Remove uses of FILENAME_MAX in the runtime (#26381)

Replace uses of `FILENAME_MAX` for buffer sizes in the runtime,
replacing them with heap-allocated strings of the proper size that are
reallocated as needed.

Merges in and builds on the work by @rchinmay in
#17059.

Completes the second part of
#8757 (with
#26357).

[reviewed by @jabraham17 , thanks!]

Testing:
- [x] paratest
- [x] gasnet paratest
- [x] C backend paratest
- [x] GPU tests
- [x] manual run of a nightly config that covers (some) affected code
(`test-hpe-cray-ex-ofi.bash`)

runtime/include/chpl-mem-desc.h

@@ -57,6 +57,7 @@ extern "C" {
   m(SET_WIDE_STRING,      "set wide string",                          true ), \
   m(GET_WIDE_STRING,      "get wide string",                          true ), \
   m(COMMAND_BUFFER,       "command buffer",                           true ), \
+  m(FILENAME,             "filename string",                          true ), \
   m(COMM_UTIL,            "comm layer utility space",                 false), \
   m(COMM_XMIT_RCV_BUF,    "comm layer transmit/receive buffer",       false), \
   m(COMM_FRK_SND_INFO,    "comm layer sent remote fork info",         false), \

runtime/include/chpllaunch.h

@@ -45,6 +45,9 @@ typedef struct {
 int chpl_doDryRun(void);
 void chpl_append_to_largv(int* largc, const char*** largv, int* largv_len,
                           const char* arg);
+void chpl_append_to_cmd(char** cmdBufPtr, int* charsWritten,
+                        const char* format, ...)
+  __attribute__((format(printf, 3, 4)));
 int chpl_run_utility1K(const char *command, char *const argv[],
                        char *outbuf, int outbuflen);
 int chpl_run_cmdstr(const char *commandStr, char *outbuf, int outbuflen);

runtime/src/chpl-launcher-common.c

@@ -27,6 +27,7 @@
 #include <sys/select.h>
 #include <errno.h>
 #include <string.h>
+#include <assert.h>
 #include "chplcgfns.h"
 #include "chpl-comm-launch.h"
 #include "chpl-comm-locales.h"
@@ -102,6 +103,45 @@ void chpl_append_to_largv(int* largc, const char*** largv, int* largv_len,
   (*largv)[(*largc)++] = (arg);
 }
 
+// Helper for appending arguments to a variable-size command buffer.
+// - Requires cmdBufPtr points to an uninitialized pointer on first call, and
+//   charsWritten is 0.
+// - After exceeding an initial allocated size estimate, each call will allocate
+//   additional memory as needed.
+void chpl_append_to_cmd(char** cmdBufPtr, int* charsWritten,
+                        const char* format, ...) {
+  // Estimate of a buffer size that probably won't require extending, to avoid
+  // reallocations and copying.
+  static const int initialSize = 2048;
+
+  va_list argsForLen, argsForPrint;
+  va_start(argsForLen, format);
+  va_copy(argsForPrint, argsForLen);
+
+  // Allocate buffer to initial size on first call
+  if (*cmdBufPtr == NULL) {
+    assert(*charsWritten == 0);
+    *cmdBufPtr = (char*)chpl_mem_allocMany(initialSize, sizeof(char),
+                                    CHPL_RT_MD_COMMAND_BUFFER, -1, 0);
+  }
+
+  // Determine additional characters to be written
+  const int addedLen = vsnprintf(NULL, 0, format, argsForLen);
+  va_end(argsForLen);
+  int newLen = *charsWritten + addedLen;
+
+  // Allocate more memory if needed
+  if (newLen >= initialSize) {
+    *cmdBufPtr = (char*)chpl_mem_realloc(*cmdBufPtr, newLen * sizeof(char),
+                                        CHPL_RT_MD_COMMAND_BUFFER, -1, 0);
+  }
+
+  // Write the new characters
+  vsnprintf(*cmdBufPtr + *charsWritten, addedLen + 1, format, argsForPrint);
+  va_end(argsForPrint);
+  *charsWritten = newLen;
+}
+
 //
 // Use this function to run short utility programs that will return less
 //  than 1024 characters of output.  The program must not expect any input.

