ref: e33368493eae299479a49cf528b4b6060e069c67
parent: 72ba278a188950bf0d09f4459e396269d6ec8505
author: Ori Bernstein <ori@eigenstate.org>
date: Sun Jun 4 11:07:16 EDT 2023
add missing file
--- /dev/null
+++ b/get.c
@@ -1,0 +1,419 @@
+#include <u.h>
+#include <libc.h>
+
+#include "git.h"
+
+char *fetchbranch;
+char *upstream = "origin";
+int listonly;
+
+int
+resolveremote(Hash *h, char *ref)
+{+ char buf[128], *s;
+ int r, f;
+
+ ref = strip(ref);
+ if((r = hparse(h, ref)) != -1)
+ return r;
+ /* Slightly special handling: translate remote refs to local ones. */
+ if(strcmp(ref, "HEAD") == 0){+ snprint(buf, sizeof(buf), ".git/HEAD");
+ }else if(strstr(ref, "refs/heads") == ref){+ ref += strlen("refs/heads");+ snprint(buf, sizeof(buf), ".git/refs/remotes/%s/%s", upstream, ref);
+ }else if(strstr(ref, "refs/tags") == ref){+ ref += strlen("refs/tags");+ snprint(buf, sizeof(buf), ".git/refs/tags/%s/%s", upstream, ref);
+ }else{+ return -1;
+ }
+
+ r = -1;
+ s = strip(buf);
+ if((f = open(s, OREAD)) == -1)
+ return -1;
+ if(readn(f, buf, sizeof(buf)) >= 40)
+ r = hparse(h, buf);
+ close(f);
+
+ if(r == -1 && strstr(buf, "ref:") == buf)
+ return resolveremote(h, buf + strlen("ref:"));+ return r;
+}
+
+int
+rename(char *pack, char *idx, Hash h)
+{+ char name[128];
+ Dir st;
+
+ nulldir(&st);
+ st.name = name;
+ snprint(name, sizeof(name), "%H.pack", h);
+ if(access(name, AEXIST) == 0)
+ fprint(2, "warning, pack %s already fetched\n", name);
+ else if(dirwstat(pack, &st) == -1)
+ return -1;
+ snprint(name, sizeof(name), "%H.idx", h);
+ if(access(name, AEXIST) == 0)
+ fprint(2, "warning, pack %s already indexed\n", name);
+ else if(dirwstat(idx, &st) == -1)
+ return -1;
+ return 0;
+}
+
+int
+checkhash(int fd, vlong sz, Hash *hcomp)
+{+ DigestState *st;
+ Hash hexpect;
+ char buf[Pktmax];
+ vlong n, r;
+ int nr;
+
+ if(sz < 28){+ werrstr("undersize packfile");+ return -1;
+ }
+
+ st = nil;
+ n = 0;
+ while(n != sz - 20){+ nr = sizeof(buf);
+ if(sz - n - 20 < sizeof(buf))
+ nr = sz - n - 20;
+ r = readn(fd, buf, nr);
+ if(r != nr)
+ return -1;
+ st = sha1((uchar*)buf, nr, nil, st);
+ n += r;
+ }
+ sha1(nil, 0, hcomp->h, st);
+ if(readn(fd, hexpect.h, sizeof(hexpect.h)) != sizeof(hexpect.h))
+ sysfatal("truncated packfile");+ if(!hasheq(hcomp, &hexpect)){+ werrstr("bad hash: %H != %H", *hcomp, hexpect);+ return -1;
+ }
+ return 0;
+}
+
+int
+mkoutpath(char *path)
+{+ char s[128];
+ char *p;
+ int fd;
+
+ snprint(s, sizeof(s), "%s", path);
+ for(p=strchr(s+1, '/'); p; p=strchr(p+1, '/')){+ *p = 0;
+ if(access(s, AEXIST) != 0){+ fd = create(s, OREAD, DMDIR | 0775);
+ if(fd == -1)
+ return -1;
+ close(fd);
+ }
+ *p = '/';
+ }
+ return 0;
+}
+
+int
+branchmatch(char *br, char *pat)
+{+ char name[128];
+
+ if(strstr(pat, "refs/heads") == pat)
+ snprint(name, sizeof(name), "%s", pat);
+ else if(strstr(pat, "heads"))
+ snprint(name, sizeof(name), "refs/%s", pat);
+ else
+ snprint(name, sizeof(name), "refs/heads/%s", pat);
+ return strcmp(br, name) == 0;
+}
+
+char *
+matchcap(char *s, char *cap, int full)
+{+ if(strncmp(s, cap, strlen(cap)) == 0)
+ if(!full || strlen(s) == strlen(cap))
+ return s + strlen(cap);
+ return nil;
+}
+
+void
+handlecaps(char *caps)
+{+ char *p, *n, *c, *r;
+
+ for(p = caps; p != nil; p = n){+ n = strchr(p, ' ');
+ if(n != nil)
+ *n++ = 0;
+ if((c = matchcap(p, "symref=", 0)) != nil){+ if((r = strchr(c, ':')) != nil){+ *r++ = '\0';
+ print("symref %s %s\n", c, r);+ }
+ }
+ }
+}
+
+void
+fail(char *pack, char *idx, char *msg, ...)
