e2fsprogs/misc/logsave.c

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/*
* logsave.c --- A program which saves the output of a program until
* /var/log is mounted.
*
* Copyright (C) 2003 Theodore Ts'o.
*
* %Begin-Header%
* This file may be redistributed under the terms of the GNU Public
* License.
* %End-Header%
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <fcntl.h>
#include <time.h>
#include <errno.h>
#ifdef HAVE_GETOPT_H
#include <getopt.h>
#else
extern char *optarg;
extern int optind;
#endif
int outfd = -1;
int outbufsize = 0;
void *outbuf = 0;
int verbose = 0;
int do_skip = 0;
int skip_mode = 0;
static void usage(char *progname)
{
printf("Usage: %s [-v] [-d dir] logfile program\n", progname);
exit(1);
}
#define SEND_LOG 0x01
#define SEND_CONSOLE 0x02
#define SEND_BOTH 0x03
static void send_output(const char *buffer, int c, int flag)
{
char *n;
if (c == 0)
c = strlen(buffer);
if (flag & SEND_CONSOLE)
write(1, buffer, c);
if (!(flag & SEND_LOG))
return;
if (outfd > 0)
write(outfd, buffer, c);
else {
n = realloc(outbuf, outbufsize + c);
if (n) {
outbuf = n;
memcpy(((char *)outbuf)+outbufsize, buffer, c);
outbufsize += c;
}
}
}
static int do_read(int fd)
{
int c;
char buffer[4096], *cp, *sep;
c = read(fd, buffer, sizeof(buffer)-1);
if (c <= 0)
return c;
if (do_skip) {
send_output(buffer, c, SEND_CONSOLE);
buffer[c] = 0;
cp = buffer;
while (*cp) {
if (skip_mode) {
cp = strchr(cp, '\002');
if (!cp)
return 0;
cp++;
skip_mode = 0;
continue;
}
sep = strchr(cp, '\001');
if (sep)
*sep = 0;
send_output(cp, 0, SEND_LOG);
if (sep) {
cp = sep + 1;
skip_mode = 1;
} else
break;
}
} else
send_output(buffer, c, SEND_BOTH);
return c;
}
static int run_program(char **argv)
{
int fds[2];
int status, rc, pid;
char buffer[80];
if (pipe(fds) < 0) {
perror("pipe");
exit(1);
}
pid = fork();
if (pid < 0) {
perror("vfork");
exit(1);
}
if (pid == 0) {
dup2(fds[1],1); /* fds[1] replaces stdout */
dup2(fds[1],2); /* fds[1] replaces stderr */
close(fds[0]); /* don't need this here */
execvp(argv[0], argv);
perror(argv[0]);
exit(1);
}
close(fds[1]);
while (!(waitpid(pid, &status, WNOHANG ))) {
do_read(fds[0]);
}
do_read(fds[0]);
close(fds[0]);
if ( WIFEXITED(status) ) {
rc = WEXITSTATUS(status);
if (rc) {
send_output(argv[0], 0, SEND_BOTH);
sprintf(buffer, " died with exit status %d\n", rc);
send_output(buffer, 0, SEND_BOTH);
}
} else {
if (WIFSIGNALED(status)) {
send_output(argv[0], 0, SEND_BOTH);
sprintf(buffer, "died with signal %d\n",
WTERMSIG(status));
send_output(buffer, 0, SEND_BOTH);
rc = 1;
}
rc = 0;
}
return rc;
}
static int copy_from_stdin(void)
{
int c, bad_read = 0;
while (1) {
c = do_read(0);
if ((c == 0 ) ||
((c < 0) && ((errno == EAGAIN) || (errno == EINTR)))) {
if (bad_read++ > 3)
break;
continue;
}
if (c < 0) {
perror("read");
exit(1);
}
bad_read = 0;
}
return 0;
}
int main(int argc, char **argv)
{
int c, pid, rc;
char *outfn, **cpp;
int openflags = O_CREAT|O_WRONLY|O_TRUNC;
int send_flag = SEND_LOG;
int do_stdin;
time_t t;
while ((c = getopt(argc, argv, "+asv")) != EOF) {
switch (c) {
case 'a':
openflags &= ~O_TRUNC;
openflags |= O_APPEND;
break;
case 's':
do_skip = 1;
break;
case 'v':
verbose++;
send_flag |= SEND_CONSOLE;
break;
}
}
if (optind == argc || optind+1 == argc)
usage(argv[0]);
outfn = argv[optind];
optind++;
argv += optind;
argc -= optind;
outfd = open(outfn, openflags, 0644);
do_stdin = !strcmp(argv[0], "-");
send_output("Log of ", 0, send_flag);
if (do_stdin)
send_output("stdin", 0, send_flag);
else {
for (cpp = argv; *cpp; cpp++) {
send_output(*cpp, 0, send_flag);
send_output(" ", 0, send_flag);
}
}
send_output("\n", 0, send_flag);
t = time(0);
send_output(ctime(&t), 0, send_flag);
send_output("\n", 0, send_flag);
if (do_stdin)
rc = copy_from_stdin();
else
rc = run_program(argv);
send_output("\n", 0, send_flag);
t = time(0);
send_output(ctime(&t), 0, send_flag);
send_output("----------------\n", 0, send_flag);
if (outbuf) {
pid = fork();
if (pid < 0) {
perror("fork");
exit(1);
}
if (pid) {
if (verbose)
printf("Backgrounding to save %s later\n",
outfn);
exit(rc);
}
setsid(); /* To avoid getting killed by init */
while (outfd < 0) {
outfd = open(outfn, openflags, 0644);
sleep(1);
}
write(outfd, outbuf, outbufsize);
free(outbuf);
}
close(outfd);
exit(rc);
}