+/**
+ * @file apply-default-acl.c
+ *
+ * @brief The command-line interface.
+ *
+ */
+
/* On Linux, ftw.h needs this special voodoo to work. */
#define _XOPEN_SOURCE 500
-
-#include <errno.h>
-#include <ftw.h> /* nftw() et al. */
-#include <getopt.h>
-#include <libgen.h> /* dirname() */
-#include <limits.h> /* PATH_MAX */
-#include <stdbool.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <sys/stat.h>
-#include <unistd.h>
-
-/* ACLs */
-#include <acl/libacl.h> /* acl_get_perm, not portable */
-#include <sys/types.h>
-#include <sys/acl.h>
-
-
-mode_t get_mode(const char* path) {
- /*
- * Get the mode bits from path.
- */
- if (path == NULL) {
- errno = ENOENT;
- return -1;
- }
-
- struct stat s;
- int result = stat(path, &s);
-
- if (result == 0) {
- return s.st_mode;
- }
- else {
- /* errno will be set already by stat() */
- return result;
- }
-}
-
-
-bool is_regular_file(const char* path) {
- /*
- * Returns true if path is a regular file, false otherwise.
- */
+#define _GNU_SOURCE
+
+#include <fcntl.h> /* AT_FOO constants */
+#include <ftw.h> /* nftw() et al. */
+#include <getopt.h> /* getopt_long() */
+#include <stdbool.h> /* the "bool" type */
+#include <stdio.h> /* perror() */
+#include <stdlib.h> /* EXIT_FAILURE, EXIT_SUCCESS */
+#include <unistd.h> /* faccessat() */
+
+#include "libadacl.h"
+
+
+
+/**
+ * @brief Determine whether or not the given path is accessible.
+ *
+ * @param path
+ * The path to test.
+ *
+ * @return true if @c path is accessible to the current effective
+ * user/group, false otherwise.
+ */
+bool path_accessible(const char* path) {
if (path == NULL) {
return false;
}
- struct stat s;
- int result = stat(path, &s);
- if (result == 0) {
- return S_ISREG(s.st_mode);
- }
- else {
- return false;
- }
-}
+ /* Test for access using the effective user and group rather than
+ the real one. */
+ int flags = AT_EACCESS;
-bool is_directory(const char* path) {
- /*
- * Returns true if path is a directory, false otherwise.
- */
- if (path == NULL) {
- return false;
- }
+ /* Don't follow symlinks when checking for a path's existence,
+ since we won't follow them to set its ACLs either. */
+ flags |= AT_SYMLINK_NOFOLLOW;
- struct stat s;
- int result = stat(path, &s);
- if (result == 0) {
- return S_ISDIR(s.st_mode);
+ /* If the path is relative, interpret it relative to the current
+ working directory (just like the access() system call). */
+ if (faccessat(AT_FDCWD, path, F_OK, flags) == 0) {
+ return true;
}
else {
return false;
}
+/**
+ * @brief Display program usage information.
+ *
+ * @param program_name
+ * The program name to use in the output.
+ *
+ */
+void usage(const char* program_name) {
+ printf("Apply any applicable default ACLs to the given files or "
+ "directories.\n\n");
+ printf("Usage: %s [flags] <target1> [<target2> [ <target3>...]]\n\n",
+ program_name);
+ printf("Flags:\n");
+ printf(" -h, --help Print this help message\n");
+ printf(" -r, --recursive Act on any given directories recursively\n");
+ printf(" -x, --no-exec-mask Apply execute permissions unconditionally\n");
-int acl_set_entry(acl_t* aclp,
- acl_entry_t entry) {
- /*
- * Update or create the given entry.
