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-rw-r--r--toys/xargs.c174
1 files changed, 174 insertions, 0 deletions
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+/* 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);
+ }
+}