runtime/src/launch/pbs-aprun/launch-pbs-aprun.c

@@ -50,7 +50,7 @@ static char* walltime = NULL;
 static char* queue = NULL;
 static int generate_qsub_script = 0;
 
-static char expectFilename[FILENAME_MAX];
+static char* expectFilename = NULL;
 
 extern int fileno(FILE *stream);
 
@@ -236,8 +236,12 @@ static char** chpl_launch_create_argv(int argc, char* argv[],
   } else {
     mypid = 0;
   }
-  snprintf(expectFilename, FILENAME_MAX, "%s%d",
-           baseExpectFilename, (int)mypid);
+  int expectFilenameLen =
+      strlen(baseExpectFilename) + snprintf(NULL, 0, "%d", (int)mypid) + 1;
+  expectFilename = (char*)chpl_mem_allocMany(expectFilenameLen, sizeof(char),
+                                             CHPL_RT_MD_FILENAME, -1, 0);
+  snprintf(expectFilename, expectFilenameLen, "%s%d", baseExpectFilename,
+           (int)mypid);
 
   initAprunAttributes();
   numCoresPerLocale = getCoresPerLocale();
@@ -386,10 +390,15 @@ static void genQsubScript(int argc, char *argv[], int numLocales) {
 static void chpl_launch_cleanup(void) {
   if (!chpl_doDryRun() && !debug) {
     if (unlink(expectFilename)) {
-      char msg[FILENAME_MAX + 35];
-      snprintf(msg, FILENAME_MAX + 35, "Error removing temporary file '%s': %s",
+      char* format = "Error removing temporary file '%s': %s";
+      int msgLen =
+          strlen(format) + strlen(expectFilename) + strlen(strerror(errno));
+      char* msg = (char*)chpl_mem_allocMany(msgLen, sizeof(char),
+                                            CHPL_RT_MD_COMMAND_BUFFER, -1, 0);
+      snprintf(msg, msgLen, "Error removing temporary file '%s': %s",
                expectFilename, strerror(errno));
       chpl_warning(msg, 0, 0);
+      chpl_mem_free(msg, 0, 0);
     }
   }
 }
@@ -414,7 +423,7 @@ int chpl_launch(int argc, char* argv[], int32_t numLocales,
                                   argv[0]);
     chpl_launch_cleanup();
   }
-
+  chpl_mem_free(expectFilename, 0, 0);
   return retcode;
 }
 

runtime/src/launch/pbs-gasnetrun_ibv/launch-pbs-gasnetrun_ibv.c

@@ -41,8 +41,8 @@ static char* walltime = NULL;
 #define basePBSFilename ".chpl-pbs-qsub-"
 #define baseExpectFilename ".chpl-expect-"
 
-char pbsFilename[FILENAME_MAX];
-char expectFilename[FILENAME_MAX];
+char* pbsFilename = NULL;
+char* expectFilename = NULL;
 
 #define launcherAccountEnvvar "CHPL_LAUNCHER_ACCOUNT"
 
@@ -167,10 +167,17 @@ static char* chpl_launch_create_command(int argc, char* argv[],
 #else
   mypid = 0;
 #endif
-  snprintf(expectFilename, sizeof(expectFilename), "%s%d", baseExpectFilename,
-           (int)mypid);
-  snprintf(pbsFilename, sizeof(pbsFilename), "%s%d", basePBSFilename,
+  int expectFilenameLen =
+      strlen(baseExpectFilename) + snprintf(NULL, 0, "%d", (int)mypid) + 1;
+  expectFilename = (char*)chpl_mem_allocMany(expectFilenameLen, sizeof(char),
+                                             CHPL_RT_MD_FILENAME, -1, 0);
+  int pbsFilenameLen =
+      strlen(basePBSFilename) + snprintf(NULL, 0, "%d", (int)mypid) + 1;
+  pbsFilename = (char*)chpl_mem_allocMany(pbsFilenameLen, sizeof(char),
+                                          CHPL_RT_MD_FILENAME, -1, 0);
+  snprintf(expectFilename, expectFilenameLen, "%s%d", baseExpectFilename,
            (int)mypid);
+  snprintf(pbsFilename, pbsFilenameLen, "%s%d", basePBSFilename, (int)mypid);
 
   pbsFile = fopen(pbsFilename, "w");
   fprintf(pbsFile, "#!/bin/sh\n\n");
@@ -254,6 +261,8 @@ static void chpl_launch_cleanup(void) {
     }
   }
 #endif
+  chpl_mem_free(pbsFilename, 0, 0);
+  chpl_mem_free(expectFilename, 0, 0);
 }
 
