aboutsummaryrefslogtreecommitdiff
path: root/liolib.c
diff options
context:
space:
mode:
Diffstat (limited to 'liolib.c')
-rw-r--r--liolib.c54
1 files changed, 6 insertions, 48 deletions
diff --git a/liolib.c b/liolib.c
index 75e10ded..21305b8c 100644
--- a/liolib.c
+++ b/liolib.c
@@ -133,50 +133,6 @@ static int l_checkmode (const char *mode) {
133/* }====================================================== */ 133/* }====================================================== */
134 134
135 135
136/*
137** {======================================================
138** 'resourcetryagain'
139** This function uses 'errno' to check whether the last error was
140** related to lack of resources (e.g., not enough memory or too many
141** open files). If so, the function performs a full garbage collection
142** to try to release resources, and then it returns 1 to signal to
143** the caller that it is worth trying again the failed operation.
144** Otherwise, it returns 0. Because error codes are not ANSI C, the
145** code must handle any combination of error codes that are defined.
146** =======================================================
147*/
148
149static int resourcetryagain (lua_State *L) {
150
151/* these are the resource-related errors in Linux */
152#if defined(EMFILE) || defined(ENFILE) || defined(ENOMEM)
153
154#if !defined(EMFILE) /* too many open files in the process */
155#define EMFILE -1 /* if not defined, use an impossible value */
156#endif
157
158#if !defined(ENFILE) /* too many open files in the system */
159#define ENFILE -1
160#endif
161
162#if !defined(ENOMEM) /* not enough memory */
163#define ENOMEM -1
164#endif
165
166 if (errno == EMFILE || errno == ENFILE || errno == ENOMEM) {
167 lua_gc(L, LUA_GCCOLLECT); /* try to release resources with a full GC */
168 return 1; /* signal to try again the creation */
169 }
170
171#endif
172
173 return 0; /* else, asume errors are not due to lack of resources */
174
175}
176
177/* }====================================================== */
178
179
180 136
181#define IO_PREFIX "_IO_" 137#define IO_PREFIX "_IO_"
182#define IOPREF_LEN (sizeof(IO_PREFIX)/sizeof(char) - 1) 138#define IOPREF_LEN (sizeof(IO_PREFIX)/sizeof(char) - 1)
@@ -292,12 +248,12 @@ static LStream *newfile (lua_State *L) {
292 248
293/* 249/*
294** Equivalent to 'fopen', but if it fails due to a lack of resources 250** Equivalent to 'fopen', but if it fails due to a lack of resources
295** (see 'resourcetryagain'), do an "emergency" garbage collection to try 251** (see 'luaL_resourcetryagain'), do an "emergency" garbage collection
296** to close some files and then tries to open the file again. 252** to try to close some files and then tries to open the file again.
297*/ 253*/
298static FILE *trytoopen (lua_State *L, const char *path, const char *mode) { 254static FILE *trytoopen (lua_State *L, const char *path, const char *mode) {
299 FILE *f = fopen(path, mode); 255 FILE *f = fopen(path, mode);
300 if (f == NULL && resourcetryagain(L)) /* resource failure? */ 256 if (f == NULL && luaL_resourcetryagain(L)) /* resource failure? */
301 f = fopen(path, mode); /* try to open again */ 257 f = fopen(path, mode); /* try to open again */
302 return f; 258 return f;
303} 259}
@@ -336,7 +292,7 @@ static int io_popen (lua_State *L) {
336 const char *mode = luaL_optstring(L, 2, "r"); 292 const char *mode = luaL_optstring(L, 2, "r");
337 LStream *p = newprefile(L); 293 LStream *p = newprefile(L);
338 p->f = l_popen(L, filename, mode); 294 p->f = l_popen(L, filename, mode);
339 if (p->f == NULL && resourcetryagain(L)) /* resource failure? */ 295 if (p->f == NULL && luaL_resourcetryagain(L)) /* resource failure? */
340 p->f = l_popen(L, filename, mode); /* try to open again */ 296 p->f = l_popen(L, filename, mode); /* try to open again */
341 p->closef = &io_pclose; 297 p->closef = &io_pclose;
342 return (p->f == NULL) ? luaL_fileresult(L, 0, filename) : 1; 298 return (p->f == NULL) ? luaL_fileresult(L, 0, filename) : 1;
@@ -346,6 +302,8 @@ static int io_popen (lua_State *L) {
346static int io_tmpfile (lua_State *L) { 302static int io_tmpfile (lua_State *L) {
347 LStream *p = newfile(L); 303 LStream *p = newfile(L);
348 p->f = tmpfile(); 304 p->f = tmpfile();
305 if (p->f == NULL && luaL_resourcetryagain(L)) /* resource failure? */
306 p->f = tmpfile(); /* try to open again */
349 return (p->f == NULL) ? luaL_fileresult(L, 0, NULL) : 1; 307 return (p->f == NULL) ? luaL_fileresult(L, 0, NULL) : 1;
350} 308}
351 309