521 lines
12 KiB
C
521 lines
12 KiB
C
#include "refs.h"
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#include "cache.h"
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#include <errno.h>
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/* We allow "recursive" symbolic refs. Only within reason, though */
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#define MAXDEPTH 5
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const char *resolve_ref(const char *path, unsigned char *sha1, int reading)
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{
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int depth = MAXDEPTH, len;
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char buffer[256];
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for (;;) {
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struct stat st;
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char *buf;
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int fd;
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if (--depth < 0)
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return NULL;
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/* Special case: non-existing file.
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* Not having the refs/heads/new-branch is OK
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* if we are writing into it, so is .git/HEAD
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* that points at refs/heads/master still to be
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* born. It is NOT OK if we are resolving for
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* reading.
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*/
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if (lstat(path, &st) < 0) {
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if (reading || errno != ENOENT)
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return NULL;
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memset(sha1, 0, 20);
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return path;
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}
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/* Follow "normalized" - ie "refs/.." symlinks by hand */
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if (S_ISLNK(st.st_mode)) {
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len = readlink(path, buffer, sizeof(buffer)-1);
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if (len >= 5 && !memcmp("refs/", buffer, 5)) {
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path = git_path("%.*s", len, buffer);
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continue;
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}
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}
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/*
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* Anything else, just open it and try to use it as
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* a ref
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*/
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fd = open(path, O_RDONLY);
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if (fd < 0)
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return NULL;
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len = read(fd, buffer, sizeof(buffer)-1);
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close(fd);
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/*
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* Is it a symbolic ref?
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*/
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if (len < 4 || memcmp("ref:", buffer, 4))
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break;
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buf = buffer + 4;
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len -= 4;
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while (len && isspace(*buf))
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buf++, len--;
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while (len && isspace(buf[len-1]))
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buf[--len] = 0;
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path = git_path("%.*s", len, buf);
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}
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if (len < 40 || get_sha1_hex(buffer, sha1))
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return NULL;
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return path;
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}
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int create_symref(const char *git_HEAD, const char *refs_heads_master)
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{
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const char *lockpath;
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char ref[1000];
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int fd, len, written;
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#ifndef NO_SYMLINK_HEAD
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if (prefer_symlink_refs) {
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unlink(git_HEAD);
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if (!symlink(refs_heads_master, git_HEAD))
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return 0;
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fprintf(stderr, "no symlink - falling back to symbolic ref\n");
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}
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#endif
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len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
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if (sizeof(ref) <= len) {
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error("refname too long: %s", refs_heads_master);
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return -1;
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}
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lockpath = mkpath("%s.lock", git_HEAD);
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fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
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written = write(fd, ref, len);
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close(fd);
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if (written != len) {
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unlink(lockpath);
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error("Unable to write to %s", lockpath);
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return -2;
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}
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if (rename(lockpath, git_HEAD) < 0) {
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unlink(lockpath);
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error("Unable to create %s", git_HEAD);
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return -3;
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}
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if (adjust_shared_perm(git_HEAD)) {
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unlink(lockpath);
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error("Unable to fix permissions on %s", lockpath);
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return -4;
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}
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return 0;
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}
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int read_ref(const char *filename, unsigned char *sha1)
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{
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if (resolve_ref(filename, sha1, 1))
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return 0;
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return -1;
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}
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static int do_for_each_ref(const char *base, int (*fn)(const char *path, const unsigned char *sha1), int trim)
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{
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int retval = 0;
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DIR *dir = opendir(git_path("%s", base));
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if (dir) {
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struct dirent *de;
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int baselen = strlen(base);
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char *path = xmalloc(baselen + 257);
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if (!strncmp(base, "./", 2)) {
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base += 2;
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baselen -= 2;
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}
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memcpy(path, base, baselen);
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if (baselen && base[baselen-1] != '/')
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path[baselen++] = '/';
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while ((de = readdir(dir)) != NULL) {
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unsigned char sha1[20];
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struct stat st;
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int namelen;
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if (de->d_name[0] == '.')
