From bab9f6ff2345fb5a1db048349fe088c1ee7d440b Mon Sep 17 00:00:00 2001 From: Anonymous_Z Date: Tue, 3 Mar 2020 17:36:41 +0800 Subject: [PATCH] dhcp: recheck whether last pid was held by other process Signed-off-by: zhanglu --- client/dhclient.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/client/dhclient.c b/client/dhclient.c index 9f8ba06..97b04e0 100644 --- a/client/dhclient.c +++ b/client/dhclient.c @@ -774,15 +774,26 @@ main(int argc, char **argv) { } } else { FILE *pidfp = NULL; + FILE *commfp = NULL; long temp = 0; pid_t dhcpid = 0; int dhc_running = 0; char procfn[256] = ""; + char pidname_path[256] = ""; + char pidname[256] = ""; if ((pidfp = fopen(path_dhclient_pid, "re")) != NULL) { if ((fscanf(pidfp, "%ld", &temp)==1) && ((dhcpid=(pid_t)temp) > 0)) { snprintf(procfn,256,"/proc/%u",dhcpid); - dhc_running = (access(procfn, F_OK) == 0); + snprintf(pidname_path,256,"%s/comm",procfn); + + if(access(procfn, F_OK) == 0) { + if((commfp = fopen(pidname_path, "r")) != NULL) { + fscanf(commfp, "%s", pidname); + dhc_running = (strncmp("dhclient", pidname, strlen("dhclient")) == 0); + fclose(commfp); + } + } } fclose(pidfp); -- 1.8.3.1