Subversion Repositories planix.SVN

Rev

Rev 2 | Details | Compare with Previous | Last modification | View Log | RSS feed

Rev Author Line No. Line
2 - 1 
/*
2 
 * lock - keep a lock alive while a command runs
3 
 */
4 
 
5 
#include <u.h>
6 
#include <libc.h>
7 
#include <ctype.h>
8 
 
9 
static int debug;
10 
static int lockwait;
11 
 
12 
void	error(char*);
13 
void	notifyf(void*, char*);
14 
 
15 
static void
16 
usage(void)
17 
{
18 
	fprint(2, "usage: %s [-dw] lock [command [file]...]\n", argv0);
19 
	exits("usage");
20 
}
21 
 
22 
static Waitmsg *
23 
waitfor(int pid)
24 
{
25 
	char err[ERRMAX];
26 
	Waitmsg *w;
27 
 
28 
	for (;;) {
29 
		w = wait();
30 
		if (w == nil){
31 
			errstr(err, sizeof err);
32 
			if(strcmp(err, "interrupted") == 0)
33 
				continue;
34 
			return nil;
35 
		}
36 
		if (w->pid == pid)
37 
			return w;
38 
	}
39 
}
40 
 
41 
static int
42 
openlock(char *lock)
43 
{
44 
	int lckfd;
45 
	Dir *dir;
46 
 
47 
	/* first ensure that the lock file has the lock bit set */
48 
	dir = dirstat(lock);
49 
	if (dir == nil)
50 
		sysfatal("can't stat %s: %r", lock);
51 
	if (!(dir->mode & DMEXCL)) {
52 
		dir->mode |= DMEXCL;
53 
		dir->qid.type |= QTEXCL;
54 
		if (dirwstat(lock, dir) < 0)
55 
			sysfatal("can't make %s exclusive access: %r", lock);
56 
	}
57 
	free(dir);
58 
 
59 
	if (lockwait)
60 
		while ((lckfd = open(lock, ORDWR)) < 0)
61 
			sleep(1000);
62 
	else
63 
		lckfd = open(lock, ORDWR);
64 
	if (lckfd < 0)
65 
		sysfatal("can't open %s read/write: %r", lock);
66 
	return lckfd;
67 
}
68 
 
69 
void
70 
main(int argc, char *argv[])
71 
{
72 
	int fd, lckfd, lckpid, cmdpid;
73 
	char *cmd, *p, *lock;
74 
	char **args;
75 
	char *argarr[2];
76 
	Waitmsg *w;
77 
 
78 
	ARGBEGIN {
79 
	case 'd':
80 
		++debug;
81 
		break;
82 
	case 'w':
83 
		++lockwait;
84 
		break;
85 
	default:
86 
		usage();
87 
		break;
88 
	} ARGEND
89 
 
90 
	if (argc < 1)
91 
		usage();
92 
	if (argc == 1) {
93 
		args = argarr;
94 
		args[0] = cmd = "rc";
95 
		args[1] = nil;
96 
	} else {
97 
		cmd = argv[1];
98 
		args = &argv[1];
99 
	}
100 
 
101 
	/* set up lock and process to keep it alive */
102 
	lock = argv[0];
103 
	lckfd = openlock(lock);
104 
	lckpid = fork();
105 
	switch(lckpid){
106 
	case -1:
107 
		error("fork");
108 
	case 0:
109 
		/* keep lock alive until killed */
110 
		for (;;) {
111 
			sleep(60*1000);
112 
			seek(lckfd, 0, 0);
113 
			fprint(lckfd, "\n");
114 
		}
115 
	}
116 
 
117 
	/* spawn argument command */
118 
	cmdpid = rfork(RFFDG|RFREND|RFPROC|RFENVG);
119 
	switch(cmdpid){
120 
	case -1:
121 
		error("fork");
122 
	case 0:
123 
		fd = create("/env/prompt", OWRITE, 0666);
124 
		if (fd >= 0) {
125 
			fprint(fd, "%s%% ", lock);
126 
			close(fd);
127 
		}
128 
		exec(cmd, args);
129 
		if(cmd[0] != '/' && strncmp(cmd, "./", 2) != 0 &&
130 
		   strncmp(cmd, "../", 3) != 0)
131 
			exec(smprint("/bin/%s", cmd), args);
132 
		error(cmd);
133 
	}
134 
 
135 
	notify(notifyf);
136 
 
137 
	w = waitfor(cmdpid);
138 
	if (w == nil)
139 
		error("wait");
140 
 
141 
	postnote(PNPROC, lckpid, "die");
142 
	waitfor(lckpid);
143 
	if(w->msg[0]){
144 
		p = utfrune(w->msg, ':');
145 
		if(p && p[1])
146 
			p++;
147 
		else
148 
			p = w->msg;
149 
		while (isspace(*p))
150 
			p++;
151 
		fprint(2, "%s: %s  # status=%s\n", argv0, cmd, p);
152 
	}
153 
	exits(w->msg);
154 
}
155 
 
156 
void
157 
error(char *s)
158 
{
159 
	fprint(2, "%s: %s: %r\n", argv0, s);
160 
	exits(s);
161 
}
162 
 
163 
void
164 
notifyf(void *a, char *s)
165 
{
166 
	USED(a);
167 
	if(strcmp(s, "interrupt") == 0)
168 
		noted(NCONT);
169 
	noted(NDFLT);
170 
}