- */
-
- acl_tag_t entry_tag;
- int gt_result = acl_get_tag_type(entry, &entry_tag);
- if (gt_result == -1) {
- perror("acl_set_entry (acl_get_tag_type)");
- return -1;
- }
-
- acl_permset_t entry_permset;
- int ps_result = acl_get_permset(entry, &entry_permset);
- if (ps_result == -1) {
- perror("acl_set_entry (acl_get_permset)");
- return -1;
- }
-
- acl_entry_t existing_entry;
- /* Loop through the given ACL looking for matching entries. */
- int result = acl_get_entry(*aclp, ACL_FIRST_ENTRY, &existing_entry);
-
- while (result == 1) {
- acl_tag_t existing_tag = ACL_UNDEFINED_TAG;
- int tag_result = acl_get_tag_type(existing_entry, &existing_tag);
-
- if (tag_result == -1) {
- perror("set_acl_tag_permset (acl_get_tag_type)");
- return -1;
- }
-
- if (existing_tag == entry_tag) {
- if (entry_tag == ACL_USER_OBJ ||
- entry_tag == ACL_GROUP_OBJ ||
- entry_tag == ACL_OTHER) {
- /* Only update for these three since all other tags will have
- been wiped. */
- acl_permset_t existing_permset;
- int gep_result = acl_get_permset(existing_entry, &existing_permset);
- if (gep_result == -1) {
- perror("acl_set_entry (acl_get_permset)");
- return -1;
- }
-
- int s_result = acl_set_permset(existing_entry, entry_permset);
- if (s_result == -1) {
- perror("acl_set_entry (acl_set_permset)");
- return -1;
- }
-
- return 1;
- }
-
- }
-
- result = acl_get_entry(*aclp, ACL_NEXT_ENTRY, &existing_entry);
- }
-
- /* This catches both the initial acl_get_entry and the ones at the
- end of the loop. */
- if (result == -1) {
- perror("acl_set_entry (acl_get_entry)");
- return -1;
- }
-
- /* If we've made it this far, we need to add a new entry to the
- ACL. */
- acl_entry_t new_entry;
-
- /* We allocate memory here that we should release! */
- int c_result = acl_create_entry(aclp, &new_entry);
- if (c_result == -1) {
- perror("acl_set_entry (acl_create_entry)");
- return -1;
- }
-
- int st_result = acl_set_tag_type(new_entry, entry_tag);
- if (st_result == -1) {
- perror("acl_set_entry (acl_set_tag_type)");
- return -1;
- }
-
- int s_result = acl_set_permset(new_entry, entry_permset);
- if (s_result == -1) {
- perror("acl_set_entry (acl_set_permset)");
- return -1;
- }
-
- if (entry_tag == ACL_USER || entry_tag == ACL_GROUP) {
- /* We need to set the qualifier too. */
- void* entry_qual = acl_get_qualifier(entry);
- if (entry_qual == (void*)NULL) {
- perror("acl_set_entry (acl_get_qualifier)");
- return -1;
- }
-
- int sq_result = acl_set_qualifier(new_entry, entry_qual);
- if (sq_result == -1) {
- perror("acl_set_entry (acl_set_qualifier)");
- return -1;
- }
- }
-
- return 1;
-}
-
-
-
-int acl_entry_count(acl_t* acl) {
- /*
- * Return the number of entries in acl, or -1 on error.
- */
- acl_entry_t entry;
- int entry_count = 0;
- int result = acl_get_entry(*acl, ACL_FIRST_ENTRY, &entry);
-
- while (result == 1) {
- entry_count++;
- result = acl_get_entry(*acl, ACL_NEXT_ENTRY, &entry);
- }
-
- if (result == -1) {
- perror("acl_is_minimal (acl_get_entry)");
- return -1;
- }
-
- return entry_count;
+ return;
}
-int acl_is_minimal(acl_t* acl) {
- /* An ACL is minimal if it has fewer than four entries. Return 0 for
- * false, 1 for true, and -1 on error.
- */
-
- int ec = acl_entry_count(acl);
- if (ec == -1) {
- perror("acl_is_minimal (acl_entry_count)");
- return -1;
- }
+/**
+ * @brief Wrapper around @c apply_default_acl() for use with @c nftw().
