mirror of
https://github.com/git/git
synced 2024-08-25 02:35:46 +00:00
ed378ec7e8
The old code used to totally mix up the notion of a ref-name and the path that that ref was associated with. That was not only horribly ugly (a number of users got the path, and then wanted to try to turn it back into a ref-name again), but it fundamnetally doesn't work at all once we do any setup where a ref doesn't have a 1:1 relationship with a particular pathname. This fixes things up so that we use the ref-name throughout, and only turn it into a pathname once we actually look it up in the filesystem. That makes a lot of things much clearer and more straightforward. Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
648 lines
15 KiB
C
648 lines
15 KiB
C
#include "refs.h"
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#include "cache.h"
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#include <errno.h>
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struct ref_list {
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struct ref_list *next;
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unsigned char sha1[20];
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char name[FLEX_ARRAY];
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};
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static const char *parse_ref_line(char *line, unsigned char *sha1)
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{
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/*
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* 42: the answer to everything.
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*
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* In this case, it happens to be the answer to
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* 40 (length of sha1 hex representation)
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* +1 (space in between hex and name)
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* +1 (newline at the end of the line)
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*/
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int len = strlen(line) - 42;
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if (len <= 0)
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return NULL;
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if (get_sha1_hex(line, sha1) < 0)
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return NULL;
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if (!isspace(line[40]))
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return NULL;
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line += 41;
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if (line[len] != '\n')
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return NULL;
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line[len] = 0;
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return line;
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}
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static struct ref_list *add_ref(const char *name, const unsigned char *sha1, struct ref_list *list)
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{
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int len;
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struct ref_list **p = &list, *entry;
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/* Find the place to insert the ref into.. */
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while ((entry = *p) != NULL) {
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int cmp = strcmp(entry->name, name);
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if (cmp > 0)
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break;
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/* Same as existing entry? */
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if (!cmp)
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return list;
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p = &entry->next;
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}
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/* Allocate it and add it in.. */
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len = strlen(name) + 1;
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entry = xmalloc(sizeof(struct ref_list) + len);
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hashcpy(entry->sha1, sha1);
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memcpy(entry->name, name, len);
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entry->next = *p;
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*p = entry;
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return list;
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}
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static struct ref_list *get_packed_refs(void)
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{
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static int did_refs = 0;
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static struct ref_list *refs = NULL;
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if (!did_refs) {
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FILE *f = fopen(git_path("packed-refs"), "r");
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if (f) {
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struct ref_list *list = NULL;
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char refline[PATH_MAX];
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while (fgets(refline, sizeof(refline), f)) {
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unsigned char sha1[20];
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const char *name = parse_ref_line(refline, sha1);
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if (!name)
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continue;
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list = add_ref(name, sha1, list);
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}
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fclose(f);
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refs = list;
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}
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did_refs = 1;
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}
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return refs;
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}
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static struct ref_list *get_ref_dir(const char *base, struct ref_list *list)
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{
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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 *ref = xmalloc(baselen + 257);
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memcpy(ref, base, baselen);
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if (baselen && base[baselen-1] != '/')
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ref[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 (has_extension(de->d_name, ".lock"))
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continue;
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memcpy(ref + baselen, de->d_name, namelen+1);
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if (stat(git_path("%s", ref), &st) < 0)
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continue;
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if (S_ISDIR(st.st_mode)) {
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list = get_ref_dir(ref, list);
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continue;
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}
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if (read_ref(ref, sha1) < 0) {
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error("%s points nowhere!", ref);
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continue;
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}
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list = add_ref(ref, sha1, list);
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}
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free(ref);
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closedir(dir);
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}
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return list;
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}
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static struct ref_list *get_loose_refs(void)
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{
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static int did_refs = 0;
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static struct ref_list *refs = NULL;
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if (!did_refs) {
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refs = get_ref_dir("refs", NULL);
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did_refs = 1;
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}
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return refs;
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}
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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 *ref, 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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static char ref_buffer[256];
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for (;;) {
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const char *path = git_path("%s", ref);
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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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hashclr(sha1);
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return ref;
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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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buffer[len] = 0;
