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Refactor init(8) atexit handling.

This commit is contained in:
Jonas 'Sortie' Termansen 2016-08-21 00:35:56 +02:00
parent fdfe16ad30
commit 0b07e62259

View file

@ -53,6 +53,35 @@
#include <mount/partition.h>
#include <mount/uuid.h>
struct device_match
{
const char* path;
struct blockdevice* bdev;
};
struct mountpoint
{
struct fstab entry;
char* entry_line;
pid_t pid;
char* absolute;
};
static pid_t main_pid;
static struct harddisk** hds = NULL;
static size_t hds_used = 0;
static size_t hds_length = 0;
static struct mountpoint* mountpoints = NULL;
static size_t mountpoints_used = 0;
static size_t mountpoints_length = 0;
static bool chain_location_made = false;
static char chain_location[] = "/tmp/fs.XXXXXX";
static bool chain_location_dev_made = false;
static char chain_location_dev[] = "/tmp/fs.XXXXXX/dev";
static char* read_single_line(FILE* fp)
{
char* ret = NULL;
@ -79,8 +108,6 @@ static char* join_paths(const char* a, const char* b)
return result;
}
static pid_t main_pid;
__attribute__((noreturn))
__attribute__((format(printf, 1, 2)))
static void fatal(const char* format, ...)
@ -121,10 +148,6 @@ static void note(const char* format, ...)
va_end(ap);
}
static struct harddisk** hds = NULL;
static size_t hds_used = 0;
static size_t hds_length = 0;
static void prepare_filesystem(const char* path, struct blockdevice* bdev)
{
enum filesystem_error fserr = blockdevice_inspect_filesystem(&bdev->fs, bdev);
@ -233,12 +256,6 @@ static void prepare_block_devices(void)
fatal("iterating devices: %m");
}
struct device_match
{
const char* path;
struct blockdevice* bdev;
};
static void search_by_uuid(const char* uuid_string,
void (*cb)(void*, struct device_match*),
void* ctx)
@ -295,18 +312,6 @@ static void ensure_single_device_match(void* ctx, struct device_match* match)
*result = *match;
}
struct mountpoint
{
struct fstab entry;
char* entry_line;
pid_t pid;
char* absolute;
};
static struct mountpoint* mountpoints = NULL;
static size_t mountpoints_used = 0;
static size_t mountpoints_length = 0;
static int sort_mountpoint(const void* a_ptr, const void* b_ptr)
{
const struct mountpoint* a = (const struct mountpoint*) a_ptr;
@ -704,6 +709,29 @@ static void mountpoints_unmount(void)
}
}
// This function must be usable as an atexit handler, which means it is
// undefined behavior for it to invoke exit(), including through calls to fatal
// in any function transitively called by this function.
static void niht(void)
{
if ( getpid() != main_pid )
return;
if ( chain_location_dev_made )
{
unmount(chain_location_dev, 0);
chain_location_dev_made = false;
}
mountpoints_unmount();
if ( chain_location_made )
{
rmdir(chain_location);
chain_location_made = false;
}
}
static int init(const char* target)
{
init_early();
@ -712,8 +740,6 @@ static int init(const char* target)
set_videomode();
prepare_block_devices();
load_fstab();
if ( atexit(mountpoints_unmount) != 0 )
fatal("atexit: %m");
mountpoints_mount(false);
sigset_t oldset, sigttou;
sigemptyset(&sigttou);
@ -800,35 +826,14 @@ static int init(const char* target)
else
note("session: Unexpected unusual termination%s", back);
}
mountpoints_unmount();
return result;
}
static bool chain_location_made = false;
static char chain_location[] = "/tmp/fs.XXXXXX";
static bool chain_location_dev_made = false;
static char chain_location_dev[] = "/tmp/fs.XXXXXX/dev";
static void init_chain_atexit(void)
{
if ( chain_location_dev_made )
{
unmount(chain_location_dev, 0);
chain_location_dev_made = false;
}
if ( chain_location_made )
{
rmdir(chain_location);
chain_location_made = false;
}
}
static int init_chain(const char* target)
{
init_early();
prepare_block_devices();
load_fstab();
if ( atexit(init_chain_atexit) != 0 )
fatal("atexit: %m");
if ( !mkdtemp(chain_location) )
fatal("mkdtemp: /tmp/fs.XXXXXX: %m");
chain_location_made = true;
@ -844,8 +849,6 @@ static int init_chain(const char* target)
}
if ( !found_root )
fatal("/etc/fstab: Root filesystem not found in filesystem table");
if ( atexit(mountpoints_unmount) != 0 )
fatal("atexit: %m");
mountpoints_mount(true);
snprintf(chain_location_dev, sizeof(chain_location_dev), "%s/dev",
chain_location);
@ -917,8 +920,6 @@ static int init_chain(const char* target)
else
note("chain init: Unexpected unusual termination%s", back);
}
mountpoints_unmount();
init_chain_atexit();
return result;
}
@ -997,6 +998,9 @@ int main(int argc, char* argv[])
if ( getenv("INIT_PID") )
fatal("System is already managed by an init process");
if ( atexit(niht) != 0 )
fatal("atexit: %m");
if ( !strcmp(target, "single-user") ||
!strcmp(target, "multi-user") ||
!strcmp(target, "sysinstall") ||