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validate JSON before loading 

This commit also introduces slurp() which reads a file in its entirety. Using
this function instead of doing IO in the functions in load_layout.c again and
again makes the code cleaner (fixing at least two memory leaks) and avoids
re-reading the same file 3 times.

related to #2755
This commit is contained in:
Michael Stapelberg 2017-09-13 17:14:51 +02:00
parent 72c972a36c
commit c45c002bad
6 changed files with 131 additions and 83 deletions
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10
include/load_layout.h
View File

@ -31,6 +31,12 @@ typedef enum {
* determine whether the file contains workspaces or regular containers, which
* is important to know when deciding where (and how) to append the contents.
* */
json_content_t json_determine_content(const char *filename);
json_content_t json_determine_content(const char *buf, const size_t len);
void tree_append_json(Con *con, const char *filename, char **errormsg);
/**
* Returns true if the provided JSON could be parsed by yajl.
*
*/
bool json_validate(const char *buf, const size_t len);
void tree_append_json(Con *con, const char *buf, const size_t len, char **errormsg);

8
include/util.h
View File

@ -164,3 +164,11 @@ void kill_nagbar(pid_t *nagbar_pid, bool wait_for_it);
* if the number could be parsed.
*/
bool parse_long(const char *str, long *out, int base);
/**
* Slurp reads path in its entirety into buf, returning the length of the file
* or -1 if the file could not be read. buf is set to a buffer of appropriate
* size, or NULL if -1 is returned.
*
*/
ssize_t slurp(const char *path, char **buf);

24
src/commands.c
View File

@ -773,13 +773,25 @@ void cmd_append_layout(I3_CMD, const char *cpath) {
/* Make sure we allow paths like '~/.i3/layout.json' */
path = resolve_tilde(path);
json_content_t content = json_determine_content(path);
char *buf = NULL;
ssize_t len;
if ((len = slurp(path, &buf)) < 0) {
/* slurp already logged an error. */
goto out;
}
if (!json_validate(buf, len)) {
ELOG("Could not parse \"%s\" as JSON, not loading.\n", path);
yerror("Could not parse \"%s\" as JSON.", path);
goto out;
}
json_content_t content = json_determine_content(buf, len);
LOG("JSON content = %d\n", content);
if (content == JSON_CONTENT_UNKNOWN) {
ELOG("Could not determine the contents of \"%s\", not loading.\n", path);
yerror("Could not determine the contents of \"%s\".", path);
free(path);
return;
goto out;
}
Con *parent = focused;
@ -795,7 +807,7 @@ void cmd_append_layout(I3_CMD, const char *cpath) {
}
DLOG("Appending to parent=%p instead of focused=%p\n", parent, focused);
char *errormsg = NULL;
tree_append_json(parent, path, &errormsg);
tree_append_json(parent, buf, len, &errormsg);
if (errormsg != NULL) {
yerror(errormsg);
free(errormsg);
@ -820,8 +832,10 @@ void cmd_append_layout(I3_CMD, const char *cpath) {
if (content == JSON_CONTENT_WORKSPACE)
ipc_send_workspace_event("restored", parent, NULL);
free(path);
cmd_output->needs_tree_render = true;
out:
free(path);
free(buf);
}
/*

