From f813180f2fc1d682dd097e4a05ef4d15000204ad Mon Sep 17 00:00:00 2001 From: Roman Kollar Date: Mon, 29 Oct 2012 17:52:52 +0100 Subject: [PATCH] Add .history file locking - shared readers, exclusive writer Originally reported at Red Hat Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=648592 Patch by Vojtech Vitek (V-Teq) --- sh.c | 103 +++++++++++++++++++++++++++++++++++------------- sh.decls.h | 4 +- sh.dol.c | 2 +- sh.err.c | 16 ++++++++ sh.h | 18 +++++++++ sh.hist.c | 131 +++++++++++++++++++++++++++++++------------------------------ sh.lex.c | 8 ++-- sh.sem.c | 2 +- 8 files changed, 185 insertions(+), 99 deletions(-) diff --git a/sh.c b/sh.c index dcd9116..7f03077 100644 --- a/sh.c +++ b/sh.c @@ -140,6 +140,7 @@ struct saved_state { int cantell; struct Bin B; int justpr; + int close_unit; }; static int srccat (Char *, Char *); @@ -1369,7 +1370,7 @@ main(int argc, char **argv) /* * Source history before .login so that it is available in .login */ - loadhist(NULL, 0); + loadhist(NULL, HIST_FILE_RDLCK); #ifndef LOGINFIRST if (loginsh) (void) srccat(varval(STRhome), STRsldotlogin); @@ -1492,7 +1493,7 @@ static int srccat(Char *cp, Char *dp) { if (cp[0] == '/' && cp[1] == '\0') - return srcfile(short2str(dp), (mflag ? 0 : 1), 0, NULL); + return srcfile(short2str(dp), (mflag ? 0 : HIST_ONLY), 0, NULL); else { Char *ep; char *ptr; @@ -1508,7 +1509,7 @@ srccat(Char *cp, Char *dp) cleanup_push(ep, xfree); ptr = short2str(ep); - rv = srcfile(ptr, (mflag ? 0 : 1), 0, NULL); + rv = srcfile(ptr, (mflag ? 0 : HIST_ONLY), 0, NULL); cleanup_until(ep); return rv; } @@ -1522,20 +1523,49 @@ static int #else int #endif /*WINNT_NATIVE*/ -srcfile(const char *f, int onlyown, int flag, Char **av) +srcfile(const char *f, int onlyown, int flg, Char **av) { - int unit; - - if ((unit = xopen(f, O_RDONLY|O_LARGEFILE)) == -1) - return 0; - cleanup_push(&unit, open_cleanup); - unit = dmove(unit, -1); - cleanup_ignore(&unit); - cleanup_until(&unit); - - (void) close_on_exec(unit, 1); - srcunit(unit, onlyown, flag, av); - return 1; + int *unit; + + unit = xmalloc(sizeof(*unit)); + cleanup_push(unit, xfree); + *unit = xopen(f, O_LARGEFILE | + ((flg & HIST_FILE_WRLCK) ? (O_CREAT|O_RDWR) : O_RDONLY), 0600); + if (*unit == -1) + return 0; /* Error. */ + + cleanup_push(unit, open_cleanup); + *unit = dmove(*unit, -1); + (void) close_on_exec(*unit, 1); + + if (flg & (HIST_FILE_WRLCK | HIST_FILE_RDLCK)) { + struct flock fl; + + fl.l_type = (flg & HIST_FILE_WRLCK) ? F_WRLCK : F_RDLCK; + fl.l_whence = SEEK_SET; + fl.l_start = 0; + fl.l_len = 0; + + cleanup_push(unit, fcntl_cleanup); + if (fcntl(*unit, F_SETLKW, &fl) == -1) + cleanup_ignore(unit); + } + + srcunit(*unit, onlyown, flg, av); + + /* Unlock the unit, if we don't want to leave it locked (or open). */ + if ((flg & (HIST_FILE_WRLCK | HIST_FILE_RDLCK)) && + (!(flg & HIST_FILE_LOCK) || !(flg & HIST_FILE_OPEN))) + cleanup_until(unit); /* fcntl_cleanup */ + + /* Close the unit, if we don't want to leave it open. */ + if (!