]> git.ipfire.org Git - thirdparty/git.git/blobdiff - upload-pack.c
upload-pack: avoid sending an incomplete pack upon failure
[thirdparty/git.git] / upload-pack.c
index 47560c9527b9c17db34f10e78d7c1f0d99b746e1..a9a8f2ed121a3327714364792d4bf8732addc33d 100644 (file)
@@ -5,6 +5,9 @@
 #include "object.h"
 #include "commit.h"
 #include "exec_cmd.h"
+#include <signal.h>
+#include <sys/poll.h>
+#include <sys/wait.h>
 
 static const char upload_pack_usage[] = "git-upload-pack [--strict] [--timeout=nn] <dir>";
 
@@ -33,17 +36,20 @@ static int strip(char *line, int len)
 
 static void create_pack_file(void)
 {
-       int fd[2];
-       pid_t pid;
+       /* Pipes between rev-list to pack-objects and pack-objects to us. */
+       int lp_pipe[2], pu_pipe[2];
+       pid_t pid_rev_list, pid_pack_objects;
        int create_full_pack = (nr_our_refs == nr_needs && !nr_has);
+       char data[8193];
+       int buffered = -1;
 
-       if (pipe(fd) < 0)
+       if (pipe(lp_pipe) < 0)
                die("git-upload-pack: unable to create pipe");
-       pid = fork();
-       if (pid < 0)
+       pid_rev_list = fork();
+       if (pid_rev_list < 0)
                die("git-upload-pack: unable to fork git-rev-list");
 
-       if (!pid) {
+       if (!pid_rev_list) {
                int i;
                int args;
                const char **argv;
@@ -60,10 +66,10 @@ static void create_pack_file(void)
                argv = (const char **) p;
                buf = xmalloc(args * 45);
 
