ref: a3b95d3e567c0ef60f9f1ead26124fb706dec20d
dir: /sys/src/cmd/git/serve.c/
#include <u.h> #include <libc.h> #include <ctype.h> #include <auth.h> #include "git.h" char *pathpfx = nil; int allowwrite; int showrefs(Conn *c) { int i, ret, nrefs; Hash head, *refs; char **names; ret = -1; nrefs = 0; refs = nil; names = nil; if(resolveref(&head, "HEAD") != -1) if(fmtpkt(c, "%H HEAD\n", head) == -1) goto error; if((nrefs = listrefs(&refs, &names)) == -1) sysfatal("listrefs: %r"); for(i = 0; i < nrefs; i++){ if(strncmp(names[i], "heads/", strlen("heads/")) != 0) continue; if(fmtpkt(c, "%H refs/%s\n", refs[i], names[i]) == -1) goto error; } if(flushpkt(c) == -1) goto error; ret = 0; error: for(i = 0; i < nrefs; i++) free(names[i]); free(names); free(refs); return ret; } int servnegotiate(Conn *c, Hash **head, int *nhead, Hash **tail, int *ntail) { char pkt[Pktmax]; int n, acked; Object *o; Hash h; if(showrefs(c) == -1) return -1; *head = nil; *tail = nil; *nhead = 0; *ntail = 0; while(1){ if((n = readpkt(c, pkt, sizeof(pkt))) == -1) goto error; if(n == 0) break; if(strncmp(pkt, "want ", 5) != 0){ werrstr(" protocol garble %s", pkt); goto error; } if(hparse(&h, &pkt[5]) == -1){ werrstr(" garbled want"); goto error; } if((o = readobject(h)) == nil){ werrstr("requested nonexistent object"); goto error; } unref(o); *head = erealloc(*head, (*nhead + 1)*sizeof(Hash)); (*head)[*nhead] = h; *nhead += 1; } acked = 0; while(1){ if((n = readpkt(c, pkt, sizeof(pkt))) == -1) goto error; if(strncmp(pkt, "done", 4) == 0) break; if(n == 0){ if(!acked && fmtpkt(c, "NAK") == -1) goto error; } if(strncmp(pkt, "have ", 5) != 0){ werrstr(" protocol garble %s", pkt); goto error; } if(hparse(&h, &pkt[5]) == -1){ werrstr(" garbled have"); goto error; } if((o = readobject(h)) == nil) continue; if(!acked){ if(fmtpkt(c, "ACK %H", h) == -1) goto error; acked = 1; } unref(o); *tail = erealloc(*tail, (*ntail + 1)*sizeof(Hash)); (*tail)[*ntail] = h; *ntail += 1; } if(!acked && fmtpkt(c, "NAK\n") == -1) goto error; return 0; error: fmtpkt(c, "ERR %r\n"); free(*head); free(*tail); return -1; } int servpack(Conn *c) { Hash *head, *tail, h; int nhead, ntail; dprint(1, "negotiating pack\n"); if(servnegotiate(c, &head, &nhead, &tail, &ntail) == -1) sysfatal("negotiate: %r"); dprint(1, "writing pack\n"); if(writepack(c->wfd, head, nhead, tail, ntail, &h) == -1) sysfatal("send: %r"); return 0; } int validref(char *s) { if(strncmp(s, "refs/", 5) != 0) return 0; for(; *s != '\0'; s++) if(!isalnum(*s) && strchr("/-_.", *s) == nil) return 0; return 1; } int recvnegotiate(Conn *c, Hash **cur, Hash **upd, char ***ref, int *nupd) { char pkt[Pktmax], *sp[4]; Hash old, new; int n, i; if(showrefs(c) == -1) return -1; *cur = nil; *upd = nil; *ref = nil; *nupd = 0; while(1){ if((n = readpkt(c, pkt, sizeof(pkt))) == -1) goto error; if(n == 0) break; if(getfields(pkt, sp, nelem(sp), 1, " \t\n\r") != 3){ fmtpkt(c, "ERR protocol garble %s\n", pkt); goto error; } if(hparse(&old, sp[0]) == -1){ fmtpkt(c, "ERR bad old hash %s\n", sp[0]); goto error; } if(hparse(&new, sp[1]) == -1){ fmtpkt(c, "ERR bad new hash %s\n", sp[1]); goto error; } if(!validref(sp[2])){ fmtpkt(c, "ERR invalid ref %s\n", sp[2]); goto error; } *cur = erealloc(*cur, (*nupd + 1)*sizeof(Hash)); *upd = erealloc(*upd, (*nupd + 1)*sizeof(Hash)); *ref = erealloc(*ref, (*nupd + 1)*sizeof(Hash)); (*cur)[*nupd] = old; (*upd)[*nupd] = new; (*ref)[*nupd] = estrdup(sp[2]); *nupd += 1; } return 0; error: free(*cur); free(*upd); for(i = 0; i < *nupd; i++) free((*ref)[i]); free(*ref); return -1; } int rename(char *pack, char *idx, Hash h) { char name[128], path[196]; Dir st; nulldir(&st); st.name = name; snprint(name, sizeof(name), "%H.pack", h); snprint(path, sizeof(path), ".git/objects/pack/%s", name); if(access(path, AEXIST) == 0) fprint(2, "warning, pack %s already pushed\n", name); else if(dirwstat(pack, &st) == -1) return -1; snprint(name, sizeof(name), "%H.idx", h); snprint(path, sizeof(path), ".git/objects/pack/%s", name); if(access(path, 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; if(seek(fd, 0, 0) == -1) sysfatal("packfile seek: %r"); 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){ werrstr("short read"); 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 mkdir(char *dir) { char buf[ERRMAX]; int f; if(access(dir, AEXIST) == 0) return 0; if((f = create(dir, OREAD, DMDIR | 0755)) == -1){ rerrstr(buf, sizeof(buf)); if(strstr(buf, "exist") == nil) return -1; } close(f); return 0; } int updatepack(Conn *c) { char buf[Pktmax], packtmp[128], idxtmp[128], ebuf[ERRMAX]; int n, pfd, packsz; Hash h; /* make sure the needed dirs exist */ if(mkdir(".git/objects") == -1) return -1; if(mkdir(".git/objects/pack") == -1) return -1; if(mkdir(".git/refs") == -1) return -1; if(mkdir(".git/refs/heads") == -1) return -1; snprint(packtmp, sizeof(packtmp), ".git/objects/pack/recv-%d.pack.tmp", getpid()); snprint(idxtmp, sizeof(idxtmp), ".git/objects/pack/recv-%d.idx.tmp", getpid()); if((pfd = create(packtmp, ORDWR, 0644)) == -1) return -1; packsz = 0; while(1){ n = read(c->rfd, buf, sizeof(buf)); if(n == 0) break; if(n == -1){ rerrstr(ebuf, sizeof(ebuf)); if(strstr(ebuf, "hungup") == nil) return -1; break; } if(write(pfd, buf, n) != n) return -1; packsz += n; } if(checkhash(pfd, packsz, &h) == -1){ dprint(1, "hash mismatch\n"); goto error1; } if(indexpack(packtmp, idxtmp, h) == -1){ dprint(1, "indexing failed: %r\n"); goto error1; } if(rename(packtmp, idxtmp, h) == -1){ dprint(1, "rename failed: %r\n"); goto error2; } return 0; error2: remove(idxtmp); error1: remove(packtmp); return -1; } int lockrepo(void) { int fd, i; for(i = 0; i < 10; i++) { if((fd = create(".git/_lock", ORCLOSE|ORDWR|OTRUNC|OEXCL, 0644))!= -1) return fd; sleep(250); } return -1; } int updaterefs(Conn *c, Hash *cur, Hash *upd, char **ref, int nupd) { char refpath[512], buf[128]; int i, newidx, hadref, fd, ret, lockfd; vlong newtm; Object *o; Hash h; ret = -1; hadref = 0; newidx = -1; /* * Date of Magna Carta. * Wrong because it was computed using * the proleptic gregorian calendar. */ newtm = -23811206400; if((lockfd = lockrepo()) == -1){ snprint(buf, sizeof(buf), "repo locked\n"); return -1; } for(i = 0; i < nupd; i++){ if(resolveref(&h, ref[i]) == 0){ hadref = 1; if(!hasheq(&h, &cur[i])){ snprint(buf, sizeof(buf), "old ref changed: %s", ref[i]); goto error; } } if(snprint(refpath, sizeof(refpath), ".git/%s", ref[i]) == sizeof(refpath)){ snprint(buf, sizeof(buf), "ref path too long: %s", ref[i]); goto error; } if(hasheq(&upd[i], &Zhash)){ remove(refpath); continue; } if((o = readobject(upd[i])) == nil){ snprint(buf, sizeof(buf), "update to nonexistent hash %H", upd[i]); goto error; } if(o->type != GCommit){ snprint(buf, sizeof(buf), "not commit: %H", upd[i]); goto error; } if(o->commit->mtime > newtm){ newtm = o->commit->mtime; newidx = i; } unref(o); if((fd = create(refpath, OWRITE|OTRUNC, 0644)) == -1){ snprint(buf, sizeof(buf), "open ref: %r"); goto error; } if(fprint(fd, "%H", upd[i]) == -1){ snprint(buf, sizeof(buf), "upate ref: %r"); close(fd); goto error; } close(fd); } /* * Heuristic: * If there are no valid refs, and HEAD is invalid, then * pick the ref with the newest commits as the default * branch. * * Several people have been caught out by pushing to * a repo where HEAD named differently from what got * pushed, and this is going to be more of a footgun * when 'master', 'main', and 'front' are all in active * use. This should make us pick a useful default in * those cases, instead of silently failing. */ if(resolveref(&h, "HEAD") == -1 && hadref == 0 && newidx != -1){ if((fd = create(".git/HEAD", OWRITE|OTRUNC, 0644)) == -1){ snprint(buf, sizeof(buf), "open HEAD: %r"); goto error; } if(fprint(fd, "ref: %s", ref[0]) == -1){ snprint(buf, sizeof(buf), "write HEAD ref: %r"); goto error; } close(fd); } ret = 0; error: fmtpkt(c, "ERR %s", buf); close(lockfd); werrstr(buf); return ret; } int recvpack(Conn *c) { Hash *cur, *upd; char **ref; int nupd; if(recvnegotiate(c, &cur, &upd, &ref, &nupd) == -1) sysfatal("negotiate refs: %r"); if(nupd != 0 && updatepack(c) == -1) sysfatal("update pack: %r"); if(nupd != 0 && updaterefs(c, cur, upd, ref, nupd) == -1) sysfatal("update refs: %r"); return 0; } char* parsecmd(char *buf, char *cmd, int ncmd) { int i; char *p; for(p = buf, i = 0; *p && i < ncmd - 1; i++, p++){ if(*p == ' ' || *p == '\t'){ cmd[i] = 0; break; } cmd[i] = *p; } while(*p == ' ' || *p == '\t') p++; return p; } void usage(void) { fprint(2, "usage: %s [-dw] [-r rel]\n", argv0); exits("usage"); } void main(int argc, char **argv) { char *repo, cmd[32], buf[512]; Conn c; ARGBEGIN{ case 'd': chattygit++; break; case 'r': pathpfx = EARGF(usage()); if(*pathpfx != '/') sysfatal("path prefix must begin with '/'"); break; case 'w': allowwrite++; break; default: usage(); break; }ARGEND; gitinit(); interactive = 0; if(rfork(RFNAMEG) == -1) sysfatal("rfork: %r"); if(pathpfx != nil){ if(bind(pathpfx, "/", MREPL) == -1) sysfatal("bind: %r"); } if(rfork(RFNOMNT) == -1) sysfatal("rfork: %r"); initconn(&c, 0, 1); if(readpkt(&c, buf, sizeof(buf)) == -1) sysfatal("readpkt: %r"); repo = parsecmd(buf, cmd, sizeof(cmd)); cleanname(repo); if(strncmp(repo, "../", 3) == 0) sysfatal("invalid path %s\n", repo); if(bind(repo, "/", MREPL) == -1){ fmtpkt(&c, "ERR no repo %r\n"); sysfatal("enter %s: %r", repo); } if(chdir("/") == -1) sysfatal("chdir: %r"); if(access(".git", AREAD) == -1) sysfatal("no git repository"); if(strcmp(cmd, "git-receive-pack") == 0 && allowwrite) recvpack(&c); else if(strcmp(cmd, "git-upload-pack") == 0) servpack(&c); else sysfatal("unsupported command '%s'", cmd); exits(nil); }