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https://github.com/git/git
synced 2024-08-24 18:26:02 +00:00
![Shawn Pearce](/assets/img/avatar_default.png)
Corrected the log starting time displayed in the error message (as it was always showing the epoch due to a bad input to strtoul). Improved the log parser so we only scan backwards towards the '\n' from the end of the prior log; during this scan the last '>' is remembered to improve performance (rather than scanning forward to it). If the log record matched is the last log record in the file only use its new sha1 value if the date matches exactly; otherwise we leave the passed in sha1 alone as it already contains the current value of the ref. This way lookups of dates later than the log end to stick with the current ref value in case the ref was updated without logging. If it looks like someone changed the ref without logging it and we are going to return the sha1 which should have been valid during the missing period then warn the user that there might be log data missing and thus their query result may not be accurate. The check isn't perfect as its just based on comparing the old and new sha1 values between the two log records but its better than not checking at all. Implemented test cases based on git-rev-parse for most of the boundary conditions. Signed-off-by: Shawn O. Pearce <spearce@spearce.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
511 lines
12 KiB
C
511 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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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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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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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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error("Can't read ref %s", path);
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unlock_ref(lock);
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return NULL;
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}
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lock->ref_file = strdup(path);
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lock->lock_file = strdup(mkpath("%s.lock", lock->ref_file));
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lock->log_file = strdup(git_path("logs/%s", lock->ref_file + plen));
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if (safe_create_leading_directories(lock->lock_file))
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die("unable to create directory for %s", lock->lock_file);
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lock->lock_fd = open(lock->lock_file,
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O_WRONLY | O_CREAT | O_EXCL, 0666);
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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->lock_file, 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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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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unlink(lock->lock_file);
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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->lock_file)
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free(lock->lock_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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} 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 (!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->lock_file);
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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 (rename(lock->lock_file, lock->ref_file) < 0) {
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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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} 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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} 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);
|
|
date = strtoul(rec + 1, &tz_c, 10);
|
|
tz = strtoul(tz_c, NULL, 10);
|
|
if (get_sha1_hex(logdata, sha1))
|
|
die("Log %s is corrupt.", logfile);
|
|
munmap((void*)logdata, st.st_size);
|
|
fprintf(stderr, "warning: Log %s only goes back to %s.\n",
|
|
logfile, show_rfc2822_date(date, tz));
|
|
return 0;
|
|
}
|