X-Git-Url: https://git.decadent.org.uk/gitweb/?p=nfs-utils.git;a=blobdiff_plain;f=support%2Fexport%2Fxtab.c;h=2a43193c35a15345c053b005e46cf45eadabfe1b;hp=c8adc0672b3c96ba67d18530d8e0bd3057aa2652;hb=5d954d871fb265af584faef5df6e2e7e6ada7c3b;hpb=da25e1aa006bafb4dd08e2ffedbd42d7c1f4036b diff --git a/support/export/xtab.c b/support/export/xtab.c index c8adc06..2a43193 100644 --- a/support/export/xtab.c +++ b/support/export/xtab.c @@ -6,7 +6,9 @@ * Copyright (C) 1995, 1996 Olaf Kirch */ -#include "config.h" +#ifdef HAVE_CONFIG_H +#include +#endif #include #include @@ -17,27 +19,46 @@ #include "exportfs.h" #include "xio.h" #include "xlog.h" +#include "v4root.h" + +int v4root_needed; +static void cond_rename(char *newfile, char *oldfile); static int -xtab_read(char *xtab, int is_export) +xtab_read(char *xtab, char *lockfn, int is_export) { + /* is_export == 0 => reading /proc/fs/nfs/exports - we know these things are exported to kernel + * is_export == 1 => reading /var/lib/nfs/etab - these things are allowed to be exported + * is_export == 2 => reading /var/lib/nfs/xtab - these things might be known to kernel + */ struct exportent *xp; nfs_export *exp; int lockid; - if ((lockid = xflock(xtab, "r")) < 0) + if ((lockid = xflock(lockfn, "r")) < 0) return 0; setexportent(xtab, "r"); - while ((xp = getexportent()) != NULL) { - if (!(exp = export_lookup(xp->e_hostname, xp->e_path)) && - !(exp = export_create(xp))) { + if (is_export == 1) + v4root_needed = 1; + while ((xp = getexportent(is_export==0, 0)) != NULL) { + if (!(exp = export_lookup(xp->e_hostname, xp->e_path, is_export != 1)) && + !(exp = export_create(xp, is_export!=1))) { continue; } - if (is_export) { + switch (is_export) { + case 0: + exp->m_exported = 1; + break; + case 1: exp->m_xtabent = 1; exp->m_mayexport = 1; - } else - exp->m_exported = 1; + if ((xp->e_flags & NFSEXP_FSID) && xp->e_fsid == 0) + v4root_needed = 0; + break; + case 2: + exp->m_exported = -1;/* may be exported */ + break; + } } endexportent(); xfunlock(lockid); @@ -51,32 +72,43 @@ xtab_mount_read(void) int fd; if ((fd=open(_PATH_PROC_EXPORTS, O_RDONLY))>=0) { close(fd); - return xtab_read(_PATH_PROC_EXPORTS, 0); + return xtab_read(_PATH_PROC_EXPORTS, + _PATH_PROC_EXPORTS, 0); + } else if ((fd=open(_PATH_PROC_EXPORTS_ALT, O_RDONLY) >= 0)) { + close(fd); + return xtab_read(_PATH_PROC_EXPORTS_ALT, + _PATH_PROC_EXPORTS_ALT, 0); } else - return xtab_read(_PATH_XTAB, 1); + return xtab_read(_PATH_XTAB, _PATH_XTABLCK, 2); } int xtab_export_read(void) { - return xtab_read(_PATH_ETAB, 1); + return xtab_read(_PATH_ETAB, _PATH_ETABLCK, 1); } +/* + * mountd now keeps an open fd for the etab at all times to make sure that the + * inode number changes when the xtab_export_write is done. If you change the + * routine below such that the files are edited in place, then you'll need to + * fix the auth_reload logic as well... + */ static int -xtab_write(char *xtab, char *xtabtmp, int is_export) +xtab_write(char *xtab, char *xtabtmp, char *lockfn, int is_export) { struct exportent xe; nfs_export *exp; int lockid, i; - if ((lockid = xflock(xtab, "w")) < 0) { + if ((lockid = xflock(lockfn, "w")) < 0) { xlog(L_ERROR, "can't lock %s for writing", xtab); return 0; } setexportent(xtabtmp, "w"); for (i = 0; i < MCL_MAXTYPES; i++) { - for (exp = exportlist[i]; exp; exp = exp->m_next) { + for (exp = exportlist[i].p_head; exp; exp = exp->m_next) { if (is_export && !exp->m_xtabent) continue; if (!is_export && ! exp->m_exported) @@ -84,16 +116,13 @@ xtab_write(char *xtab, char *xtabtmp, int is_export) /* write out the export entry using the FQDN */ xe = exp->m_export; - strncpy(xe.e_hostname, - exp->m_client->m_hostname, - sizeof (xe.e_hostname) - 1); - xe.e_hostname[sizeof (xe.e_hostname) - 1] = '\0'; + xe.e_hostname = exp->m_client->m_hostname; putexportent(&xe); } } endexportent(); - rename(xtabtmp, xtab); + cond_rename(xtabtmp, xtab); xfunlock(lockid); @@ -103,13 +132,13 @@ xtab_write(char *xtab, char *xtabtmp, int is_export) int xtab_export_write() { - return xtab_write(_PATH_ETAB, _PATH_ETABTMP, 1); + return xtab_write(_PATH_ETAB, _PATH_ETABTMP, _PATH_ETABLCK, 1); } int xtab_mount_write() { - return xtab_write(_PATH_XTAB, _PATH_XTABTMP, 0); + return xtab_write(_PATH_XTAB, _PATH_XTABTMP, _PATH_XTABLCK, 0); } void @@ -118,16 +147,57 @@ xtab_append(nfs_export *exp) struct exportent xe; int lockid; - if ((lockid = xflock(_PATH_XTAB, "w")) < 0) + if ((lockid = xflock(_PATH_XTABLCK, "w")) < 0) return; setexportent(_PATH_XTAB, "a"); xe = exp->m_export; - strncpy(xe.e_hostname, exp->m_client->m_hostname, - sizeof (xe.e_hostname) - 1); - xe.e_hostname[sizeof (xe.e_hostname) - 1] = '\0'; + xe.e_hostname = exp->m_client->m_hostname; putexportent(&xe); endexportent(); xfunlock(lockid); exp->m_xtabent = 1; } +/* + * rename newfile onto oldfile unless + * they are identical + */ +static void cond_rename(char *newfile, char *oldfile) +{ + int nfd, ofd; + char nbuf[4096], obuf[4096]; + int ncnt, ocnt; + + nfd = open(newfile, 0); + if (nfd < 0) + return; + ofd = open(oldfile, 0); + if (ofd < 0) { + close(nfd); + rename(newfile, oldfile); + return; + } + + do { + ncnt = read(nfd, nbuf, sizeof(nbuf)); + if (ncnt < 0) + break; + ocnt = read(ofd, obuf, sizeof(obuf)); + if (ocnt < 0) + break; + if (ncnt != ocnt) + break; + if (ncnt == 0) { + close(nfd); + close(ofd); + unlink(newfile); + return; + } + } while (memcmp(obuf, nbuf, ncnt) == 0); + + /* some mis-match */ + close(nfd); + close(ofd); + rename(newfile, oldfile); + return; +}