Date: Wed, 11 Jan 2017 15:53:31 +0300 From: Sergey Kandaurov <pluknet@gmail.com> To: Alan Somers <asomers@freebsd.org> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r311895 - in head: etc/mtree usr.bin/tail usr.bin/tail/tests Message-ID: <CAE-mSOKThkVLJgeBy-WUR48D0Vscwt2cMs2YwCOy=tCPzU3EjA@mail.gmail.com> In-Reply-To: <201701102043.v0AKhWuv073169@repo.freebsd.org> References: <201701102043.v0AKhWuv073169@repo.freebsd.org>
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On 10 January 2017 at 23:43, Alan Somers <asomers@freebsd.org> wrote: > Author: asomers > Date: Tue Jan 10 20:43:32 2017 > New Revision: 311895 > URL: https://svnweb.freebsd.org/changeset/base/311895 > > Log: > Fix memory leaks during "tail -r" of an irregular file > [..] -typedef struct bf { > - struct bf *next; > - struct bf *prev; > - int len; > - char *l; > -} BF; > +static const size_t bsz = 128 * 1024; > +typedef struct bfelem { > + TAILQ_ENTRY(bfelem) entries; > + size_t len; > + char l[bsz]; > +} bfelem_t; > > This breaks on gcc that doesn't respect const for some reason: reverse.c:177: error: variably modified 'l' at file scope > /* > * r_buf -- display a non-regular file in reverse order by line. > @@ -189,64 +190,42 @@ typedef struct bf { > static void > r_buf(FILE *fp, const char *fn) > { > - BF *mark, *tl, *tr; > - int ch, len, llen; > + struct bfelem *tl, *temp, *first = NULL; > + size_t len, llen; > reverse.c:194: warning: 'len' may be used uninitialized in this function I suspect this is due to a typo on line 254. [..] > /* > - * Step through the blocks in the reverse order read. The last > char > - * is special, ignore whether newline or not. > + * Now print the lines in reverse order > + * Outline: > + * Scan backward for "\n", > + * print forward to the end of the buffers > + * free any buffers that start after the "\n" just found > + * Loop > */ > - for (mark = tl;;) { > - for (p = tl->l + (len = tl->len) - 1, llen = 0; len--; > - --p, ++llen) > - if (*p == '\n') { > - if (llen) { > + tl = TAILQ_LAST(&head, bfhead); > + first = TAILQ_FIRST(&head); > + while (tl != NULL) { > + for (p = tl->l + tl->len - 1, llen = 0; p >= tl->l; > + --p, ++llen) { > + int start = (tl == first && p == tl->l); > + > + if ((*p == '\n') || start) { > + struct bfelem *tr; > + > + if (start && len) > here joint patch to fix build on gcc (not tested, although tests pass) Index: reverse.c =================================================================== --- reverse.c (revision 311927) +++ reverse.c (working copy) @@ -170,11 +170,11 @@ ierr(fn); } -static const size_t bsz = 128 * 1024; +#define BSZ (128 * 1024) typedef struct bfelem { TAILQ_ENTRY(bfelem) entries; size_t len; - char l[bsz]; + char l[BSZ]; } bfelem_t; /* @@ -216,9 +216,9 @@ /* Fill the block with input data. */ len = 0; - while ((!feof(fp)) && len < bsz) { + while ((!feof(fp)) && len < BSZ) { p = tl->l + len; - len += fread(p, 1, bsz - len, fp); + len += fread(p, 1, BSZ - len, fp); if (ferror(fp)) { ierr(fn); return; @@ -251,7 +251,7 @@ if ((*p == '\n') || start) { struct bfelem *tr; - if (start && len) + if (start && llen) WR(p, llen + 1); else if (llen) WR(p + 1, llen); -- wbr, pluknet
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