98
src/load_layout.c
View File

@ -538,36 +538,42 @@ static int json_determine_content_string(void *ctx, const unsigned char *val, si
return 0;
}
/*
* Returns true if the provided JSON could be parsed by yajl.
*
*/
bool json_validate(const char *buf, const size_t len) {
bool valid = true;
yajl_handle hand = yajl_alloc(NULL, NULL, NULL);
/* Allowing comments allows for more user-friendly layout files. */
yajl_config(hand, yajl_allow_comments, true);
/* Allow multiple values, i.e. multiple nodes to attach */
yajl_config(hand, yajl_allow_multiple_values, true);
setlocale(LC_NUMERIC, "C");
if (yajl_parse(hand, (const unsigned char *)buf, len) != yajl_status_ok) {
unsigned char *str = yajl_get_error(hand, 1, (const unsigned char *)buf, len);
ELOG("JSON parsing error: %s\n", str);
yajl_free_error(hand, str);
valid = false;
}
setlocale(LC_NUMERIC, "");
yajl_complete_parse(hand);
yajl_free(hand);
return valid;
}
/* Parses the given JSON file until it encounters the first “type” property to
* determine whether the file contains workspaces or regular containers, which
* is important to know when deciding where (and how) to append the contents.
* */
json_content_t json_determine_content(const char *filename) {
FILE *f;
if ((f = fopen(filename, "r")) == NULL) {
ELOG("Cannot open file \"%s\"\n", filename);
return JSON_CONTENT_UNKNOWN;
}
struct stat stbuf;
if (fstat(fileno(f), &stbuf) != 0) {
ELOG("Cannot fstat() \"%s\"\n", filename);
fclose(f);
return JSON_CONTENT_UNKNOWN;
}
char *buf = smalloc(stbuf.st_size);
int n = fread(buf, 1, stbuf.st_size, f);
if (n != stbuf.st_size) {
ELOG("File \"%s\" could not be read entirely, not loading.\n", filename);
fclose(f);
return JSON_CONTENT_UNKNOWN;
}
DLOG("read %d bytes\n", n);
json_content_t json_determine_content(const char *buf, const size_t len) {
// We default to JSON_CONTENT_CON because it is legal to not include
// “"type": "con"” in the JSON files for better readability.
content_result = JSON_CONTENT_CON;
content_level = 0;
yajl_gen g;
yajl_handle hand;
static yajl_callbacks callbacks = {
.yajl_string = json_determine_content_string,
.yajl_map_key = json_key,
@ -576,51 +582,27 @@ json_content_t json_determine_content(const char *filename) {
.yajl_end_map = json_determine_content_shallower,
.yajl_end_array = json_determine_content_shallower,
};
g = yajl_gen_alloc(NULL);
hand = yajl_alloc(&callbacks, NULL, (void *)g);
yajl_handle hand = yajl_alloc(&callbacks, NULL, NULL);
/* Allowing comments allows for more user-friendly layout files. */
yajl_config(hand, yajl_allow_comments, true);
/* Allow multiple values, i.e. multiple nodes to attach */
yajl_config(hand, yajl_allow_multiple_values, true);
yajl_status stat;
setlocale(LC_NUMERIC, "C");
stat = yajl_parse(hand, (const unsigned char *)buf, n);
const yajl_status stat = yajl_parse(hand, (const unsigned char *)buf, len);
if (stat != yajl_status_ok && stat != yajl_status_client_canceled) {
unsigned char *str = yajl_get_error(hand, 1, (const unsigned char *)buf, n);
unsigned char *str = yajl_get_error(hand, 1, (const unsigned char *)buf, len);
ELOG("JSON parsing error: %s\n", str);
yajl_free_error(hand, str);
}
setlocale(LC_NUMERIC, "");
yajl_complete_parse(hand);
fclose(f);
yajl_free(hand);
return content_result;
}
void tree_append_json(Con *con, const char *filename, char **errormsg) {
FILE *f;
if ((f = fopen(filename, "r")) == NULL) {
ELOG("Cannot open file \"%s\"\n", filename);
return;
}
struct stat stbuf;
if (fstat(fileno(f), &stbuf) != 0) {
ELOG("Cannot fstat() \"%s\"\n", filename);
fclose(f);
return;
}
char *buf = smalloc(stbuf.st_size);
int n = fread(buf, 1, stbuf.st_size, f);
if (n != stbuf.st_size) {
ELOG("File \"%s\" could not be read entirely, not loading.\n", filename);
fclose(f);
return;
}
DLOG("read %d bytes\n", n);
yajl_gen g;
yajl_handle hand;
void tree_append_json(Con *con, const char *buf, const size_t len, char **errormsg) {
static yajl_callbacks callbacks = {
.yajl_boolean = json_bool,
.yajl_integer = json_int,
@ -631,13 +613,11 @@ void tree_append_json(Con *con, const char *filename, char **errormsg) {
.yajl_end_map = json_end_map,
.yajl_end_array = json_end_array,
};
g = yajl_gen_alloc(NULL);
hand = yajl_alloc(&callbacks, NULL, (void *)g);
yajl_handle hand = yajl_alloc(&callbacks, NULL, NULL);
/* Allowing comments allows for more user-friendly layout files. */
yajl_config(hand, yajl_allow_comments, true);
/* Allow multiple values, i.e. multiple nodes to attach */
yajl_config(hand, yajl_allow_multiple_values, true);
yajl_status stat;
json_node = con;
to_focus = NULL;
incomplete = 0;
@ -649,9 +629,9 @@ void tree_append_json(Con *con, const char *filename, char **errormsg) {
parsing_focus = false;
parsing_marks = false;
setlocale(LC_NUMERIC, "C");
stat = yajl_parse(hand, (const unsigned char *)buf, n);
const yajl_status stat = yajl_parse(hand, (const unsigned char *)buf, len);
if (stat != yajl_status_ok) {
unsigned char *str = yajl_get_error(hand, 1, (const unsigned char *)buf, n);
unsigned char *str = yajl_get_error(hand, 1, (const unsigned char *)buf, len);
ELOG("JSON parsing error: %s\n", str);
if (errormsg != NULL)
*errormsg = sstrdup((const char *)str);
@ -672,10 +652,8 @@ void tree_append_json(Con *con, const char *filename, char **errormsg) {
setlocale(LC_NUMERIC, "");
yajl_complete_parse(hand);
yajl_free(hand);
yajl_gen_free(g);
fclose(f);
free(buf);
if (to_focus)
if (to_focus) {
con_focus(to_focus);
}
}

