/**
* \param[in] rPath path to file
* \param[in] rUser user name
* \return true = success, false = failure
*/
bool copy_from_file(const std::string& rPath, const std::string& rUser)
{
fprintf(stderr, "copying table from file '%s'\n", rPath.c_str());
IncronTab tab;
std::string s(rPath);
if (s == "-")
s = "/dev/stdin";
if (!tab.Load(s)) {
fprintf(stderr, "cannot load table from file '%s'\n", rPath.c_str());
return false;
}
std::string out(IncronTab::GetUserTablePath(rUser));
if (!tab.Save(out)) {
fprintf(stderr, "cannot create table for user '%s'\n", rUser.c_str());
return false;
}
struct passwd* ppwd = getpwnam(rUser.c_str());
if (ppwd == NULL) {
fprintf(stderr, "cannot find user '%s': %s\n", rUser.c_str(), strerror(errno));
return false;
}
if (chown(out.c_str(), ppwd->pw_uid, -1) != 0) {
fprintf(stderr, "cannot set owner '%s' to table '%s': %s\n", rUser.c_str(), out.c_str(), strerror(errno));
return false;
}
return true;
}
/**
* \param[in] rPath path to file
* \param[in] rUser user name
* \return true = success, false = failure
*/
bool copy_from_file(const std::string& rPath, const std::string& rUser)
{
fprintf(stderr, "copying table from file '%s'\n", rPath.c_str());
IncronTab tab;
std::string s(rPath);
if (s == "-")
s = "/dev/stdin";
if (!tab.Load(s)) {
fprintf(stderr, "cannot load table from file '%s'\n", rPath.c_str());
return false;
}
std::string out(IncronTab::GetUserTablePath(rUser));
if (!tab.Save(out)) {
fprintf(stderr, "cannot create table for user '%s'\n", rUser.c_str());
return false;
}
return true;
}
/**
* \param[in] rUser user name
* \return true = success, false = failure
*
* \attention This function is very complex and may contain
* various bugs including security ones. Please keep
* it in mind..
*/
bool edit_table(const std::string& rUser)
{
std::string tp(IncronTab::GetUserTablePath(rUser));
struct passwd* ppwd = getpwnam(rUser.c_str());
if (ppwd == NULL) {
fprintf(stderr, "cannot find user '%s': %s\n", rUser.c_str(), strerror(errno));
return false;
}
uid_t uid = ppwd->pw_uid;
uid_t gid = ppwd->pw_gid;
char s[NAME_MAX];
strcpy(s, "/tmp/incron.table-XXXXXX");
uid_t iu = geteuid();
uid_t ig = getegid();
if (setegid(gid) != 0 || seteuid(uid) != 0) {
fprintf(stderr, "cannot change effective UID/GID for user '%s': %s\n", rUser.c_str(), strerror(errno));
return false;
}
int fd = mkstemp(s);
if (fd == -1) {
fprintf(stderr, "cannot create temporary file: %s\n", strerror(errno));
return false;
}
bool ok = false;
FILE* out = NULL;
FILE* in = NULL;
time_t mt = (time_t) 0;
const char* e = NULL;
std::string ed;
if (setegid(ig) != 0 || seteuid(iu) != 0) {
fprintf(stderr, "cannot change effective UID/GID: %s\n", strerror(errno));
close(fd);
goto end;
}
out = fdopen(fd, "w");
if (out == NULL) {
fprintf(stderr, "cannot write to temporary file: %s\n", strerror(errno));
close(fd);
goto end;
}
in = fopen(tp.c_str(), "r");
if (in == NULL) {
if (errno == ENOENT) {
in = fopen("/dev/null", "r");
if (in == NULL) {
fprintf(stderr, "cannot get empty table for '%s': %s\n", rUser.c_str(), strerror(errno));
fclose(out);
goto end;
}
}
else {
fprintf(stderr, "cannot read old table for '%s': %s\n", rUser.c_str(), strerror(errno));
fclose(out);
goto end;
}
}
char buf[1024];
while (fgets(buf, 1024, in) != NULL) {
fputs(buf, out);
}
fclose(in);
fclose(out);
struct stat st;
if (stat(s, &st) != 0) {
fprintf(stderr, "cannot stat temporary file: %s\n", strerror(errno));
goto end;
}
mt = st.st_mtime; // save modification time for detecting its change
// Editor selecting algorithm:
// 1. Check EDITOR environment variable
// 2. Check VISUAL environment variable
// 3. Try to get from configuration
// 4. Check presence of /etc/alternatives/editor
// 5. Use hard-wired editor
e = getenv("EDITOR");
if (e == NULL) {
e = getenv("VISUAL");
if (e == NULL) {
if (!IncronCfg::GetValue("editor", ed))
throw InotifyException("configuration is corrupted", EINVAL);
if (!ed.empty()) {
e = ed.c_str();
}
else {
if (access(INCRON_ALT_EDITOR, X_OK) == 0)
e = INCRON_ALT_EDITOR;
else
e = INCRON_DEFAULT_EDITOR;
}
}
}
// this block is explicite due to gotos' usage simplification
{
pid_t pid = fork();
if (pid == 0) {
if (setgid(gid) != 0 || setuid(uid) != 0) {
fprintf(stderr, "cannot set user '%s': %s\n", rUser.c_str(), strerror(errno));
goto end;
}
execlp(e, e, s, (const char*) NULL);
_exit(1);
}
else if (pid > 0) {
int status;
if (wait(&status) != pid) {
perror("error while waiting for editor");
goto end;
}
if (!(WIFEXITED(status)) || WEXITSTATUS(status) != 0) {
perror("editor finished with error");
goto end;
}
}
else {
perror("cannot start editor");
goto end;
}
}
if (stat(s, &st) != 0) {
fprintf(stderr, "cannot stat temporary file: %s\n", strerror(errno));
goto end;
}
if (st.st_mtime == mt) {
fprintf(stderr, "table unchanged\n");
ok = true;
goto end;
}
{
IncronTab ict;
if (ict.Load(s) && ict.Save(tp)) {
if (chmod(tp.c_str(), S_IRUSR | S_IWUSR) != 0) {
fprintf(stderr, "cannot change mode of temporary file: %s\n", strerror(errno));
}
}
else {
fprintf(stderr, "cannot move temporary table: %s\n", strerror(errno));
goto end;
}
}
ok = true;
fprintf(stderr, "table updated\n");
end:
unlink(s);
return ok;
}
