DF-2233 / fix.diff
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 | --- a/sys/libiconv/iconv.c +++ b/sys/libiconv/iconv.c @@ -47,6 +47,7 @@ MODULE_VERSION(libiconv, 2); static struct lock iconv_lock; +static unsigned iconv_refs; /* in-flight callers (unload drain guard) */ #ifdef notnow /* @@ -82,7 +83,13 @@ { struct iconv_cspair *csp; + if (iconv_refs) + return EBUSY; lockmgr(&iconv_lock, LK_EXCLUSIVE); + if (iconv_refs) { + lockmgr(&iconv_lock, LK_RELEASE); + return EBUSY; + } TAILQ_FOREACH(csp, &iconv_cslist, cp_link) { if (csp->cp_refcount) { lockmgr(&iconv_lock, LK_RELEASE); @@ -93,6 +100,14 @@ while ((csp = TAILQ_FIRST(&iconv_cslist)) != NULL) iconv_unregister_cspair(csp); lockmgr(&iconv_lock, LK_RELEASE); + /* + * Drain guard: callers take iconv_refs BEFORE acquiring the lock and + * drop it after release, so refs==0 here guarantees nobody is + * executing inside this module any more. If someone raced in, + * refuse the unload (kldunload returns EBUSY; retry). + */ + if (iconv_refs) + return EBUSY; lockuninit(&iconv_lock); return 0; } @@ -143,7 +158,7 @@ } static int -iconv_lookupconv(const char *name, struct iconv_converter_class **dcpp) +iconv_lookupconv_locked(const char *name, struct iconv_converter_class **dcpp) { struct iconv_converter_class *dcp; @@ -160,7 +175,8 @@ } static int -iconv_lookupcs(const char *to, const char *from, struct iconv_cspair **cspp) +iconv_lookupcs_locked(const char *to, const char *from, + struct iconv_cspair **cspp) { struct iconv_cspair *csp; @@ -184,7 +200,7 @@ char *cp; int csize, ucsto, ucsfrom; - if (iconv_lookupcs(to, from, NULL) == 0) + if (iconv_lookupcs_locked(to, from, NULL) == 0) return EEXIST; csize = sizeof(*csp); ucsto = strcmp(to, iconv_unicode_string) == 0; @@ -237,12 +253,18 @@ const char *cnvname; int error; + atomic_add_int(&iconv_refs, 1); /* * First, lookup fully qualified cspairs */ - error = iconv_lookupcs(to, from, &csp); - if (error == 0) - return ICONV_CONVERTER_OPEN(csp->cp_dcp, csp, NULL, handle); + lockmgr(&iconv_lock, LK_SHARED); + error = iconv_lookupcs_locked(to, from, &csp); + if (error == 0) { + error = ICONV_CONVERTER_OPEN(csp->cp_dcp, csp, NULL, handle); + lockmgr(&iconv_lock, LK_RELEASE); + atomic_sub_int(&iconv_refs, 1); + return error; + } /* * Well, nothing found. Now try to construct a composite conversion @@ -252,17 +274,22 @@ cnvname = ICONV_CONVERTER_NAME(dcp); if (cnvname == NULL) continue; - error = iconv_lookupcs(cnvname, from, &cspfrom); + error = iconv_lookupcs_locked(cnvname, from, &cspfrom); if (error) continue; - error = iconv_lookupcs(to, cnvname, &cspto); + error = iconv_lookupcs_locked(to, cnvname, &cspto); if (error) continue; /* * Fine, we're found a pair which can be combined together */ - return ICONV_CONVERTER_OPEN(dcp, cspto, cspfrom, handle); + error = ICONV_CONVERTER_OPEN(dcp, cspto, cspfrom, handle); + lockmgr(&iconv_lock, LK_RELEASE); + atomic_sub_int(&iconv_refs, 1); + return error; } + lockmgr(&iconv_lock, LK_RELEASE); + atomic_sub_int(&iconv_refs, 1); return ENOENT; } @@ -325,6 +352,7 @@ int error; error = 0; + atomic_add_int(&iconv_refs, 1); lockmgr(&iconv_lock, LK_SHARED); TAILQ_FOREACH(dcp, &iconv_converters, cc_link) { @@ -336,6 +364,7 @@ break; } lockmgr(&iconv_lock, LK_RELEASE); + atomic_sub_int(&iconv_refs, 1); if (error) return error; spc = 0; @@ -360,6 +389,7 @@ bzero(&csi, sizeof(csi)); csi.cs_version = ICONV_CSPAIR_INFO_VER; + atomic_add_int(&iconv_refs, 1); lockmgr(&iconv_lock, LK_SHARED); TAILQ_FOREACH(csp, &iconv_cslist, cp_link) { csi.cs_id = csp->cp_id; @@ -372,6 +402,7 @@ break; } lockmgr(&iconv_lock, LK_RELEASE); + atomic_sub_int(&iconv_refs, 1); return error; } @@ -383,11 +414,16 @@ { struct iconv_converter_class *dcp; struct iconv_cspair *csp; + int error; - if (iconv_lookupconv(converter, &dcp) != 0) + lockmgr(&iconv_lock, LK_EXCLUSIVE); + if (iconv_lookupconv_locked(converter, &dcp) != 0) { + lockmgr(&iconv_lock, LK_RELEASE); return EINVAL; - - return iconv_register_cspair(to, from, dcp, NULL, &csp); + } + error = iconv_register_cspair(to, from, dcp, NULL, &csp); + lockmgr(&iconv_lock, LK_RELEASE); + return error; } /* @@ -415,12 +451,17 @@ return EINVAL; if (strlen(din.ia_converter) >= ICONV_CNVNMAXLEN) return EINVAL; - if (iconv_lookupconv(din.ia_converter, &dcp) != 0) - return EINVAL; + atomic_add_int(&iconv_refs, 1); lockmgr(&iconv_lock, LK_EXCLUSIVE); + if (iconv_lookupconv_locked(din.ia_converter, &dcp) != 0) { + lockmgr(&iconv_lock, LK_RELEASE); + atomic_sub_int(&iconv_refs, 1); + return EINVAL; + } error = iconv_register_cspair(din.ia_to, din.ia_from, dcp, NULL, &csp); if (error) { lockmgr(&iconv_lock, LK_RELEASE); + atomic_sub_int(&iconv_refs, 1); return error; } if (din.ia_datalen) { @@ -434,11 +475,13 @@ if (error) goto bad; lockmgr(&iconv_lock, LK_RELEASE); + atomic_sub_int(&iconv_refs, 1); ICDEBUG("%s => %s, %d bytes\n",din.ia_from, din.ia_to, din.ia_datalen); return 0; bad: iconv_unregister_cspair(csp); lockmgr(&iconv_lock, LK_RELEASE); + atomic_sub_int(&iconv_refs, 1); return error; } |