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Add ‘soft(un)link’ commands.
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Soft symbolic links are only effective when original path was not found
in the first place. Can be used to redirect missing content to safer
defaults.
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@skullernet
skullernet committed Dec 8, 2012
1 parent c4aeb5e commit 84e0b00
Showing 1 changed file with 124 additions and 55 deletions.
179 changes: 124 additions & 55 deletions src/common/files.c
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Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
*/

#include "shared/shared.h"
#include "shared/list.h"
#include "common/common.h"
#include "common/cvar.h"
#include "common/error.h"
Expand Down Expand Up @@ -72,6 +73,12 @@ QUAKE FILESYSTEM

#define PATH_NOT_CHECKED -1

#define FOR_EACH_SYMLINK(link, list) \
LIST_FOR_EACH(symlink_t, link, list, entry)

#define FOR_EACH_SYMLINK_SAFE(link, next, list) \
LIST_FOR_EACH_SAFE(symlink_t, link, next, list, entry)

//
// in memory
//
Expand Down Expand Up @@ -143,8 +150,8 @@ typedef struct {
size_t length; // total cached file length
} file_t;

typedef struct symlink_s {
struct symlink_s *next;
typedef struct {
list_t entry;
size_t targlen;
size_t namelen;
char *target;
Expand All @@ -158,7 +165,8 @@ char fs_gamedir[MAX_OSPATH];
static searchpath_t *fs_searchpaths;
static searchpath_t *fs_base_searchpaths;

static symlink_t *fs_links;
static list_t fs_hard_links;
static list_t fs_soft_links;

static file_t fs_files[MAX_FILE_HANDLES];

Expand Down Expand Up @@ -434,12 +442,12 @@ static void cleanup_path(char *s)
}

// expects a buffer of at least MAX_OSPATH bytes!
static symlink_t *expand_links(char *buffer, size_t *len_p)
static symlink_t *expand_links(list_t *list, char *buffer, size_t *len_p)
{
symlink_t *link;
size_t namelen = *len_p;

for (link = fs_links; link; link = link->next) {
FOR_EACH_SYMLINK(link, list) {
if (link->namelen > namelen) {
continue;
}
Expand Down Expand Up @@ -1286,35 +1294,19 @@ static ssize_t open_from_disk(file_t *file, const char *fullpath)
// Finds the file in the search path.
// Fills file_t and returns file length.
// Used for streaming data out of either a pak file or a seperate file.
static ssize_t open_file_read(file_t *file, const char *name, qboolean unique)
static ssize_t open_file_read(file_t *file, const char *normalized, size_t namelen, qboolean unique)
{
char normalized[MAX_OSPATH], fullpath[MAX_OSPATH];
char fullpath[MAX_OSPATH];
searchpath_t *search;
pack_t *pak;
unsigned hash;
packfile_t *entry;
ssize_t ret;
int valid;
size_t len, namelen;
size_t len;

FS_COUNT_READ;

// normalize path
namelen = FS_NormalizePathBuffer(normalized, name, MAX_OSPATH);
if (namelen >= MAX_OSPATH) {
return Q_ERR_NAMETOOLONG;
}

// expand symlinks
if (expand_links(normalized, &namelen) && namelen >= MAX_OSPATH) {
return Q_ERR_NAMETOOLONG;
}

// reject empty paths
if (namelen == 0) {
return Q_ERR_NAMETOOSHORT;
}

hash = FS_HashPath(normalized, 0);

valid = PATH_NOT_CHECKED;
Expand Down Expand Up @@ -1395,6 +1387,43 @@ static ssize_t open_file_read(file_t *file, const char *name, qboolean unique)
return ret;
}

// Normalizes quake path, expands symlinks
static ssize_t expand_open_file_read(file_t *file, const char *name, qboolean unique)
{
char normalized[MAX_OSPATH];
ssize_t ret;
size_t namelen;

// normalize path
namelen = FS_NormalizePathBuffer(normalized, name, MAX_OSPATH);
if (namelen >= MAX_OSPATH) {
return Q_ERR_NAMETOOLONG;
}

// expand hard symlinks
if (expand_links(&fs_hard_links, normalized, &namelen) && namelen >= MAX_OSPATH) {
return Q_ERR_NAMETOOLONG;
}