 

runtime/src/launch/slurm-gasnetrun_common/slurm-gasnetrun_common.h

@@ -56,7 +56,7 @@ static char* nodelist = NULL;
 static char* partition = NULL;
 static char* exclude = NULL;
 static char* gpusPerNode = NULL;
-char slurmFilename[FILENAME_MAX];
+char* slurmFilename = NULL;
 
 /* copies of binary to run per node */
 #define procsPerNode 1
@@ -173,17 +173,21 @@ static void genNumLocalesOptions(FILE* slurmFile, sbatchVersion sbatch,
   }
 }
 
-static int propagate_environment(char* buf, size_t size)
+// Append environment variables using chpl_append_to_cmd.
+// charsWritten may be NULL, in which case it is ignored.
+static void propagate_environment(char** buf, int* charsWritten)
 {
-  int len = 0;
+  int ignoredCharsWritten;
+  if (!charsWritten) {
+    charsWritten = &ignoredCharsWritten;
+  }
 
   // Indiscriminately propagate all environment variables.
   // We could do this more selectively, but we would be likely
   // to leave out something important.
   char *enviro_keys = chpl_get_enviro_keys(',');
   if (enviro_keys)
-    len += snprintf(buf, size, " -E '%s'", enviro_keys);
-  return len;
+    chpl_append_to_cmd(buf, charsWritten, " -E '%s'", enviro_keys);
 }
 
 static char* chpl_launch_create_command(int argc, char* argv[],
@@ -192,8 +196,7 @@ static char* chpl_launch_create_command(int argc, char* argv[],
 
   int i;
   int size;
-  char baseCommand[2*FILENAME_MAX];
-  char envProp[2*FILENAME_MAX];
+  char* baseCommand = NULL;
   char* command;
   FILE* slurmFile;
   char* projectString = getenv(launcherAccountEnvvar);
@@ -273,7 +276,12 @@ static char* chpl_launch_create_command(int argc, char* argv[],
   } else {
     mypid = getpid();
   }
-  snprintf(slurmFilename, sizeof(slurmFilename), "%s%d", baseSBATCHFilename, (int)mypid);
+  int slurmFilenameLen =
+      strlen(baseSBATCHFilename) + snprintf(NULL, 0, "%d", (int)mypid) + 1;
+  slurmFilename = (char*)chpl_mem_allocMany(slurmFilenameLen, sizeof(char),
+                                            CHPL_RT_MD_FILENAME, -1, 0);
+  snprintf(slurmFilename, slurmFilenameLen, "%s%d", baseSBATCHFilename,
+           (int)mypid);
 
   if (getenv("CHPL_LAUNCHER_USE_SBATCH") != NULL) {
     slurmFile = fopen(slurmFilename, "w");
@@ -297,8 +305,10 @@ static char* chpl_launch_create_command(int argc, char* argv[],
             CHPL_THIRD_PARTY, WRAP_TO_STR(LAUNCH_PATH), GASNETRUN_LAUNCHER,
             numLocales, numLocales);
 
-    propagate_environment(envProp, sizeof(envProp));
+    char* envProp = NULL;
+    propagate_environment(&envProp, NULL);
     fprintf(slurmFile, "%s", envProp);
+    chpl_mem_free(envProp, 0, 0);
 
     fprintf(slurmFile, " %s %s", chpl_get_real_binary_wrapper(), chpl_get_real_binary_name());
 
