From 7698bfd9807600ee164a896a44aad2417382cfac Mon Sep 17 00:00:00 2001
From: Yorhel <git@yorhel.nl>
Date: Thu, 23 Apr 2009 19:44:37 +0200
Subject: [PATCH] Split path handling into path.c and replaced rpath() with a
better implementation
This is the first step into replacing all code that relies on PATH_MAX,
more changes will follow.
---
src/Makefile.am | 4 +-
src/calc.c | 124 +-----------------------
src/path.c | 243 ++++++++++++++++++++++++++++++++++++++++++++++++
src/path.h | 47 ++++++++++
4 files changed, 296 insertions(+), 122 deletions(-)
create mode 100644 src/path.c
create mode 100644 src/path.h
diff --git a/src/Makefile.am b/src/Makefile.am
index e9d0b52..0a3764a 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,5 +1,5 @@
bin_PROGRAMS = ncdu
-ncdu_SOURCES = browser.c calc.c delete.c exclude.c help.c main.c util.c
+ncdu_SOURCES = browser.c calc.c delete.c exclude.c help.c main.c path.c util.c
-noinst_HEADERS = browser.h calc.h delete.h exclude.h help.h ncdu.h util.h
+noinst_HEADERS = browser.h calc.h delete.h exclude.h help.h ncdu.h path.h util.h
diff --git a/src/calc.c b/src/calc.c
index 8db2d91..ee97de7 100644
--- a/src/calc.c
+++ b/src/calc.c
@@ -28,6 +28,7 @@
#include "exclude.h"
#include "util.h"
#include "browser.h"
+#include "path.h"
#include <string.h>
#include <stdlib.h>
@@ -45,21 +46,6 @@
# define S_BLKSIZE 512
#endif
-#ifndef LINK_MAX
-# ifdef _POSIX_LINK_MAX
-# define LINK_MAX _POSIX_LINK_MAX
-# else
-# define LINK_MAX 32
-# endif
-#endif
-
-#ifndef S_ISLNK
-# ifndef S_IFLNK
-# define S_IFLNK 0120000
-# endif
-# define S_ISLNK(x) (x & S_IFLNK)
-#endif
-
/* external vars */
int calc_delay = 100;
@@ -77,107 +63,6 @@ long lastupdate; /* time of the last screen update */
int anpos; /* position of the animation string */
-/* My own implementation of realpath()
- - assumes that *every* possible path fits in PATH_MAX bytes
- - does not set errno on error
- - has not yet been fully tested
-*/
-char *rpath(const char *from, char *to) {
- char tmp[PATH_MAX], cwd[PATH_MAX], cur[PATH_MAX], app[PATH_MAX];
- int i, j, l, k, last, ll = 0;
- struct stat st;
-
- getcwd(cwd, PATH_MAX);
- strcpy(cur, from);
- app[0] = 0;
-
- loop:
- /* not an absolute path, add current directory */
- if(cur[0] != '/') {
- if(!(cwd[0] == '/' && cwd[1] == 0))
- strcpy(tmp, cwd);
- else
- tmp[0] = 0;
- if(strlen(cur) + 2 > PATH_MAX - strlen(tmp))
- return(NULL);
- strcat(tmp, "/");
- strcat(tmp, cur);
- } else
- strcpy(tmp, cur);
-
- /* now fix things like '.' and '..' */
- i = j = last = 0;
- l = strlen(tmp);
- while(1) {
- if(tmp[i] == 0)
- break;
- /* . */
- if(l >= i+2 && tmp[i] == '/' && tmp[i+1] == '.' && (tmp[i+2] == 0 || tmp[i+2] == '/')) {
- i+= 2;
- continue;
- }
- /* .. */
- if(l >= i+3 && tmp[i] == '/' && tmp[i+1] == '.' && tmp[i+2] == '.' && (tmp[i+3] == 0 || tmp[i+3] == '/')) {
- for(k=j; --k>0;)
- if(to[k] == '/' && k != j-1)
- break;
- j -= j-k;
- if(j < 1) j = 1;
- i += 3;
- continue;
- }
- /* remove double slashes */
- if(tmp[i] == '/' && i>0 && tmp[i-1] == '/') {
- i++;
- continue;
- }
- to[j++] = tmp[i++];
- }
- /* remove leading slashes */
- while(--j > 0) {
- if(to[j] != '/')
- break;
- }
- to[j+1] = 0;
- /* make sure we do have something left in case our path is / */
- if(to[0] == 0) {
- to[0] = '/';
- to[1] = 0;
- }
