Using forx in parallel mode with a large number of arguments can lead to
all instances not being able to finish their jobs due to resource
constrains. With an option to specify a max amount of parallel instances
this can be handled properly.
Signed-off-by: Sertonix <serto...@posteo.net>
---
doc/forx.html | 5 ++++-
src/execline/forx.c | 34 ++++++++++++++++++++++++----------
2 files changed, 28 insertions(+), 11 deletions(-)
diff --git a/doc/forx.html b/doc/forx.html
index 8f1d558..0dc43c2 100644
--- a/doc/forx.html
+++ b/doc/forx.html
@@ -29,7 +29,7 @@
</p>
<pre>
- forx [ -E | -e ] [ -p ] [ -o <em>okcodes</em> | -x <em>breakcodes</em> ]
<em>variable</em> { <em>args...</em> } <em>loop...</em>
+ forx [ -E | -e ] [ -p | -P <em>maxpar</em> ] [ -o <em>okcodes</em> | -x
<em>breakcodes</em> ] <em>variable</em> { <em>args...</em> } <em>loop...</em>
</pre>
<ul>
@@ -63,6 +63,9 @@ will exit 0 if all of the exit codes are in the values listed
in the <em>okcodes
list, else it will exit 1. If the <tt>-x</tt> option has been given,
<tt>forx</tt> will exit 0 if none of the exit codes are in the values
listed in the <em>breakcodes</em> list, else it will exit 1. </li>
+ <li> <tt>-P</tt> : like <tt>-p</tt> but run up to <em>maxpar</em>
instances
+in parallel. 0 means unlimited. When <em>maxpar</em> is not 0 <em>forx</em>
+may not spawn all instances. </li>
<li> <tt>-e</tt> : no autoimport. This is the default. </li>
<li> <tt>-E</tt> : autoimport. Instead of spawning
<em>loop...</em>, spawn <tt>importas -ui <em>variable</em> <em>variable</em>
diff --git a/src/execline/forx.c b/src/execline/forx.c
index 1695c00..3f7b9c2 100644
--- a/src/execline/forx.c
+++ b/src/execline/forx.c
@@ -23,10 +23,10 @@ static int fx_isok (unsigned short const *tab, unsigned int
n, int code)
return i < n ;
}
-static int waitn_code (unsigned short const *tab, unsigned int nbc, pid_t
*pids, unsigned int n, int not)
+static int waitn_code (unsigned short const *tab, unsigned int nbc, pid_t
*pids, unsigned int n, int not, int once)
{
int ok = 1 ;
- while (n)
+ do
{
int wstat ;
unsigned int i = 0 ;
@@ -39,6 +39,7 @@ static int waitn_code (unsigned short const *tab, unsigned
int nbc, pid_t *pids,
pids[i] = pids[--n] ;
}
}
+ while (n && !once) ;
return ok ;
}
@@ -47,18 +48,19 @@ int main (int argc, char const **argv)
char const *var ;
unsigned short okcodes[256] ;
size_t nbc = 0 ;
- int flagpar = 0, not = 1, doimport = 0 ;
- unsigned int argc1 ;
+ int not = 1, doimport = 0 ;
+ unsigned int argc1, maxpar = 1 ;
PROG = "forx" ;
{
subgetopt l = SUBGETOPT_ZERO ;
for (;;)
{
- int opt = subgetopt_r(argc, argv, "po:x:Ee", &l) ;
+ int opt = subgetopt_r(argc, argv, "pP:o:x:Ee", &l) ;
if (opt == -1) break ;
switch (opt)
{
- case 'p' : flagpar = 1 ; break ;
+ case 'p' : maxpar = 0 ; break ;
+ case 'P' : if (!uint0_scan(l.arg, &maxpar)) dieusage() ; break ;
case 'o' :
not = 0 ;
if (!ushort_scanlist(okcodes, 256, l.arg, &nbc)) dieusage() ;
@@ -81,14 +83,26 @@ int main (int argc, char const **argv)
argc1 = el_semicolon(argv) ;
if (argc1 >= argc) strerr_dief1x(100, "unterminated block") ;
if (!argc1 || (argc1 + 1 == argc)) return 0 ;
+ if (!maxpar || maxpar > argc1) maxpar = argc1;
{
- pid_t pids[flagpar ? argc1 : 1] ;
+ pid_t pids[maxpar] ;
+ int r = 0 ;
for (unsigned int i = 0 ; i < argc1 ; i++)
{
pid_t pid = el_modif_and_spawn(argv + argc1 + 1, var, argv[i], doimport)
;
if (!pid) strerr_diefu2sys(111, "spawn ", argv[argc1+1]) ;
- if (flagpar) pids[i] = pid ;
+ if (maxpar != 1) {
+ if (i < maxpar-1)
+ pids[i] = pid ;
+ else
+ {
+ r = waitn_code(okcodes, nbc, pids, maxpar, not, 1) ;
+ if (r < 0) strerr_diefu1sys(111, "waitn") ;
+ else if (!r) break ;
+ pids[maxpar-1] = pid ;
+ }
+ }
else
{
int wstat ;
@@ -99,9 +113,9 @@ int main (int argc, char const **argv)
}
}
- if (flagpar)
+ if (maxpar != 1)
{
- int r = waitn_code(okcodes, nbc, pids, argc1, not) ;
+ r = waitn_code(okcodes, nbc, pids, maxpar, not, 0) || r ;
if (r < 0) strerr_diefu1sys(111, "waitn") ;
else if (!r) return 1 ;
}
--
2.45.2
