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/*
* filelist.c
*
* Copyright (c) 2012-2013 Pacman Development Team <pacman-dev@archlinux.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <limits.h>
#include <string.h>
#include <sys/stat.h>
/* libalpm */
#include "filelist.h"
#include "util.h"
/** Helper function for comparing strings when sorting */
static int _alpm_filelist_strcmp(const void *s1, const void *s2)
{
return strcmp(*(char **)s1, *(char **)s2);
}
/* TODO make sure callers check the return value so we can bail on errors.
* For now we soldier on as best we can, skipping paths that are too long to
* resolve and using the original filenames on memory errors. */
/**
* @brief Resolves a symlink and its children.
*
* @attention Pre-condition: files must be sorted!
*
* @param files filelist to resolve
* @param i pointer to the index in files to start processing, will point to
* the last file processed on return
* @param path absolute path for the symlink being resolved
* @param root_len length of the root portion of path
* @param resolving is file \i in \files a symlink that needs to be resolved
*
* @return 0 on success, -1 on error
*/
int _alpm_filelist_resolve_link(alpm_filelist_t *files, size_t *i,
char *path, size_t root_len, int resolving)
{
char *causal_dir = NULL; /* symlink being resolved */
char *filename_r = NULL; /* resolved filename */
size_t causal_dir_len = 0, causal_dir_r_len = 0;
if(resolving) {
/* deal with the symlink being resolved */
MALLOC(filename_r, PATH_MAX, goto error);
causal_dir = files->files[*i].name;
causal_dir_len = strlen(causal_dir);
if(realpath(path, filename_r) == NULL) {
files->resolved_path[*i] = causal_dir;
FREE(filename_r);
return -1;
}
causal_dir_r_len = strlen(filename_r + root_len) + 1;
if(causal_dir_r_len >= PATH_MAX) {
files->resolved_path[*i] = causal_dir;
FREE(filename_r);
return -1;
}
/* remove root_r from filename_r */
memmove(filename_r, filename_r + root_len, causal_dir_r_len);
filename_r[causal_dir_r_len - 1] = '/';
filename_r[causal_dir_r_len] = '\0';
STRDUP(files->resolved_path[*i], filename_r, goto error);
(*i)++;
}
for(; *i < files->count; (*i)++) {
char *filename = files->files[*i].name;
size_t filename_len = strlen(filename);
size_t filename_r_len = filename_len;
struct stat sbuf;
int exists;
if(resolving) {
if(filename_len < causal_dir_len || strncmp(filename, causal_dir, causal_dir_len) != 0) {
/* not inside causal_dir anymore */
break;
}
filename_r_len = filename_len + causal_dir_r_len - causal_dir_len;
if(filename_r_len >= PATH_MAX) {
/* resolved path is too long */
files->resolved_path[*i] = filename;
continue;
}
strcpy(filename_r + causal_dir_r_len, filename + causal_dir_len);
}
/* deal with files and paths too long to resolve*/
if(filename[filename_len - 1] != '/' || root_len + filename_r_len >= PATH_MAX) {
if(resolving) {
STRDUP(files->resolved_path[*i], filename_r, goto error);
} else {
files->resolved_path[*i] = filename;
}
continue;
}
/* construct absolute path and stat() */
strcpy(path + root_len, resolving ? filename_r : filename);
exists = !_alpm_lstat(path, &sbuf);
/* deal with symlinks */
if(exists && S_ISLNK(sbuf.st_mode)) {
_alpm_filelist_resolve_link(files, i, path, root_len, 1);
continue;
}
/* deal with normal directories */
if(resolving) {
STRDUP(files->resolved_path[*i], filename_r, goto error);
} else {
files->resolved_path[*i] = filename;
}
/* deal with children of non-existent directories to reduce lstat() calls */
if(!exists) {
for((*i)++; *i < files->count; (*i)++) {
char *f = files->files[*i].name;
size_t f_len = strlen(f);
size_t f_r_len;
if(f_len < filename_len || strncmp(f, filename, filename_len) != 0) {
/* not inside the non-existent dir anymore */
break;
}
f_r_len = f_len + causal_dir_r_len - causal_dir_len;
if(resolving && f_r_len <= PATH_MAX) {
strcpy(filename_r + causal_dir_r_len, f + causal_dir_len);
STRDUP(files->resolved_path[*i], filename_r, goto error);
} else {
files->resolved_path[*i] = f;
}
}
(*i)--;
}
}
(*i)--;
FREE(filename_r);
return 0;
error:
FREE(filename_r);
/* out of memory, set remaining files to their original names */
for(; *i < files->count; (*i)++) {
files->resolved_path[*i] = files->files[*i].name;
}
(*i)--;
return -1;
}
/**
* @brief Takes a file list and resolves all directory paths according to the
* filesystem
*
* @attention Pre-condition: files must be sorted!
