Actual source code: grpath.c

  1: #define PETSC_DESIRE_FEATURE_TEST_MACROS /* for realpath() */
  2: #include <petscsys.h>
  3: #if defined(PETSC_HAVE_PWD_H)
  4:   #include <pwd.h>
  5: #endif
  6: #include <ctype.h>
  7: #include <sys/stat.h>
  8: #if defined(PETSC_HAVE_UNISTD_H)
  9:   #include <unistd.h>
 10: #endif
 11: #if defined(PETSC_HAVE_SYS_UTSNAME_H)
 12:   #include <sys/utsname.h>
 13: #endif
 14: #if defined(PETSC_HAVE_SYS_SYSTEMINFO_H)
 15:   #include <sys/systeminfo.h>
 16: #endif

 18: /*@C
 19:    PetscGetRealPath - Get the path without symbolic links etc. in absolute form.

 21:    Not Collective

 23:    Input Parameter:
 24: .  path - path to resolve

 26:    Output Parameter:
 27: .  rpath - resolved path

 29:    Level: developer

 31:    Notes:
 32:    rpath is assumed to be of length `PETSC_MAX_PATH_LEN`.

 34:    Systems that use the automounter often generate absolute paths
 35:    of the form "/tmp_mnt....".  However, the automounter will fail to
 36:    mount this path if it is not already mounted, so we remove this from
 37:    the head of the line.  This may cause problems if, for some reason,
 38:    /tmp_mnt is valid and not the result of the automounter.

 40: .seealso: `PetscGetFullPath()`
 41: @*/
 42: PetscErrorCode PetscGetRealPath(const char path[], char rpath[])
 43: {
 44: #if !defined(PETSC_HAVE_REALPATH) && defined(PETSC_HAVE_READLINK)
 45:   char tmp1[PETSC_MAX_PATH_LEN], char tmp3[PETSC_MAX_PATH_LEN], tmp4[PETSC_MAX_PATH_LEN], *tmp2;
 46:   size_t N, len1, len2;
 47:   int    n, m;
 48: #endif
 49:   size_t len;

 51:   PetscFunctionBegin;
 52: #if defined(PETSC_HAVE_REALPATH)
 53:   PetscCheck(realpath(path, rpath), PETSC_COMM_SELF, PETSC_ERR_LIB, "realpath()");
 54: #else
 55:   #if defined(PETSC_HAVE_READLINK)
 56:   /* Algorithm: we move through the path, replacing links with the real paths.   */
 57:   PetscCall(PetscStrlen(path, &N));
 58:   PetscCall(PetscStrncpy(rpath, path, N + 1)); /* assuming adequate buffer */
 59:   PetscCall(PetscStrlen(rpath, &N));
 60:   while (N) {
 61:     PetscCall(PetscStrncpy(tmp1, rpath, N));
 62:     tmp1[N] = 0;
 63:     n       = readlink(tmp1, tmp3, PETSC_MAX_PATH_LEN);
 64:     if (n > 0) {
 65:       tmp3[n] = 0; /* readlink does not automatically add 0 to string end */
 66:       if (tmp3[0] != '/') {
 67:         PetscCall(PetscStrchr(tmp1, '/', &tmp2));
 68:         PetscCall(PetscStrlen(tmp1, &len1));
 69:         PetscCall(PetscStrlen(tmp2, &len2));
 70:         m = len1 - len2;
 71:         PetscCall(PetscStrncpy(tmp4, tmp1, m));
 72:         tmp4[m] = 0;
 73:         PetscCall(PetscStrlen(tmp4, &len));
 74:         PetscCall(PetscStrlcat(tmp4, "/", PETSC_MAX_PATH_LEN));
 75:         PetscCall(PetscStrlcat(tmp4, tmp3, PETSC_MAX_PATH_LEN));
 76:         PetscCall(PetscGetRealPath(tmp4, rpath));
 77:         PetscCall(PetscStrlcat(rpath, path + N, PETSC_MAX_PATH_LEN));
 78:       } else {
 79:         PetscCall(PetscGetRealPath(tmp3, tmp1));
 80:         PetscCall(PetscStrncpy(rpath, tmp1, PETSC_MAX_PATH_LEN));
 81:         PetscCall(PetscStrlcat(rpath, path + N, PETSC_MAX_PATH_LEN));
 82:       }
 83:       PetscFunctionReturn(PETSC_SUCCESS);
 84:     }
 85:     PetscCall(PetscStrchr(tmp1, '/', &tmp2));
 86:     if (tmp2) {
 87:       PetscCall(PetscStrlen(tmp1, &len1));
 88:       PetscCall(PetscStrlen(tmp2, &len2));
 89:       N = len1 - len2;
 90:     } else {
 91:       PetscCall(PetscStrlen(tmp1, &N));
 92:     }
 93:   }
 94:   #endif
 95:   PetscCall(PetscStrncpy(rpath, path, PETSC_MAX_PATH_LEN)); /* assuming adequate buffer */
 96: #endif

 98:   /* remove garbage some automounters put at the beginning of the path */
 99:   {
100:     const char   garbage[]   = "/tmp_mnt/";
101:     const size_t garbage_len = sizeof(garbage) - 1; // 9
102:     PetscBool    flg;

104:     PetscCall(PetscStrncmp(garbage, rpath, garbage_len, &flg));
105:     if (flg) {
106:       const size_t no_slash_len = garbage_len - 1; // 8

108:       PetscCall(PetscStrlen(rpath, &len));
109:       // shift the array left by no_slash_len
110:       PetscCall(PetscArraymove(rpath, rpath + no_slash_len, len - no_slash_len));
111:       // zero out the end we just moved from
112:       PetscCall(PetscArrayzero(rpath + len - no_slash_len, no_slash_len));
113:     }
114:   }
115:   PetscFunctionReturn(PETSC_SUCCESS);
116: }