20
src/tree.c
View File

@ -64,12 +64,19 @@ static Con *_create___i3(void) {
*
*/
bool tree_restore(const char *path, xcb_get_geometry_reply_t *geometry) {
bool result = false;
char *globbed = resolve_tilde(path);
if (!path_exists(globbed)) {
LOG("%s does not exist, not restoring tree\n", globbed);
free(globbed);
return false;
goto out;
}
char *buf = NULL;
ssize_t len;
if ((len = slurp(globbed, &buf)) < 0) {
/* slurp already logged an error. */
goto out;
}
/* TODO: refactor the following */
@ -81,8 +88,7 @@ bool tree_restore(const char *path, xcb_get_geometry_reply_t *geometry) {
geometry->height};
focused = croot;
tree_append_json(focused, globbed, NULL);
free(globbed);
tree_append_json(focused, buf, len, NULL);
DLOG("appended tree, using new root\n");
croot = TAILQ_FIRST(&(croot->nodes_head));
@ -104,8 +110,12 @@ bool tree_restore(const char *path, xcb_get_geometry_reply_t *geometry) {
}
restore_open_placeholder_windows(croot);
result = true;
return true;
out:
free(globbed);
free(buf);
return result;
}
/*

32
src/util.c
View File

@ -475,3 +475,35 @@ bool parse_long(const char *str, long *out, int base) {
*out = result;
return true;
}
/*
* Slurp reads path in its entirety into buf, returning the length of the file
* or -1 if the file could not be read. buf is set to a buffer of appropriate
* size, or NULL if -1 is returned.
*
*/
ssize_t slurp(const char *path, char **buf) {
FILE *f;
if ((f = fopen(path, "r")) == NULL) {
ELOG("Cannot open file \"%s\": %s\n", path, strerror(errno));
return -1;
}
struct stat stbuf;
if (fstat(fileno(f), &stbuf) != 0) {
ELOG("Cannot fstat() \"%s\": %s\n", path, strerror(errno));
fclose(f);
return -1;
}
/* Allocate one extra NUL byte to make the buffer usable with C string
* functions. yajl doesn’t need this, but this makes slurp safer. */
*buf = scalloc(stbuf.st_size + 1, 1);
size_t n = fread(*buf, 1, stbuf.st_size, f);
fclose(f);
if ((ssize_t)n != stbuf.st_size) {
ELOG("File \"%s\" could not be read entirely: got %zd, want %zd\n", path, n, stbuf.st_size);
free(buf);
*buf = NULL;
return -1;
}
return (ssize_t)n;
}