+ *
+ * For parameter information, see the @c nftw man page.
+ *
+ * @return If the ACL was applied to @c target successfully, we return
+ * @c FTW_CONTINUE to signal to @ nftw() that we should proceed onto
+ * the next file or directory. Otherwise, we return @c FTW_STOP to
+ * signal failure.
+ *
+ */
+int apply_default_acl_nftw(const char *target,
+ const struct stat *sp,
+ int info,
+ struct FTW *ftw) {
- if (ec < 4) {
- return 1;
+ if (apply_default_acl(target, sp, false)) {
+ return FTW_CONTINUE;
}
else {
- return 0;
- }
-}
-
-
-int any_can_execute(const char* path) {
- /* Returns 1 if any ACL entry has execute access, 0 if none do, and
- * -1 on error.
- */
- acl_t acl = acl_get_file(path, ACL_TYPE_ACCESS);
-
- if (acl == (acl_t)NULL) {
- return 0;
- }
-
- /* Our return value. */
- int result = 0;
-
- if (acl_is_minimal(&acl)) {
- mode_t mode = get_mode(path);
- if (mode & (S_IXUSR | S_IXOTH | S_IXGRP)) {
- result = 1;
- goto cleanup;
- }
- else {
- result = 0;
- goto cleanup;
- }
- }
-
- acl_entry_t entry;
- int ge_result = acl_get_entry(acl, ACL_FIRST_ENTRY, &entry);
-
- while (ge_result == 1) {
- acl_permset_t permset;
-
- int ps_result = acl_get_permset(entry, &permset);
- if (ps_result == -1) {
- perror("any_can_execute (acl_get_permset)");
- result = -1;
- goto cleanup;
- }
-
- int gp_result = acl_get_perm(permset, ACL_EXECUTE);
- if (gp_result == -1) {
- perror("any_can_execute (acl_get_perm)");
- result = -1;
- goto cleanup;
- }
-
- if (gp_result == 1) {
- result = 1;
- goto cleanup;
- }
-
- ge_result = acl_get_entry(acl, ACL_NEXT_ENTRY, &entry);
- }
-
- if (ge_result == -1) {
- perror("any_can_execute (acl_get_entry)");
- result = -1;
- goto cleanup;
- }
-
- cleanup:
- acl_free(acl);
- return result;
-}
-
-
-int inherit_default_acl(const char* path, const char* parent) {
- /* Inherit the default ACL from parent to path. This overwrites any
- * existing default ACL. Returns 1 for success, 0 for failure, and
- * -1 on error.
- */
-
- /* Our return value. */
- int result = 1;
-
- if (path == NULL) {
- errno = ENOENT;
- return -1;
- }
-
- if (!is_directory(path) || !is_directory(parent)) {
- return 0;
- }
-
- acl_t parent_acl = acl_get_file(parent, ACL_TYPE_DEFAULT);
- if (parent_acl == (acl_t)NULL) {
- return 0;
- }
-
- acl_t path_acl = acl_dup(parent_acl);
-
- if (path_acl == (acl_t)NULL) {
- perror("inherit_default_acl (acl_dup)");
- acl_free(parent_acl);
- return -1;
- }
-
- int sf_result = acl_set_file(path, ACL_TYPE_DEFAULT, path_acl);
- if (sf_result == -1) {
- perror("inherit_default_acl (acl_set_file)");
- result = -1;
- goto cleanup;
- }
-
- cleanup:
- acl_free(path_acl);
- return result;
-}
-
-
-int wipe_acls(const char* path) {
- /* Remove ACL_USER, ACL_GROUP, and ACL_MASK entries from
- path. Returns 1 for success, 0 for failure, and -1 on error. */
-
- if (path == NULL) {
- errno = ENOENT;
- return -1;
- }
-
- /* Finally, remove individual named/mask entries. */
- acl_t acl = acl_get_file(path, ACL_TYPE_ACCESS);
- if (acl == (acl_t)NULL) {
- perror("wipe_acls (acl_get_file)");
- return -1;
- }
-
- /* Our return value. */
- int result = 1;
-
