void sc_do_umount(const char *target, int flags)
{
char buf[10000] = { 0 };
const char *umount_cmd = NULL;
if (sc_is_debug_enabled()) {
#ifdef SNAP_CONFINE_DEBUG_BUILD
umount_cmd = sc_umount_cmd(buf, sizeof(buf), target, flags);
#else
umount_cmd = use_debug_build;
#endif
debug("performing operation: %s", umount_cmd);
}
if (sc_faulty("umount", NULL) || umount2(target, flags) < 0) {
// Save errno as ensure can clobber it.
int saved_errno = errno;
// Drop privileges so that we can compute our nice error message
// without risking an attack on one of the string functions there.
sc_privs_drop();
// Compute the equivalent umount command.
umount_cmd = sc_umount_cmd(buf, sizeof(buf), target, flags);
// Restore errno and die.
errno = saved_errno;
die("cannot perform operation: %s", umount_cmd);
}
}
void sc_do_mount(const char *source, const char *target,
const char *fs_type, unsigned long mountflags,
const void *data)
{
char buf[10000] = { 0 };
const char *mount_cmd = NULL;
if (sc_is_debug_enabled()) {
#ifdef SNAP_CONFINE_DEBUG_BUILD
mount_cmd = sc_mount_cmd(buf, sizeof(buf), source,
target, fs_type, mountflags, data);
#else
mount_cmd = use_debug_build;
#endif
debug("performing operation: %s", mount_cmd);
}
if (sc_faulty("mount", NULL)
|| mount(source, target, fs_type, mountflags, data) < 0) {
// Save errno as ensure can clobber it.
int saved_errno = errno;
// Drop privileges so that we can compute our nice error message
// without risking an attack on one of the string functions there.
sc_privs_drop();
// Compute the equivalent mount command.
mount_cmd = sc_mount_cmd(buf, sizeof(buf), source,
target, fs_type, mountflags, data);
// Restore errno and die.
errno = saved_errno;
die("cannot perform operation: %s", mount_cmd);
}
}
void debug(const char *msg, ...)
{
if (sc_is_debug_enabled()) {
va_list va;
va_start(va, msg);
fprintf(stderr, "DEBUG: ");
vfprintf(stderr, msg, va);
fprintf(stderr, "\n");
va_end(va);
}
}
int main(int argc, char **argv)
{
if (sc_is_debug_enabled()) {
for (int i = 0; i < argc; i++) {
printf("-%s-\n", argv[i]);
}
}
// signal gdb to stop here
printf("\n\n");
printf("Welcome to `snap run --gdb`.\n");
printf("You are right before your application is execed():\n");
printf("- set any options you may need\n");
printf("- use 'cont' to start\n");
printf("\n\n");
raise(SIGTRAP);
const char *executable = argv[1];
execv(executable, (char *const *)&argv[1]);
perror("execv failed");
// very different exit code to make an execve failure easy to distinguish
return 101;
}
static bool sc_do_mount_ex(const char *source, const char *target,
const char *fs_type,
unsigned long mountflags, const void *data,
bool optional)
{
char buf[10000] = { 0 };
const char *mount_cmd = NULL;
if (sc_is_debug_enabled()) {
#ifdef SNAP_CONFINE_DEBUG_BUILD
mount_cmd = sc_mount_cmd(buf, sizeof(buf), source,
target, fs_type, mountflags, data);
#else
mount_cmd = use_debug_build;
#endif
debug("performing operation: %s", mount_cmd);
}
if (sc_faulty("mount", NULL)
|| mount(source, target, fs_type, mountflags, data) < 0) {
int saved_errno = errno;
if (optional && saved_errno == ENOENT) {
// The special-cased value that is allowed to fail.
return false;
}
// Drop privileges so that we can compute our nice error message
// without risking an attack on one of the string functions there.
sc_privs_drop();
// Compute the equivalent mount command.
mount_cmd = sc_mount_cmd(buf, sizeof(buf), source,
target, fs_type, mountflags, data);
// Restore errno and die.
errno = saved_errno;
die("cannot perform operation: %s", mount_cmd);
}
return true;
}