(flg & HIST_FILE_OPEN)) { + cleanup_until(unit); /* open_cleanup */ + cleanup_until(unit); /* xfree */ + return -1; /* Not error but invalid file descriptor. */ + } + + return *unit; /* File descriptor (fd > FSAFE). */ } @@ -1544,7 +1574,7 @@ srcfile(const char *f, int onlyown, int flag, Char **av) * fd. */ static void -st_save(struct saved_state *st, int unit, int hflg, Char **al, Char **av) +st_save(struct saved_state *st, int unit, int flg, Char **al, Char **av) { st->insource = insource; st->SHIN = SHIN; @@ -1593,10 +1623,14 @@ st_save(struct saved_state *st, int unit, int hflg, Char **al, Char **av) st->onelflg = onelflg; st->enterhist = enterhist; st->justpr = justpr; - if (hflg) + if (flg & (HIST_ONLY | HIST_MERGE)) st->HIST = HIST; else st->HIST = '\0'; + if (flg & HIST_FILE_OPEN) + st->close_unit = 0; + else + st->close_unit = 1; st->cantell = cantell; cpybin(st->B, B); @@ -1635,7 +1669,7 @@ st_save(struct saved_state *st, int unit, int hflg, Char **al, Char **av) evalp = 0; alvec = al; alvecp = 0; - enterhist = hflg; + enterhist = flg & (HIST_ONLY | HIST_MERGE); if (enterhist) HIST = '\0'; insource = 1; @@ -1668,7 +1702,8 @@ st_restore(void *xst) } cpybin(B, st->B); - xclose(SHIN); + if (st->close_unit) + xclose(SHIN); insource = st->insource; SHIN = st->SHIN; @@ -1704,7 +1739,7 @@ st_restore(void *xst) * we don't chance it. This occurs on ".cshrc"s and the like. */ static void -srcunit(int unit, int onlyown, int hflg, Char **av) +srcunit(int unit, int onlyown, int flg, Char **av) { struct saved_state st; @@ -1730,7 +1765,7 @@ srcunit(int unit, int onlyown, int hflg, Char **av) } /* Save the current state and move us to a new state */ - st_save(&st, unit, hflg, NULL, av); + st_save(&st, unit, flg, NULL, av); /* * Now if we are allowing commands to be interrupted, we let ourselves be @@ -2156,21 +2191,28 @@ process(int catch) void dosource(Char **t, struct command *c) { + (void) dosource_flg(t, c, 0); +} + +int +dosource_flg(Char **t, struct command *c, int flg) +{ Char *f; - int hflg = 0; char *file; + int fd; + int newflg = 0; USE(c); t++; if (*t && eq(*t, STRmh)) { if (*++t == NULL) stderror(ERR_NAME | ERR_HFLAG); - hflg++; + newflg |= HIST_ONLY; } else if (*t && eq(*t, STRmm)) { if (*++t == NULL) stderror(ERR_NAME | ERR_MFLAG); - hflg = 2; + newflg |= HIST_MERGE; } f = globone(*t++, G_ERROR); @@ -2178,9 +2220,16 @@ dosource(Char **t, struct command *c) cleanup_push(file, xfree); xfree(f); t = glob_all_or_error(t); - if ((!srcfile(file, 0, hflg, t)) && (!hflg) && (!bequiet)) + fd = srcfile(file, 0, (flg | newflg), t); + if ((!fd) && (!newflg) && (!bequiet)) stderror(ERR_SYSTEM, file, strerror(errno)); - cleanup_until(file); + + /* We need to preserve fd and it's cleaning routines on the top of the + * cleaning stack. Don't call cleanup_until() but clean it manually. */ + cleanup_ignore(file); + xfree(file); + + return