setup.c

   1 #include "cache.h"
   2
   3 const char *prefix_path(const char *prefix, int len, const char *path)
   4 {
   5         const char *orig = path;
   6         for (;;) {
   7                 char c;
   8                 if (*path != '.')
   9                         break;
  10                 c = path[1];
  11                 /* "." */
  12                 if (!c) {
  13                         path++;
  14                         break;
  15                 }
  16                 /* "./" */
  17                 if (c == '/') {
  18                         path += 2;
  19                         continue;
  20                 }
  21                 if (c != '.')
  22                         break;
  23                 c = path[2];
  24                 if (!c)
  25                         path += 2;
  26                 else if (c == '/')
  27                         path += 3;
  28                 else
  29                         break;
  30                 /* ".." and "../" */
  31                 /* Remove last component of the prefix */
  32                 do {
  33                         if (!len)
  34                                 die("'%s' is outside repository", orig);
  35                         len--;
  36                 } while (len && prefix[len-1] != '/');
  37                 continue;
  38         }
  39         if (len) {
  40                 int speclen = strlen(path);
  41                 char *n = xmalloc(speclen + len + 1);
  42
  43                 memcpy(n, prefix, len);
  44                 memcpy(n + len, path, speclen+1);
  45                 path = n;
  46         }
  47         return path;
  48 }
  49
  50 const char **get_pathspec(const char *prefix, const char **pathspec)
  51 {
  52         const char *entry = *pathspec;
  53         const char **p;
  54         int prefixlen;
  55
  56         if (!prefix && !entry)
  57                 return NULL;
  58
  59         if (!entry) {
  60                 static const char *spec[2];
  61                 spec[0] = prefix;
  62                 spec[1] = NULL;
  63                 return spec;
  64         }
  65
  66         /* Otherwise we have to re-write the entries.. */
  67         p = pathspec;
  68         prefixlen = prefix ? strlen(prefix) : 0;
  69         do {
  70                 *p = prefix_path(prefix, prefixlen, entry);
  71         } while ((entry = *++p) != NULL);
  72         return (const char **) pathspec;
  73 }
  74
  75 /*
  76  * Test it it looks like we're at the top
  77  * level git directory. We want to see a
  78  *
  79  *  - either a .git/objects/ directory _or_ the proper
  80  *    GIT_OBJECT_DIRECTORY environment variable
  81  *  - a refs/ directory under ".git"
  82  *  - either a HEAD symlink or a HEAD file that is formatted as
  83  *    a proper "ref:".
  84  */
  85 static int is_toplevel_directory(void)
  86 {
  87         if (access(".git/refs/", X_OK) ||
  88             access(getenv(DB_ENVIRONMENT) ?
  89                    getenv(DB_ENVIRONMENT) : ".git/objects/", X_OK) ||
  90             validate_symref(".git/HEAD"))
  91                 return 0;
  92         return 1;
  93 }
  94
  95 const char *setup_git_directory(void)
  96 {
  97         static char cwd[PATH_MAX+1];
  98         int len, offset;
  99
 100         /*
 101          * If GIT_DIR is set explicitly, we're not going
 102          * to do any discovery
 103          */
 104         if (getenv(GIT_DIR_ENVIRONMENT))
 105                 return NULL;
 106
 107         if (!getcwd(cwd, sizeof(cwd)) || cwd[0] != '/')
 108                 die("Unable to read current working directory");
 109
 110         offset = len = strlen(cwd);
 111         for (;;) {
 112                 if (is_toplevel_directory())
 113                         break;
 114                 chdir("..");
 115                 do {
 116                         if (!offset)
 117                                 die("Not a git repository");
 118                 } while (cwd[--offset] != '/');
 119         }
 120
 121         if (offset == len)
 122                 return NULL;
 123
 124         /* Make "offset" point to past the '/', and add a '/' at the end */
 125         offset++;
 126         cwd[len++] = '/';
 127         cwd[len] = 0;
 128         return cwd + offset;
 129 }