+{+ char buf[ERRMAX];
+ va_list ap;
+
+ va_start(ap, msg);
+ snprint(buf, sizeof(buf), msg, ap);
+ va_end(ap);
+
+ remove(pack);
+ remove(idx);
+ fprint(2, "%s", buf);
+ exits(buf);
+}
+
+void
+enqueueparent(Objq *q, Object *o)
+{+ Object *p;
+ int i;
+
+ if(o->type != GCommit)
+ return;
+ for(i = 0; i < o->commit->nparent; i++){+ if((p = readobject(o->commit->parent[i])) == nil)
+ continue;
+ qput(q, p, 0);
+ unref(p);
+ }
+}
+
+int
+fetchpack(Conn *c)
+{+ char buf[Pktmax], *sp[3], *ep;
+ char *packtmp, *idxtmp, **ref, *caps;
+ Hash h, *have, *want;
+ int nref, refsz, first, nsent;
+ int i, l, n, req, pfd;
+ vlong packsz;
+ Objset hadobj;
+ Object *o;
+ Objq haveq;
+ Qelt e;
+
+ nref = 0;
+ refsz = 16;
+ first = 1;
+ have = eamalloc(refsz, sizeof(have[0]));
+ want = eamalloc(refsz, sizeof(want[0]));
+ ref = eamalloc(refsz, sizeof(ref[0]));
+ while(1){+ n = readpkt(c, buf, sizeof(buf));
+ if(n == -1)
+ return -1;
+ if(n == 0)
+ break;
+ if(strncmp(buf, "ERR ", 4) == 0)
+ sysfatal("%s", buf + 4);+
+ if(first && n > strlen(buf))
+ handlecaps(buf + strlen(buf) + 1);
+ first = 0;
+
+ getfields(buf, sp, nelem(sp), 1, " \t\n\r");
+ if(strstr(sp[1], "^{}"))+ continue;
+ if(fetchbranch && !branchmatch(sp[1], fetchbranch))
+ continue;
+ if(refsz == nref + 1){+ refsz *= 2;
+ have = earealloc(have, refsz, sizeof(have[0]));
+ want = earealloc(want, refsz, sizeof(want[0]));
+ ref = earealloc(ref, refsz, sizeof(ref[0]));
+ }
+ if(hparse(&want[nref], sp[0]) == -1)
+ sysfatal("invalid hash %s", sp[0]);+ if (resolveremote(&have[nref], sp[1]) == -1)
+ memset(&have[nref], 0, sizeof(have[nref]));
+ ref[nref] = estrdup(sp[1]);
+ nref++;
+ }
+ if(listonly){+ flushpkt(c);
+ goto showrefs;
+ }
+
+ if(writephase(c) == -1)
+ sysfatal("write: %r");+ req = 0;
+ caps = " multi_ack";
+ for(i = 0; i < nref; i++){+ if(hasheq(&have[i], &want[i]))
+ continue;
+ if((o = readobject(want[i])) != nil){+ unref(o);
+ continue;
+ }
+ if(fmtpkt(c, "want %H%s\n", want[i], caps) == -1)
+ sysfatal("could not send want for %H", want[i]);+ caps = "";
+ req = 1;
+ }
+ flushpkt(c);
+
+ nsent = 0;
+ qinit(&haveq);
+ osinit(&hadobj);
+ /*
+ * We know we have these objects, and we want to make sure that
+ * they end up at the front of the queue. Send the 'have lines'
+ * first, and then enqueue their parents for a second round of
+ * sends.
+ */
+ for(i = 0; i < nref; i++){+ if(hasheq(&have[i], &Zhash) || oshas(&hadobj, have[i]))
+ continue;
+ if((o = readobject(have[i])) == nil)
+ sysfatal("missing object we should have: %H", have[i]);+ if(fmtpkt(c, "have %H", o->hash) == -1)
+ sysfatal("write: %r");+ enqueueparent(&haveq, o);
+ osadd(&hadobj, o);
+ unref(o);
+ }
+ /*
+ * While we could short circuit this and check if upstream has
+ * acked our objects, for the first 256 haves, this is simple
+ * enough.
