1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
|
/* ISC license. */
#include <sys/types.h>
#include <sys/uio.h>
#include <errno.h>
#include <unistd.h>
#include <signal.h>
#include <sys/ioctl.h>
#include <sys/inotify.h>
#include <skalibs/allreadwrite.h>
#include <skalibs/sgetopt.h>
#include <skalibs/bytestr.h>
#include <skalibs/strerr2.h>
#include <skalibs/error.h>
#include <skalibs/buffer.h>
#include <skalibs/bufalloc.h>
#include <skalibs/sig.h>
#include <skalibs/djbunix.h>
#include <skalibs/iopause.h>
#include <skalibs/types.h>
#define USAGE "s6-logwatch [ -m maxbuffer ] logdir"
#define dieusage() strerr_dieusage(100, USAGE)
#define N 4096
#define IESIZE 100
typedef enum bstate_e bstate_t, *bstate_t_ref ;
enum bstate_e
{
B_TAILING = 0,
B_WAITING = 1
} ;
static void X (void)
{
strerr_diefu1x(101, "follow file state changes (race condition triggered). Sorry.") ;
}
static size_t nbcat (int fdcurrent)
{
char buf[N+1] ;
buffer b = BUFFER_INIT(&fd_readv, fdcurrent, buf, N+1) ;
struct iovec v[2] ;
size_t bytes = 0 ;
for (;;)
{
ssize_t r = sanitize_read(buffer_fill(&b)) ;
if (!r) break ;
if (r < 0)
{
if (errno == EPIPE) break ;
else strerr_diefu1sys(111, "buffer_fill") ;
}
buffer_rpeek(&b, v) ;
if (!bufalloc_putv(bufalloc_1, v, 2))
strerr_diefu1sys(111, "bufalloc_putv") ;
buffer_rseek(&b, r) ;
bytes += r ;
}
return bytes ;
}
int main (int argc, char const *const *argv)
{
char const *dir = "." ;
unsigned long maxlen = 4000 ;
PROG = "s6-logwatch" ;
{
subgetopt_t l = SUBGETOPT_ZERO ;
for (;;)
{
int opt = subgetopt_r(argc, argv, "m:", &l) ;
if (opt == -1) break ;
switch (opt)
{
case 'm' : if (!ulong0_scan(l.arg, &maxlen)) dieusage() ; break ;
default : dieusage() ;
}
}
argc -= l.ind ; argv += l.ind ;
}
if (argc) dir = *argv ;
if (chdir(dir) < 0) strerr_diefu2sys(111, "chdir to ", dir) ;
{
iopause_fd x[1] = { { -1, IOPAUSE_READ, 0 } } ;
size_t pos = 0 ;
int fdcurrent = -1 ;
int w ;
bstate_t state = B_TAILING ;
x[0].fd = inotify_init() ;
if (x[0].fd < 0) strerr_diefu1sys(111, "inotify_init") ;
if (ndelay_on(x[0].fd) < 0) strerr_diefu1sys(111, "ndelay_on inotify fd") ;
w = inotify_add_watch(x[0].fd, ".", IN_CREATE | IN_MODIFY | IN_CLOSE_WRITE) ;
if (w < 0) strerr_diefu1sys(111, "inotify_add_watch") ;
if (sig_ignore(SIGPIPE) == -1) strerr_diefu1sys(111, "sig_ignore(SIGPIPE)") ;
fdcurrent = open_readb("current") ;
if (fdcurrent < 0)
if (errno != ENOENT) strerr_diefu1sys(111, "open_readb current") ;
else state = B_WAITING ;
else pos = nbcat(fdcurrent) ;
for (;;)
{
int rr ;
if (!bufalloc_flush(bufalloc_1)) strerr_diefu1sys(111, "write to stdout") ;
rr = iopause(x, 1, 0, 0) ;
if (rr < 0) strerr_diefu1sys(111, "iopause") ;
if (x[0].revents & IOPAUSE_READ)
{
char iebuf[IESIZE] ;
while (bufalloc_len(bufalloc_1) < maxlen)
{
size_t i = 0 ;
ssize_t r = sanitize_read(fd_read(x[0].fd, iebuf, IESIZE)) ;
if (r < 0) strerr_diefu1sys(111, "read from inotify fd") ;
if (!r) break ;
while (i < (size_t)r)
{
struct inotify_event *ie = (struct inotify_event *)(iebuf + i) ;
if ((ie->wd != w) || !ie->len || str_diff(ie->name, "current")) goto cont ;
if (ie->mask & IN_MODIFY)
{
if (state) X() ;
pos += nbcat(fdcurrent) ;
}
else if (ie->mask & IN_CLOSE_WRITE)
{
if (state) X() ;
fd_close(fdcurrent) ;
fdcurrent = -1 ;
pos = 0 ;
state = B_WAITING ;
}
else if (ie->mask & IN_CREATE)
{
if (!state) X() ;
fdcurrent = open_readb("current") ;
if (fdcurrent < 0)
{
if (errno != ENOENT) strerr_diefu1sys(111, "open_readb current") ;
else goto cont ;
}
pos = nbcat(fdcurrent) ;
state = B_TAILING ;
}
cont:
i += sizeof(struct inotify_event) + ie->len ;
}
}
}
}
}
return 0 ;
}
|
