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/arch/um/kernel/umid.c

https://bitbucket.org/evzijst/gittest
C | 325 lines | 257 code | 43 blank | 25 comment | 58 complexity | b361304afaa7a957d2ca789e4e41b4dc MD5 | raw file
  1/* 
  2 * Copyright (C) 2001, 2002 Jeff Dike (jdike@karaya.com)
  3 * Licensed under the GPL
  4 */
  5
  6#include <stdio.h>
  7#include <unistd.h>
  8#include <errno.h>
  9#include <string.h>
 10#include <stdlib.h>
 11#include <dirent.h>
 12#include <signal.h>
 13#include <sys/stat.h>
 14#include <sys/param.h>
 15#include "user.h"
 16#include "umid.h"
 17#include "init.h"
 18#include "os.h"
 19#include "user_util.h"
 20#include "choose-mode.h"
 21
 22#define UMID_LEN 64
 23#define UML_DIR "~/.uml/"
 24
 25/* Changed by set_umid and make_umid, which are run early in boot */
 26static char umid[UMID_LEN] = { 0 };
 27
 28/* Changed by set_uml_dir and make_uml_dir, which are run early in boot */
 29static char *uml_dir = UML_DIR;
 30
 31/* Changed by set_umid */
 32static int umid_is_random = 1;
 33static int umid_inited = 0;
 34
 35static int make_umid(int (*printer)(const char *fmt, ...));
 36
 37static int __init set_umid(char *name, int is_random,
 38			   int (*printer)(const char *fmt, ...))
 39{
 40	if(umid_inited){
 41		(*printer)("Unique machine name can't be set twice\n");
 42		return(-1);
 43	}
 44
 45	if(strlen(name) > UMID_LEN - 1)
 46		(*printer)("Unique machine name is being truncated to %d "
 47			   "characters\n", UMID_LEN);
 48	strlcpy(umid, name, sizeof(umid));
 49
 50	umid_is_random = is_random;
 51	umid_inited = 1;
 52	return 0;
 53}
 54
 55static int __init set_umid_arg(char *name, int *add)
 56{
 57	*add = 0;
 58	return(set_umid(name, 0, printf));
 59}
 60
 61__uml_setup("umid=", set_umid_arg,
 62"umid=<name>\n"
 63"    This is used to assign a unique identity to this UML machine and\n"
 64"    is used for naming the pid file and management console socket.\n\n"
 65);
 66
 67int __init umid_file_name(char *name, char *buf, int len)
 68{
 69	int n;
 70
 71	if(!umid_inited && make_umid(printk)) return(-1);
 72
 73	n = strlen(uml_dir) + strlen(umid) + strlen(name) + 1;
 74	if(n > len){
 75		printk("umid_file_name : buffer too short\n");
 76		return(-1);
 77	}
 78
 79	sprintf(buf, "%s%s/%s", uml_dir, umid, name);
 80	return(0);
 81}
 82
 83extern int tracing_pid;
 84
 85static int __init create_pid_file(void)
 86{
 87	char file[strlen(uml_dir) + UMID_LEN + sizeof("/pid\0")];
 88	char pid[sizeof("nnnnn\0")];
 89	int fd, n;
 90
 91	if(umid_file_name("pid", file, sizeof(file))) return 0;
 92
 93	fd = os_open_file(file, of_create(of_excl(of_rdwr(OPENFLAGS()))), 
 94			  0644);
 95	if(fd < 0){
 96		printf("Open of machine pid file \"%s\" failed: %s\n",
 97		       file, strerror(-fd));
 98		return 0;
 99	}
100
101	sprintf(pid, "%d\n", os_getpid());
102	n = os_write_file(fd, pid, strlen(pid));
103	if(n != strlen(pid))
104		printf("Write of pid file failed - err = %d\n", -n);
105	os_close_file(fd);
106	return 0;
107}
108
109static int actually_do_remove(char *dir)
110{
111	DIR *directory;
112	struct dirent *ent;
113	int len;
114	char file[256];
115
116	directory = opendir(dir);
117	if(directory == NULL){
118		printk("actually_do_remove : couldn't open directory '%s', "
119		       "errno = %d\n", dir, errno);
120		return(1);
121	}
122	while((ent = readdir(directory)) != NULL){
123		if(!strcmp(ent->d_name, ".") || !strcmp(ent->d_name, ".."))
