to inquire ACL of a symbolic link without
bit4 or bit5 resp. with no suitable link target
*/
int aaip_get_acl_text(char *path, char **text, int flag)
{
#ifdef Libisofs_with_aaip_acL
acl_t acl= NULL;
struct stat stbuf;
int ret;
if(flag & (1 << 15)) {
if(*text != NULL)
acl_free(*text);
*text= NULL;
return(1);
}
*text= NULL;
if(flag & 32)
ret= stat(path, &stbuf);
else
ret= lstat(path, &stbuf);
if(ret == -1)
return(-1);
if((stbuf.st_mode & S_IFMT) == S_IFLNK) {
if(flag & 16)
return(2);
return(-2);
}
acl= acl_get_file(path, (flag & 1) ? ACL_TYPE_DEFAULT : ACL_TYPE_ACCESS);
if(acl == NULL) {
if(errno == ENOTSUP) {
/* filesystem does not support ACL */
if(flag & 16)
return(2);
/* >>> ??? fake ACL from POSIX permissions ? */;
return(0);
}
return(-1);
}
*text= acl_to_text(acl, NULL);
acl_free(acl);
if(*text == NULL)
return(-1);
if(flag & 16) {
ret = aaip_cleanout_st_mode(*text, &(stbuf.st_mode), 2);
if(!(ret & (7 | 64)))
(*text)[0]= 0;
}
if(flag & (1 | 16)) {
if((*text)[0] == 0 || strcmp(*text, "\n") == 0) {
acl_free(*text);
*text= NULL;
return(2);
}
}
return(1);
#else /* Libisofs_with_aaip_acL */
return(0);
#endif /* ! Libisofs_with_aaip_acL */
}
/* Obtain the Extended Attributes and/or the ACLs of the given file in a form
that is ready for aaip_encode().
@param path Path to the file
@param num_attrs Will return the number of name-value pairs
@param names Will return an array of pointers to 0-terminated names
@param value_lengths Will return an arry with the lenghts of values
@param values Will return an array of pointers to 8-bit values
@param flag Bitfield for control purposes
bit0= obtain ACL (access and eventually default)
bit1= use numeric ACL qualifiers rather than names
bit2= do not obtain attributes other than ACL
bit3= do not ignore eventual non-user attributes
I.e. those with a name which does not begin
by "user."
bit4= do not return trivial ACL that matches st_mode
bit5= in case of symbolic link: inquire link target
bit15= free memory of names, value_lengths, values
@return >0 ok
<=0 error
*/
int aaip_get_attr_list(char *path, size_t *num_attrs, char ***names,
size_t **value_lengths, char ***values, int flag)
{
int ret;
char *list= NULL;
ssize_t list_size= 0, i, num_names= 0;
unsigned char *acl= NULL;
char *a_acl_text= NULL, *d_acl_text= NULL;
#ifdef Libisofs_with_aaip_acL
size_t acl_len= 0;
#endif
#ifdef Libisofs_with_aaip_xattR
ssize_t value_ret, retry= 0;
#endif
if(flag & (1 << 15)) { /* Free memory */
{ret= 1; goto ex;}
}
*num_attrs= 0;
*names= NULL;
*value_lengths= NULL;
*values= NULL;
/* Set up arrays */
if(!(flag & 4)) { /* Get xattr names */
#ifdef Libisofs_with_aaip_xattR
if(flag & 32)
list_size= listxattr(path, list, 0);
else
list_size= llistxattr(path, list, 0);
if(list_size == -1)
{ret= -1; goto ex;}
list= calloc(list_size, 1);
if(list == NULL)
{ret= -1; goto ex;}
if(flag & 32)
list_size= listxattr(path, list, list_size);
else
list_size= llistxattr(path, list, list_size);
if(list_size == -1)
{ret= -1; goto ex;}
#else /* Libisofs_with_aaip_xattR */
list= strdup("");
#endif /* ! Libisofs_with_aaip_xattR */
for(i= 0; i < list_size; i+= strlen(list + i) + 1)
num_names++;
}
#ifdef Libisofs_with_aaip_acL
if(flag & 1)
num_names++;
#endif
if(num_names == 0)
{ret= 1; goto ex;}
(*names)= calloc(num_names, sizeof(char *));
(*value_lengths)= calloc(num_names, sizeof(size_t));
(*values)= calloc(num_names, sizeof(char *));
if(*names == NULL || *value_lengths == NULL || *values == NULL)
{ret= -1; goto ex;}
for(i= 0; i < num_names; i++) {
