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author | Laurent Bercot <ska-skaware@skarnet.org> | 2014-09-19 15:01:58 +0000 |
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committer | Laurent Bercot <ska-skaware@skarnet.org> | 2014-09-19 15:01:58 +0000 |
commit | 54b6467013bfbdb3ee606961c02fbff1271ca582 (patch) | |
tree | e3969743e61542979f12fca01017e67c4480eca8 /src/minutils/s6-logwatch.c | |
download | s6-linux-utils-54b6467013bfbdb3ee606961c02fbff1271ca582.tar.gz s6-linux-utils-54b6467013bfbdb3ee606961c02fbff1271ca582.tar.xz s6-linux-utils-54b6467013bfbdb3ee606961c02fbff1271ca582.zip |
initial commit
Diffstat (limited to 'src/minutils/s6-logwatch.c')
-rw-r--r-- | src/minutils/s6-logwatch.c | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/src/minutils/s6-logwatch.c b/src/minutils/s6-logwatch.c new file mode 100644 index 0000000..a2c493d --- /dev/null +++ b/src/minutils/s6-logwatch.c @@ -0,0 +1,156 @@ +/* ISC license. */ + +#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/siovec.h> +#include <skalibs/djbunix.h> +#include <skalibs/iopause.h> +#include <skalibs/ulong.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 unsigned long nbcat (int fdcurrent) +{ + char buf[N+1] ; + buffer b = BUFFER_INIT(&buffer_read, fdcurrent, buf, N+1) ; + siovec_t v[2] ; + unsigned long bytes = 0 ; + for (;;) + { + int 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 (;;) + { + register 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 } } ; + int fdcurrent = -1 ; + unsigned long pos = 0 ; + 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 r ; + if (!bufalloc_flush(bufalloc_1)) strerr_diefu1sys(111, "write to stdout") ; + r = iopause(x, 1, 0, 0) ; + if (r < 0) strerr_diefu1sys(111, "iopause") ; + if (x[0].revents & IOPAUSE_READ) + { + char iebuf[IESIZE] ; + while (bufalloc_len(bufalloc_1) < maxlen) + { + unsigned int i = 0 ; + 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 < (unsigned int)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 ; +} |