+ *
+ * Also, doing multiple rounds of reference discovery breaks
+ * when using smart http.
+ */
+ while(req && qpop(&haveq, &e) && nsent < 256){+ if(oshas(&hadobj, e.o->hash))
+ continue;
+ if((o = readobject(e.o->hash)) == nil)
+ sysfatal("missing object we should have: %H", have[i]);+ if(fmtpkt(c, "have %H", o->hash) == -1)
+ sysfatal("write: %r");+ enqueueparent(&haveq, o);
+ osadd(&hadobj, o);
+ unref(o);
+ nsent++;
+ }
+ osclear(&hadobj);
+ qclear(&haveq);
+ if(!req)
+ flushpkt(c);
+ if(fmtpkt(c, "done\n") == -1)
+ sysfatal("write: %r");+ if(!req)
+ goto showrefs;
+ if(readphase(c) == -1)
+ sysfatal("read: %r");+ if((n = readpkt(c, buf, sizeof(buf))) == -1)
+ sysfatal("read: %r");+ buf[n] = 0;
+
+ if((packtmp = smprint(".git/objects/pack/fetch.%d.pack", getpid())) == nil)+ sysfatal("smprint: %r");+ if((idxtmp = smprint(".git/objects/pack/fetch.%d.idx", getpid())) == nil)+ sysfatal("smprint: %r");+ if(mkoutpath(packtmp) == -1)
+ sysfatal("could not create %s: %r", packtmp);+ if((pfd = create(packtmp, ORDWR, 0664)) == -1)
+ sysfatal("could not create %s: %r", packtmp);+
+ fprint(2, "fetching...\n");
+ /*
+ * Work around torvalds git bug: we get duplicate have lines
+ * somtimes, even though the protocol is supposed to start the
+ * pack file immediately.
+ *
+ * Skip ahead until we read 'PACK' off the wire
+ */
+ while(1){+ if(readn(c->rfd, buf, 4) != 4)
+ sysfatal("fetch packfile: short read");+ buf[4] = 0;
+ if(strncmp(buf, "PACK", 4) == 0)
+ break;
+ l = strtol(buf, &ep, 16);
+ if(ep != buf + 4)
+ sysfatal("fetch packfile: junk pktline");+ if(readn(c->rfd, buf, l-4) != l-4)
+ sysfatal("fetch packfile: short read");+ }
+ if(write(pfd, "PACK", 4) != 4)
+ sysfatal("write pack header: %r");+ packsz = 4;
+ while(1){+ n = read(c->rfd, buf, sizeof buf);
+ if(n == 0)
+ break;
+ if(n == -1 || write(pfd, buf, n) != n)
+ sysfatal("fetch packfile: %r");+ packsz += n;
+ }
+
+ closeconn(c);
+ if(seek(pfd, 0, 0) == -1)
+ fail(packtmp, idxtmp, "packfile seek: %r");
+ if(checkhash(pfd, packsz, &h) == -1)
+ fail(packtmp, idxtmp, "corrupt packfile: %r");
+ close(pfd);
+ if(indexpack(packtmp, idxtmp, h) == -1)
+ fail(packtmp, idxtmp, "could not index fetched pack: %r");
+ if(rename(packtmp, idxtmp, h) == -1)
+ fail(packtmp, idxtmp, "could not rename indexed pack: %r");
+
+showrefs:
+ for(i = 0; i < nref; i++){+ print("remote %s %H local %H\n", ref[i], want[i], have[i]);+ free(ref[i]);
+ }
+ free(ref);
+ free(want);
+ free(have);
+ return 0;
+}
+
+void
+usage(void)
+{+ fprint(2, "usage: %s [-dl] [-b br] [-u upstream] remote\n", argv0);
+ fprint(2, "\t-b br: only fetch matching branch 'br'\n");
+ fprint(2, "remote: fetch from this repository\n");
+ exits("usage");+}
+
+void
+main(int argc, char **argv)
+{+ Conn c;
+
+ ARGBEGIN{+ case 'b': fetchbranch=EARGF(usage()); break;
+ case 'u': upstream=EARGF(usage()); break;
+ case 'd': chattygit++; break;
+ case 'l': listonly++; break;
+ default: usage(); break;
+ }ARGEND;
+
+ gitinit();
+ if(argc != 1)
+ usage();
+
+ if(gitconnect(&c, argv[0], "upload") == -1)
+ sysfatal("could not dial %s: %r", argv[0]);+ if(fetchpack(&c) == -1)
+ sysfatal("fetch failed: %r");+ closeconn(&c);
+ exits(nil);
+}