shell.c

   1 #include "cache.h"
   2 #include "quote.h"
   3 #include "exec_cmd.h"
   4 #include "strbuf.h"
   5
   6 /* Stubs for functions that make no sense for git-shell. These stubs
   7  * are provided here to avoid linking in external redundant modules.
   8  */
   9 void release_pack_memory(size_t need, int fd){}
  10 void trace_argv_printf(const char **argv, const char *fmt, ...){}
  11 void trace_printf(const char *fmt, ...){}
  12
  13
  14 static int do_generic_cmd(const char *me, char *arg)
  15 {
  16         const char *my_argv[4];
  17
  18         setup_path();
  19         if (!arg || !(arg = sq_dequote(arg)))
  20                 die("bad argument");
  21         if (prefixcmp(me, "git-"))
  22                 die("bad command");
  23
  24         my_argv[0] = me + 4;
  25         my_argv[1] = arg;
  26         my_argv[2] = NULL;
  27
  28         return execv_git_cmd(my_argv);
  29 }
  30
  31 static int do_cvs_cmd(const char *me, char *arg)
  32 {
  33         const char *cvsserver_argv[3] = {
  34                 "cvsserver", "server", NULL
  35         };
  36
  37         if (!arg || strcmp(arg, "server"))
  38                 die("git-cvsserver only handles server: %s", arg);
  39
  40         setup_path();
  41         return execv_git_cmd(cvsserver_argv);
  42 }
  43
  44
  45 static struct commands {
  46         const char *name;
  47         int (*exec)(const char *me, char *arg);
  48 } cmd_list[] = {
  49         { "git-receive-pack", do_generic_cmd },
  50         { "git-upload-pack", do_generic_cmd },
  51         { "cvs", do_cvs_cmd },
  52         { NULL },
  53 };
  54
  55 int main(int argc, char **argv)
  56 {
  57         char *prog;
  58         struct commands *cmd;
  59         int devnull_fd;
  60
  61         /*
  62          * Always open file descriptors 0/1/2 to avoid clobbering files
  63          * in die().  It also avoids not messing up when the pipes are
  64          * dup'ed onto stdin/stdout/stderr in the child processes we spawn.
  65          */
  66         devnull_fd = open("/dev/null", O_RDWR);
  67         while (devnull_fd >= 0 && devnull_fd <= 2)
  68                 devnull_fd = dup(devnull_fd);
  69         if (devnull_fd == -1)
  70                 die("opening /dev/null failed (%s)", strerror(errno));
  71         close (devnull_fd);
  72
  73         /*
  74          * Special hack to pretend to be a CVS server
  75          */
  76         if (argc == 2 && !strcmp(argv[1], "cvs server"))
  77                 argv--;
  78
  79         /*
  80          * We do not accept anything but "-c" followed by "cmd arg",
  81          * where "cmd" is a very limited subset of git commands.
  82          */
  83         else if (argc != 3 || strcmp(argv[1], "-c"))
  84                 die("What do you think I am? A shell?");
  85
  86         prog = argv[2];
  87         if (!strncmp(prog, "git", 3) && isspace(prog[3]))
  88                 /* Accept "git foo" as if the caller said "git-foo". */
  89                 prog[3] = '-';
  90
  91         for (cmd = cmd_list ; cmd->name ; cmd++) {
  92                 int len = strlen(cmd->name);
  93                 char *arg;
  94                 if (strncmp(cmd->name, prog, len))
  95                         continue;
  96                 arg = NULL;
  97                 switch (prog[len]) {
  98                 case '\0':
  99                         arg = NULL;
 100                         break;
 101                 case ' ':
 102                         arg = prog + len + 1;
 103                         break;
 104                 default:
 105                         continue;
 106                 }
 107                 exit(cmd->exec(cmd->name, arg));
 108         }
 109         die("unrecognized command '%s'", prog);
 110 }