- /* append 'app' */
- if(app[0] != 0)
- strcat(to, app);
-
- j = strlen(to);
- /* check for symlinks */
- for(i=1; i<=j; i++) {
- if(to[i] == '/' || to[i] == 0) {
- strncpy(tmp, to, i);
- tmp[i] = 0;
- if(lstat(tmp, &st) < 0)
- return(NULL);
- if(S_ISLNK(st.st_mode)) {
- if(++ll > LINK_MAX || (k = readlink(tmp, cur, PATH_MAX)) < 0)
- return(NULL);
- cur[k] = 0;
- if(to[i] != 0)
- strcpy(app, &to[i]);
- strcpy(cwd, tmp);
- for(k=strlen(cwd); --k>0;)
- if(cwd[k] == '/')
- break;
- cwd[k] = 0;
- goto loop;
- }
- if(!S_ISDIR(st.st_mode))
- return(NULL);
- }
- }
-
- return(to);
-}
-
-
int calc_item(struct dir *par, char *path, char *name) {
char tmp[PATH_MAX];
struct dir *t, *d;
@@ -400,12 +285,12 @@ int calc_key(int ch) {
void calc_process() {
- char tmp[PATH_MAX];
+ char *tmp;
struct stat fs;
struct dir *t;
/* check root directory */
- if(rpath(curpath, tmp) == NULL || lstat(tmp, &fs) != 0 || !S_ISDIR(fs.st_mode)) {
+ if((tmp = path_real(curpath)) == NULL || lstat(tmp, &fs) != 0 || !S_ISDIR(fs.st_mode)) {
failed = 1;
strcpy(errmsg, "Directory not found");
goto fail;
@@ -416,8 +301,7 @@ void calc_process() {
t->size = fs.st_blocks * S_BLKSIZE;
t->asize = fs.st_size;
t->flags |= FF_DIR;
- t->name = (char *) malloc(strlen(tmp)+1);
- strcpy(t->name, orig ? orig->name : tmp);
+ t->name = tmp;
root = t;
curdev = fs.st_dev;
diff --git a/src/path.c b/src/path.c
new file mode 100644
index 0000000..6d07d3d
--- /dev/null
+++ b/src/path.c
@@ -0,0 +1,243 @@
+/* ncdu - NCurses Disk Usage
+
+ Copyright (c) 2007-2009 Yoran Heling
+
+ Permission is hereby granted, free of charge, to any person obtaining
+ a copy of this software and associated documentation files (the
+ "Software"), to deal in the Software without restriction, including
+ without limitation the rights to use, copy, modify, merge, publish,
+ distribute, sublicense, and/or sell copies of the Software, and to
+ permit persons to whom the Software is furnished to do so, subject to
+ the following conditions:
+
+ The above copyright notice and this permission notice shall be included
+ in all copies or substantial portions of the Software.
+
+ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+*/
+
+#include "path.h"
+
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <unistd.h>
+#include <limits.h>
+#include <dirent.h>
+
+#ifndef LINK_MAX
+# ifdef _POSIX_LINK_MAX
+# define LINK_MAX _POSIX_LINK_MAX
+# else
+# define LINK_MAX 32
+# endif
+#endif
+
+
+#define RPATH_CNKSZ 256
+
+
+/* splits a path into components and does a bit of cannonicalization.
+ a pointer to a reversed array of components is stored in res and the
+ number of components is returned.
+ cur is modified, and res has to be free()d after use */
+int path_split(char *cur, char ***res) {
+ char **old;
+ int i, j, n;
+
+ cur += strspn(cur, "/");
+ n = strlen(cur);
+
+ /* replace slashes with zeros */
+ for(i=j=0; i<n; i++)
+ if(cur[i] == '/') {
+ cur[i] = 0;
+ if(cur[i-1] != 0)
+ j++;
+ }
+
+ /* create array of the components */
+ old = malloc((j+1)*sizeof(char *));
+ *res = malloc((j+1)*sizeof(char *));
+ for(i=j=0; i<n; i++)
+ if(i == 0 || (cur[i-1] == 0 && cur[i] != 0))
+ old[j++] = cur+i;
+
+ /* re-order and remove parts */
+ for(i=n=0; --j>=0; ) {
+ if(!strcmp(old[j], "..")) {
+ n++;
+ continue;
+ }
+ if(!strcmp(old[j], "."))
