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Capture and log STDOUT and STDERR output from dhcp-script.

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This commit is contained in:
Petr Menšík
2017-04-16 20:20:08 +01:00
committed by Simon Kelley
parent bc515b71ec
commit c77fb9d8f0
6 changed files with 100 additions and 33 deletions
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56
src/helper.c
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@@ -14,6 +14,7 @@
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdio.h>
#include "dnsmasq.h"
#ifdef HAVE_SCRIPT
@@ -135,7 +136,7 @@ int create_helper(int event_fd, int err_fd, uid_t uid, gid_t gid, long max_fd)
max_fd != STDIN_FILENO && max_fd != pipefd[0] &&
max_fd != event_fd && max_fd != err_fd)
close(max_fd);
#ifdef HAVE_LUASCRIPT
if (daemon->luascript)
{
@@ -189,6 +190,7 @@ int create_helper(int event_fd, int err_fd, uid_t uid, gid_t gid, long max_fd)
unsigned char *buf = (unsigned char *)daemon->namebuff;
unsigned char *end, *extradata, *alloc_buff = NULL;
int is6, err = 0;
int pipeout[2];
free(alloc_buff);
@@ -472,16 +474,54 @@ int create_helper(int event_fd, int err_fd, uid_t uid, gid_t gid, long max_fd)
if (!daemon->lease_change_command)
continue;
/* Pipe to capture stdout and stderr from script */
if (!option_bool(OPT_DEBUG) && pipe(pipeout) == -1)
continue;
/* possible fork errors are all temporary resource problems */
while ((pid = fork()) == -1 && (errno == EAGAIN || errno == ENOMEM))
sleep(2);
if (pid == -1)
continue;
{
if (!option_bool(OPT_DEBUG))
{
close(pipeout[0]);
close(pipeout[1]);
}
continue;
}
/* wait for child to complete */
if (pid != 0)
{
if (!option_bool(OPT_DEBUG))
{
FILE *fp;
close(pipeout[1]);
/* Read lines sent to stdout/err by the script and pass them back to be logged */
if (!(fp = fdopen(pipeout[0], "r")))
close(pipeout[0]);
else
{
while (fgets(daemon->packet, daemon->packet_buff_sz, fp))
{
/* do not include new lines, log will append them */
size_t len = strlen(daemon->packet);
if (len > 0)
{
--len;
if (daemon->packet[len] == '\n')
daemon->packet[len] = 0;
}
send_event(event_fd, EVENT_SCRIPT_LOG, 0, daemon->packet);
}
fclose(fp);
}
}
/* reap our children's children, if necessary */
while (1)
{
@@ -504,6 +544,15 @@ int create_helper(int event_fd, int err_fd, uid_t uid, gid_t gid, long max_fd)
continue;
}
if (!option_bool(OPT_DEBUG))
{
/* map stdout/stderr of script to pipeout */
close(pipeout[0]);
dup2(pipeout[1], STDOUT_FILENO);
dup2(pipeout[1], STDERR_FILENO);
close(pipeout[1]);
}
if (data.action != ACTION_TFTP && data.action != ACTION_ARP)
{
@@ -580,7 +629,8 @@ int create_helper(int event_fd, int err_fd, uid_t uid, gid_t gid, long max_fd)
hostname = NULL;
my_setenv("DNSMASQ_LOG_DHCP", option_bool(OPT_LOG_OPTS) ? "1" : NULL, &err);
}
}
/* we need to have the event_fd around if exec fails */
if ((i = fcntl(event_fd, F_GETFD)) != -1)
fcntl(event_fd, F_SETFD, i | FD_CLOEXEC);