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git/t/helper/test-config.c
Jeff King f1de981e8b config: fix leaks from git_config_get_string_const()
There are two functions to get a single config string:

  - git_config_get_string()

  - git_config_get_string_const()

One might naively think that the first one allocates a new string and
the second one just points us to the internal configset storage. But
in fact they both allocate a new copy; the second one exists only to
avoid having to cast when using it with a const global which we never
intend to free.

The documentation for the function explains that clearly, but it seems
I'm not alone in being surprised by this. Of 17 calls to the function,
13 of them leak the resulting value.

We could obviously fix these by adding the appropriate free(). But it
would be simpler still if we actually had a non-allocating way to get
the string. There's git_config_get_value() but that doesn't quite do
what we want. If the config key is present but is a boolean with no
value (e.g., "[foo]bar" in the file), then we'll get NULL (whereas the
string versions will print an error and die).

So let's introduce a new variant, git_config_get_string_tmp(), that
behaves as these callers expect. We need a new name because we have new
semantics but the same function signature (so even if we converted the
four remaining callers, topics in flight might be surprised). The "tmp"
is because this value should only be held onto for a short time. In
practice it's rare for us to clear and refresh the configset,
invalidating the pointer, but hopefully the "tmp" makes callers think
about the lifetime. In each of the converted cases here the value only
needs to last within the local function or its immediate caller.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-14 10:52:04 -07:00

195 lines
4.8 KiB
C

#include "test-tool.h"
#include "cache.h"
#include "config.h"
#include "string-list.h"
/*
* This program exposes the C API of the configuration mechanism
* as a set of simple commands in order to facilitate testing.
*
* Reads stdin and prints result of command to stdout:
*
* get_value -> prints the value with highest priority for the entered key
*
* get_value_multi -> prints all values for the entered key in increasing order
* of priority
*
* get_int -> print integer value for the entered key or die
*
* get_bool -> print bool value for the entered key or die
*
* get_string -> print string value for the entered key or die
*
* configset_get_value -> returns value with the highest priority for the entered key
* from a config_set constructed from files entered as arguments.
*
* configset_get_value_multi -> returns value_list for the entered key sorted in
* ascending order of priority from a config_set
* constructed from files entered as arguments.
*
* iterate -> iterate over all values using git_config(), and print some
* data for each
*
* Examples:
*
* To print the value with highest priority for key "foo.bAr Baz.rock":
* test-tool config get_value "foo.bAr Baz.rock"
*
*/
static int iterate_cb(const char *var, const char *value, void *data)
{
static int nr;
if (nr++)
putchar('\n');
printf("key=%s\n", var);
printf("value=%s\n", value ? value : "(null)");
printf("origin=%s\n", current_config_origin_type());
printf("name=%s\n", current_config_name());
printf("lno=%d\n", current_config_line());
printf("scope=%s\n", config_scope_name(current_config_scope()));
return 0;
}
static int early_config_cb(const char *var, const char *value, void *vdata)
{
const char *key = vdata;
if (!strcmp(key, var))
printf("%s\n", value);
return 0;
}
int cmd__config(int argc, const char **argv)
{
int i, val;
const char *v;
const struct string_list *strptr;
struct config_set cs;
if (argc == 3 && !strcmp(argv[1], "read_early_config")) {
read_early_config(early_config_cb, (void *)argv[2]);
return 0;
}
setup_git_directory();
git_configset_init(&cs);
if (argc < 2) {
fprintf(stderr, "Please, provide a command name on the command-line\n");
goto exit1;
} else if (argc == 3 && !strcmp(argv[1], "get_value")) {
if (!git_config_get_value(argv[2], &v)) {
if (!v)
printf("(NULL)\n");
else
printf("%s\n", v);
goto exit0;
} else {
printf("Value not found for \"%s\"\n", argv[2]);
goto exit1;
}
} else if (argc == 3 && !strcmp(argv[1], "get_value_multi")) {
strptr = git_config_get_value_multi(argv[2]);
if (strptr) {
for (i = 0; i < strptr->nr; i++) {
v = strptr->items[i].string;
if (!v)
printf("(NULL)\n");
else
printf("%s\n", v);
}
goto exit0;
} else {
printf("Value not found for \"%s\"\n", argv[2]);
goto exit1;
}
} else if (argc == 3 && !strcmp(argv[1], "get_int")) {
if (!git_config_get_int(argv[2], &val)) {
printf("%d\n", val);
goto exit0;
} else {
printf("Value not found for \"%s\"\n", argv[2]);
goto exit1;
}
} else if (argc == 3 && !strcmp(argv[1], "get_bool")) {
if (!git_config_get_bool(argv[2], &val)) {
printf("%d\n", val);
goto exit0;
} else {
printf("Value not found for \"%s\"\n", argv[2]);
goto exit1;
}
} else if (argc == 3 && !strcmp(argv[1], "get_string")) {
if (!git_config_get_string_tmp(argv[2], &v)) {
printf("%s\n", v);
goto exit0;
} else {
printf("Value not found for \"%s\"\n", argv[2]);
goto exit1;
}
} else if (!strcmp(argv[1], "configset_get_value")) {
for (i = 3; i < argc; i++) {
int err;
if ((err = git_configset_add_file(&cs, argv[i]))) {
fprintf(stderr, "Error (%d) reading configuration file %s.\n", err, argv[i]);
goto exit2;
}
}
if (!git_configset_get_value(&cs, argv[2], &v)) {
if (!v)
printf("(NULL)\n");
else
printf("%s\n", v);
goto exit0;
} else {
printf("Value not found for \"%s\"\n", argv[2]);
goto exit1;
}
} else if (!strcmp(argv[1], "configset_get_value_multi")) {
for (i = 3; i < argc; i++) {
int err;
if ((err = git_configset_add_file(&cs, argv[i]))) {
fprintf(stderr, "Error (%d) reading configuration file %s.\n", err, argv[i]);
goto exit2;
}
}
strptr = git_configset_get_value_multi(&cs, argv[2]);
if (strptr) {
for (i = 0; i < strptr->nr; i++) {
v = strptr->items[i].string;
if (!v)
printf("(NULL)\n");
else
printf("%s\n", v);
}
goto exit0;
} else {
printf("Value not found for \"%s\"\n", argv[2]);
goto exit1;
}
} else if (!strcmp(argv[1], "iterate")) {
git_config(iterate_cb, NULL);
goto exit0;
}
die("%s: Please check the syntax and the function name", argv[0]);
exit0:
git_configset_clear(&cs);
return 0;
exit1:
git_configset_clear(&cs);
return 1;
exit2:
git_configset_clear(&cs);
return 2;
}