// reject empty paths
if (namelen == 0) {
return Q_ERR_NAMETOOSHORT;
}

ret = open_file_read(file, normalized, namelen, unique);
if (ret == Q_ERR_NOENT) {
// expand soft symlinks
if (expand_links(&fs_soft_links, normalized, &namelen)) {
if (namelen >= MAX_OSPATH) {
return Q_ERR_NAMETOOLONG;
}
ret = open_file_read(file, normalized, namelen, unique);
}
}

return ret;
}

static ssize_t read_pak_file(file_t *file, void *buf, size_t len)
{
size_t result;
Expand Down Expand Up @@ -1608,7 +1637,7 @@ ssize_t FS_FOpenFile(const char *name, qhandle_t *f, unsigned mode)
file->mode = mode;

if ((mode & FS_MODE_MASK) == FS_MODE_READ) {
ret = open_file_read(file, name, qtrue);
ret = expand_open_file_read(file, name, qtrue);
} else {
ret = open_file_write(file, name);
}
Expand Down Expand Up @@ -1783,7 +1812,7 @@ ssize_t FS_LoadFileEx(const char *path, void **buffer, unsigned flags, memtag_t
file->mode = (flags & ~FS_MODE_MASK) | FS_MODE_READ;

// look for it in the filesystem or pack files
len = open_file_read(file, path, qfalse);
len = expand_open_file_read(file, path, qfalse);
if (len < 0) {
return len;
}
Expand Down Expand Up @@ -2914,7 +2943,7 @@ static void FS_Dir_f(void)
============
FS_WhereIs_f
Verbosely looks up a filename with exactly the same logic as open_file_read.
Verbosely looks up a filename with exactly the same logic as expand_open_file_read.
============
*/
static void FS_WhereIs_f(void)
Expand Down Expand Up @@ -2943,8 +2972,8 @@ static void FS_WhereIs_f(void)
return;
}

// expand symlinks
link = expand_links(normalized, &namelen);
// expand hard symlinks
link = expand_links(&fs_hard_links, normalized, &namelen);
if (link) {
if (namelen >= MAX_OSPATH) {
Com_Printf("Oversize symbolic link ('%s --> '%s').\n",
Expand All @@ -2956,22 +2985,25 @@ static void FS_WhereIs_f(void)
link->name, link->target);
}

report_all = Cmd_Argc() >= 3;
total = 0;
link = NULL;

// reject empty paths
if (namelen == 0) {
Com_Printf("Refusing to lookup empty path.\n");
return;
}

recheck:

// warn about non-standard path length
if (namelen >= MAX_QPATH) {
Com_Printf("Not searching for '%s' in pack files "
"since path length exceedes %d characters.\n",
normalized, MAX_QPATH - 1);
}

report_all = Cmd_Argc() >= 3;
total = 0;

hash = FS_HashPath(normalized, 0);

valid = PATH_NOT_CHECKED;
Expand Down Expand Up @@ -3054,6 +3086,22 @@ static void FS_WhereIs_f(void)
}
}

if ((total == 0 || report_all) && link == NULL) {
// expand soft symlinks
link = expand_links(&fs_soft_links, normalized, &namelen);
if (link) {
if (namelen >= MAX_OSPATH) {
Com_Printf("Oversize symbolic link ('%s --> '%s').\n",
link->name, link->target);
return;
}

Com_Printf("Symbolic link ('%s' --> '%s') in effect.\n",
link->name, link->target);
goto recheck;
}
}

if (total) {
Com_Printf("%d instances of %s\n", total, normalized);
} else {
Expand Down Expand Up @@ -3160,9 +3208,15 @@ static void FS_Stats_f(void)

static void FS_Link_g(genctx_t *ctx)
{
list_t *list;
symlink_t *link;

for (link = fs_links; link; link = link->next) {
if (!strncmp(Cmd_Argv(ctx->argnum - 1), "soft", 4))
list = &fs_soft_links;
else
list = &fs_hard_links;

FOR_EACH_SYMLINK(link, list) {
if (!Prompt_AddMatch(ctx, link->name)) {
break;
}
Expand All @@ -3176,16 +3230,16 @@ static void FS_Link_c(genctx_t *ctx, int argnum)
}
}

static void free_all_links(void)
static void free_all_links(list_t *list)
{
symlink_t *link, *next;

for (link = fs_links; link; link = next) {
next = link->next;
FOR_EACH_SYMLINK_SAFE(link, next, list) {
Z_Free(link->target);
Z_Free(link);
}
fs_links = NULL;