- acl_entry_t entry;
- int ge_result = acl_get_entry(acl, ACL_FIRST_ENTRY, &entry);
-
- while (ge_result == 1) {
- int d_result = acl_delete_entry(acl, entry);
- if (d_result == -1) {
- perror("wipe_acls (acl_delete_entry)");
- result = -1;
- goto cleanup;
- }
-
- ge_result = acl_get_entry(acl, ACL_NEXT_ENTRY, &entry);
+ return FTW_STOP;
}
-
- /* Catches the first acl_get_entry as well as the ones at the end of
- the loop. */
- if (ge_result == -1) {
- perror("wipe_acls (acl_get_entry)");
- result = -1;
- goto cleanup;
- }
-
- int sf_result = acl_set_file(path, ACL_TYPE_ACCESS, acl);
- if (sf_result == -1) {
- perror("wipe_acls (acl_set_file)");
- result = -1;
- goto cleanup;
- }
-
- cleanup:
- acl_free(acl);
- return result;
}
-int apply_default_acl(const char* path) {
- /* Really apply the default ACL by looping through it. Returns one
- * for success, zero for failure (i.e. no ACL), and -1 on unexpected
- * errors.
- */
- if (path == NULL) {
- return 0;
- }
-
- if (!is_regular_file(path) && !is_directory(path)) {
- return 0;
- }
-
- /* dirname mangles its argument */
- char path_copy[PATH_MAX];
- strncpy(path_copy, path, PATH_MAX-1);
- path_copy[PATH_MAX-1] = 0;
-
- char* parent = dirname(path_copy);
- if (!is_directory(parent)) {
- /* Make sure dirname() did what we think it did. */
- return 0;
- }
-
- int ace_result = any_can_execute(path);
- if (ace_result == -1) {
- perror("apply_default_acl (any_can_execute)");
- return -1;
- }
- bool allow_exec = (bool)ace_result;
-
- acl_t defacl = acl_get_file(parent, ACL_TYPE_DEFAULT);
-
- if (defacl == (acl_t)NULL) {
- perror("apply_default_acl (acl_get_file)");
- return -1;
- }
-
- /* Our return value. */
- int result = 1;
-
- int wipe_result = wipe_acls(path);
- if (wipe_result == -1) {
- perror("apply_default_acl (wipe_acls)");
- result = -1;
- goto cleanup;
- }
-
- /* Do this after wipe_acls(), otherwise we'll overwrite the wiped
- ACL with this one. */
- acl_t acl = acl_get_file(path, ACL_TYPE_ACCESS);
- if (acl == (acl_t)NULL) {
- perror("apply_default_acl (acl_get_file)");
- return -1;
- }
-
- /* If it's a directory, inherit the parent's default. */
- int inherit_result = inherit_default_acl(path, parent);
- if (inherit_result == -1) {
- perror("apply_default_acl (inherit_acls)");
- result = -1;
- goto cleanup;
- }
-
- acl_entry_t entry;
- int ge_result = acl_get_entry(defacl, ACL_FIRST_ENTRY, &entry);
-
- while (ge_result == 1) {
- acl_tag_t tag = ACL_UNDEFINED_TAG;
- int tag_result = acl_get_tag_type(entry, &tag);
-
- if (tag_result == -1) {
- perror("has_default_tag_acl (acl_get_tag_type)");
- result = -1;
- goto cleanup;
- }
-
-
- /* We've got an entry/tag from the default ACL. Get its permset. */
- acl_permset_t permset;
- int ps_result = acl_get_permset(entry, &permset);
- if (ps_result == -1) {
- perror("apply_default_acl (acl_get_permset)");
- result = -1;
- goto cleanup;
- }
-
- /* If this is a default mask, fix it up. */
- if (tag == ACL_MASK ||
- tag == ACL_USER_OBJ ||
- tag == ACL_GROUP_OBJ ||
- tag == ACL_OTHER) {
- if (!allow_exec) {
- /* The mask doesn't affect acl_user_obj, acl_group_obj (in