+ continue;
+ if(n) {
+ n--;
+ continue;
+ }
+ (*res)[i++] = old[j];
+ }
+ free(old);
+ return i;
+}
+
+
+/* copies path and prepends cwd if needed, to ensure an absolute path
+ return value has to be free()'d manually */
+char *path_absolute(const char *path) {
+ int i, n;
+ char *ret;
+
+ /* not an absolute path? prepend cwd */
+ if(path[0] != '/') {
+ n = RPATH_CNKSZ;
+ ret = malloc(n);
+ errno = 0;
+ while(!getcwd(ret, n) && errno == ERANGE) {
+ n += RPATH_CNKSZ;
+ ret = realloc(ret, n);
+ errno = 0;
+ }
+ if(errno) {
+ free(ret);
+ return NULL;
+ }
+
+ i = strlen(path) + strlen(ret) + 2;
+ if(i > n)
+ ret = realloc(ret, i);
+ strcat(ret, "/");
+ strcat(ret, path);
+ /* otherwise, just make a copy */
+ } else {
+ ret = malloc(strlen(path)+1);
+ strcpy(ret, path);
+ }
+ return ret;
+}
+
+
+/* NOTE: cwd and the memory cur points to are unreliable after calling this function */
+char *path_real_rec(char *cur, int *links) {
+ int i, j, n, tmpl, lnkl = 0;
+ char **arr, *tmp, *lnk, *ret = NULL;
+
+ tmpl = strlen(cur);
+ tmp = malloc(tmpl);
+
+ /* split path */
+ i = path_split(cur, &arr);
+
+ /* re-create full path */
+ strcpy(tmp, "/");
+ if(i > 0) {
+ j = 1;
+ lnkl = RPATH_CNKSZ;
+ lnk = malloc(lnkl);
+ if(chdir("/") < 0)
+ goto path_real_done;
+ }
+
+ while(--i>=0) {
+ if(arr[i][0] == 0)
+ continue;
+ /* check for symlink */
+ while((n = readlink(arr[i], lnk, lnkl)) == lnkl || (n < 0 && errno == ERANGE)) {
+ lnkl += RPATH_CNKSZ;
+ lnk = realloc(lnk, lnkl);
+ }
+ if(n < 0 && errno != EINVAL)
+ goto path_real_done;
+ if(n > 0) {
+ if(++*links > LINK_MAX) {
+ errno = ELOOP;
+ goto path_real_done;
+ }
+ lnk[n] = 0;
+ /* create new path and call path_real_rec() again */
+ if(lnk[0] != '/') {
+ n += strlen(tmp) + 1;
+ if(tmpl < n) {
+ tmpl = n;
+ tmp = realloc(tmp, tmpl);
+ }
+ strcat(tmp, lnk);
+ } else
+ strcpy(tmp, lnk);
+ ret = path_real_rec(tmp, links);
+ goto path_real_done;
+ }
+ /* not a symlink, append component and go to the next part */
+ strcat(tmp, arr[i]);
+ if(i) {
+ if(chdir(arr[i]) < 0)
+ goto path_real_done;
+ strcat(tmp, "/");
+ }
+ }
+ ret = tmp;
+
+path_real_done:
+ if(ret != tmp)
+ free(tmp);
+ if(lnkl > 0)
+ free(lnk);
+ free(arr);
+ return ret;
+}
+
+
+char *path_real(const char *orig) {
+ int links = 0;
+ char *tmp, *ret;
+ DIR *d;
+
+ if(orig == NULL)
+ return NULL;
+ if((d = opendir(".")) == NULL)
+ return NULL;
+
+ tmp = path_absolute(orig);
+ ret = path_real_rec(tmp, &links);
+ free(tmp);
+ fchdir(dirfd(d));
+ closedir(d);
+ return ret;
+}
+
+
+int path_chdir(const char *path) {
+ char **arr, *cur;
+ int i, r = -1;
+ DIR *d;
+
+ if((d = opendir(".")) == NULL)
+ return -1;
+
+ if((cur = path_absolute(path)) == NULL)
+ return -1;
+
+ i = path_split(cur, &arr);
+ if(chdir("/") < 0)
+ goto path_chdir_done;
+ while(--i >= 0)
+ if(chdir(arr[i]) < 0)
+ goto path_chdir_done;
+ r = 0;
+
+path_chdir_done:
+ if(r < 0)
+ fchdir(dirfd(d));
+ free(cur);
+ free(arr);
+ return r;
+}
+
diff --git a/src/path.h b/src/path.h
new file mode 100644
index 0000000..c3312eb
--- /dev/null
+++ b/src/path.h
@@ -0,0 +1,47 @@
+/* ncdu - NCurses Disk Usage
+
+ Copyright (c) 2007-2009 Yoran Heling
+
+ Permission is hereby granted, free of charge, to any person obtaining
+ a copy of this software and associated documentation files (the
+ "Software"), to deal in the Software without restriction, including
+ without limitation the rights to use, copy, modify, merge, publish,
+ distribute, sublicense, and/or sell copies of the Software, and to
+ permit persons to whom the Software is furnished to do so, subject to
+ the following conditions:
+
+ The above copyright notice and this permission notice shall be included
+ in all copies or substantial portions of the Software.
+
+ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+*/
+/*
+ path.c reimplements realpath() and chdir(), both functions accept
+ arbitrary long path names not limited by PATH_MAX.
+
+ Caveats/bugs:
+ - path_real uses chdir(), so it's not thread safe
+ - Process requires +x access for all directory components
+ - Potentionally slow
+ - Doesn't check return value of malloc() and realloc()
+ - path_real doesn't check for the existance of the last component
+*/
+
+#ifndef _path_h
+#define _path_h
+
+/* path_real reimplements realpath(). The returned string is allocated
+ by malloc() and should be manually free()d by the programmer. */
+extern char *path_real(const char *);
+
+/* works exactly the same as chdir() */
+extern int path_chdir(const char *);
+
+#endif
--
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