mirror of
https://github.com/git/git
synced 2024-09-12 21:04:12 +00:00
b1c71b7281
When the repository on the remote side is corrupted, rev-list spawned from upload-pack would die with error, but pack-objects that reads from the rev-list happily created a packfile that can be unpacked by the downloader. When this happens, the resulting packfile is not corrupted and unpacks cleanly, but the list of the objects contained in it is not what the protocol exchange computed. This update makes upload-pack to monitor its subprocesses, and when either of them dies with error, sends an incomplete pack data to the downloader to cause it to fail. Signed-off-by: Junio C Hamano <junkio@cox.net>
442 lines
9.6 KiB
C
442 lines
9.6 KiB
C
#include "cache.h"
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#include "refs.h"
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#include "pkt-line.h"
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#include "tag.h"
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#include "object.h"
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#include "commit.h"
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#include "exec_cmd.h"
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#include <signal.h>
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#include <sys/poll.h>
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#include <sys/wait.h>
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static const char upload_pack_usage[] = "git-upload-pack [--strict] [--timeout=nn] <dir>";
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#define THEY_HAVE (1U << 0)
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#define OUR_REF (1U << 1)
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#define WANTED (1U << 2)
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#define MAX_HAS 256
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#define MAX_NEEDS 256
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static int nr_has = 0, nr_needs = 0, multi_ack = 0, nr_our_refs = 0;
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static int use_thin_pack = 0;
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static unsigned char has_sha1[MAX_HAS][20];
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static unsigned char needs_sha1[MAX_NEEDS][20];
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static unsigned int timeout = 0;
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static void reset_timeout(void)
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{
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alarm(timeout);
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}
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static int strip(char *line, int len)
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{
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if (len && line[len-1] == '\n')
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line[--len] = 0;
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return len;
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}
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static void create_pack_file(void)
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{
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/* Pipes between rev-list to pack-objects and pack-objects to us. */
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int lp_pipe[2], pu_pipe[2];
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pid_t pid_rev_list, pid_pack_objects;
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int create_full_pack = (nr_our_refs == nr_needs && !nr_has);
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char data[8193];
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int buffered = -1;
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if (pipe(lp_pipe) < 0)
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die("git-upload-pack: unable to create pipe");
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pid_rev_list = fork();
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if (pid_rev_list < 0)
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die("git-upload-pack: unable to fork git-rev-list");
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if (!pid_rev_list) {
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int i;
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int args;
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const char **argv;
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char *buf;
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char **p;
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if (create_full_pack) {
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args = 10;
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use_thin_pack = 0; /* no point doing it */
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}
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else
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args = nr_has + nr_needs + 5;
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p = xmalloc(args * sizeof(char *));
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argv = (const char **) p;
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buf = xmalloc(args * 45);
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dup2(lp_pipe[1], 1);
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close(0);
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close(lp_pipe[0]);
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close(lp_pipe[1]);
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*p++ = "rev-list";
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*p++ = use_thin_pack ? "--objects-edge" : "--objects";
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if (create_full_pack || MAX_NEEDS <= nr_needs)
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*p++ = "--all";
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else {
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for (i = 0; i < nr_needs; i++) {
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*p++ = buf;
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memcpy(buf, sha1_to_hex(needs_sha1[i]), 41);
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buf += 41;
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}
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}
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if (!create_full_pack)
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for (i = 0; i < nr_has; i++) {
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*p++ = buf;
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*buf++ = '^';
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memcpy(buf, sha1_to_hex(has_sha1[i]), 41);
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buf += 41;
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}
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*p++ = NULL;
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execv_git_cmd(argv);
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die("git-upload-pack: unable to exec git-rev-list");
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}
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if (pipe(pu_pipe) < 0)
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die("git-upload-pack: unable to create pipe");
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pid_pack_objects = fork();
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if (pid_pack_objects < 0) {
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/* daemon sets things up to ignore TERM */
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kill(pid_rev_list, SIGKILL);
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die("git-upload-pack: unable to fork git-pack-objects");
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}
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if (!pid_pack_objects) {
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dup2(lp_pipe[0], 0);
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dup2(pu_pipe[1], 1);
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close(lp_pipe[0]);
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close(lp_pipe[1]);
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close(pu_pipe[0]);
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close(pu_pipe[1]);
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execl_git_cmd("pack-objects", "--stdout", NULL);
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kill(pid_rev_list, SIGKILL);
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die("git-upload-pack: unable to exec git-pack-objects");
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}
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close(lp_pipe[0]);
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close(lp_pipe[1]);
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/* We read from pu_pipe[0] to capture the pack data.
