upload-pack.con commit Exec git programs without using PATH. (77cb17e)
   1#include "cache.h"
   2#include "refs.h"
   3#include "pkt-line.h"
   4#include "tag.h"
   5#include "object.h"
   6#include "commit.h"
   7#include "exec_cmd.h"
   8
   9static const char upload_pack_usage[] = "git-upload-pack [--strict] [--timeout=nn] <dir>";
  10
  11#define THEY_HAVE (1U << 0)
  12#define OUR_REF (1U << 1)
  13#define WANTED (1U << 2)
  14#define MAX_HAS 256
  15#define MAX_NEEDS 256
  16static int nr_has = 0, nr_needs = 0, multi_ack = 0, nr_our_refs = 0;
  17static unsigned char has_sha1[MAX_HAS][20];
  18static unsigned char needs_sha1[MAX_NEEDS][20];
  19static unsigned int timeout = 0;
  20
  21static void reset_timeout(void)
  22{
  23        alarm(timeout);
  24}
  25
  26static int strip(char *line, int len)
  27{
  28        if (len && line[len-1] == '\n')
  29                line[--len] = 0;
  30        return len;
  31}
  32
  33static void create_pack_file(void)
  34{
  35        int fd[2];
  36        pid_t pid;
  37        int create_full_pack = (nr_our_refs == nr_needs && !nr_has);
  38
  39        if (pipe(fd) < 0)
  40                die("git-upload-pack: unable to create pipe");
  41        pid = fork();
  42        if (pid < 0)
  43                die("git-upload-pack: unable to fork git-rev-list");
  44
  45        if (!pid) {
  46                int i;
  47                int args;
  48                char **argv;
  49                char *buf;
  50                char **p;
  51
  52                if (create_full_pack)
  53                        args = 10;
  54                else
  55                        args = nr_has + nr_needs + 5;
  56                argv = xmalloc(args * sizeof(char *));
  57                buf = xmalloc(args * 45);
  58                p = argv;
  59
  60                dup2(fd[1], 1);
  61                close(0);
  62                close(fd[0]);
  63                close(fd[1]);
  64                *p++ = "rev-list";
  65                *p++ = "--objects";
  66                if (create_full_pack || MAX_NEEDS <= nr_needs)
  67                        *p++ = "--all";
  68                else {
  69                        for (i = 0; i < nr_needs; i++) {
  70                                *p++ = buf;
  71                                memcpy(buf, sha1_to_hex(needs_sha1[i]), 41);
  72                                buf += 41;
  73                        }
  74                }
  75                if (!create_full_pack)
  76                        for (i = 0; i < nr_has; i++) {
  77                                *p++ = buf;
  78                                *buf++ = '^';
  79                                memcpy(buf, sha1_to_hex(has_sha1[i]), 41);
  80                                buf += 41;
  81                        }
  82                *p++ = NULL;
  83                execv_git_cmd(argv);
  84                die("git-upload-pack: unable to exec git-rev-list");
  85        }
  86        dup2(fd[0], 0);
  87        close(fd[0]);
  88        close(fd[1]);
  89        execl_git_cmd("pack-objects", "--stdout", NULL);
  90        die("git-upload-pack: unable to exec git-pack-objects");
  91}
  92
  93static int got_sha1(char *hex, unsigned char *sha1)
  94{
  95        if (get_sha1_hex(hex, sha1))
  96                die("git-upload-pack: expected SHA1 object, got '%s'", hex);
  97        if (!has_sha1_file(sha1))
  98                return 0;
  99        if (nr_has < MAX_HAS) {
 100                struct object *o = lookup_object(sha1);
 101                if (!(o && o->parsed))
 102                        o = parse_object(sha1);
 103                if (!o)
 104                        die("oops (%s)", sha1_to_hex(sha1));
 105                if (o->type == commit_type) {
 106                        struct commit_list *parents;
 107                        if (o->flags & THEY_HAVE)
 108                                return 0;
 109                        o->flags |= THEY_HAVE;
 110                        for (parents = ((struct commit*)o)->parents;
 111                             parents;
 112                             parents = parents->next)
 113                                parents->item->object.flags |= THEY_HAVE;
 114                }
 115                memcpy(has_sha1[nr_has++], sha1, 20);
 116        }
 117        return 1;
 118}
 119
 120static int get_common_commits(void)
 121{
 122        static char line[1000];
 123        unsigned char sha1[20], last_sha1[20];
 124        int len;
 125
 126        track_object_refs = 0;
 127        save_commit_buffer = 0;
 128
 129        for(;;) {
 130                len = packet_read_line(0, line, sizeof(line));
 131                reset_timeout();
 132
 133                if (!len) {
 134                        if (nr_has == 0 || multi_ack)
 135                                packet_write(1, "NAK\n");
 136                        continue;
 137                }
 138                len = strip(line, len);
 139                if (!strncmp(line, "have ", 5)) {
 140                        if (got_sha1(line+5, sha1) &&
 141                                        (multi_ack || nr_has == 1)) {
 142                                if (nr_has >= MAX_HAS)
 143                                        multi_ack = 0;