*
* @note A symlink and directory at the same path in two difference packages
* causes a conflict so the filepath can not change as packages get installed
*
* @param handle the context handle
* @param files list of files to resolve
*
* @return 0 on success, -1 on error
*/
int _alpm_filelist_resolve(alpm_handle_t *handle, alpm_filelist_t *files)
{
char path[PATH_MAX];
size_t root_len, i = 0;
int ret = 0;
if(!files || files->resolved_path) {
return 0;
}
CALLOC(files->resolved_path, files->count, sizeof(char *), return -1);
/* not much point in going on if we can't even resolve root */
if(realpath(handle->root, path) == NULL){
return -1;
}
root_len = strlen(path);
if(root_len + 1 >= PATH_MAX) {
return -1;
}
/* append '/' if root is not "/" */
if(path[root_len - 1] != '/') {
path[root_len] = '/';
root_len++;
path[root_len] = '\0';
}
ret = _alpm_filelist_resolve_link(files, &i, path, root_len, 0);
qsort(files->resolved_path, files->count, sizeof(char *),
_alpm_filelist_strcmp);
return ret;
}
/* Returns the difference of the provided two lists of files.
* Pre-condition: both lists are sorted!
* When done, free the list but NOT the contained data.
*/
alpm_list_t *_alpm_filelist_difference(alpm_filelist_t *filesA,
alpm_filelist_t *filesB)
{
alpm_list_t *ret = NULL;
size_t ctrA = 0, ctrB = 0;
while(ctrA < filesA->count && ctrB < filesB->count) {
char *strA = filesA->resolved_path[ctrA];
char *strB = filesB->resolved_path[ctrB];
int cmp = strcmp(strA, strB);
if(cmp < 0) {
/* item only in filesA, qualifies as a difference */
ret = alpm_list_add(ret, strA);
ctrA++;
} else if(cmp > 0) {
ctrB++;
} else {
ctrA++;
ctrB++;
}
}
/* ensure we have completely emptied pA */
while(ctrA < filesA->count) {
ret = alpm_list_add(ret, filesA->resolved_path[ctrA]);
ctrA++;
}
return ret;
}
/* Returns the intersection of the provided two lists of files.
* Pre-condition: both lists are sorted!
* When done, free the list but NOT the contained data.
*/
alpm_list_t *_alpm_filelist_intersection(alpm_filelist_t *filesA,
alpm_filelist_t *filesB)
{
alpm_list_t *ret = NULL;
size_t ctrA = 0, ctrB = 0;
while(ctrA < filesA->count && ctrB < filesB->count) {
int cmp, isdirA, isdirB;
char *strA, *strB;
isdirA = 0;
strA = filesA->resolved_path[ctrA];
if(strA[strlen(strA)-1] == '/') {
isdirA = 1;
strA = strndup(filesA->resolved_path[ctrA], strlen(strA)-1);
}
isdirB = 0;
strB = filesB->resolved_path[ctrB];
if(strB[strlen(strB)-1] == '/') {
isdirB = 1;
strB = strndup(filesB->resolved_path[ctrB], strlen(strB)-1);
}
cmp = strcmp(strA, strB);
if(cmp < 0) {
ctrA++;
} else if(cmp > 0) {
ctrB++;
} else {
/* TODO: this creates conflicts between a symlink to a directory in
* one package and a real directory in the other. For example,
* lib -> /usr/lib in pkg1 and /lib in pkg2. This would be allowed
* when installing one package at a time _provided_ pkg1 is installed
* first. This will need adjusted if the order of package install can
* be guaranteed to install the symlink first */
/* when not directories, item in both qualifies as an intersect */
if(! (isdirA && isdirB)) {
ret = alpm_list_add(ret, filesA->resolved_path[ctrA]);
}
ctrA++;
ctrB++;
}
if(isdirA) {
free(strA);
}
if(isdirB) {
free(strB);
}
}
return ret;
}
/* Helper function for comparing files list entries
*/
int _alpm_files_cmp(const void *f1, const void *f2)
{
const alpm_file_t *file1 = f1;
const alpm_file_t *file2 = f2;
return strcmp(file1->name, file2->name);
}
char *alpm_filelist_contains(alpm_filelist_t *filelist,
const char *path)
{
alpm_file_t key, *match;
if(!filelist) {
return NULL;
}
key.name = (char *)path;
match = bsearch(&key, filelist->files, filelist->count,
sizeof(alpm_file_t), _alpm_files_cmp);
if(match) {
return match->name;
} else if(filelist->resolved_path) {
return bsearch(&path, filelist->resolved_path, filelist->count,
sizeof(char *), _alpm_filelist_strcmp);
} else {
return NULL;
}
}
/* vim: set ts=2 sw=2 noet: */
|