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*/
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close(pu_pipe[1]);
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while (1) {
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const char *who;
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struct pollfd pfd[2];
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pid_t pid;
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int status;
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ssize_t sz;
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int pu, pollsize;
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pollsize = 0;
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pu = -1;
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if (0 <= pu_pipe[0]) {
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pfd[pollsize].fd = pu_pipe[0];
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pfd[pollsize].events = POLLIN;
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pu = pollsize;
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pollsize++;
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}
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if (pollsize) {
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if (poll(pfd, pollsize, -1) < 0) {
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if (errno != EINTR) {
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error("poll failed, resuming: %s",
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strerror(errno));
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sleep(1);
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}
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continue;
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}
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if (0 <= pu && (pfd[pu].revents & (POLLIN|POLLHUP))) {
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/* Data ready; we keep the last byte
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* to ourselves in case we detect
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* broken rev-list, so that we can
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* leave the stream corrupted. This
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* is unfortunate -- unpack-objects
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* would happily accept a valid pack
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* data with trailing garbage, so
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* appending garbage after we pass all
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* the pack data is not good enough to
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* signal breakage to downstream.
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*/
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char *cp = data;
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ssize_t outsz = 0;
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if (0 <= buffered) {
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*cp++ = buffered;
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outsz++;
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}
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sz = read(pu_pipe[0], cp,
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sizeof(data) - outsz);
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if (0 < sz)
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;
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else if (sz == 0) {
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close(pu_pipe[0]);
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pu_pipe[0] = -1;
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}
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else
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goto fail;
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sz += outsz;
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if (1 < sz) {
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buffered = data[sz-1] & 0xFF;
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sz--;
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}
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else
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buffered = -1;
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sz = xwrite(1, data, sz);
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if (sz < 0)
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goto fail;
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}
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}
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/* See if the children are still there */
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if (pid_rev_list || pid_pack_objects) {
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pid = waitpid(-1, &status, WNOHANG);
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if (!pid)
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continue;
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who = ((pid == pid_rev_list) ? "git-rev-list" :
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(pid == pid_pack_objects) ? "git-pack-objects" :
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NULL);
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if (!who) {
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if (pid < 0) {
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error("git-upload-pack: %s",
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strerror(errno));
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goto fail;
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}
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error("git-upload-pack: we weren't "
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"waiting for %d", pid);
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continue;
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}
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if (!WIFEXITED(status) || WEXITSTATUS(status) > 0) {
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error("git-upload-pack: %s died with error.",
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who);
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goto fail;
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}
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if (pid == pid_rev_list)
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pid_rev_list = 0;
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if (pid == pid_pack_objects)
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pid_pack_objects = 0;
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if (pid_rev_list || pid_pack_objects)
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continue;
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}
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/* both died happily */
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if (pollsize)
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continue;
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/* flush the data */
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if (0 <= buffered) {
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data[0] = buffered;
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sz = xwrite(1, data, 1);
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if (sz < 0)
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goto fail;
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fprintf(stderr, "flushed.\n");
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}
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return;
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}
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fail:
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if (pid_pack_objects)
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kill(pid_pack_objects, SIGKILL);
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if (pid_rev_list)
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kill(pid_rev_list, SIGKILL);
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die("git-upload-pack: aborting due to possible repository corruption on the remote side.");
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}
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static int got_sha1(char *hex, unsigned char *sha1)
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{
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if (get_sha1_hex(hex, sha1))
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die("git-upload-pack: expected SHA1 object, got '%s'", hex);
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if (!has_sha1_file(sha1))
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return 0;
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if (nr_has < MAX_HAS) {
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struct object *o = lookup_object(sha1);
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if (!(o && o->parsed))
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o = parse_object(sha1);
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if (!o)
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die("oops (%s)", sha1_to_hex(sha1));
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if (o->type == TYPE_COMMIT) {
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struct commit_list *parents;
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if (o->flags & THEY_HAVE)
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return 0;
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o->flags |= THEY_HAVE;
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for (parents = ((struct commit*)o)->parents;
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parents;
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parents = parents->next)
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parents->item->object.flags |= THEY_HAVE;
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}
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memcpy(has_sha1[nr_has++], sha1, 20);
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}
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return 1;
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}
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static int get_common_commits(void)
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{
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static char line[1000];
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unsigned char sha1[20], last_sha1[20];
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int len;
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track_object_refs = 0;
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save_commit_buffer = 0;