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continue;
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namelen = strlen(de->d_name);
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if (namelen > 255)
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continue;
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if (namelen>5 && !strcmp(de->d_name+namelen-5,".lock"))
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continue;
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memcpy(path + baselen, de->d_name, namelen+1);
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if (stat(git_path("%s", path), &st) < 0)
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continue;
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if (S_ISDIR(st.st_mode)) {
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retval = do_for_each_ref(path, fn, trim);
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if (retval)
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break;
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continue;
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}
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if (read_ref(git_path("%s", path), sha1) < 0) {
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error("%s points nowhere!", path);
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continue;
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}
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if (!has_sha1_file(sha1)) {
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error("%s does not point to a valid "
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"commit object!", path);
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continue;
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}
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retval = fn(path + trim, sha1);
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if (retval)
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break;
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}
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free(path);
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closedir(dir);
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}
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return retval;
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}
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int head_ref(int (*fn)(const char *path, const unsigned char *sha1))
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{
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unsigned char sha1[20];
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if (!read_ref(git_path("HEAD"), sha1))
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return fn("HEAD", sha1);
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return 0;
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}
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int for_each_ref(int (*fn)(const char *path, const unsigned char *sha1))
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{
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return do_for_each_ref("refs", fn, 0);
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}
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int for_each_tag_ref(int (*fn)(const char *path, const unsigned char *sha1))
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{
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return do_for_each_ref("refs/tags", fn, 10);
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}
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int for_each_branch_ref(int (*fn)(const char *path, const unsigned char *sha1))
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{
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return do_for_each_ref("refs/heads", fn, 11);
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}
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int for_each_remote_ref(int (*fn)(const char *path, const unsigned char *sha1))
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{
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return do_for_each_ref("refs/remotes", fn, 13);
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}
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int get_ref_sha1(const char *ref, unsigned char *sha1)
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{
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if (check_ref_format(ref))
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return -1;
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return read_ref(git_path("refs/%s", ref), sha1);
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}
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/*
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* Make sure "ref" is something reasonable to have under ".git/refs/";
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* We do not like it if:
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*
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* - any path component of it begins with ".", or
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* - it has double dots "..", or
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* - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
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* - it ends with a "/".
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*/
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static inline int bad_ref_char(int ch)
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{
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return (((unsigned) ch) <= ' ' ||
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ch == '~' || ch == '^' || ch == ':' ||
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/* 2.13 Pattern Matching Notation */
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ch == '?' || ch == '*' || ch == '[');
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}
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int check_ref_format(const char *ref)
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{
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int ch, level;
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const char *cp = ref;
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level = 0;
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while (1) {
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while ((ch = *cp++) == '/')
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; /* tolerate duplicated slashes */
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if (!ch)
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return -1; /* should not end with slashes */
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/* we are at the beginning of the path component */
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if (ch == '.' || bad_ref_char(ch))
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return -1;
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/* scan the rest of the path component */
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while ((ch = *cp++) != 0) {
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if (bad_ref_char(ch))
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return -1;
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if (ch == '/')
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break;
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if (ch == '.' && *cp == '.')
