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Merge "Add utility to prepare files in a similar way to directories" into nyc-dev

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am: 6a29fe931d

* commit '6a29fe931d9fd3bf7f2aad3713dc70c080970763':
  Add utility to prepare files in a similar way to directories

Change-Id: I288024d55e8cead1c902950938b03bfa8dcc3df3
This commit is contained in:
Calin Juravle 2016-06-02 10:24:54 +00:00 committed by android-build-merger
commit 65d7c4722c
2 changed files with 31 additions and 9 deletions
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7
include/cutils/fs.h
View file

@ -51,6 +51,13 @@ extern int fs_prepare_dir(const char* path, mode_t mode, uid_t uid, gid_t gid);
*/
extern int fs_prepare_dir_strict(const char* path, mode_t mode, uid_t uid, gid_t gid);
/*
* Ensure that file exists with given mode and owners. If it exists
* with different owners, they are not fixed and -1 is returned.
*/
extern int fs_prepare_file_strict(const char* path, mode_t mode, uid_t uid, gid_t gid);
/*
* Read single plaintext integer from given file, correctly handling files
* partially written with fs_write_atomic_int().

33
libcutils/fs.c
View file

@ -37,10 +37,11 @@
#define ALL_PERMS (S_ISUID | S_ISGID | S_ISVTX | S_IRWXU | S_IRWXG | S_IRWXO)
#define BUF_SIZE 64
static int fs_prepare_dir_impl(const char* path, mode_t mode, uid_t uid, gid_t gid,
int allow_fixup) {
static int fs_prepare_path_impl(const char* path, mode_t mode, uid_t uid, gid_t gid,
int allow_fixup, int prepare_as_dir) {
// Check if path needs to be created
struct stat sb;
int create_result = -1;
if (TEMP_FAILURE_RETRY(lstat(path, &sb)) == -1) {
if (errno == ENOENT) {
goto create;
@ -51,10 +52,12 @@ static int fs_prepare_dir_impl(const char* path, mode_t mode, uid_t uid, gid_t g
}
// Exists, verify status
if (!S_ISDIR(sb.st_mode)) {
ALOGE("Not a directory: %s", path);
int type_ok = prepare_as_dir ? S_ISDIR(sb.st_mode) : S_ISREG(sb.st_mode);
if (!type_ok) {
ALOGE("Not a %s: %s", (prepare_as_dir ? "directory" : "regular file"), path);
return -1;
}
int owner_match = ((sb.st_uid == uid) && (sb.st_gid == gid));
int mode_match = ((sb.st_mode & ALL_PERMS) == mode);
if (owner_match && mode_match) {
@ -74,13 +77,21 @@ static int fs_prepare_dir_impl(const char* path, mode_t mode, uid_t uid, gid_t g
}
create:
if (TEMP_FAILURE_RETRY(mkdir(path, mode)) == -1) {
create_result = prepare_as_dir
? TEMP_FAILURE_RETRY(mkdir(path, mode))
: TEMP_FAILURE_RETRY(open(path, O_CREAT | O_CLOEXEC | O_NOFOLLOW | O_RDONLY));
if (create_result == -1) {
if (errno != EEXIST) {
ALOGE("Failed to mkdir(%s): %s", path, strerror(errno));
ALOGE("Failed to %s(%s): %s",
(prepare_as_dir ? "mkdir" : "open"), path, strerror(errno));
return -1;
}
} else if (!prepare_as_dir) {
// For regular files we need to make sure we close the descriptor
if (close(create_result) == -1) {
ALOGW("Failed to close file after create %s: %s", path, strerror(errno));
}
}
fixup:
if (TEMP_FAILURE_RETRY(chmod(path, mode)) == -1) {
ALOGE("Failed to chmod(%s, %d): %s", path, mode, strerror(errno));
@ -95,11 +106,15 @@ fixup:
}
int fs_prepare_dir(const char* path, mode_t mode, uid_t uid, gid_t gid) {
return fs_prepare_dir_impl(path, mode, uid, gid, 1);
return fs_prepare_path_impl(path, mode, uid, gid, /*allow_fixup*/ 1, /*prepare_as_dir*/ 1);
}
int fs_prepare_dir_strict(const char* path, mode_t mode, uid_t uid, gid_t gid) {
return fs_prepare_dir_impl(path, mode, uid, gid, 0);
return fs_prepare_path_impl(path, mode, uid, gid, /*allow_fixup*/ 0, /*prepare_as_dir*/ 1);
}
int fs_prepare_file_strict(const char* path, mode_t mode, uid_t uid, gid_t gid) {
return fs_prepare_path_impl(path, mode, uid, gid, /*allow_fixup*/ 0, /*prepare_as_dir*/ 0);
}
int fs_read_atomic_int(const char* path, int* out_value) {