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for(;;) {
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len = packet_read_line(0, line, sizeof(line));
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reset_timeout();
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if (!len) {
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if (nr_has == 0 || multi_ack)
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packet_write(1, "NAK\n");
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continue;
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}
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len = strip(line, len);
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if (!strncmp(line, "have ", 5)) {
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if (got_sha1(line+5, sha1) &&
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(multi_ack || nr_has == 1)) {
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if (nr_has >= MAX_HAS)
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multi_ack = 0;
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packet_write(1, "ACK %s%s\n",
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sha1_to_hex(sha1),
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multi_ack ? " continue" : "");
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if (multi_ack)
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memcpy(last_sha1, sha1, 20);
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}
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continue;
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}
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if (!strcmp(line, "done")) {
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if (nr_has > 0) {
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if (multi_ack)
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packet_write(1, "ACK %s\n",
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sha1_to_hex(last_sha1));
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return 0;
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}
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packet_write(1, "NAK\n");
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return -1;
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}
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die("git-upload-pack: expected SHA1 list, got '%s'", line);
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}
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}
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static int receive_needs(void)
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{
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static char line[1000];
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int len, needs;
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needs = 0;
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for (;;) {
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struct object *o;
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unsigned char dummy[20], *sha1_buf;
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len = packet_read_line(0, line, sizeof(line));
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reset_timeout();
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if (!len)
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return needs;
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sha1_buf = dummy;
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if (needs == MAX_NEEDS) {
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fprintf(stderr,
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"warning: supporting only a max of %d requests. "
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"sending everything instead.\n",
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MAX_NEEDS);
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}
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else if (needs < MAX_NEEDS)
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sha1_buf = needs_sha1[needs];
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if (strncmp("want ", line, 5) || get_sha1_hex(line+5, sha1_buf))
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die("git-upload-pack: protocol error, "
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"expected to get sha, not '%s'", line);
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if (strstr(line+45, "multi_ack"))
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multi_ack = 1;
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if (strstr(line+45, "thin-pack"))
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use_thin_pack = 1;
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/* We have sent all our refs already, and the other end
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* should have chosen out of them; otherwise they are
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* asking for nonsense.
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*
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* Hmph. We may later want to allow "want" line that
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* asks for something like "master~10" (symbolic)...
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* would it make sense? I don't know.
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*/
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o = lookup_object(sha1_buf);
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if (!o || !(o->flags & OUR_REF))
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die("git-upload-pack: not our ref %s", line+5);
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if (!(o->flags & WANTED)) {
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o->flags |= WANTED;
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needs++;
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}
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}
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}
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static int send_ref(const char *refname, const unsigned char *sha1)
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{
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static char *capabilities = "multi_ack thin-pack";
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struct object *o = parse_object(sha1);
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if (!o)
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die("git-upload-pack: cannot find object %s:", sha1_to_hex(sha1));
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if (capabilities)
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packet_write(1, "%s %s%c%s\n", sha1_to_hex(sha1), refname,
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0, capabilities);
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else
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packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname);
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capabilities = NULL;
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if (!(o->flags & OUR_REF)) {
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o->flags |= OUR_REF;
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nr_our_refs++;
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}
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if (o->type == TYPE_TAG) {
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o = deref_tag(o, refname, 0);
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packet_write(1, "%s %s^{}\n", sha1_to_hex(o->sha1), refname);
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}
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return 0;
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}
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static int upload_pack(void)
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{
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reset_timeout();
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head_ref(send_ref);
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for_each_ref(send_ref);
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packet_flush(1);
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nr_needs = receive_needs();
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if (!nr_needs)
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return 0;
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get_common_commits();
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create_pack_file();
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return 0;
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}
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int main(int argc, char **argv)
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{
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char *dir;
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int i;
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int strict = 0;
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for (i = 1; i < argc; i++) {
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char *arg = argv[i];
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if (arg[0] != '-')
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break;
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if (!strcmp(arg, "--strict")) {
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strict = 1;
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continue;
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}
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if (!strncmp(arg, "--timeout=", 10)) {
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timeout = atoi(arg+10);
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continue;
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}
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if (!strcmp(arg, "--")) {
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i++;
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break;
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}
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}
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if (i != argc-1)
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usage(upload_pack_usage);
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dir = argv[i];
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if (!enter_repo(dir, strict))
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die("'%s': unable to chdir or not a git archive", dir);
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upload_pack();
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return 0;
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}
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