List_Init(list);
}

static void FS_UnLink_f(void)
Expand All @@ -3195,10 +3249,16 @@ static void FS_UnLink_f(void)
{ "h", "help", "display this message" },
{ NULL }
};
symlink_t *link, **next_p;
list_t *list;
symlink_t *link;
char *name;
int c;

if (!strncmp(Cmd_Argv(0), "soft", 4))
list = &fs_soft_links;
else
list = &fs_hard_links;

while ((c = Cmd_ParseOptions(options)) != -1) {
switch (c) {
case 'h':
Expand All @@ -3207,7 +3267,7 @@ static void FS_UnLink_f(void)
Cmd_PrintHelp(options);
return;
case 'a':
free_all_links();
free_all_links(list);
Com_Printf("Deleted all symbolic links.\n");
return;
default:
Expand All @@ -3222,37 +3282,41 @@ static void FS_UnLink_f(void)
return;
}

for (link = fs_links, next_p = &fs_links; link; link = link->next) {
FOR_EACH_SYMLINK(link, list) {
if (!FS_pathcmp(link->name, name)) {
break;
List_Remove(&link->entry);
Z_Free(link->target);
Z_Free(link);
return;
}
next_p = &link->next;
}
if (!link) {
Com_Printf("Symbolic link '%s' does not exist.\n", name);
return;
}

*next_p = link->next;
Z_Free(link->target);
Z_Free(link);
Com_Printf("Symbolic link '%s' does not exist.\n", name);
}

static void FS_Link_f(void)
{
int argc, count;
list_t *list;
symlink_t *link;
size_t namelen, targlen;
char name[MAX_OSPATH];
char target[MAX_OSPATH];

if (!strncmp(Cmd_Argv(0), "soft", 4))
list = &fs_soft_links;
else
list = &fs_hard_links;

argc = Cmd_Argc();
if (argc == 1) {
for (link = fs_links, count = 0; link; link = link->next, count++) {
count = 0;
FOR_EACH_SYMLINK(link, list) {
Com_Printf("%s --> %s\n", link->name, link->target);
count++;
}
Com_Printf("------------------\n"
"%d symbolic links listed.\n", count);
"%d symbolic link%s listed.\n", count, count == 1 ? "" : "s");
return;
}

Expand All @@ -3278,7 +3342,7 @@ static void FS_Link_f(void)
}

// search for existing link with this name
for (link = fs_links; link; link = link->next) {
FOR_EACH_SYMLINK(link, list) {
if (!FS_pathcmp(link->name, name)) {
Z_Free(link->target);
goto update;
Expand All @@ -3289,8 +3353,7 @@ static void FS_Link_f(void)
link = FS_Malloc(sizeof(*link) + namelen);
memcpy(link->name, name, namelen + 1);
link->namelen = namelen;
link->next = fs_links;
fs_links = link;
List_Append(list, &link->entry);

update:
link->target = FS_CopyString(target);
Expand Down Expand Up @@ -3426,6 +3489,8 @@ static const cmdreg_t c_fs[] = {
{ "whereis", FS_WhereIs_f },
{ "link", FS_Link_f, FS_Link_c },
{ "unlink", FS_UnLink_f, FS_Link_c },
{ "softlink", FS_Link_f, FS_Link_c },
{ "softunlink", FS_UnLink_f, FS_Link_c },
{ "fs_restart", FS_Restart_f },

{ NULL }
Expand Down Expand Up @@ -3454,7 +3519,8 @@ void FS_Shutdown(void)
}

// free symbolic links
free_all_links();
free_all_links(&fs_hard_links);
free_all_links(&fs_soft_links);

// free search paths
free_all_paths();
Expand Down Expand Up @@ -3521,6 +3587,9 @@ void FS_Init(void)
{
Com_Printf("------- FS_Init -------\n");

List_Init(&fs_hard_links);
List_Init(&fs_soft_links);

Cmd_Register(c_fs);

#ifdef _DEBUG
Expand Down

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