unix-socket.c

   1 #include "cache.h"
   2 #include "unix-socket.h"
   3
   4 static int chdir_len(const char *orig, int len)
   5 {
   6         char *path = xmemdupz(orig, len);
   7         int r = chdir(path);
   8         free(path);
   9         return r;
  10 }
  11
  12 struct unix_sockaddr_context {
  13         char *orig_dir;
  14 };
  15
  16 static void unix_sockaddr_cleanup(struct unix_sockaddr_context *ctx)
  17 {
  18         if (!ctx->orig_dir)
  19                 return;
  20         /*
  21          * If we fail, we can't just return an error, since we have
  22          * moved the cwd of the whole process, which could confuse calling
  23          * code.  We are better off to just die.
  24          */
  25         if (chdir(ctx->orig_dir) < 0)
  26                 die("unable to restore original working directory");
  27         free(ctx->orig_dir);
  28 }
  29
  30 static int unix_sockaddr_init(struct sockaddr_un *sa, const char *path,
  31                               struct unix_sockaddr_context *ctx)
  32 {
  33         int size = strlen(path) + 1;
  34
  35         ctx->orig_dir = NULL;
  36         if (size > sizeof(sa->sun_path)) {
  37                 const char *slash = find_last_dir_sep(path);
  38                 const char *dir;
  39                 struct strbuf cwd = STRBUF_INIT;
  40
  41                 if (!slash) {
  42                         errno = ENAMETOOLONG;
  43                         return -1;
  44                 }
  45
  46                 dir = path;
  47                 path = slash + 1;
  48                 size = strlen(path) + 1;
  49                 if (size > sizeof(sa->sun_path)) {
  50                         errno = ENAMETOOLONG;
  51                         return -1;
  52                 }
  53                 if (strbuf_getcwd(&cwd))
  54                         return -1;
  55                 ctx->orig_dir = strbuf_detach(&cwd, NULL);
  56                 if (chdir_len(dir, slash - dir) < 0)
  57                         return -1;
  58         }
  59
  60         memset(sa, 0, sizeof(*sa));
  61         sa->sun_family = AF_UNIX;
  62         memcpy(sa->sun_path, path, size);
  63         return 0;
  64 }
  65
  66 int unix_stream_connect(const char *path)
  67 {
  68         int fd = -1, saved_errno;
  69         struct sockaddr_un sa;
  70         struct unix_sockaddr_context ctx;
  71
  72         if (unix_sockaddr_init(&sa, path, &ctx) < 0)
  73                 return -1;
  74         fd = socket(AF_UNIX, SOCK_STREAM, 0);
  75         if (fd < 0)
  76                 goto fail;
  77
  78         if (connect(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0)
  79                 goto fail;
  80         unix_sockaddr_cleanup(&ctx);
  81         return fd;
  82
  83 fail:
  84         saved_errno = errno;
  85         if (fd != -1)
  86                 close(fd);
  87         unix_sockaddr_cleanup(&ctx);
  88         errno = saved_errno;
  89         return -1;
  90 }
  91
  92 int unix_stream_listen(const char *path)
  93 {
  94         int fd = -1, saved_errno;
  95         struct sockaddr_un sa;
  96         struct unix_sockaddr_context ctx;
  97
  98         unlink(path);
  99
 100         if (unix_sockaddr_init(&sa, path, &ctx) < 0)
 101                 return -1;
 102         fd = socket(AF_UNIX, SOCK_STREAM, 0);
 103         if (fd < 0)
 104                 goto fail;
 105
 106         if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0)
 107                 goto fail;
 108
 109         if (listen(fd, 5) < 0)
 110                 goto fail;
 111
 112         unix_sockaddr_cleanup(&ctx);
 113         return fd;
 114
 115 fail:
 116         saved_errno = errno;
 117         if (fd != -1)
 118                 close(fd);
 119         unix_sockaddr_cleanup(&ctx);
 120         errno = saved_errno;
 121         return -1;
 122 }