Mercurial > hg > toybox
view toys/posix/split.c @ 1531:3ff823086c99 draft
Teach ln -f to leave original target alone if link creation fails.
Suggested by Ashwini Sharma, I wound up implementing it by creating the new
link at a temporary name and renaming it over the old one instead of renaming
the old file out of the way and putting it back if it failed.
(Because "mkdir -p one/one/blah && ln -sf /bin/one one" would otherwise
rename one/one out of the way and only notice it can't delete it way at the
end when recovery's darn awkward, vs create new thing and if rename fails
(including EISDIR) that's the main error path. And yes the temporary name
is in the same directory as the destination so we never rename between mounts.)
link over the old one instead of renaming the old file and renaming it back.
author | Rob Landley <rob@landley.net> |
---|---|
date | Wed, 22 Oct 2014 17:11:06 -0500 |
parents | 0752b2d58909 |
children | 59a3fd32329c |
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/* split.c - split a file into smaller files * * Copyright 2013 Rob Landley <rob@landley.net> * * See http://pubs.opengroup.org/onlinepubs/9699919799/utilities/split.html * * Standard does not cover: * - should splitting an empty file produce an empty outfile? (Went with "no".) * - permissions on output file USE_SPLIT(NEWTOY(split, ">2a#<1=2>9b#<1l#<1", TOYFLAG_USR|TOYFLAG_BIN)) config SPLIT bool "split" default y help usage: split [-a SUFFIX_LEN] [-b BYTES] [-l LINES] [INPUT [OUTPUT]] Copy INPUT (or stdin) data to a series of OUTPUT (or "x") files with alphabetically increasing suffix (aa, ab, ac... az, ba, bb...). -a Suffix length (default 2) -b BYTES/file (10, 10k, 10m, 10g...) -l LINES/file (default 1000) */ #define FOR_split #include "toys.h" GLOBALS( long lines; long bytes; long suflen; char *outfile; ) void do_split(int infd, char *in) { unsigned long bytesleft, linesleft, filenum, len, pos; int outfd = -1; struct stat st; // posix doesn't cover permissions on output file, so copy input (or 0777) st.st_mode = 0777; fstat(infd, &st); len = pos = filenum = bytesleft = linesleft = 0; for (;;) { int i, j; // Refill toybuf? if (len == pos) { if (!(len = xread(infd, toybuf, sizeof(toybuf)))) break; pos = 0; } // Start new output file? if ((TT.bytes && !bytesleft) || (TT.lines && !linesleft)) { char *s = TT.outfile + strlen(TT.outfile); j = filenum++; for (i = 0; i<TT.suflen; i++) { *(--s) = 'a'+(j%26); j /= 26; } if (j) error_exit("bad suffix"); bytesleft = TT.bytes; linesleft = TT.lines; if (outfd != -1) close(outfd); outfd = xcreate(TT.outfile, O_RDWR|O_CREAT|O_TRUNC, st.st_mode & 0777); } // Write next chunk of output. if (TT.lines) { for (i = pos; i < len; ) { if (toybuf[i++] == '\n' && !--linesleft) break; if (!--bytesleft) break; } j = i - pos; } else { j = len - pos; if (j > bytesleft) j = bytesleft; bytesleft -= j; } xwrite(outfd, toybuf+pos, j); pos += j; } if (CFG_TOYBOX_FREE) { if (outfd != -1) close(outfd); if (infd) close(infd); free(TT.outfile); } xexit(); } void split_main(void) { if (!TT.bytes && !TT.lines) TT.lines = 1000; // Allocate template for output filenames TT.outfile = xmprintf("%s% *c", (toys.optc == 2) ? toys.optargs[1] : "x", (int)TT.suflen, ' '); // We only ever use one input, but this handles '-' or no input for us. loopfiles(toys.optargs, do_split); }