 144                                packet_write(1, "ACK %s%s\n",
 145                                        sha1_to_hex(sha1),
 146                                        multi_ack ?  " continue" : "");
 147                                if (multi_ack)
 148                                        memcpy(last_sha1, sha1, 20);
 149                        }
 150                        continue;
 151                }
 152                if (!strcmp(line, "done")) {
 153                        if (nr_has > 0) {
 154                                if (multi_ack)
 155                                        packet_write(1, "ACK %s\n",
 156                                                        sha1_to_hex(last_sha1));
 157                                return 0;
 158                        }
 159                        packet_write(1, "NAK\n");
 160                        return -1;
 161                }
 162                die("git-upload-pack: expected SHA1 list, got '%s'", line);
 163        }
 164}
 165
 166static int receive_needs(void)
 167{
 168        static char line[1000];
 169        int len, needs;
 170
 171        needs = 0;
 172        for (;;) {
 173                struct object *o;
 174                unsigned char dummy[20], *sha1_buf;
 175                len = packet_read_line(0, line, sizeof(line));
 176                reset_timeout();
 177                if (!len)
 178                        return needs;
 179
 180                sha1_buf = dummy;
 181                if (needs == MAX_NEEDS) {
 182                        fprintf(stderr,
 183                                "warning: supporting only a max of %d requests. "
 184                                "sending everything instead.\n",
 185                                MAX_NEEDS);
 186                }
 187                else if (needs < MAX_NEEDS)
 188                        sha1_buf = needs_sha1[needs];
 189
 190                if (strncmp("want ", line, 5) || get_sha1_hex(line+5, sha1_buf))
 191                        die("git-upload-pack: protocol error, "
 192                            "expected to get sha, not '%s'", line);
 193                if (strstr(line+45, "multi_ack"))
 194                        multi_ack = 1;
 195
 196                /* We have sent all our refs already, and the other end
 197                 * should have chosen out of them; otherwise they are
 198                 * asking for nonsense.
 199                 *
 200                 * Hmph.  We may later want to allow "want" line that
 201                 * asks for something like "master~10" (symbolic)...
 202                 * would it make sense?  I don't know.
 203                 */
 204                o = lookup_object(sha1_buf);
 205                if (!o || !(o->flags & OUR_REF))
 206                        die("git-upload-pack: not our ref %s", line+5);
 207                if (!(o->flags & WANTED)) {
 208                        o->flags |= WANTED;
 209                        needs++;
 210                }
 211        }
 212}
 213
 214static int send_ref(const char *refname, const unsigned char *sha1)
 215{
 216        static char *capabilities = "multi_ack";
 217        struct object *o = parse_object(sha1);
 218
 219        if (capabilities)
 220                packet_write(1, "%s %s%c%s\n", sha1_to_hex(sha1), refname,
 221                        0, capabilities);
 222        else
 223                packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname);
 224        capabilities = NULL;
 225        if (!(o->flags & OUR_REF)) {
 226                o->flags |= OUR_REF;
 227                nr_our_refs++;
 228        }
 229        if (o->type == tag_type) {
 230                o = deref_tag(o, refname, 0);
 231                packet_write(1, "%s %s^{}\n", sha1_to_hex(o->sha1), refname);
 232        }
 233        return 0;
 234}
 235
 236static int upload_pack(void)
 237{
 238        reset_timeout();
 239        head_ref(send_ref);
 240        for_each_ref(send_ref);
 241        packet_flush(1);
 242        nr_needs = receive_needs();
 243        if (!nr_needs)
 244                return 0;
 245        get_common_commits();
 246        create_pack_file();
 247        return 0;
 248}
 249
 250int main(int argc, char **argv)
 251{
 252        char *dir;
 253        int i;
 254        int strict = 0;
 255
 256        for (i = 1; i < argc; i++) {
 257                char *arg = argv[i];
 258
 259                if (arg[0] != '-')
 260                        break;
 261                if (!strcmp(arg, "--strict")) {
 262                        strict = 1;
 263                        continue;
 264                }
 265                if (!strncmp(arg, "--timeout=", 10)) {
 266                        timeout = atoi(arg+10);
 267                        continue;
 268                }
 269                if (!strcmp(arg, "--")) {
 270                        i++;
 271                        break;
 272                }
 273        }
 274        
 275        if (i != argc-1)
 276                usage(upload_pack_usage);
 277        dir = argv[i];
 278
 279        if (!enter_repo(dir, strict))
 280                die("'%s': unable to chdir or not a git archive", dir);
 281
 282        upload_pack();
 283        return 0;
 284}