- minimal ACLs) or acl_other entries, so if execute should be
- masked, we have to do it manually. */
- int d_result = acl_delete_perm(permset, ACL_EXECUTE);
- if (d_result == -1) {
- perror("apply_default_acl (acl_delete_perm)");
- result = -1;
- goto cleanup;
- }
-
- int sp_result = acl_set_permset(entry, permset);
- if (sp_result == -1) {
- perror("apply_default_acl (acl_set_permset)");
- result = -1;
- goto cleanup;
- }
- }
- }
-
- /* Finally, add the permset to the access ACL. */
- int set_result = acl_set_entry(&acl, entry);
- if (set_result == -1) {
- perror("apply_default_acl (acl_set_entry)");
- result = -1;
- goto cleanup;
- }
-
- ge_result = acl_get_entry(defacl, ACL_NEXT_ENTRY, &entry);
- }
-
- /* Catches the first acl_get_entry as well as the ones at the end of
- the loop. */
- if (ge_result == -1) {
- perror("apply_default_acl (acl_get_entry)");
- result = -1;
- goto cleanup;
- }
-
- int sf_result = acl_set_file(path, ACL_TYPE_ACCESS, acl);
- if (sf_result == -1) {
- perror("apply_default_acl (acl_set_file)");
- result = -1;
- goto cleanup;
- }
-
- cleanup:
- acl_free(defacl);
- return result;
-}
-
-
-void usage(char* program_name) {
- /*
- * Print usage information.
- */
- printf("Apply any applicable default ACLs to the given files or "
- "directories.\n\n");
- printf("Usage: %s [flags] <target1> [<target2> [ <target3>...]]\n\n",
- program_name);
- printf("Flags:\n");
- printf(" -h, --help Print this help message\n");
- printf(" -r, --recursive Act on any given directories recursively\n");
-}
-
-
-int apply_default_acl_nftw(const char *target,
- const struct stat *s,
+/**
+ * @brief Wrapper around @c apply_default_acl() for use with @c nftw().
+ *
+ * This is identical to @c apply_default_acl_nftw(), except it passes
+ * @c true to @c apply_default_acl() as its no_exec_mask argument.
+ *
+ */
+int apply_default_acl_nftw_x(const char *target,
+ const struct stat *sp,
int info,
struct FTW *ftw) {
- /* A wrapper around the apply_default_acl() function for use with
- * nftw(). We need to adjust the return value so that nftw() doesn't
- * think we've failed.
- */
- bool reapp_result = apply_default_acl(target);
- if (reapp_result) {
- return 0;
+
+ if (apply_default_acl(target, sp, true)) {
+ return FTW_CONTINUE;
}
else {
- return 1;
+ return FTW_STOP;
}
}
-bool apply_default_acl_recursive(const char *target) {
- /* Attempt to apply default ACLs recursively. If target is a
- * directory, we recurse through its entries. If not, we just
- * apply the default ACL to target.
- *
- * We ignore symlinks for consistency with chmod -r.
- *
- */
- if (!is_directory(target)) {
- return apply_default_acl(target);
- }
+/**
+ * @brief Recursive version of @c apply_default_acl().
+ *
+ * If @c target is a directory, we use @c nftw() to call @c
+ * apply_default_acl() recursively on all of its children. Otherwise,
+ * we just delegate to @c apply_default_acl().
+ *
+ * We ignore symlinks for consistency with chmod -r.
+ *
+ * @param target
+ * The root (path) of the recursive application.
+ *
+ * @param no_exec_mask
+ * The value (either true or false) of the --no-exec-mask flag.