-               dup2(fd[1], 1);
+               dup2(lp_pipe[1], 1);
                close(0);
-               close(fd[0]);
-               close(fd[1]);
+               close(lp_pipe[0]);
+               close(lp_pipe[1]);
                *p++ = "rev-list";
                *p++ = use_thin_pack ? "--objects-edge" : "--objects";
                if (create_full_pack || MAX_NEEDS <= nr_needs)
@@ -86,11 +92,154 @@ static void create_pack_file(void)
                execv_git_cmd(argv);
                die("git-upload-pack: unable to exec git-rev-list");
        }
-       dup2(fd[0], 0);
-       close(fd[0]);
-       close(fd[1]);
-       execl_git_cmd("pack-objects", "--stdout", NULL);
-       die("git-upload-pack: unable to exec git-pack-objects");
+
+       if (pipe(pu_pipe) < 0)
+               die("git-upload-pack: unable to create pipe");
+       pid_pack_objects = fork();
+       if (pid_pack_objects < 0) {
+               /* daemon sets things up to ignore TERM */
+               kill(pid_rev_list, SIGKILL);
+               die("git-upload-pack: unable to fork git-pack-objects");
+       }
+       if (!pid_pack_objects) {
+               dup2(lp_pipe[0], 0);
+               dup2(pu_pipe[1], 1);
+
+               close(lp_pipe[0]);
+               close(lp_pipe[1]);
+               close(pu_pipe[0]);
+               close(pu_pipe[1]);
+               execl_git_cmd("pack-objects", "--stdout", NULL);
+               kill(pid_rev_list, SIGKILL);
+               die("git-upload-pack: unable to exec git-pack-objects");
+       }
+
+       close(lp_pipe[0]);
+       close(lp_pipe[1]);
+
+       /* We read from pu_pipe[0] to capture the pack data.
+        */
+       close(pu_pipe[1]);
+
+       while (1) {
+               const char *who;
+               struct pollfd pfd[2];
+               pid_t pid;
+               int status;
+               ssize_t sz;
+               int pu, pollsize;
+
+               pollsize = 0;
+               pu = -1;
+
+               if (0 <= pu_pipe[0]) {
+                       pfd[pollsize].fd = pu_pipe[0];
+                       pfd[pollsize].events = POLLIN;
+                       pu = pollsize;
+                       pollsize++;
+               }
+
+               if (pollsize) {
+                       if (poll(pfd, pollsize, -1) < 0) {
+                               if (errno != EINTR) {
+                                       error("poll failed, resuming: %s",
+                                             strerror(errno));
+                                       sleep(1);
+                               }
+                               continue;
+                       }
+                       if (0 <= pu && (pfd[pu].revents & (POLLIN|POLLHUP))) {
+                               /* Data ready; we keep the last byte
+                                * to ourselves in case we detect
+                                * broken rev-list, so that we can
+                                * leave the stream corrupted.  This
+                                * is unfortunate -- unpack-objects
+                                * would happily accept a valid pack
+                                * data with trailing garbage, so
+                                * appending garbage after we pass all
+                                * the pack data is not good enough to
+                                * signal breakage to downstream.
+                                */
+                               char *cp = data;
+                               ssize_t outsz = 0;
+                               if (0 <= buffered) {
+                                       *cp++ = buffered;
+                                       outsz++;
+                               }
+                               sz = read(pu_pipe[0], cp,
+                                         sizeof(data) - outsz);
+                               if (0 < sz)
+                                               ;
+                               else if (sz == 0) {
+                                       close(pu_pipe[0]);
+                                       pu_pipe[0] = -1;
+                               }
+                               else
+                                       goto fail;
+                               sz += outsz;
+                               if (1 < sz) {
+                                       buffered = data[sz-1] & 0xFF;
+                                       sz--;
+                               }
+                               else
+                                       buffered = -1;
+                               sz = xwrite(1, data, sz);
+                               if (sz < 0)
+                                       goto fail;
+                       }
+               }
+
+               /* See if the children are still there */
+               if (pid_rev_list || pid_pack_objects) {
+                       pid = waitpid(-1, &status, WNOHANG);
+                       if (!pid)
+                               continue;
+                       who = ((pid == pid_rev_list) ? "git-rev-list" :
+                              (pid == pid_pack_objects) ? "git-pack-objects" :
+                              NULL);
+                       if (!who) {
+                               if (pid < 0) {
+                                       error("git-upload-pack: %s",
+                                             strerror(errno));
+                                       goto fail;
+                               }
+                               error("git-upload-pack: we weren't "
+                                     "waiting for %d", pid);
+                               continue;
+                       }
+                       if (!WIFEXITED(status) || WEXITSTATUS(status) > 0) {
+                               error("git-upload-pack: %s died with error.",
+                                     who);
+                               goto fail;
+                       }
+                       if (pid == pid_rev_list)
+                               pid_rev_list = 0;
+                       if (pid == pid_pack_objects)
+                               pid_pack_objects = 0;
+                       if (pid_rev_list || pid_pack_objects)
+                               continue;
+               }
+
+               /* both died happily */
+               if (pollsize)
+                       continue;
+
+               /* flush the data */
+               if (0 <= buffered) {
+                       data[0] = buffered;
+                       sz = xwrite(1, data, 1);
+                       if (sz < 0)
+                               goto fail;
+                       fprintf(stderr, "flushed.\n");
+               }
+               return;
+       }
+ fail:
+       if (pid_pack_objects)
+               kill(pid_pack_objects, SIGKILL);
+       if (pid_rev_list)
+               kill(pid_rev_list, SIGKILL);
+       die("git-upload-pack: aborting due to possible repository corruption on the remote side.");
 }
 
 static int got_sha1(char *hex, unsigned char *sha1)
@@ -105,7 +254,7 @@ static int got_sha1(char *hex, unsigned char *sha1)
                        o = parse_object(sha1);
                if (!o)
                        die("oops (%s)", sha1_to_hex(sha1));
-               if (o->type == commit_type) {
+               if (o->type == TYPE_COMMIT) {
                        struct commit_list *parents;
                        if (o->flags & THEY_HAVE)
                                return 0;
@@ -234,7 +383,7 @@ static int send_ref(const char *refname, const unsigned char *sha1)
                o->flags |= OUR_REF;
                nr_our_refs++;
        }
-       if (o->type == tag_type) {
+       if (o->type == TYPE_TAG) {
                o = deref_tag(o, refname, 0);
                packet_write(1, "%s %s^{}\n", sha1_to_hex(o->sha1), refname);
        }