diff options
Diffstat (limited to 'arch/um/os-Linux')
| -rw-r--r-- | arch/um/os-Linux/mem.c | 21 | ||||
| -rw-r--r-- | arch/um/os-Linux/umid.c | 97 |
2 files changed, 81 insertions, 37 deletions
diff --git a/arch/um/os-Linux/mem.c b/arch/um/os-Linux/mem.c index c6432e72924..560c8063c77 100644 --- a/arch/um/os-Linux/mem.c +++ b/arch/um/os-Linux/mem.c @@ -55,7 +55,7 @@ static void __init find_tempdir(void) */ static int next(int fd, char *buf, int size, char c) { - int n; + int n, len; char *ptr; while((ptr = strchr(buf, c)) == NULL){ @@ -69,7 +69,17 @@ static int next(int fd, char *buf, int size, char c) } ptr++; - memmove(buf, ptr, strlen(ptr) + 1); + len = strlen(ptr); + memmove(buf, ptr, len + 1); + + /* Refill the buffer so that if there's a partial string that we care + * about, it will be completed, and we can recognize it. + */ + n = read(fd, &buf[len], size - len - 1); + if(n < 0) + return -errno; + + buf[len + n] = '\0'; return 1; } @@ -200,8 +210,11 @@ int create_tmp_file(unsigned long long len) exit(1); } - if (lseek64(fd, len, SEEK_SET) < 0) { - perror("os_seek_file"); + /* Seek to len - 1 because writing a character there will + * increase the file size by one byte, to the desired length. + */ + if (lseek64(fd, len - 1, SEEK_SET) < 0) { + perror("os_seek_file"); exit(1); } diff --git a/arch/um/os-Linux/umid.c b/arch/um/os-Linux/umid.c index 362db059fe3..48092b95c8a 100644 --- a/arch/um/os-Linux/umid.c +++ b/arch/um/os-Linux/umid.c @@ -67,32 +67,53 @@ err: return err; } -static int actually_do_remove(char *dir) +/* + * Unlinks the files contained in @dir and then removes @dir. + * Doesn't handle directory trees, so it's not like rm -rf, but almost such. We + * ignore ENOENT errors for anything (they happen, strangely enough - possibly due + * to races between multiple dying UML threads). + */ +static int remove_files_and_dir(char *dir) { DIR *directory; struct dirent *ent; int len; char file[256]; + int ret; directory = opendir(dir); - if(directory == NULL) - return -errno; + if (directory == NULL) { + if (errno != ENOENT) + return -errno; + else + return 0; + } - while((ent = readdir(directory)) != NULL){ - if(!strcmp(ent->d_name, ".") || !strcmp(ent->d_name, "..")) + while ((ent = readdir(directory)) != NULL) { + if (!strcmp(ent->d_name, ".") || !strcmp(ent->d_name, "..")) continue; len = strlen(dir) + sizeof("/") + strlen(ent->d_name) + 1; - if(len > sizeof(file)) - return -E2BIG; + if (len > sizeof(file)) { + ret = -E2BIG; + goto out; + } sprintf(file, "%s/%s", dir, ent->d_name); - if(unlink(file) < 0) - return -errno; + if (unlink(file) < 0 && errno != ENOENT) { + ret = -errno; + goto out; + } } - if(rmdir(dir) < 0) - return -errno; - return 0; + if (rmdir(dir) < 0 && errno != ENOENT) { + ret = -errno; + goto out; + } + + ret = 0; +out: + closedir(directory); + return ret; } /* This says that there isn't already a user of the specified directory even if @@ -103,9 +124,10 @@ static int actually_do_remove(char *dir) * something other than UML sticking stuff in the directory * this boot racing with a shutdown of the other UML * In any of these cases, the directory isn't useful for anything else. + * + * Boolean return: 1 if in use, 0 otherwise. */ - -static int not_dead_yet(char *dir) +static inline int is_umdir_used(char *dir) { char file[strlen(uml_dir) + UMID_LEN + sizeof("/pid\0")]; char pid[sizeof("nnnnn\0")], *end; @@ -113,7 +135,7 @@ static int not_dead_yet(char *dir) n = snprintf(file, sizeof(file), "%s/pid", dir); if(n >= sizeof(file)){ - printk("not_dead_yet - pid filename too long\n"); + printk("is_umdir_used - pid filename too long\n"); err = -E2BIG; goto out; } @@ -123,7 +145,7 @@ static int not_dead_yet(char *dir) if(fd < 0) { fd = -errno; if(fd != -ENOENT){ - printk("not_dead_yet : couldn't open pid file '%s', " + printk("is_umdir_used : couldn't open pid file '%s', " "err = %d\n", file, -fd); } goto out; @@ -132,18 +154,18 @@ static int not_dead_yet(char *dir) err = 0; n = read(fd, pid, sizeof(pid)); if(n < 0){ - printk("not_dead_yet : couldn't read pid file '%s', " + printk("is_umdir_used : couldn't read pid file '%s', " "err = %d\n", file, errno); goto out_close; } else if(n == 0){ - printk("not_dead_yet : couldn't read pid file '%s', " + printk("is_umdir_used : couldn't read pid file '%s', " "0-byte read\n", file); goto out_close; } p = strtoul(pid, &end, 0); if(end == pid){ - printk("not_dead_yet : couldn't parse pid file '%s', " + printk("is_umdir_used : couldn't parse pid file '%s', " "errno = %d\n", file, errno); goto out_close; } @@ -153,19 +175,32 @@ static int not_dead_yet(char *dir) return 1; } - err = actually_do_remove(dir); - if(err) - printk("not_dead_yet - actually_do_remove failed with " - "err = %d\n", err); - - return err; - out_close: close(fd); out: return 0; } +/* + * Try to remove the directory @dir unless it's in use. + * Precondition: @dir exists. + * Returns 0 for success, < 0 for failure in removal or if the directory is in + * use. + */ +static int umdir_take_if_dead(char *dir) +{ + int ret; + if (is_umdir_used(dir)) + return -EEXIST; + + ret = remove_files_and_dir(dir); + if (ret) { + printk("is_umdir_used - remove_files_and_dir failed with " + "err = %d\n", ret); + } + return ret; +} + static void __init create_pid_file(void) { char file[strlen(uml_dir) + UMID_LEN + sizeof("/pid\0")]; @@ -244,11 +279,7 @@ int __init make_umid(void) if(err != -EEXIST) goto err; - /* 1 -> this umid is already in use - * < 0 -> we couldn't remove the umid directory - * In either case, we can't use this umid, so return -EEXIST. - */ - if(not_dead_yet(tmp) != 0) + if (umdir_take_if_dead(tmp) < 0) goto err; err = mkdir(tmp, 0777); @@ -344,9 +375,9 @@ static void remove_umid_dir(void) char dir[strlen(uml_dir) + UMID_LEN + 1], err; sprintf(dir, "%s%s", uml_dir, umid); - err = actually_do_remove(dir); + err = remove_files_and_dir(dir); if(err) - printf("remove_umid_dir - actually_do_remove failed with " + printf("remove_umid_dir - remove_files_and_dir failed with " "err = %d\n", err); } |