Mercurial > hg > toybox
changeset 396:7ca3bef07f0d
Implement truncate.
author | Rob Landley <rob@landley.net> |
---|---|
date | Sun, 11 Dec 2011 03:58:43 -0600 |
parents | 32c7b6af5b29 |
children | b7afbc6b753a |
files | toys/truncate.c |
diffstat | 1 files changed, 47 insertions(+), 0 deletions(-) [+] |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/toys/truncate.c Sun Dec 11 03:58:43 2011 -0600 @@ -0,0 +1,47 @@ +/* vi: set sw=4 ts=4: + * + * truncate.c - set file length, extending sparsely if necessary + * + * Copyright 2011 Rob Landley <rob@landley.net> + * + * Not in SUSv4 + +USE_TRUNCATE(NEWTOY(truncate, "<1s#|c", TOYFLAG_BIN)) + +config TRUNCATE + bool "truncate" + default y + help + usage: truncate [-c] -s file... + Set length of file(s), extending sparsely if necessary. + + -c Don't create file if it doesn't exist. + -s New size +*/ + +#include "toys.h" + +DEFINE_GLOBALS( + long size; +) + +#define TT this.truncate + +static void do_truncate(int fd, char *name) +{ + if (fd<0) return; + if (ftruncate(fd, TT.size)) { + perror_msg("failed to set '%s' to '%ld'", name, TT.size); + toys.exitval = EXIT_FAILURE; + } +} + +void truncate_main(void) +{ + int cr = !(toys.optflags&1); + + // Create files with mask rwrwrw. + // Nonexistent files are only an error if we're supposed to create them. + loopfiles_rw(toys.optargs, O_WRONLY|(cr ? O_CREAT : 0), 0666, cr, + do_truncate); +}