fd; /* Valid/invalid file descriptor (>FSAVE, -1). Zero on error. */ } /* diff --git a/sh.decls.h b/sh.decls.h index db90288..fb15a01 100644 --- a/sh.decls.h +++ b/sh.decls.h @@ -38,6 +38,7 @@ */ extern Char *gethdir (const Char *); extern void dosource (Char **, struct command *); +extern int dosource_flg (Char **, struct command *, int); extern void exitstat (void); extern void goodbye (Char **, struct command *); extern void importpath (Char *); @@ -98,6 +99,7 @@ extern void cleanup_until_mark(void); extern size_t cleanup_push_mark(void); extern void cleanup_pop_mark(size_t); extern void open_cleanup(void *); +extern void fcntl_cleanup(void *); extern void opendir_cleanup(void *); extern void sigint_cleanup(void *); extern void sigprocmask_cleanup(void *); @@ -219,7 +221,7 @@ extern struct Hist *enthist (int, struct wordent *, int, int, int); extern void savehist (struct wordent *, int); extern char *fmthist (int, ptr_t); extern void rechist (Char *, int); -extern void loadhist (Char *, int); +extern int loadhist (Char *, int); extern void displayHistStats(const char *); /* diff --git a/sh.dol.c b/sh.dol.c index 45b10e0..2ce7cb5 100644 --- a/sh.dol.c +++ b/sh.dol.c @@ -1110,6 +1110,6 @@ again: *obp = 0; tmp = short2str(obuf); (void) xwrite(0, tmp, strlen (tmp)); - (void) lseek(0, (off_t) 0, L_SET); + (void) lseek(0, (off_t) 0, SEEK_SET); cleanup_until(&inheredoc); } diff --git a/sh.err.c b/sh.err.c index e157d6a..29d41c3 100644 --- a/sh.err.c +++ b/sh.err.c @@ -514,6 +514,22 @@ open_cleanup(void *xptr) } void +fcntl_cleanup(void *xptr) +{ + int *ptr; + struct flock fl; + + ptr = xptr; + + fl.l_type = F_UNLCK; + fl.l_whence = SEEK_SET; + fl.l_start = 0; + fl.l_len = 0; + + fcntl(*ptr, F_SETLK, &fl); +} + +void opendir_cleanup(void *xdir) { DIR *dir; diff --git a/sh.h b/sh.h index 691add3..4e3f13c 100644 --- a/sh.h +++ b/sh.h @@ -50,6 +50,24 @@ # include #endif +#include +#include + +/* + * History flags. + */ +#define HIST_ONLY 0x001 +#define HIST_SAVE 0x002 +#define HIST_LOAD 0x004 +#define HIST_REV 0x008 +#define HIST_CLEAR 0x010 +#define HIST_MERGE 0x020 +#define HIST_TIME 0x040 +#define HIST_FILE_WRLCK 0x080 /* Write lock */ +#define HIST_FILE_RDLCK 0x100 /* Read lock */ +#define HIST_FILE_OPEN 0x200 /* Leave file open */ +#define HIST_FILE_LOCK 0x400 /* Leave file locked */ + #if !defined(HAVE_STDINT_H) && !defined(HAVE_INTTYPES_H) && !defined(WINNT_NATIVE) typedef unsigned long intptr_t; #endif diff --git a/sh.hist.c b/sh.hist.c index 6a12737..7e53c65 100644 --- a/sh.hist.c +++ b/sh.hist.c @@ -44,14 +44,6 @@ Char HistLit = 0; static int heq (const struct wordent *, const struct wordent *); static void hfree (struct Hist *); -#define HIST_ONLY 0x01 -#define HIST_SAVE 0x02 -#define HIST_LOAD 0x04 -#define HIST_REV 0x08 -#define HIST_CLEAR 0x10 -#define HIST_MERGE 0x20 -#define HIST_TIME 0x40 - /* * C shell */ @@ -143,7 +135,7 @@ discardExcess(int histlen) void savehist( struct wordent *sp, - int mflg) /* true if -m (merge) specified */ + int flg) { int histlen = 0; Char *cp; @@ -160,7 +152,7 @@ savehist( histlen = histlen * 10 + *cp++ - '0'; } if (sp) - (void) enthist(++eventno, sp, 1, mflg, histlen); + (void) enthist(++eventno, sp, 1, flg, histlen); discardExcess(histlen); } @@ -933,7 +925,7 @@ enthist( int event, /* newly incremented global eventno */ struct wordent *lp, int docopy, - int mflg, /* true if merge requested */ + int flg, int histlen) /* -1 if unknown */ { struct Hist *p = NULL, *pp = &Histlist, *pTime = NULL; @@ -953,7 +945,7 @@ enthist( Htime = p->Htime; /* If we are merging, and the old entry is at the place we want * to insert the new entry, then remember the place. */ - if (mflg && Htime != 0 && p->Hprev->Htime >= Htime) + if ((flg & HIST_MERGE) && Htime != 0 && p->Hprev->Htime >= Htime) pTime = p->Hprev; if (!fastMergeErase) renumberHist(p); /* Reset Href of subsequent entries */ @@ -1012,7 +1004,7 @@ enthist( /* The head of history list is the default insertion point. If merging, advance insertion point, in pp, according to Htime. */ /* XXX -- In histdup=all, Htime values can be non-monotonic. */ - if (mflg) { /* merge according to np->Htime */ + if (flg & HIST_MERGE) { /* merge according to np->Htime */ pp = mergeInsertionPoint(np, pTime); for (p = pp->Hnext; p && p->Htime == np->Htime; pp = p, p = p->Hnext) { if (heq(&p->Hlex, &np->Hlex)) { @@ -1051,9 +1043,9 @@ hfree(struct Hist *hp) } PG_STATIC void -phist(struct Hist *hp, int hflg) +phist(struct Hist *hp, int flg) { - if (hflg & HIST_ONLY) { + if (flg & HIST_ONLY) { int old_output_raw; /* @@ -1065,7 +1057,7 @@ phist(struct Hist *hp, int hflg) old_output_raw = output_raw; output_raw = 1; cleanup_push(&old_output_raw, output_raw_restore); - if (hflg & HIST_TIME) + if (flg & HIST_TIME) /* * Make file entry with history time in format: * "+NNNNNNNNNN" (10 digits, left padded with ascii '0') @@ -1096,7 +1088,7 @@ phist(struct Hist *hp, int hflg) } PG_STATIC void -dophist(int n, int hflg) +dophist(int n, int flg) { struct Hist *hp; if (setintr) { @@ -1105,7 +1097,7 @@ dophist(int n, int hflg) pintr_push_enable(&old_pintr_disabled); cleanup_until(&old_pintr_disabled); } - if ((hflg & HIST_REV) == 0) { + if (!(flg & HIST_REV)) { /* Since the history list is stored most recent first, non-reversing * print needs to print (backwards) up the list. */ if ((unsigned)n >= histCount) @@ -1119,10 +1111,10 @@ dophist(int n, int hflg) if (hp == NULL) return; /* nothing to print */ for (; hp != &Histlist; hp = hp->Hprev) - phist(hp, hflg); + phist(hp, flg); } else { for (hp = Histlist.Hnext; n-- > 0 && hp != NULL; hp = hp->Hnext) - phist(hp, hflg); + phist(hp, flg); } } @@ -1130,7 +1122,7 @@ dophist(int n, int hflg) void dohist(Char **vp, struct command *c) { - int n, hflg = 0; + int n, flg = 0; USE(c); if (getn(varval(STRhistory)) == 0) @@ -1141,40 +1133,40 @@ dohist(Char **vp, struct command *c) while (*++vp2) switch (*vp2) { case 'c': - hflg |= HIST_CLEAR; + flg |= HIST_CLEAR; break; case 'h': - hflg |= HIST_ONLY; + flg |= HIST_ONLY; break; case 'r': - hflg |= HIST_REV; + flg |= HIST_REV; break; case 'S': - hflg |= HIST_SAVE; + flg |= HIST_SAVE; break; case 'L': - hflg |= HIST_LOAD; + flg |= HIST_LOAD; break; case 'M': - hflg |= HIST_MERGE; + flg |= HIST_MERGE; break; case 'T': - hflg |= HIST_TIME; + flg |= HIST_TIME; break; default: stderror(ERR_HISTUS, "chrSLMT"); break; } } - if (hflg & HIST_CLEAR) { + if (flg & HIST_CLEAR) { struct Hist *np, *hp; for (hp = &Histlist; (np = hp->Hnext) != NULL;) hremove(np), hfree(np); } - if (hflg & (HIST_LOAD | HIST_MERGE)) - loadhist(*vp, (hflg & HIST_MERGE) ? 1 : 0); - else if (hflg & HIST_SAVE) + if (flg & (HIST_LOAD | HIST_MERGE)) + loadhist(*vp, (flg | HIST_FILE_RDLCK)); + else if (flg & HIST_SAVE) rechist(*vp, 1); else { if (*vp) @@ -1182,7 +1174,7 @@ dohist(Char **vp, struct command *c) else { n = getn(varval(STRhistory)); } - dophist(n, hflg); + dophist(n, flg); } } @@ -1224,8 +1216,8 @@ fmthist(int fmt, ptr_t ptr) void rechist(Char *fname, int ref) { - Char *snum; - int fp, ftmp, oldidfds; + Char *snum; + int fd = -1, ftmp, oldidfds; struct varent *shist; static Char *dumphist[] = {STRhistory, STRmhT, 0, 0}; @@ -1255,15 +1247,12 @@ rechist(Char *fname, int ref) * with numerous shells being in simultaneous use. Imagine * any kind of window system. All these shells 'share' the same * ~/.history file for recording their command line history. - * Currently the automatic merge can only succeed when the shells - * nicely quit one after another. - * - * Users that like to nuke their environment require here an atomic - * loadhist-creat-dohist(dumphist)-close - * sequence. * - * jw. - */ + * Atomic merge loadhist-creat/ftrunc-dohist(dumphist)-close + * implemented using fcntl (shared readers, exclusive writer) + * by Vojtech Vitek (V-Teq) . + */ + /* * We need the didfds stuff before loadhist otherwise * exec in a script will fail to print if merge is set. @@ -1271,32 +1260,42 @@ rechist(Char *fname, int ref) */ oldidfds = didfds; didfds = 0; - if ((shist = adrof(STRsavehist)) != NULL && shist->vec != NULL) - if (shist->vec[1] && eq(shist->vec[1], STRmerge)) - loadhist(fname, 1); - - fp = xcreat(short2str(fname), 0600); - cleanup_until(fname); - if (fp == -1) { - didfds = oldidfds; - return; + if (((shist = adrof(STRsavehist)) != NULL && shist->vec != NULL) && + (shist->vec[1] && eq(shist->vec[1], STRmerge))) { + /* Read .history file, leave it's fd open for writing. */ + fd = loadhist(fname, HIST_MERGE|HIST_FILE_WRLCK|HIST_FILE_OPEN|HIST_FILE_LOCK); + if (fd > 0) { + /* Truncate the .history file. */ + (void) ftruncate(fd, 0); + (void) lseek(fd, (off_t) 0, SEEK_SET); + } + } + if (fd <= 0) { + /* Open .history file for writing (if not open yet). */ + fd = xopen(short2str(fname), O_LARGEFILE|O_CREAT|O_WRONLY|O_TRUNC, 0600); + if (fd != -1) + cleanup_push(&fd, open_cleanup); + } + if (fd != -1) { + ftmp = SHOUT; + SHOUT = fd; + dumphist[2] = snum; + /* Write history to the .history file. */ + dohist(dumphist, NULL); + SHOUT = ftmp; } - ftmp = SHOUT; - SHOUT = fp; - dumphist[2] = snum; - dohist(dumphist, NULL); - xclose(fp); - SHOUT = ftmp; didfds = oldidfds; + cleanup_until(fname); } /* This is the entry point for loading history data from a file. */ -void -loadhist(Char *fname, int mflg) +int +loadhist(Char *fname, int flg) { static Char *loadhist_cmd[] = {STRsource, NULL, NULL, NULL}; - loadhist_cmd[1] = mflg ? STRmm : STRmh; + int fd; + loadhist_cmd[1] = (flg & HIST_MERGE) ? STRmm : STRmh; if (fname != NULL) loadhist_cmd[2] = fname; @@ -1305,15 +1304,17 @@ loadhist(Char *fname, int mflg) else loadhist_cmd[2] = STRtildothist; - dosource(loadhist_cmd, NULL); + fd = dosource_flg(loadhist_cmd, NULL, flg); - /* During history merging (enthist sees mflg set), we disable management of - * Hnum and Href (because fastMergeErase is true). So now reset all the + /* During history merging (enthist sees merge flag), we disable management + * of Hnum and Href (because fastMergeErase is true). So now reset all the * values based on the final ordering of the history list. */ - if (mflg) { + if (flg & HIST_MERGE) { int n = eventno; struct Hist *hp = &Histlist; while ((hp = hp->Hnext)) hp->Hnum = hp->Href = n--; } + + return fd; /* Valid/invalid file descriptor (>FSAVE, -1). Zero on error. */ } diff --git a/sh.lex.c b/sh.lex.c index 80643f7..57ec7a9 100644 --- a/sh.lex.c +++ b/sh.lex.c @@ -1595,7 +1595,7 @@ wide_read(int fildes, Char *buf, size_t nchars, int use_fclens) /* Throwing away possible partial multibyte characters on error if the stream is not seekable */ err = errno; - lseek(fildes, -(off_t)partial, L_INCR); + lseek(fildes, -(off_t)partial, SEEK_CUR); errno = err; return res != 0 ? res : r; } @@ -1610,7 +1610,7 @@ bgetc(void) if (cantell) { if (fseekp < fbobp || fseekp > feobp) { fbobp = feobp = fseekp; - (void) lseek(SHIN, fseekp, L_SET); + (void) lseek(SHIN, fseekp, SEEK_SET); } if (fseekp == feobp) { #ifdef WIDE_STRINGS @@ -1814,7 +1814,7 @@ btell(struct Ain *l) void btoeof(void) { - (void) lseek(SHIN, (off_t) 0, L_XTND); + (void) lseek(SHIN, (off_t) 0, SEEK_END); aret = TCSH_F_SEEK; fseekp = feobp; alvec = NULL; @@ -1832,7 +1832,7 @@ settell(void) cantell = 0; if (arginp || onelflg || intty) return; - if ((x = lseek(SHIN, (off_t) 0, L_INCR)) == -1) + if ((x = lseek(SHIN, (off_t) 0, SEEK_CUR)) == -1) return; fbuf = xcalloc(2, sizeof(Char **)); fblocks = 1; diff --git a/sh.sem.c b/sh.sem.c index c880974..bc51b50 100644 --- a/sh.sem.c +++ b/sh.sem.c @@ -892,7 +892,7 @@ doio(struct command *t, int *pipein, int *pipeout) fd = xopen(tmp, O_WRONLY|O_APPEND|O_LARGEFILE); #else /* !O_APPEND */ fd = xopen(tmp, O_WRONLY|O_LARGEFILE); - (void) lseek(fd, (off_t) 0, L_XTND); + (void) lseek(fd, (off_t) 0, SEEK_END); #endif /* O_APPEND */ } else -- 1.7.11.7