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alsactl: Fix the file locking routines (for the state management)

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This commit is contained in:
Jaroslav Kysela 2014-09-24 10:35:53 +02:00
parent f58ce3619d
commit 1363f852e9
3 changed files with 46 additions and 20 deletions
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3
alsactl/alsactl.h
View file

@ -25,7 +25,8 @@ void dbg_(const char *fcn, long line, const char *fmt, ...);
#endif
int init(const char *file, const char *cardname);
int state_lock(const char *file, int lock, int timeout);
int state_lock(const char *file, int timeout);
int state_unlock(int fd, const char *file);
int save_state(const char *file, const char *cardname);
int load_state(const char *file, const char *initfile, const char *cardname,
int do_init);

41
alsactl/lock.c
View file

@ -30,7 +30,7 @@
#include <sys/stat.h>
#include "alsactl.h"
static int state_lock_(const char *file, int lock, int timeout)
static int state_lock_(const char *file, int lock, int timeout, int _fd)
{
int fd = -1, err = 0;
struct flock lck;
@ -50,9 +50,14 @@ static int state_lock_(const char *file, int lock, int timeout)
snprintf(lcktxt, sizeof(lcktxt), "%10li\n", (long)getpid());
} else {
snprintf(lcktxt, sizeof(lcktxt), "%10s\n", "");
fd = _fd;
}
while (fd < 0 && timeout-- > 0) {
fd = open(nfile, O_RDWR);
if (!lock && fd < 0) {
err = -EIO;
goto out;
}
if (fd < 0) {
fd = open(nfile, O_RDWR|O_CREAT|O_EXCL, 0644);
if (fd < 0) {
@ -74,12 +79,12 @@ static int state_lock_(const char *file, int lock, int timeout)
err = -errno;
goto out;
}
if (st.st_size != 11) {
if (st.st_size != 11 || !lock) {
if (write(fd, lcktxt, 11) != 11) {
err = -EIO;
goto out;
}
if (lseek(fd, 0, SEEK_SET)) {
if (lock && lseek(fd, 0, SEEK_SET)) {
err = -errno;
goto out;
}
@ -96,21 +101,37 @@ static int state_lock_(const char *file, int lock, int timeout)
err = -EBUSY;
goto out;
}
if (write(fd, lcktxt, 11) != 11) {
err = -EIO;
goto out;
if (lock) {
if (write(fd, lcktxt, 11) != 11) {
err = -EIO;
goto out;
}
return fd;
}
err = 0;
out:
if (fd >= 0)
close(fd);
return err;
}
int state_lock(const char *file, int lock, int timeout)
int state_lock(const char *file, int timeout)
{
int err;
err = state_lock_(file, lock, timeout);
err = state_lock_(file, 1, timeout, -1);
if (err < 0)
error("file %s %slock error: %s", file,
lock ? "" : "un", strerror(-err));
error("file %s lock error: %s", file, strerror(-err));
return err;
}
int state_unlock(int _fd, const char *file)
{
int err;
err = state_lock_(file, 0, 10, _fd);
if (err < 0)
error("file %s unlock error: %s", file, strerror(-err));
return err;
}

22
alsactl/state.c
View file

@ -1544,6 +1544,7 @@ int save_state(const char *file, const char *cardname)
snd_output_t *out;
int stdio;
char *nfile = NULL;
int lock_fd = -EINVAL;
err = snd_config_top(&config);
if (err < 0) {
@ -1555,12 +1556,16 @@ int save_state(const char *file, const char *cardname)
nfile = malloc(strlen(file) + 5);
if (nfile == NULL) {
error("No enough memory...");
err = -ENOMEM;
goto out;
}
strcpy(nfile, file);
strcat(nfile, ".new");
if (state_lock(file, 1, 10) != 0)
lock_fd = state_lock(file, 10);
if (lock_fd < 0) {
err = lock_fd;
goto out;
}
}
if (!stdio && (err = snd_input_stdio_open(&in, file, "r")) >= 0) {
err = snd_config_load(config, in);
@ -1632,8 +1637,8 @@ int save_state(const char *file, const char *cardname)
error("rename failed: %s (%s)", strerror(-err), file);
}
out:
if (!stdio)
state_lock(file, 0, 10);
if (!stdio && lock_fd >= 0)
state_unlock(lock_fd, file);
free(nfile);
snd_config_delete(config);
snd_config_update_free_global();
@ -1646,7 +1651,7 @@ int load_state(const char *file, const char *initfile, const char *cardname,
int err, finalerr = 0;
snd_config_t *config;
snd_input_t *in;
int stdio, locked = 0;
int stdio, lock_fd = -EINVAL;
err = snd_config_top(&config);
if (err < 0) {
@ -1657,15 +1662,14 @@ int load_state(const char *file, const char *initfile, const char *cardname,
if (stdio) {
err = snd_input_stdio_attach(&in, stdin, 0);
} else {
err = state_lock(file, 1, 10);
locked = err >= 0;
err = err >= 0 ? snd_input_stdio_open(&in, file, "r") : err;
lock_fd = state_lock(file, 10);
err = lock_fd >= 0 ? snd_input_stdio_open(&in, file, "r") : lock_fd;
}
if (err >= 0) {
err = snd_config_load(config, in);
snd_input_close(in);
if (locked)
state_lock(file, 0, 10);
if (lock_fd >= 0)
state_unlock(lock_fd, file);
if (err < 0) {
error("snd_config_load error: %s", snd_strerror(err));
goto out;