124			continue;
125		len = strlen(dir) + sizeof("/") + strlen(ent->d_name) + 1;
126		if(len > sizeof(file)){
127			printk("Not deleting '%s' from '%s' - name too long\n",
128			       ent->d_name, dir);
129			continue;
130		}
131		sprintf(file, "%s/%s", dir, ent->d_name);
132		if(unlink(file) < 0){
133			printk("actually_do_remove : couldn't remove '%s' "
134			       "from '%s', errno = %d\n", ent->d_name, dir, 
135			       errno);
136			return(1);
137		}
138	}
139	if(rmdir(dir) < 0){
140		printk("actually_do_remove : couldn't rmdir '%s', "
141		       "errno = %d\n", dir, errno);
142		return(1);
143	}
144	return(0);
145}
146
147void remove_umid_dir(void)
148{
149	char dir[strlen(uml_dir) + UMID_LEN + 1];
150	if(!umid_inited) return;
151
152	sprintf(dir, "%s%s", uml_dir, umid);
153	actually_do_remove(dir);
154}
155
156char *get_umid(int only_if_set)
157{
158	if(only_if_set && umid_is_random) return(NULL);
159	return(umid);
160}
161
162int not_dead_yet(char *dir)
163{
164	char file[strlen(uml_dir) + UMID_LEN + sizeof("/pid\0")];
165	char pid[sizeof("nnnnn\0")], *end;
166	int dead, fd, p, n;
167
168	sprintf(file, "%s/pid", dir);
169	dead = 0;
170	fd = os_open_file(file, of_read(OPENFLAGS()), 0);
171	if(fd < 0){
172		if(fd != -ENOENT){
173			printk("not_dead_yet : couldn't open pid file '%s', "
174			       "err = %d\n", file, -fd);
175			return(1);
176		}
177		dead = 1;
178	}
179	if(fd > 0){
180		n = os_read_file(fd, pid, sizeof(pid));
181		if(n < 0){
182			printk("not_dead_yet : couldn't read pid file '%s', "
183			       "err = %d\n", file, -n);
184			return(1);
185		}
186		p = strtoul(pid, &end, 0);
187		if(end == pid){
188			printk("not_dead_yet : couldn't parse pid file '%s', "
189			       "errno = %d\n", file, errno);
190			dead = 1;
191		}
192		if(((kill(p, 0) < 0) && (errno == ESRCH)) ||
193		   (p == CHOOSE_MODE(tracing_pid, os_getpid())))
194			dead = 1;
195	}
196	if(!dead) return(1);
197	return(actually_do_remove(dir));
198}
199
200static int __init set_uml_dir(char *name, int *add)
201{
202	if((strlen(name) > 0) && (name[strlen(name) - 1] != '/')){
203		uml_dir = malloc(strlen(name) + 2);
204		if(uml_dir == NULL){
205			printf("Failed to malloc uml_dir - error = %d\n",
206			       errno);
207			uml_dir = name;
208			/* Return 0 here because do_initcalls doesn't look at
209			 * the return value.
210			 */
211			return(0);
212		}
213		sprintf(uml_dir, "%s/", name);
214	}
215	else uml_dir = name;
216	return(0);
217}
218
219static int __init make_uml_dir(void)
220{
221	char dir[MAXPATHLEN + 1] = { '\0' };
222	int len;
223
224	if(*uml_dir == '~'){
225		char *home = getenv("HOME");
226
227		if(home == NULL){
228			printf("make_uml_dir : no value in environment for "
229			       "$HOME\n");
230			exit(1);
231		}
232		strlcpy(dir, home, sizeof(dir));
233		uml_dir++;
234	}
235	len = strlen(dir);
236	strncat(dir, uml_dir, sizeof(dir) - len);
237	len = strlen(dir);
238	if((len > 0) && (len < sizeof(dir) - 1) && (dir[len - 1] != '/')){
239		dir[len] = '/';
240		dir[len + 1] = '\0';
241	}
242
243	uml_dir = malloc(strlen(dir) + 1);
244	if(uml_dir == NULL){
245		printf("make_uml_dir : malloc failed, errno = %d\n", errno);
246		exit(1);
247	}
248	strcpy(uml_dir, dir);
249	
250	if((mkdir(uml_dir, 0777) < 0) && (errno != EEXIST)){
251	        printf("Failed to mkdir %s: %s\n", uml_dir, strerror(errno));
252		return(-1);
253	}
254	return 0;
255}
256
257static int __init make_umid(int (*printer)(const char *fmt, ...))
258{
259	int fd, err;
260	char tmp[strlen(uml_dir) + UMID_LEN + 1];
261
262	strlcpy(tmp, uml_dir, sizeof(tmp));
263
264	if(!umid_inited){
265		strcat(tmp, "XXXXXX");
266		fd = mkstemp(tmp);
267		if(fd < 0){
268			(*printer)("make_umid - mkstemp(%s) failed: %s\n",
269				   tmp,strerror(errno));
270			return(1);
271		}
272
273		os_close_file(fd);
274		/* There's a nice tiny little race between this unlink and
275		 * the mkdir below.  It'd be nice if there were a mkstemp
276		 * for directories.
277		 */
278		unlink(tmp);
279		set_umid(&tmp[strlen(uml_dir)], 1, printer);
280	}
281	
282	sprintf(tmp, "%s%s", uml_dir, umid);
283
284	err = mkdir(tmp, 0777);
285	if(err < 0){
286		if(errno == EEXIST){
287			if(not_dead_yet(tmp)){
288				(*printer)("umid '%s' is in use\n", umid);
289				return(-1);
290			}
291			err = mkdir(tmp, 0777);
292		}
293	}
294	if(err < 0){
295		(*printer)("Failed to create %s - errno = %d\n", umid, errno);
296		return(-1);
297	}
298
299	return(0);
300}
301
302__uml_setup("uml_dir=", set_uml_dir,
303"uml_dir=<directory>\n"
304"    The location to place the pid and umid files.\n\n"
305);
306
307static int __init make_umid_setup(void)
308{
309	/* one function with the ordering we need ... */
310	make_uml_dir();
311	make_umid(printf);
312	return create_pid_file();
313}
314__uml_postsetup(make_umid_setup);
315
316/*
317 * Overrides for Emacs so that we follow Linus's tabbing style.
318 * Emacs will notice this stuff at the end of the file and automatically
319 * adjust the settings for this buffer only.  This must remain at the end
320 * of the file.
321 * ---------------------------------------------------------------------------
322 * Local variables:
323 * c-file-style: "linux"
324 * End:
325 */