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strcpy(ref_buffer, buffer);
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ref = ref_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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len--;
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buf[len] = 0;
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memcpy(ref_buffer, buf, len + 1);
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ref = ref_buffer;
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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 ref;
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}
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int create_symref(const char *ref_target, 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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const char *git_HEAD = git_path("%s", ref_target);
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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 *ref, unsigned char *sha1)
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{
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if (resolve_ref(ref, 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;
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struct ref_list *packed = get_packed_refs();
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struct ref_list *loose = get_loose_refs();
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while (packed && loose) {
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struct ref_list *entry;
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int cmp = strcmp(packed->name, loose->name);
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if (!cmp) {
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packed = packed->next;
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continue;
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}
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if (cmp > 0) {
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entry = loose;
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loose = loose->next;
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} else {
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entry = packed;
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packed = packed->next;
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}
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if (strncmp(base, entry->name, trim))
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continue;
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if (is_null_sha1(entry->sha1))
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continue;
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if (!has_sha1_file(entry->sha1)) {
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error("%s does not point to a valid object!", entry->name);
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continue;
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}
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retval = fn(entry->name + trim, entry->sha1);
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if (retval)
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return retval;
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}
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packed = packed ? packed : loose;
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while (packed) {
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if (!strncmp(base, packed->name, trim)) {
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retval = fn(packed->name + trim, packed->sha1);
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if (retval)
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return retval;
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}
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packed = packed->next;
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}
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return 0;
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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("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(mkpath("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 (hashcmp(lock->old_sha1, old_sha1)) {
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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 *ref,
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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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const char *orig_ref = ref;
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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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ref = resolve_ref(ref, lock->old_sha1, mustexist);
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if (!ref) {
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int last_errno = errno;
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error("unable to resolve reference %s: %s",
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orig_ref, strerror(errno));
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unlock_ref(lock);
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errno = last_errno;
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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 = xstrdup(git_path("%s", ref));
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lock->log_file = xstrdup(git_path("logs/%s", ref));
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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, 1);
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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(mkpath("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(ref, 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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free(lock->ref_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 *committer;
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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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committer = git_committer_info(1);
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if (msg) {
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maxlen = strlen(committer) + 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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committer,
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msg);
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}
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else {
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maxlen = strlen(committer) + 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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committer);
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}
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written = len <= maxlen ? write(logfd, logrec, len) : -1;
|
|
free(logrec);
|
|
close(logfd);
|
|
if (written != len)
|
|
return error("Unable to append to %s", lock->log_file);
|
|
return 0;
|
|
}
|
|
|
|
int write_ref_sha1(struct ref_lock *lock,
|
|
const unsigned char *sha1, const char *logmsg)
|
|
{
|
|
static char term = '\n';
|
|
|
|
if (!lock)
|
|
return -1;
|
|
if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
|
|
unlock_ref(lock);
|
|
return 0;
|
|
}
|
|
if (write(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
|
|
write(lock->lock_fd, &term, 1) != 1
|
|
|| close(lock->lock_fd) < 0) {
|
|
error("Couldn't write %s", lock->lk->filename);
|
|
unlock_ref(lock);
|
|
return -1;
|
|
}
|
|
if (log_ref_write(lock, sha1, logmsg) < 0) {
|
|
unlock_ref(lock);
|
|
return -1;
|
|
}
|
|
if (commit_lock_file(lock->lk)) {
|
|
error("Couldn't set %s", lock->ref_file);
|
|
unlock_ref(lock);
|
|
return -1;
|
|
}
|
|
lock->lock_fd = -1;
|
|
unlock_ref(lock);
|
|
return 0;
|
|
}
|
|
|
|
int read_ref_at(const char *ref, unsigned long at_time, unsigned char *sha1)
|
|
{
|
|
const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
|
|
char *tz_c;
|
|
int logfd, tz;
|
|
struct stat st;
|
|
unsigned long date;
|
|
unsigned char logged_sha1[20];
|
|
|
|
logfile = git_path("logs/%s", ref);
|
|
logfd = open(logfile, O_RDONLY, 0);
|
|
if (logfd < 0)
|
|
die("Unable to read log %s: %s", logfile, strerror(errno));
|
|
fstat(logfd, &st);
|
|
if (!st.st_size)
|
|
die("Log %s is empty.", logfile);
|
|
logdata = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, logfd, 0);
|
|
close(logfd);
|
|
|
|
lastrec = NULL;
|
|
rec = logend = logdata + st.st_size;
|
|
while (logdata < rec) {
|
|
if (logdata < rec && *(rec-1) == '\n')
|
|
rec--;
|
|
lastgt = NULL;
|
|
while (logdata < rec && *(rec-1) != '\n') {
|
|
rec--;
|
|
if (*rec == '>')
|
|
lastgt = rec;
|
|
}
|
|
if (!lastgt)
|
|
die("Log %s is corrupt.", logfile);
|
|
date = strtoul(lastgt + 1, &tz_c, 10);
|
|
if (date <= at_time) {
|
|
if (lastrec) {
|
|
if (get_sha1_hex(lastrec, logged_sha1))
|
|
die("Log %s is corrupt.", logfile);
|
|
if (get_sha1_hex(rec + 41, sha1))
|
|
die("Log %s is corrupt.", logfile);
|
|
if (hashcmp(logged_sha1, sha1)) {
|
|
tz = strtoul(tz_c, NULL, 10);
|
|
fprintf(stderr,
|
|
"warning: Log %s has gap after %s.\n",
|
|
logfile, show_rfc2822_date(date, tz));
|
|
}
|
|
}
|
|
else if (date == at_time) {
|
|
if (get_sha1_hex(rec + 41, sha1))
|
|
die("Log %s is corrupt.", logfile);
|
|
}
|
|
else {
|
|
if (get_sha1_hex(rec + 41, logged_sha1))
|
|
die("Log %s is corrupt.", logfile);
|
|
if (hashcmp(logged_sha1, sha1)) {
|
|
tz = strtoul(tz_c, NULL, 10);
|
|
fprintf(stderr,
|
|
"warning: Log %s unexpectedly ended on %s.\n",
|
|
logfile, show_rfc2822_date(date, tz));
|
|
}
|
|
}
|
|
munmap((void*)logdata, st.st_size);
|
|
return 0;
|
|
}
|
|
lastrec = rec;
|
|
}
|
|
|
|
rec = logdata;
|
|
while (rec < logend && *rec != '>' && *rec != '\n')
|
|
rec++;
|
|
if (rec == logend || *rec == '\n')
|
|
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;
|
|
}
|