(*names)[i]= NULL;
(*values)[i]= NULL;
(*value_lengths)[i]= 0;
}
if(!(flag & 4)) {
for(i= 0; i < list_size && num_names > *num_attrs;
i+= strlen(list + i) + 1) {
if(!(flag & 8))
if(strncmp(list + i, "user.", 5))
continue;
(*names)[(*num_attrs)++]= strdup(list + i);
if((*names)[(*num_attrs) - 1] == NULL)
{ret= -1; goto ex;}
}
}
#ifdef Libisofs_with_aaip_xattR
if(!(flag & 4)) { /* Get xattr values */
for(i= 0; i < *num_attrs; i++) {
if(!(flag & 8))
if(strncmp((*names)[i], "user.", 5))
continue;
if(flag & 32)
value_ret= getxattr(path, (*names)[i], NULL, 0);
else
value_ret= lgetxattr(path, (*names)[i], NULL, 0);
if(value_ret == -1)
continue;
(*values)[i]= calloc(value_ret + 1, 1);
if((*values)[i] == NULL)
{ret= -1; goto ex;}
if(flag & 32)
value_ret= getxattr(path, (*names)[i], (*values)[i], value_ret);
else
value_ret= lgetxattr(path, (*names)[i], (*values)[i], value_ret);
if(value_ret == -1) { /* there could be a race condition */
if(retry++ > 5)
{ret= -1; goto ex;}
i--;
continue;
}
(*value_lengths)[i]= value_ret;
retry= 0;
}
}
#endif /* Libisofs_with_aaip_xattR */
#ifdef Libisofs_with_aaip_acL
if(flag & 1) { /* Obtain ACL */
aaip_get_acl_text(path, &a_acl_text, flag & (16 | 32));
aaip_get_acl_text(path, &d_acl_text, 1 | (flag & 32));
if(a_acl_text == NULL && d_acl_text == NULL)
{ret= 1; goto ex;}
ret= aaip_encode_both_acl(a_acl_text, d_acl_text, (mode_t) 0,
&acl_len, &acl, (flag & 2));
if(ret <= 0)
goto ex;
/* Set as attribute with empty name */;
(*names)[*num_attrs]= strdup("");
if((*names)[*num_attrs] == NULL)
{ret= -1; goto ex;}
(*values)[*num_attrs]= (char *) acl;
acl= NULL;
(*value_lengths)[*num_attrs]= acl_len;
(*num_attrs)++;
}
#endif /* Libisofs_with_aaip_acL */
ret= 1;
ex:;
if(a_acl_text != NULL)
aaip_get_acl_text("", &a_acl_text, 1 << 15); /* free */
if(d_acl_text != NULL)
aaip_get_acl_text("", &d_acl_text, 1 << 15); /* free */
if(ret <= 0 || (flag & (1 << 15))) {
if(list != NULL)
free(list);
if(*names != NULL) {
for(i= 0; i < *num_attrs; i++)
free((*names)[i]);
free(*names);
}
*names= NULL;
if(*value_lengths != NULL)
free(*value_lengths);
*value_lengths= NULL;
if(*values != NULL) {
for(i= 0; i < *num_attrs; i++)
free((*values)[i]);
free(*values);
}
if(acl != NULL)
free(acl);
*values= NULL;
*num_attrs= 0;
}
return(ret);
}
/* ------------------------------ Setters --------------------------------- */
/* Set the ACL of the given file to a given list in long text form.
@param path Path to the file
@param text The input text (0 terminated, ACL long text form)
@param flag Bitfield for control purposes
bit0= set default ACL rather than access ACL
bit5= in case of symbolic link: manipulate link target
@return >0 ok
0 ACL support not enabled at compile time
-1 failure of system ACL service (see errno)
-2 attempt to manipulate ACL of a symbolic link
without bit5 resp. with no suitable link target
*/
int aaip_set_acl_text(char *path, char *text, int flag)
{
#ifdef Libisofs_with_aaip_acL
int ret;
acl_t acl= NULL;
struct stat stbuf;
if(flag & 32)
ret= stat(path, &stbuf);
else
ret= lstat(path, &stbuf);
if(ret == -1)
return(-1);
if((stbuf.st_mode & S_IFMT) == S_IFLNK)
return(-2);
acl= acl_from_text(text);
if(acl == NULL) {
ret= -1; goto ex;
}
ret= acl_set_file(path, (flag & 1) ? ACL_TYPE_DEFAULT : ACL_TYPE_ACCESS, acl);
if(ret == -1)
goto ex;
ret= 1;
ex:
if(acl != NULL)
acl_free(acl);
return(ret);
#else /* Libisofs_with_aaip_acL */
return(0);
#endif /* ! Libisofs_with_aaip_acL */
}
/* Bring the given attributes and/or ACLs into effect with the given file.
