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#include "refs.h"
#include "cache.h"
#include <errno.h>
static char *ref_file_name(const char *ref)
{
char *base = get_refs_directory();
int baselen = strlen(base);
int reflen = strlen(ref);
char *ret = xmalloc(baselen + 2 + reflen);
sprintf(ret, "%s/%s", base, ref);
return ret;
}
static char *ref_lock_file_name(const char *ref)
{
char *base = get_refs_directory();
int baselen = strlen(base);
int reflen = strlen(ref);
char *ret = xmalloc(baselen + 7 + reflen);
sprintf(ret, "%s/%s.lock", base, ref);
return ret;
}
static int read_ref_file(const char *filename, unsigned char *sha1) {
int fd = open(filename, O_RDONLY);
char hex[41];
if (fd < 0) {
return error("Couldn't open %s\n", filename);
}
if ((read(fd, hex, 41) < 41) ||
(hex[40] != '\n') ||
get_sha1_hex(hex, sha1)) {
error("Couldn't read a hash from %s\n", filename);
close(fd);
return -1;
}
close(fd);
return 0;
}
int get_ref_sha1(const char *ref, unsigned char *sha1)
{
char *filename;
int retval;
if (check_ref_format(ref))
return -1;
filename = ref_file_name(ref);
retval = read_ref_file(filename, sha1);
free(filename);
return retval;
}
static int lock_ref_file(const char *filename, const char *lock_filename,
const unsigned char *old_sha1)
{
int fd = open(lock_filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
unsigned char current_sha1[20];
int retval;
if (fd < 0) {
return error("Couldn't open lock file for %s: %s",
filename, strerror(errno));
}
retval = read_ref_file(filename, current_sha1);
if (old_sha1) {
if (retval) {
close(fd);
unlink(lock_filename);
return error("Could not read the current value of %s",
filename);
}
if (memcmp(current_sha1, old_sha1, 20)) {
close(fd);
unlink(lock_filename);
error("The current value of %s is %s",
filename, sha1_to_hex(current_sha1));
return error("Expected %s",
sha1_to_hex(old_sha1));
}
} else {
if (!retval) {
close(fd);
unlink(lock_filename);
return error("Unexpectedly found a value of %s for %s",
sha1_to_hex(current_sha1), filename);
}
}
return fd;
}
int lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
{
char *filename;
char *lock_filename;
int retval;
if (check_ref_format(ref))
return -1;
filename = ref_file_name(ref);
lock_filename = ref_lock_file_name(ref);
retval = lock_ref_file(filename, lock_filename, old_sha1);
free(filename);
free(lock_filename);
return retval;
}
static int write_ref_file(const char *filename,
const char *lock_filename, int fd,
const unsigned char *sha1)
{
char *hex = sha1_to_hex(sha1);
char term = '\n';
if (write(fd, hex, 40) < 40 ||
write(fd, &term, 1) < 1) {
error("Couldn't write %s\n", filename);
close(fd);
return -1;
}
close(fd);
rename(lock_filename, filename);
return 0;
}
int write_ref_sha1(const char *ref, int fd, const unsigned char *sha1)
{
char *filename;
char *lock_filename;
int retval;
if (fd < 0)
return -1;
if (check_ref_format(ref))
return -1;
filename = ref_file_name(ref);
lock_filename = ref_lock_file_name(ref);
retval = write_ref_file(filename, lock_filename, fd, sha1);
free(filename);
free(lock_filename);
return retval;
}
int check_ref_format(const char *ref)
{
char *middle;
if (ref[0] == '.' || ref[0] == '/')
return -1;
middle = strchr(ref, '/');
if (!middle || !middle[1])
return -1;
if (strchr(middle + 1, '/'))
return -1;
return 0;
}
int write_ref_sha1_unlocked(const char *ref, const unsigned char *sha1)
{
char *filename;
char *lock_filename;
int fd;
int retval;
if (check_ref_format(ref))
return -1;
filename = ref_file_name(ref);
lock_filename = ref_lock_file_name(ref);
fd = open(lock_filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
if (fd < 0) {
error("Writing %s", lock_filename);
perror("Open");
}
retval = write_ref_file(filename, lock_filename, fd, sha1);
free(filename);
free(lock_filename);
return retval;
}
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