Date: Wed, 11 Jan 2017 09:09:57 -0700 From: Alan Somers <asomers@freebsd.org> To: Sergey Kandaurov <pluknet@gmail.com> Cc: "src-committers@freebsd.org" <src-committers@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "svn-src-head@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: <CAOtMX2g82bT_YFPJWxdDG5_=DPJWXefLE_EGwRfko8QHD=rRoQ@mail.gmail.com> In-Reply-To: <CAE-mSOKThkVLJgeBy-WUR48D0Vscwt2cMs2YwCOy=tCPzU3EjA@mail.gmail.com> References: <201701102043.v0AKhWuv073169@repo.freebsd.org> <CAE-mSOKThkVLJgeBy-WUR48D0Vscwt2cMs2YwCOy=tCPzU3EjA@mail.gmail.com>
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On Wed, Jan 11, 2017 at 5:53 AM, Sergey Kandaurov <pluknet@gmail.com> wrote: > 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 Thanks for the tip, Sergey. Fixed in 311928.
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