@param flag Bitfield for control purposes
bit0= decode and set ACLs
bit1= first clear all existing attributes of the file
bit2= do not set attributes other than ACLs
bit3= do not ignore eventual non-user attributes.
I.e. those with a name which does not begin
by "user."
bit5= in case of symbolic link: manipulate link target
@return 1 success
-1 error memory allocation
-2 error with decoding of ACL
-3 error with setting ACL
-4 error with setting attribute
-5 error with deleting attributes
-6 support of xattr not enabled at compile time
-7 support of ACL not enabled at compile time
*/
int aaip_set_attr_list(char *path, size_t num_attrs, char **names,
size_t *value_lengths, char **values, int flag)
{
int ret, has_default_acl= 0;
size_t i, consumed, acl_text_fill, acl_idx= 0, h_consumed;
char *acl_text= NULL, *list= NULL;
#ifdef Libisofs_with_aaip_xattR
size_t list_size= 0;
#endif
#ifdef Libisofs_with_aaip_xattR
if(flag & 2) { /* Delete all file attributes */
if(flag & 32)
list_size= listxattr(path, list, 0);
else
list_size= llistxattr(path, list, 0);
}
if(list_size > 0) { /* Delete all file attributes */
list= calloc(list_size, 1);
if(list == NULL)
{ret= -5; goto ex;}
if(flag & 32)
list_size= listxattr(path, list, list_size);
else
list_size= llistxattr(path, list, list_size);
if(list_size == -1)
{ret= -5; goto ex;}
for(i= 0; i < list_size; i+= strlen(list + i) + 1) {
if(!(flag & 8))
if(strncmp(list + i, "user.", 5))
continue;
if(flag & 32)
ret= removexattr(path, list + i);
else
ret= lremovexattr(path, list + i);
if(ret == -1)
{ret= -5; goto ex;}
}
free(list); list= NULL;
}
#endif /* Libisofs_with_aaip_xattR */
for(i= 0; i < num_attrs; i++) {
if(names[i] == NULL || values[i] == NULL)
continue;
if(names[i][0] == 0) { /* ACLs */
if(flag & 1)
acl_idx= i + 1;
continue;
}
/* Extended Attribute */
if((flag & 1) && !(flag & 8))
if(strncmp(names[i], "user.", 5))
continue;
#ifdef Libisofs_with_aaip_xattR
if(flag & 32)
ret= setxattr(path, names[i], values[i], value_lengths[i], 0);
else
ret= lsetxattr(path, names[i], values[i], value_lengths[i], 0);
if(ret == -1)
{ret= -4; goto ex;}
#else
{ret= -6; goto ex;}
#endif /* Libisofs_with_aaip_xattR */
}
/* Decode ACLs */
if(acl_idx == 0)
{ret= 1; goto ex;}
i= acl_idx - 1;
/* "access" ACL */
ret= aaip_decode_acl((unsigned char *) values[i], value_lengths[i],
&consumed, NULL, 0, &acl_text_fill, 1);
if(ret <= 0)
{ret= -2; goto ex;}
acl_text= calloc(acl_text_fill, 1);
if(acl_text == NULL)
{ret= -1; goto ex;}
ret= aaip_decode_acl((unsigned char *) values[i], value_lengths[i],
&consumed, acl_text, acl_text_fill, &acl_text_fill, 0);
if(ret <= 0)
{ret= -2; goto ex;}
has_default_acl= (ret == 2);
#ifdef Libisofs_with_aaip_acL
ret= aaip_set_acl_text(path, acl_text, flag & 32);
if(ret <= 0)
{ret= -3; goto ex;}
#else
{ret= -7; goto ex;}
#endif
/* "default" ACL */
if(has_default_acl) {
free(acl_text);
acl_text= NULL;
ret= aaip_decode_acl((unsigned char *) (values[i] + consumed),
value_lengths[i] - consumed, &h_consumed,
NULL, 0, &acl_text_fill, 1);
if(ret <= 0)
{ret= -2; goto ex;}
acl_text= calloc(acl_text_fill, 1);
if(acl_text == NULL)
{ret= -1; goto ex;}
ret= aaip_decode_acl((unsigned char *) (values[i] + consumed),
value_lengths[i] - consumed, &h_consumed,
acl_text, acl_text_fill, &acl_text_fill, 0);
if(ret <= 0)
{ret= -2; goto ex;}
ret= aaip_set_acl_text(path, acl_text, 1 | (flag & 32));
if(ret <= 0)
{ret= -3; goto ex;}
}
ret= 1;
ex:;
if(acl_text != NULL)
free(acl_text);
if(list != NULL)
free(list);
return(ret);
}
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