Add a WriteStringToFile overload that cares about permissions.
Change-Id: I857a80b61768d4e9610bdd149eff2d9d8e48d2c0
diff --git a/include/utils/file.h b/include/utils/file.h
index 108cabc..d6b7057 100644
--- a/include/utils/file.h
+++ b/include/utils/file.h
@@ -18,11 +18,14 @@
#define UTILS_FILE_H
#include <string>
+#include <sys/stat.h>
namespace android {
bool ReadFileToString(const std::string& path, std::string* content);
bool WriteStringToFile(const std::string& content, const std::string& path);
+bool WriteStringToFile(const std::string& content, const std::string& path,
+ mode_t mode, uid_t owner, gid_t group);
} // namespace android
diff --git a/libutils/file.cpp b/libutils/file.cpp
index aa35ff2..bfd1f55 100644
--- a/libutils/file.cpp
+++ b/libutils/file.cpp
@@ -46,14 +46,7 @@
}
}
-bool android::WriteStringToFile(const std::string& content, const std::string& path) {
- int fd = TEMP_FAILURE_RETRY(open(path.c_str(),
- O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC | O_NOFOLLOW,
- DEFFILEMODE));
- if (fd == -1) {
- return false;
- }
-
+static bool WriteStringToFd(const std::string& content, int fd) {
const char* p = content.data();
size_t left = content.size();
while (left > 0) {
@@ -68,3 +61,37 @@
TEMP_FAILURE_RETRY(close(fd));
return true;
}
+
+static bool CleanUpAfterFailedWrite(const std::string& path) {
+ // Something went wrong. Let's not leave a corrupt file lying around.
+ int saved_errno = errno;
+ unlink(path.c_str());
+ errno = saved_errno;
+ return false;
+}
+
+bool android::WriteStringToFile(const std::string& content, const std::string& path,
+ mode_t mode, uid_t owner, gid_t group) {
+ int fd = TEMP_FAILURE_RETRY(open(path.c_str(),
+ O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC | O_NOFOLLOW,
+ mode));
+ if (fd == -1) {
+ return false;
+ }
+ // We do an explicit fchmod here because we assume that the caller really meant what they
+ // said and doesn't want the umask-influenced mode.
+ if (fchmod(fd, mode) != -1 && fchown(fd, owner, group) == -1 && WriteStringToFd(content, fd)) {
+ return true;
+ }
+ return CleanUpAfterFailedWrite(path);
+}
+
+bool android::WriteStringToFile(const std::string& content, const std::string& path) {
+ int fd = TEMP_FAILURE_RETRY(open(path.c_str(),
+ O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC | O_NOFOLLOW,
+ DEFFILEMODE));
+ if (fd == -1) {
+ return false;
+ }
+ return WriteStringToFd(content, fd) || CleanUpAfterFailedWrite(path);
+}