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return -1;
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}
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level++;
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if (!ch) {
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if (level < 2)
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return -1; /* at least of form "heads/blah" */
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return 0;
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}
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}
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}
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static struct ref_lock *verify_lock(struct ref_lock *lock,
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const unsigned char *old_sha1, int mustexist)
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{
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char buf[40];
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int nr, fd = open(lock->ref_file, O_RDONLY);
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if (fd < 0 && (mustexist || errno != ENOENT)) {
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error("Can't verify ref %s", lock->ref_file);
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unlock_ref(lock);
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return NULL;
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}
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nr = read(fd, buf, 40);
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close(fd);
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if (nr != 40 || get_sha1_hex(buf, lock->old_sha1) < 0) {
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error("Can't verify ref %s", lock->ref_file);
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unlock_ref(lock);
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return NULL;
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}
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if (memcmp(lock->old_sha1, old_sha1, 20)) {
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error("Ref %s is at %s but expected %s", lock->ref_file,
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sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
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unlock_ref(lock);
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return NULL;
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}
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return lock;
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}
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static struct ref_lock *lock_ref_sha1_basic(const char *path,
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int plen,
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const unsigned char *old_sha1, int mustexist)
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{
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struct ref_lock *lock;
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struct stat st;
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lock = xcalloc(1, sizeof(struct ref_lock));
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lock->lock_fd = -1;
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plen = strlen(path) - plen;
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path = resolve_ref(path, lock->old_sha1, mustexist);
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if (!path) {
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unlock_ref(lock);
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return NULL;
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}
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lock->lk = xcalloc(1, sizeof(struct lock_file));
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lock->ref_file = strdup(path);
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lock->log_file = strdup(git_path("logs/%s", lock->ref_file + plen));
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lock->force_write = lstat(lock->ref_file, &st) && errno == ENOENT;
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if (safe_create_leading_directories(lock->ref_file))
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die("unable to create directory for %s", lock->ref_file);
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lock->lock_fd = hold_lock_file_for_update(lock->lk, lock->ref_file);
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if (lock->lock_fd < 0) {
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error("Couldn't open lock file %s: %s",
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lock->lk->filename, strerror(errno));
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unlock_ref(lock);
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return NULL;
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}
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return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
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}
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struct ref_lock *lock_ref_sha1(const char *ref,
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const unsigned char *old_sha1, int mustexist)
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{
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if (check_ref_format(ref))
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return NULL;
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return lock_ref_sha1_basic(git_path("refs/%s", ref),
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5 + strlen(ref), old_sha1, mustexist);
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}
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struct ref_lock *lock_any_ref_for_update(const char *ref,
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const unsigned char *old_sha1, int mustexist)
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{
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return lock_ref_sha1_basic(git_path("%s", ref),
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strlen(ref), old_sha1, mustexist);
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}
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void unlock_ref(struct ref_lock *lock)
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{
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if (lock->lock_fd >= 0) {
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close(lock->lock_fd);
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/* Do not free lock->lk -- atexit() still looks at them */
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if (lock->lk)
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rollback_lock_file(lock->lk);
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}
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if (lock->ref_file)
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free(lock->ref_file);
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if (lock->log_file)
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free(lock->log_file);
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free(lock);
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}
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static int log_ref_write(struct ref_lock *lock,
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const unsigned char *sha1, const char *msg)
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{
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int logfd, written, oflags = O_APPEND | O_WRONLY;
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unsigned maxlen, len;
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char *logrec;
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const char *comitter;
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if (log_all_ref_updates) {
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if (safe_create_leading_directories(lock->log_file) < 0)
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return error("unable to create directory for %s",
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lock->log_file);
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oflags |= O_CREAT;
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}
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logfd = open(lock->log_file, oflags, 0666);
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if (logfd < 0) {
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if (!log_all_ref_updates && errno == ENOENT)
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return 0;
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return error("Unable to append to %s: %s",
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lock->log_file, strerror(errno));
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}
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setup_ident();
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comitter = git_committer_info(1);
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if (msg) {
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maxlen = strlen(comitter) + strlen(msg) + 2*40 + 5;
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logrec = xmalloc(maxlen);
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len = snprintf(logrec, maxlen, "%s %s %s\t%s\n",
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sha1_to_hex(lock->old_sha1),
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sha1_to_hex(sha1),
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comitter,
