Implement xargs (first pass, not full SUSv4 yet).

diff --git a/toys/xargs.c b/toys/xargs.c
new file mode 100644 (file)
index 0000000..67e88cf
--- /dev/null
+++ b/toys/xargs.c
@@ -0,0 +1,174 @@
+/* vi: set sw=4 ts=4:
+ *
+ * xargs.c - Run command with arguments taken from stdin.
+ *
+ * Copyright 2011 Rob Landley <rob@landley.net>
+ *
+ * See http://opengroup.org/onlinepubs/9699919799/utilities/xargs.html
+
+USE_XARGS(NEWTOY(xargs, "n#s#0", TOYFLAG_USR|TOYFLAG_BIN))
+
+config XARGS
+       bool "xargs"
+       default y
+       help
+         usage: xargs [-ptxr0] [-s NUM] [-n NUM] [-L NUM] [-E STR] COMMAND...
+
+         Run command line one or more times, appending arguments from stdin.
+
+         -s    Size in bytes per command line
+         -n    Max number of arguments per command
+         -0    Each argument is NULL terminated, no whitespace or quote processing
+*/
+
+#include "toys.h"
+
+DEFINE_GLOBALS(
+       long max_bytes;
+       long max_entries;
+       long L;
+       char *E;
+       char *I;
+
+       long entries, bytes;
+       char delim;
+)
+
+#define TT this.xargs
+
+// According to man execv(5), the actual ARGS_MAX for linux is 128k (131072)
+// meaning the theoretical maximum arguments (each one char) is 65536... but
+// we can just use toybuf (1024 pointer on 32 bit, 512 on 64 bit).
+
+#define ACTUAL_ARGS_MAX 131072
+
+// If out==NULL count TT.bytes and TT.entries, stopping at max.
+// Otherwise, fill out out[] 
+
+// Returning NULL means need more data.
+// Returning 1 means hit data limits, but consumed all data
+// Returning char * means hit data limits, start of data left over
+
+static char *handle_entries(char *data, char **entry)
+{
+       if (TT.delim) { 
+               char *s = data;
+
+               // Chop up whitespace delimited string into args
+               while (*s) {
+                       char *save;
+
+                       while (isspace(*s)) {
+                               if (entry) *s = 0;
+                               s++;
+                       }
+
+                       if (TT.entries >= TT.max_entries && TT.max_entries)
+                               return *s ? (char *)1: s;
+
+                       if (!*s) break;
+                       save = s;
+
+                       for (;;) {
+                               if (++TT.bytes >= TT.max_bytes && TT.max_bytes) return save;
+                               if (!*s || isspace(*s)) break;
+                               s++;
+                       }
+                       if (entry) entry[TT.entries] = save;
+                       ++TT.entries;
+               }
+       } else {
+               if (entry) entry[TT.entries] = data;
+               TT.bytes += strlen(data);
+               if (TT.bytes >= TT.max_bytes || ++TT.entries >= TT.max_entries)
+                       return (char *)1;
+       }
+
+       return NULL;
+}
+
+void xargs_main(void)
+{
+       struct double_list *dlist = NULL;
+       int entries, bytes, done = 0, status;
+       char *data = NULL;
+
+       if (!(toys.optflags&1)) TT.delim = '\n';
+
+       // If no optargs, call echo.
+       if (!toys.optc) {
+               free(toys.optargs);
+               *(toys.optargs=xzalloc(2*sizeof(char *)))="echo";
+               toys.optc=1;
+       }
+
+       for (entries = 0, bytes = -1; entries < toys.optc; entries++, bytes++)
+               bytes += strlen(toys.optargs[entries]);
+
+       // Loop through exec chunks.
+       while (!done) {
+               TT.entries = 0;
+               TT.bytes = bytes;
+               char **out;
+
+               // Loop reading input
+               for (;;) {
+
+                       // Read line
+                       if (!data) {
+                               ssize_t l = 0;
+                               l = getdelim(&data, (size_t *)&l, TT.delim, stdin);
+
+                               if (l<0) {
+                                       data = 0;
+                                       done++;
+                                       break;
+                               }
+                       }
+                       dlist_add(&dlist, data);
+
+                       // Count data used
+                       data = handle_entries(data, NULL);
+                       if (!data) continue;
+                       if (data == (char *)1) data = 0;
+                       else data = xstrdup(data);
+
+                       break;
+               }
+
+               // Accumulate cally thing
+
+               if (data && !TT.entries) error_exit("argument too long");
+               out = xzalloc((entries+TT.entries+1)*sizeof(char *));
+
+               if (dlist) {
+                       struct double_list *dtemp;
+
+                       // Fill out command line to exec
+                       memcpy(out, toys.optargs, entries*sizeof(char *));
+                       TT.entries = 0;
+                       TT.bytes = bytes;
+                       dlist->prev->next = 0;
+                       for (dtemp = dlist; dtemp; dtemp = dtemp->next)
+                               handle_entries(dtemp->data, out+entries);
+               }
+               pid_t pid=fork();
+               if (!pid) {
+                       xclose(0);
+                       open("/dev/null", O_RDONLY);
+                       xexec(out);
+               }
+               waitpid(pid, &status, 0);
+               status = WEXITSTATUS(status);
+
+               // Abritrary number of execs, can't just leak memory each time...
+               while (dlist) {
+                       struct double_list *dtemp = dlist->next;
+
+                       free(dlist->data);
+                       free(dlist);
+                       dlist = dtemp;
+               }
+               free(out);
+       }
+}