diff options
| -rw-r--r-- | src/chmod.c | 73 |
1 files changed, 69 insertions, 4 deletions
diff --git a/src/chmod.c b/src/chmod.c index 3a073fedb..132d1ccd8 100644 --- a/src/chmod.c +++ b/src/chmod.c @@ -23,6 +23,8 @@ #include <sys/types.h> #include "system.h" +#include "dev-ino.h" +#include "dirname.h" #include "error.h" #include "filemode.h" #include "modechange.h" @@ -71,20 +73,28 @@ static enum Verbosity verbosity = V_off; of this file. This file must exist. */ static char *reference_file; +/* Pointer to the device and inode numbers of `/', when --recursive. + Otherwise NULL. */ +static struct dev_ino *root_dev_ino; + /* For long options that have no equivalent short option, use a non-character as a pseudo short option, starting with CHAR_MAX + 1. */ enum { - REFERENCE_FILE_OPTION = CHAR_MAX + 1 + NO_PRESERVE_ROOT = CHAR_MAX + 1, + PRESERVE_ROOT, + REFERENCE_FILE_OPTION }; static struct option const long_options[] = { {"recursive", no_argument, 0, 'R'}, {"changes", no_argument, 0, 'c'}, - {"silent", no_argument, 0, 'f'}, + {"preserve-root", no_argument, 0, PRESERVE_ROOT}, + {"no-preserve-root", no_argument, 0, NO_PRESERVE_ROOT}, {"quiet", no_argument, 0, 'f'}, {"reference", required_argument, 0, REFERENCE_FILE_OPTION}, + {"silent", no_argument, 0, 'f'}, {"verbose", no_argument, 0, 'v'}, {GETOPT_HELP_OPTION_DECL}, {GETOPT_VERSION_OPTION_DECL}, @@ -158,6 +168,19 @@ change_file_mode (const char *file, const struct mode_change *changes, return 1; } + if (root_dev_ino && SAME_INODE (file_stats, *root_dev_ino)) + { + if (STREQ (file, "/")) + error (0, 0, _("it is dangerous to operate recursively on %s"), + quote (file)); + else + error (0, 0, + _("it is dangerous to operate recursively on %s (same as %s)"), + quote_n (0, file), quote_n (1, "/")); + error (0, 0, _("use --no-preserve-root to override this failsafe")); + return 1; + } + if (S_ISLNK (file_stats.st_mode)) return 0; @@ -180,7 +203,12 @@ change_file_mode (const char *file, const struct mode_change *changes, } if (recurse && S_ISDIR (file_stats.st_mode)) - errors |= change_dir_mode (file, changes); + { + char *f; + ASSIGN_STRDUPA (f, file); + strip_trailing_slashes (f); + errors |= change_dir_mode (f, changes); + } return errors; } @@ -247,6 +275,8 @@ Usage: %s [OPTION]... MODE[,MODE]... FILE...\n\ Change the mode of each FILE to MODE.\n\ \n\ -c, --changes like verbose but report only when a change is made\n\ + --preserve-root fail to operate recursively on `/'\n\ + --no-preserve-root do not treat `/' specially (the default)\n\ -f, --silent, --quiet suppress most error messages\n\ -v, --verbose output a diagnostic for every file processed\n\ --reference=RFILE use RFILE's mode instead of MODE values\n\ @@ -264,6 +294,20 @@ one or more of the letters rwxXstugo.\n\ exit (status); } +/* Call lstat to get the device and inode numbers for `/'. + Upon failure, return NULL. Otherwise, set the members of + *ROOT_D_I accordingly and return ROOT_D_I. */ +static struct dev_ino * +get_root_dev_ino (struct dev_ino *root_d_i) +{ + struct stat statbuf; + if (lstat ("/", &statbuf)) + return NULL; + root_d_i->st_ino = statbuf.st_ino; + root_d_i->st_dev = statbuf.st_dev; + return root_d_i; +} + /* Parse the ASCII mode given on the command line into a linked list of `struct mode_change' and apply that to each file argument. */ @@ -274,6 +318,7 @@ main (int argc, char **argv) int errors = 0; int modeind = 0; /* Index of the mode argument in `argv'. */ int thisind; + bool preserve_root = false; int c; initialize_main (&argc, &argv); @@ -316,11 +361,18 @@ main (int argc, char **argv) { static char char_string[2] = {0, 0}; char_string[0] = c; - error (EXIT_FAILURE, 0, _("invalid character %s in mode string %s"), + error (EXIT_FAILURE, 0, + _("invalid character %s in mode string %s"), quote_n (0, char_string), quote_n (1, argv[thisind])); } modeind = thisind; break; + case NO_PRESERVE_ROOT: + preserve_root = false; + break; + case PRESERVE_ROOT: + preserve_root = true; + break; case REFERENCE_FILE_OPTION: reference_file = optarg; break; @@ -364,6 +416,19 @@ main (int argc, char **argv) error (EXIT_FAILURE, errno, _("failed to get attributes of %s"), quote (reference_file)); + if (recurse && preserve_root) + { + static struct dev_ino dev_ino_buf; + root_dev_ino = get_root_dev_ino (&dev_ino_buf); + if (root_dev_ino == NULL) + error (EXIT_FAILURE, errno, _("failed to get attributes of %s"), + quote ("/")); + } + else + { + root_dev_ino = NULL; + } + for (; optind < argc; ++optind) errors |= change_file_mode (argv[optind], changes, 1); |