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msg);
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}
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else {
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maxlen = strlen(comitter) + 2*40 + 4;
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logrec = xmalloc(maxlen);
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len = snprintf(logrec, maxlen, "%s %s %s\n",
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sha1_to_hex(lock->old_sha1),
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sha1_to_hex(sha1),
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comitter);
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}
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written = len <= maxlen ? write(logfd, logrec, len) : -1;
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free(logrec);
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close(logfd);
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if (written != len)
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return error("Unable to append to %s", lock->log_file);
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return 0;
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}
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int write_ref_sha1(struct ref_lock *lock,
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const unsigned char *sha1, const char *logmsg)
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{
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static char term = '\n';
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if (!lock)
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return -1;
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if (!lock->force_write && !memcmp(lock->old_sha1, sha1, 20)) {
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unlock_ref(lock);
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return 0;
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}
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if (write(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
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write(lock->lock_fd, &term, 1) != 1
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|| close(lock->lock_fd) < 0) {
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error("Couldn't write %s", lock->lk->filename);
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unlock_ref(lock);
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return -1;
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}
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if (log_ref_write(lock, sha1, logmsg) < 0) {
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unlock_ref(lock);
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return -1;
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}
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if (commit_lock_file(lock->lk)) {
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error("Couldn't set %s", lock->ref_file);
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unlock_ref(lock);
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return -1;
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}
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lock->lock_fd = -1;
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unlock_ref(lock);
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return 0;
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}
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int read_ref_at(const char *ref, unsigned long at_time, unsigned char *sha1)
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{
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const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
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char *tz_c;
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int logfd, tz;
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struct stat st;
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unsigned long date;
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unsigned char logged_sha1[20];
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logfile = git_path("logs/%s", ref);
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logfd = open(logfile, O_RDONLY, 0);
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if (logfd < 0)
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die("Unable to read log %s: %s", logfile, strerror(errno));
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fstat(logfd, &st);
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if (!st.st_size)
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die("Log %s is empty.", logfile);
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logdata = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, logfd, 0);
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close(logfd);
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lastrec = NULL;
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rec = logend = logdata + st.st_size;
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while (logdata < rec) {
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if (logdata < rec && *(rec-1) == '\n')
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rec--;
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lastgt = NULL;
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while (logdata < rec && *(rec-1) != '\n') {
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rec--;
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if (*rec == '>')
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lastgt = rec;
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}
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if (!lastgt)
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die("Log %s is corrupt.", logfile);
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date = strtoul(lastgt + 1, &tz_c, 10);
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if (date <= at_time) {
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if (lastrec) {
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if (get_sha1_hex(lastrec, logged_sha1))
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die("Log %s is corrupt.", logfile);
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if (get_sha1_hex(rec + 41, sha1))
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die("Log %s is corrupt.", logfile);
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if (memcmp(logged_sha1, sha1, 20)) {
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tz = strtoul(tz_c, NULL, 10);
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fprintf(stderr,
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"warning: Log %s has gap after %s.\n",
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logfile, show_rfc2822_date(date, tz));
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}
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}
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else if (date == at_time) {
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if (get_sha1_hex(rec + 41, sha1))
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die("Log %s is corrupt.", logfile);
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}
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else {
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if (get_sha1_hex(rec + 41, logged_sha1))
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die("Log %s is corrupt.", logfile);
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if (memcmp(logged_sha1, sha1, 20)) {
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tz = strtoul(tz_c, NULL, 10);
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fprintf(stderr,
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"warning: Log %s unexpectedly ended on %s.\n",
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logfile, show_rfc2822_date(date, tz));
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}
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}
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munmap((void*)logdata, st.st_size);
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return 0;
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}
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lastrec = rec;
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}
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rec = logdata;
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while (rec < logend && *rec != '>' && *rec != '\n')
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rec++;
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if (rec == logend || *rec == '\n')
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die("Log %s is corrupt.", logfile);
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date = strtoul(rec + 1, &tz_c, 10);
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tz = strtoul(tz_c, NULL, 10);
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if (get_sha1_hex(logdata, sha1))
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die("Log %s is corrupt.", logfile);
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munmap((void*)logdata, st.st_size);
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fprintf(stderr, "warning: Log %s only goes back to %s.\n",
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logfile, show_rfc2822_date(date, tz));
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return 0;
|
|
}
|