Hello all.
Today I found that when I start some program asynchronously ("prog &")
from usbhidaction(1) and then usbhidaction(1) terminates, then "prog"
terminates too. This is caused by the fact usbhidaction(1) uses
system(3). I changed the logic to do fork+setpgid+exec dance, and now
things work as expected. The patch is at the end of letter.
--
Best wishes,
Vadim Zhukov
A: Because it messes up the order in which people normally read text.
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Index: usbhidaction.c
===================================================================
RCS file: /cvs/src/usr.bin/usbhidaction/usbhidaction.c,v
retrieving revision 1.12
diff -u -p -r1.12 usbhidaction.c
--- usbhidaction.c 21 Oct 2009 15:48:27 -0000 1.12
+++ usbhidaction.c 27 Mar 2010 08:04:37 -0000
@@ -46,6 +46,7 @@
#include <util.h>
#include <syslog.h>
#include <signal.h>
+#include <paths.h>
int verbose = 0;
int isdemon = 0;
@@ -399,6 +400,7 @@ docmd(struct command *cmd, int value, co
char cmdbuf[SIZE], *p, *q;
size_t len;
int n, r;
+ pid_t pid;
for (p = cmd->action, q = cmdbuf; *p && q < &cmdbuf[SIZE-1]; ) {
if (*p == '$') {
@@ -431,11 +433,16 @@ docmd(struct command *cmd, int value, co
}
*q = 0;
- if (verbose)
- printf("system '%s'\n", cmdbuf);
- r = system(cmdbuf);
- if (verbose > 1 && r)
- printf("return code = 0x%x\n", r);
+ pid = fork();
+ if (pid == -1)
+ warn("fork failed");
+ else if (pid == 0) {
+ setpgid(0, 0);
+ if (verbose)
+ printf("executing '%s'\n", cmdbuf);
+ r = execl(_PATH_BSHELL, "sh", "-c", cmdbuf, NULL);
+ err(1, "execl");
+ }
}
void
