builtin/remote-ext.c

   1 #include "builtin.h"
   2 #include "transport.h"
   3 #include "run-command.h"
   4 #include "pkt-line.h"
   5
   6 static const char usage_msg[] =
   7         "git remote-ext <remote> <url>";
   8
   9 /*
  10  * URL syntax:
  11  *      'command [arg1 [arg2 [...]]]'   Invoke command with given arguments.
  12  *      Special characters:
  13  *      '% ': Literal space in argument.
  14  *      '%%': Literal percent sign.
  15  *      '%S': Name of service (git-upload-pack/git-upload-archive/
  16  *              git-receive-pack.
  17  *      '%s': Same as \s, but with possible git- prefix stripped.
  18  *      '%G': Only allowed as first 'character' of argument. Do not pass this
  19  *              Argument to command, instead send this as name of repository
  20  *              in in-line git://-style request (also activates sending this
  21  *              style of request).
  22  *      '%V': Only allowed as first 'character' of argument. Used in
  23  *              conjunction with '%G': Do not pass this argument to command,
  24  *              instead send this as vhost in git://-style request (note: does
  25  *              not activate sending git:// style request).
  26  */
  27
  28 static char *git_req;
  29 static char *git_req_vhost;
  30
  31 static char *strip_escapes(const char *str, const char *service,
  32         const char **next)
  33 {
  34         size_t rpos = 0;
  35         int escape = 0;
  36         char special = 0;
  37         const char *service_noprefix = service;
  38         struct strbuf ret = STRBUF_INIT;
  39
  40         skip_prefix(service_noprefix, "git-", &service_noprefix);
  41
  42         /* Pass the service to command. */
  43         setenv("GIT_EXT_SERVICE", service, 1);
  44         setenv("GIT_EXT_SERVICE_NOPREFIX", service_noprefix, 1);
  45
  46         /* Scan the length of argument. */
  47         while (str[rpos] && (escape || str[rpos] != ' ')) {
  48                 if (escape) {
  49                         switch (str[rpos]) {
  50                         case ' ':
  51                         case '%':
  52                         case 's':
  53                         case 'S':
  54                                 break;
  55                         case 'G':
  56                         case 'V':
  57                                 special = str[rpos];
  58                                 if (rpos == 1)
  59                                         break;
  60                                 /* fallthrough */
  61                         default:
  62                                 die("Bad remote-ext placeholder '%%%c'.",
  63                                         str[rpos]);
  64                         }
  65                         escape = 0;
  66                 } else
  67                         escape = (str[rpos] == '%');
  68                 rpos++;
  69         }
  70         if (escape && !str[rpos])
  71                 die("remote-ext command has incomplete placeholder");
  72         *next = str + rpos;
  73         if (**next == ' ')
  74                 ++*next;        /* Skip over space */
  75
  76         /*
  77          * Do the actual placeholder substitution. The string will be short
  78          * enough not to overflow integers.
  79          */
  80         rpos = special ? 2 : 0;         /* Skip first 2 bytes in specials. */
  81         escape = 0;
  82         while (str[rpos] && (escape || str[rpos] != ' ')) {
  83                 if (escape) {
  84                         switch (str[rpos]) {
  85                         case ' ':
  86                         case '%':
  87                                 strbuf_addch(&ret, str[rpos]);
  88                                 break;
  89                         case 's':
  90                                 strbuf_addstr(&ret, service_noprefix);
  91                                 break;
  92                         case 'S':
  93                                 strbuf_addstr(&ret, service);
  94                                 break;
  95                         }
  96                         escape = 0;
  97                 } else
  98                         switch (str[rpos]) {
  99                         case '%':
 100                                 escape = 1;
 101                                 break;
 102                         default:
 103                                 strbuf_addch(&ret, str[rpos]);
 104                                 break;
 105                         }
 106                 rpos++;
 107         }
 108         switch (special) {
 109         case 'G':
 110                 git_req = strbuf_detach(&ret, NULL);
 111                 return NULL;
 112         case 'V':
 113                 git_req_vhost = strbuf_detach(&ret, NULL);
 114                 return NULL;
 115         default:
 116                 return strbuf_detach(&ret, NULL);
 117         }
 118 }
 119
 120 static void parse_argv(struct strvec *out, const char *arg, const char *service)
 121 {
 122         while (*arg) {
 123                 char *expanded = strip_escapes(arg, service, &arg);
 124                 if (expanded)
 125                         strvec_push(out, expanded);
 126                 free(expanded);
 127         }
 128 }
 129
 130 static void send_git_request(int stdin_fd, const char *serv, const char *repo,
 131         const char *vhost)
 132 {
 133         if (!vhost)
 134                 packet_write_fmt(stdin_fd, "%s %s%c", serv, repo, 0);
 135         else
 136                 packet_write_fmt(stdin_fd, "%s %s%chost=%s%c", serv, repo, 0,
 137                              vhost, 0);
 138 }
 139
 140 static int run_child(const char *arg, const char *service)
 141 {
 142         int r;
 143         struct child_process child = CHILD_PROCESS_INIT;
 144
 145         child.in = -1;
 146         child.out = -1;
 147         child.err = 0;
 148         parse_argv(&child.args, arg, service);
 149
 150         if (start_command(&child) < 0)
 151                 die("Can't run specified command");
 152
 153         if (git_req)
 154                 send_git_request(child.in, service, git_req, git_req_vhost);
 155
 156         r = bidirectional_transfer_loop(child.out, child.in);
 157         if (!r)
 158                 r = finish_command(&child);
 159         else
 160                 finish_command(&child);
 161         return r;
 162 }
 163
 164 #define MAXCOMMAND 4096
 165
 166 static int command_loop(const char *child)
 167 {
 168         char buffer[MAXCOMMAND];
 169
 170         while (1) {
 171                 size_t i;
 172                 const char *arg;
 173
 174                 if (!fgets(buffer, MAXCOMMAND - 1, stdin)) {
 175                         if (ferror(stdin))
 176                                 die("Command input error");
 177                         exit(0);
 178                 }
 179                 /* Strip end of line characters. */
 180                 i = strlen(buffer);
 181                 while (i > 0 && isspace(buffer[i - 1]))
 182                         buffer[--i] = 0;
 183
 184                 if (!strcmp(buffer, "capabilities")) {
 185                         printf("*connect\n\n");
 186                         fflush(stdout);
 187                 } else if (skip_prefix(buffer, "connect ", &arg)) {
 188                         printf("\n");
 189                         fflush(stdout);
 190                         return run_child(child, arg);
 191                 } else {
 192                         fprintf(stderr, "Bad command");
 193                         return 1;
 194                 }
 195         }
 196 }
 197
 198 int cmd_remote_ext(int argc,
 199                    const char **argv,
 200                    const char *prefix,
 201                    struct repository *repo UNUSED)
 202 {
 203         BUG_ON_NON_EMPTY_PREFIX(prefix);
 204
 205         if (argc != 3)
 206                 usage(usage_msg);
 207
 208         return command_loop(argv[2]);
 209 }