+ *
+ * @return
+ * If @c target is not a directory, we return the result of
+ * calling @c apply_default_acl() on @c target. Otherwise, we convert
+ * the return value of @c nftw(). If @c nftw() succeeds (returns 0),
+ * then we return @c true. Otherwise, we return @c false.
+ * \n\n
+ * If there is an error, it will be reported via @c perror, but
+ * we still return @c false.
+ */
+bool apply_default_acl_recursive(const char *target, bool no_exec_mask) {
int max_levels = 256;
int flags = FTW_PHYS; /* Don't follow links. */
- int nftw_result = nftw(target,
- apply_default_acl_nftw,
- max_levels,
- flags);
+ /* There are two separate functions that could be passed to
+ nftw(). One passes no_exec_mask = true to apply_default_acl(),
+ and the other passes no_exec_mask = false. Since the function we
+ pass to nftw() cannot have parameters, we have to create separate
+ options and make the decision here. */
+ int (*fn)(const char *, const struct stat *, int, struct FTW *) = NULL;
+ fn = no_exec_mask ? apply_default_acl_nftw_x : apply_default_acl_nftw;
+
+ int nftw_result = nftw(target, fn, max_levels, flags);
if (nftw_result == 0) {
/* Success */
return true;
}
- /* nftw will return -1 on error, or if the supplied function
+ /* nftw will return NFTW_ERROR on error, or if the supplied function
* (apply_default_acl_nftw) returns a non-zero result, nftw will
* return that.
*/
- if (nftw_result == -1) {
+ if (nftw_result == NFTW_ERROR) {
perror("apply_default_acl_recursive (nftw)");
}
}
+
+/**
+ * @brief Call apply_default_acl (possibly recursively) on each
+ * command-line argument.
+ *
+ * @return Either @c EXIT_FAILURE or @c EXIT_SUCCESS. If everything
+ * goes as expected, we return @c EXIT_SUCCESS. Otherwise, we return
+ * @c EXIT_FAILURE.
+ */
int main(int argc, char* argv[]) {
- /*
- * Call apply_default_acl on each command-line argument.
- */
+
if (argc < 2) {
usage(argv[0]);
return EXIT_FAILURE;
}
-
bool recursive = false;
+ bool no_exec_mask = false;
struct option long_options[] = {
/* These options set a flag. */
{"help", no_argument, NULL, 'h'},
{"recursive", no_argument, NULL, 'r'},
+ {"no-exec-mask", no_argument, NULL, 'x'},
{NULL, 0, NULL, 0}
};
int opt = 0;
- while ((opt = getopt_long(argc, argv, "hr", long_options, NULL)) != -1) {
+ while ((opt = getopt_long(argc, argv, "hrx", long_options, NULL)) != -1) {
switch (opt) {
case 'h':
usage(argv[0]);
case 'r':
recursive = true;
break;
+ case 'x':
+ no_exec_mask = true;
+ break;
default:
usage(argv[0]);
return EXIT_FAILURE;
const char* target = argv[arg_index];
bool reapp_result = false;
+ /* Make sure we can access the given path before we go out of our
+ * way to please it. Doing this check outside of
+ * apply_default_acl() lets us spit out a better error message for
+ * typos, too.
+ */
+ if (!path_accessible(target)) {
+ fprintf(stderr, "%s: %s: No such file or directory\n", argv[0], target);
+ result = EXIT_FAILURE;
+ continue;
+ }
+
if (recursive) {
- reapp_result = apply_default_acl_recursive(target);
+ reapp_result = apply_default_acl_recursive(target, no_exec_mask);
}
else {
- /* It's either normal file, or we're not operating recursively. */
- reapp_result = apply_default_acl(target);
+ /* It's either a normal file, or we're not operating recursively. */
+ reapp_result = apply_default_acl(target, NULL, no_exec_mask);
}
if (!reapp_result) {