git/builtin/replace.c
Jeff King 28bf9429ef avoid double close of descriptors handed to run_command
When a file descriptor is given to run_command via the
"in", "out", or "err" parameters, run_command takes
ownership. The descriptor will be closed in the parent
process whether the process is spawned successfully or not,
and closing it again is wrong.

In practice this has not caused problems, because we usually
close() right after start_command returns, meaning no other
code has opened a descriptor in the meantime. So we just get
EBADF and ignore it (rather than accidentally closing
somebody else's descriptor!).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-06-25 15:27:24 -07:00

359 lines
9.5 KiB
C

/*
* Builtin "git replace"
*
* Copyright (c) 2008 Christian Couder <chriscool@tuxfamily.org>
*
* Based on builtin/tag.c by Kristian Høgsberg <krh@redhat.com>
* and Carlos Rica <jasampler@gmail.com> that was itself based on
* git-tag.sh and mktag.c by Linus Torvalds.
*/
#include "cache.h"
#include "builtin.h"
#include "refs.h"
#include "parse-options.h"
#include "run-command.h"
static const char * const git_replace_usage[] = {
N_("git replace [-f] <object> <replacement>"),
N_("git replace [-f] --edit <object>"),
N_("git replace -d <object>..."),
N_("git replace [--format=<format>] [-l [<pattern>]]"),
NULL
};
enum replace_format {
REPLACE_FORMAT_SHORT,
REPLACE_FORMAT_MEDIUM,
REPLACE_FORMAT_LONG
};
struct show_data {
const char *pattern;
enum replace_format format;
};
static int show_reference(const char *refname, const unsigned char *sha1,
int flag, void *cb_data)
{
struct show_data *data = cb_data;
if (!wildmatch(data->pattern, refname, 0, NULL)) {
if (data->format == REPLACE_FORMAT_SHORT)
printf("%s\n", refname);
else if (data->format == REPLACE_FORMAT_MEDIUM)
printf("%s -> %s\n", refname, sha1_to_hex(sha1));
else { /* data->format == REPLACE_FORMAT_LONG */
unsigned char object[20];
enum object_type obj_type, repl_type;
if (get_sha1(refname, object))
return error("Failed to resolve '%s' as a valid ref.", refname);
obj_type = sha1_object_info(object, NULL);
repl_type = sha1_object_info(sha1, NULL);
printf("%s (%s) -> %s (%s)\n", refname, typename(obj_type),
sha1_to_hex(sha1), typename(repl_type));
}
}
return 0;
}
static int list_replace_refs(const char *pattern, const char *format)
{
struct show_data data;
if (pattern == NULL)
pattern = "*";
data.pattern = pattern;
if (format == NULL || *format == '\0' || !strcmp(format, "short"))
data.format = REPLACE_FORMAT_SHORT;
else if (!strcmp(format, "medium"))
data.format = REPLACE_FORMAT_MEDIUM;
else if (!strcmp(format, "long"))
data.format = REPLACE_FORMAT_LONG;
else
die("invalid replace format '%s'\n"
"valid formats are 'short', 'medium' and 'long'\n",
format);
for_each_replace_ref(show_reference, (void *) &data);
return 0;
}
typedef int (*each_replace_name_fn)(const char *name, const char *ref,
const unsigned char *sha1);
static int for_each_replace_name(const char **argv, each_replace_name_fn fn)
{
const char **p, *full_hex;
char ref[PATH_MAX];
int had_error = 0;
unsigned char sha1[20];
for (p = argv; *p; p++) {
if (get_sha1(*p, sha1)) {
error("Failed to resolve '%s' as a valid ref.", *p);
had_error = 1;
continue;
}
full_hex = sha1_to_hex(sha1);
snprintf(ref, sizeof(ref), "refs/replace/%s", full_hex);
/* read_ref() may reuse the buffer */
full_hex = ref + strlen("refs/replace/");
if (read_ref(ref, sha1)) {
error("replace ref '%s' not found.", full_hex);
had_error = 1;
continue;
}
if (fn(full_hex, ref, sha1))
had_error = 1;
}
return had_error;
}
static int delete_replace_ref(const char *name, const char *ref,
const unsigned char *sha1)
{
if (delete_ref(ref, sha1, 0))
return 1;
printf("Deleted replace ref '%s'\n", name);
return 0;
}
static void check_ref_valid(unsigned char object[20],
unsigned char prev[20],
char *ref,
int ref_size,
int force)
{
if (snprintf(ref, ref_size,
"refs/replace/%s",
sha1_to_hex(object)) > ref_size - 1)
die("replace ref name too long: %.*s...", 50, ref);
if (check_refname_format(ref, 0))
die("'%s' is not a valid ref name.", ref);
if (read_ref(ref, prev))
hashclr(prev);
else if (!force)
die("replace ref '%s' already exists", ref);
}
static int replace_object_sha1(const char *object_ref,
unsigned char object[20],
const char *replace_ref,
unsigned char repl[20],
int force)
{
unsigned char prev[20];
enum object_type obj_type, repl_type;
char ref[PATH_MAX];
struct ref_lock *lock;
obj_type = sha1_object_info(object, NULL);
repl_type = sha1_object_info(repl, NULL);
if (!force && obj_type != repl_type)
die("Objects must be of the same type.\n"
"'%s' points to a replaced object of type '%s'\n"
"while '%s' points to a replacement object of type '%s'.",
object_ref, typename(obj_type),
replace_ref, typename(repl_type));
check_ref_valid(object, prev, ref, sizeof(ref), force);
lock = lock_any_ref_for_update(ref, prev, 0, NULL);
if (!lock)
die("%s: cannot lock the ref", ref);
