setup.c

   1 #include "cache.h"
   2
   3 char *prefix_path(const char *prefix, int len, char *path)
   4 {
   5         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, char **pathspec)
  51 {
  52         char *entry = *pathspec;
  53         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  *  - a HEAD symlink and a refs/ directory under ".git"
  80  *  - either a .git/objects/ directory _or_ the proper
  81  *    GIT_OBJECT_DIRECTORY environment variable
  82  */
  83 static int is_toplevel_directory(void)
  84 {
  85         struct stat st;
  86
  87         return  !lstat(".git/HEAD", &st) &&
  88                 S_ISLNK(st.st_mode) &&
  89                 !access(".git/refs/", X_OK) &&
  90                 (getenv(DB_ENVIRONMENT) || !access(".git/objects/", X_OK));
  91 }
  92
  93 const char *setup_git_directory(void)
  94 {
  95         static char cwd[PATH_MAX+1];
  96         int len, offset;
  97
  98         /*
  99          * If GIT_DIR is set explicitly, we're not going
 100          * to do any discovery
 101          */
 102         if (getenv(GIT_DIR_ENVIRONMENT))
 103                 return NULL;
 104
 105         if (!getcwd(cwd, sizeof(cwd)) || cwd[0] != '/')
 106                 die("Unable to read current working directory");
 107
 108         offset = len = strlen(cwd);
 109         for (;;) {
 110                 if (is_toplevel_directory())
 111                         break;
 112                 chdir("..");
 113                 do {
 114                         if (!offset)
 115                                 die("Not a git repository");
 116                 } while (cwd[--offset] != '/');
 117         }
 118
 119         if (offset == len)
 120                 return NULL;
 121
 122         /* Make "offset" point to past the '/', and add a '/' at the end */
 123         offset++;
 124         cwd[len++] = '/';
 125         cwd[len] = 0;
 126         return cwd + offset;
 127 }