ssd: compat: match -x EXECUTABLE by /proc/pid/exe too

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/debianutils/start_stop_daemon.c b/debianutils/start_stop_daemon.c
index 495ed0a..7dadc3c 100644 (file)
--- a/debianutils/start_stop_daemon.c
+++ b/debianutils/start_stop_daemon.c
@@ -31,7 +31,8 @@ Options controlling process matching
 [TODO: can PROCESS_NAME be a full pathname? Should we require full match then
 with /proc/$PID/exe or argv[0] (comm can't be matched, it never contains path)]
         -x,--exec EXECUTABLE    Look for processes that were started with this
-                                command in /proc/$PID/cmdline.
+                                command in /proc/$PID/exe and /proc/$PID/cmdline
+                                (/proc/$PID/cmdline is a bbox extension)
                                 Unlike -n, we match against the full path:
                                 "ntpd" != "./ntpd" != "/path/to/ntpd"
         -p,--pidfile PID_FILE   Look for processes with PID from this file
@@ -68,7 +69,7 @@ Misc options:
 //usage:     "\n       -n,--name NAME          Match processes with NAME"
 //usage:     "\n                               in comm field in /proc/PID/stat"
 //usage:     "\n       -x,--exec EXECUTABLE    Match processes with this command"
-//usage:     "\n                               in /proc/PID/cmdline"
+//usage:     "\n                               in /proc/PID/{exe,cmdline}"
 //usage:     "\n       -p,--pidfile FILE       Match a process with PID from the file"
 //usage:     "\n       All specified conditions must match"
 //usage:     "\n-S only:"
@@ -198,8 +199,18 @@ static int pid_is_exec(pid_t pid)
 {
        ssize_t bytes;
        char buf[sizeof("/proc/%u/cmdline") + sizeof(int)*3];
+       char *procname, *exelink;
+       int match;
 
-       sprintf(buf, "/proc/%u/cmdline", (unsigned)pid);
+       procname = buf + sprintf(buf, "/proc/%u/exe", (unsigned)pid) - 3;
+
+       exelink = xmalloc_readlink(buf);
+       match = (exelink && strcmp(execname, exelink) == 0);
+       free(exelink);
+       if (match)
+               return match;
+
+       strcpy(procname, "cmdline");
        bytes = open_read_close(buf, G.execname_cmpbuf, G.execname_sizeof);
        if (bytes > 0) {
                G.execname_cmpbuf[bytes] = '\0';