connect.c

   1 #include "cache.h"
   2 #include <sys/wait.h>
   3
   4 /*
   5  * First, make it shell-safe.  We do this by just disallowing any
   6  * special characters. Somebody who cares can do escaping and let
   7  * through the rest. But since we're doing to feed this to ssh as
   8  * a command line, we're going to be pretty damn anal for now.
   9  */
  10 static char *shell_safe(char *url)
  11 {
  12         char *n = url;
  13         unsigned char c;
  14         static const char flags[256] = {
  15                 ['0'...'9'] = 1,
  16                 ['a'...'z'] = 1,
  17                 ['A'...'Z'] = 1,
  18                 ['.'] = 1, ['/'] = 1,
  19                 ['-'] = 1, ['+'] = 1,
  20                 [':'] = 1
  21         };
  22
  23         while ((c = *n++) != 0) {
  24                 if (flags[c] != 1)
  25                         die("I don't like '%c'. Sue me.", c);
  26         }
  27         return url;
  28 }
  29
  30 /*
  31  * Yeah, yeah, fixme. Need to pass in the heads etc.
  32  */
  33 int git_connect(int fd[2], char *url, const char *prog)
  34 {
  35         char command[1024];
  36         const char *host, *path;
  37         char *colon;
  38         int pipefd[2][2];
  39         pid_t pid;
  40
  41         url = shell_safe(url);
  42         host = NULL;
  43         path = url;
  44         colon = strchr(url, ':');
  45         if (colon) {
  46                 *colon = 0;
  47                 host = url;
  48                 path = colon+1;
  49         }
  50         snprintf(command, sizeof(command), "%s %s", prog, path);
  51         if (pipe(pipefd[0]) < 0 || pipe(pipefd[1]) < 0)
  52                 die("unable to create pipe pair for communication");
  53         pid = fork();
  54         if (!pid) {
  55                 dup2(pipefd[1][0], 0);
  56                 dup2(pipefd[0][1], 1);
  57                 close(pipefd[0][0]);
  58                 close(pipefd[0][1]);
  59                 close(pipefd[1][0]);
  60                 close(pipefd[1][1]);
  61                 if (host)
  62                         execlp("ssh", "ssh", host, command, NULL);
  63                 else
  64                         execlp("sh", "sh", "-c", command, NULL);
  65                 die("exec failed");
  66         }
  67         fd[0] = pipefd[0][0];
  68         fd[1] = pipefd[1][1];
  69         close(pipefd[0][1]);
  70         close(pipefd[1][0]);
  71         return pid;
  72 }
  73
  74 int finish_connect(pid_t pid)
  75 {
  76         int ret;
  77
  78         for (;;) {
  79                 ret = waitpid(pid, NULL, 0);
  80                 if (!ret)
  81                         break;
  82                 if (errno != EINTR)
  83                         break;
  84         }
  85         return ret;
  86 }