git/editor.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

128 lines
3 KiB
C

#include "cache.h"
#include "config.h"
#include "strbuf.h"
#include "run-command.h"
#include "sigchain.h"
#ifndef DEFAULT_EDITOR
#define DEFAULT_EDITOR "vi"
#endif
int is_terminal_dumb(void)
{
const char *terminal = getenv("TERM");
return !terminal || !strcmp(terminal, "dumb");
}
const char *git_editor(void)
{
const char *editor = getenv("GIT_EDITOR");
int terminal_is_dumb = is_terminal_dumb();
if (!editor && editor_program)
editor = editor_program;
if (!editor && !terminal_is_dumb)
editor = getenv("VISUAL");
if (!editor)
editor = getenv("EDITOR");
if (!editor && terminal_is_dumb)
return NULL;
if (!editor)
editor = DEFAULT_EDITOR;
return editor;
}
const char *git_sequence_editor(void)
{
const char *editor = getenv("GIT_SEQUENCE_EDITOR");
if (!editor)
git_config_get_string_tmp("sequence.editor", &editor);
if (!editor)
editor = git_editor();
return editor;
}
static int launch_specified_editor(const char *editor, const char *path,
struct strbuf *buffer, const char *const *env)
{
if (!editor)
return error("Terminal is dumb, but EDITOR unset");
if (strcmp(editor, ":")) {
struct strbuf realpath = STRBUF_INIT;
const char *args[] = { editor, NULL, NULL };
struct child_process p = CHILD_PROCESS_INIT;
int ret, sig;
int print_waiting_for_editor = advice_waiting_for_editor && isatty(2);
if (print_waiting_for_editor) {
/*
* A dumb terminal cannot erase the line later on. Add a
* newline to separate the hint from subsequent output.
*
* Make sure that our message is separated with a whitespace
* from further cruft that may be written by the editor.
*/
const char term = is_terminal_dumb() ? '\n' : ' ';
fprintf(stderr,
_("hint: Waiting for your editor to close the file...%c"),
term);
fflush(stderr);
}
strbuf_realpath(&realpath, path, 1);
args[1] = realpath.buf;
p.argv = args;
p.env = env;
p.use_shell = 1;
p.trace2_child_class = "editor";
if (start_command(&p) < 0) {
strbuf_release(&realpath);
return error("unable to start editor '%s'", editor);
}
sigchain_push(SIGINT, SIG_IGN);
sigchain_push(SIGQUIT, SIG_IGN);
ret = finish_command(&p);
strbuf_release(&realpath);
sig = ret - 128;
sigchain_pop(SIGINT);
sigchain_pop(SIGQUIT);
if (sig == SIGINT || sig == SIGQUIT)
raise(sig);
if (ret)
return error("There was a problem with the editor '%s'.",
editor);
if (print_waiting_for_editor && !is_terminal_dumb())
/*
* Erase the entire line to avoid wasting the
* vertical space.
*/
term_clear_line();
}
if (!buffer)
return 0;
if (strbuf_read_file(buffer, path, 0) < 0)
return error_errno("could not read file '%s'", path);
return 0;
}
int launch_editor(const char *path, struct strbuf *buffer, const char *const *env)
{
return launch_specified_editor(git_editor(), path, buffer, env);
}
int launch_sequence_editor(const char *path, struct strbuf *buffer,
const char *const *env)
{
return launch_specified_editor(git_sequence_editor(), path, buffer, env);
}