if (write_ref_sha1(lock, repl, NULL) < 0)
die("%s: cannot update the ref", ref);
return 0;
}
static int replace_object(const char *object_ref, const char *replace_ref, int force)
{
unsigned char object[20], repl[20];
if (get_sha1(object_ref, object))
die("Failed to resolve '%s' as a valid ref.", object_ref);
if (get_sha1(replace_ref, repl))
die("Failed to resolve '%s' as a valid ref.", replace_ref);
return replace_object_sha1(object_ref, object, replace_ref, repl, force);
}
/*
* Write the contents of the object named by "sha1" to the file "filename",
* pretty-printed for human editing based on its type.
*/
static void export_object(const unsigned char *sha1, const char *filename)
{
const char *argv[] = { "--no-replace-objects", "cat-file", "-p", NULL, NULL };
struct child_process cmd = { argv };
int fd;
fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
if (fd < 0)
die_errno("unable to open %s for writing", filename);
argv[3] = sha1_to_hex(sha1);
cmd.git_cmd = 1;
cmd.out = fd;
if (run_command(&cmd))
die("cat-file reported failure");
}
/*
* Read a previously-exported (and possibly edited) object back from "filename",
* interpreting it as "type", and writing the result to the object database.
* The sha1 of the written object is returned via sha1.
*/
static void import_object(unsigned char *sha1, enum object_type type,
const char *filename)
{
int fd;
fd = open(filename, O_RDONLY);
if (fd < 0)
die_errno("unable to open %s for reading", filename);
if (type == OBJ_TREE) {
const char *argv[] = { "mktree", NULL };
struct child_process cmd = { argv };
struct strbuf result = STRBUF_INIT;
cmd.argv = argv;
cmd.git_cmd = 1;
cmd.in = fd;
cmd.out = -1;
if (start_command(&cmd))
die("unable to spawn mktree");
if (strbuf_read(&result, cmd.out, 41) < 0)
die_errno("unable to read from mktree");
close(cmd.out);
if (finish_command(&cmd))
die("mktree reported failure");
if (get_sha1_hex(result.buf, sha1) < 0)
die("mktree did not return an object name");
strbuf_release(&result);
} else {
struct stat st;
int flags = HASH_FORMAT_CHECK | HASH_WRITE_OBJECT;
if (fstat(fd, &st) < 0)
die_errno("unable to fstat %s", filename);
if (index_fd(sha1, fd, &st, type, NULL, flags) < 0)
die("unable to write object to database");
/* index_fd close()s fd for us */
}
/*
* No need to close(fd) here; both run-command and index-fd
* will have done it for us.
*/
}
static int edit_and_replace(const char *object_ref, int force)
{
char *tmpfile = git_pathdup("REPLACE_EDITOBJ");
enum object_type type;
unsigned char old[20], new[20], prev[20];
char ref[PATH_MAX];
if (get_sha1(object_ref, old) < 0)
die("Not a valid object name: '%s'", object_ref);
type = sha1_object_info(old, NULL);
if (type < 0)
die("unable to get object type for %s", sha1_to_hex(old));
check_ref_valid(old, prev, ref, sizeof(ref), force);
export_object(old, tmpfile);
if (launch_editor(tmpfile, NULL, NULL) < 0)
die("editing object file failed");
import_object(new, type, tmpfile);
free(tmpfile);
if (!hashcmp(old, new))
return error("new object is the same as the old one: '%s'", sha1_to_hex(old));
return replace_object_sha1(object_ref, old, "replacement", new, force);
}
int cmd_replace(int argc, const char **argv, const char *prefix)
{
int force = 0;
const char *format = NULL;
enum {
MODE_UNSPECIFIED = 0,
MODE_LIST,
MODE_DELETE,
MODE_EDIT,
MODE_REPLACE
} cmdmode = MODE_UNSPECIFIED;
struct option options[] = {
OPT_CMDMODE('l', "list", &cmdmode, N_("list replace refs"), MODE_LIST),
OPT_CMDMODE('d', "delete", &cmdmode, N_("delete replace refs"), MODE_DELETE),
OPT_CMDMODE('e', "edit", &cmdmode, N_("edit existing object"), MODE_EDIT),
OPT_BOOL('f', "force", &force, N_("replace the ref if it exists")),
OPT_STRING(0, "format", &format, N_("format"), N_("use this format")),
OPT_END()
};
check_replace_refs = 0;
argc = parse_options(argc, argv, prefix, options, git_replace_usage, 0);
if (!cmdmode)
cmdmode = argc ? MODE_REPLACE : MODE_LIST;
if (format && cmdmode != MODE_LIST)
usage_msg_opt("--format cannot be used when not listing",
git_replace_usage, options);
if (force && cmdmode != MODE_REPLACE && cmdmode != MODE_EDIT)
usage_msg_opt("-f only makes sense when writing a replacement",
git_replace_usage, options);
switch (cmdmode) {
case MODE_DELETE:
if (argc < 1)
usage_msg_opt("-d needs at least one argument",
git_replace_usage, options);
return for_each_replace_name(argv, delete_replace_ref);
case MODE_REPLACE:
if (argc != 2)
usage_msg_opt("bad number of arguments",
git_replace_usage, options);
return replace_object(argv[0], argv[1], force);
case MODE_EDIT:
if (argc != 1)
usage_msg_opt("-e needs exactly one argument",
git_replace_usage, options);
return edit_and_replace(argv[0], force);
case MODE_LIST:
if (argc > 1)
usage_msg_opt("only one pattern can be given with -l",
git_replace_usage, options);
return list_replace_refs(argv[0], format);
default:
die("BUG: invalid cmdmode %d", (int)cmdmode);
}
}