builtin/remote-ext.c

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