@@ -309,56 +319,54 @@ static char* chpl_launch_create_command(int argc, char* argv[],
 
     fclose(slurmFile);
     chmod(slurmFilename, 0755);
-
-    snprintf(baseCommand, sizeof(baseCommand), "sbatch %s\n", slurmFilename);
+    char* format="sbatch %s\n";
+    int baseCommandLen = strlen(slurmFilename) + strlen(format);
+    baseCommand = (char*)chpl_mem_allocMany(baseCommandLen, sizeof(char),
+                                            CHPL_RT_MD_COMMAND_BUFFER, -1, 0);
+    snprintf(baseCommand, baseCommandLen, format, slurmFilename);
   } else {
-    char iCom[2*FILENAME_MAX-10];
+    char* iCom = NULL;
     int len = 0;
 
     if (!getSlurmDebug()) {
-      len += snprintf(iCom+len, sizeof(iCom)-len, "--quiet ");
+      chpl_append_to_cmd(&iCom, &len, "--quiet ");
     }
-    len += snprintf(iCom+len, sizeof(iCom)-len, "-J %s ", jobName);
-    len += snprintf(iCom+len, sizeof(iCom)-len, "-N %d ", numNodes);
-    len += snprintf(iCom+len, sizeof(iCom)-len, "--ntasks=%d ", numLocales);
-    if (nodeAccessStr != NULL)
-      len += snprintf(iCom+len, sizeof(iCom)-len, "--%s ", nodeAccessStr);
-    if (walltime)
-      len += snprintf(iCom+len, sizeof(iCom)-len, "--time=%s ", walltime);
-    if (nodelist)
-      len += snprintf(iCom+len, sizeof(iCom)-len, "--nodelist=%s ", nodelist);
-    if(partition)
-      len += snprintf(iCom+len, sizeof(iCom)-len, "--partition=%s ", partition);
-    if(exclude)
-      len += snprintf(iCom+len, sizeof(iCom)-len, "--exclude=%s ", exclude);
-    if(gpusPerNode)
-      len += snprintf(iCom+len, sizeof(iCom)-len, "--gpus-per-node=%s ", gpusPerNode);
-    if(projectString && strlen(projectString) > 0)
-      len += snprintf(iCom+len, sizeof(iCom)-len, "--account=%s ",
-                     projectString);
-    if (constraint)
-      len += snprintf(iCom+len, sizeof(iCom)-len, " -C %s", constraint);
-    len += snprintf(iCom+len, sizeof(iCom)-len,
-                   " %s/%s/%s -n %d -N %d -c 0",
+    chpl_append_to_cmd(&iCom, &len, "-J %s ", jobName);
+    chpl_append_to_cmd(&iCom, &len, "-N %d ", numNodes);
+    chpl_append_to_cmd(&iCom, &len, "--ntasks=%d ", numLocales);
+    if (nodeAccessStr != NULL) chpl_append_to_cmd(&iCom, &len, "--%s ", nodeAccessStr);
+    if (walltime) chpl_append_to_cmd(&iCom, &len, "--time=%s ", walltime);
+    if (nodelist) chpl_append_to_cmd(&iCom, &len, "--nodelist=%s ", nodelist);
+    if (partition) chpl_append_to_cmd(&iCom, &len, "--partition=%s ", partition);
+    if (exclude) chpl_append_to_cmd(&iCom, &len, "--exclude=%s ", exclude);
+    if (gpusPerNode) chpl_append_to_cmd(&iCom, &len, "--gpus-per-node=%s ", gpusPerNode);
+    if (projectString && strlen(projectString) > 0)
+      chpl_append_to_cmd(&iCom, &len, "--account=%s ", projectString);
+    if (constraint) chpl_append_to_cmd(&iCom, &len, "-C %s", constraint);
+    chpl_append_to_cmd(&iCom, &len, " %s/%s/%s -n %d -N %d -c 0",
                    CHPL_THIRD_PARTY, WRAP_TO_STR(LAUNCH_PATH),
                    GASNETRUN_LAUNCHER, numLocales, numNodes);
-    len += propagate_environment(iCom+len, sizeof(iCom) - len);
-    len += snprintf(iCom+len, sizeof(iCom)-len, " %s %s",
-                   chpl_get_real_binary_wrapper(),
+    propagate_environment(&iCom, &len);
+    chpl_append_to_cmd(&iCom, &len, " %s %s", chpl_get_real_binary_wrapper(),
                    chpl_get_real_binary_name());
     for (i=1; i<argc; i++) {
-      len += snprintf(iCom+len, sizeof(iCom)-len, " '%s'", argv[i]);
+      chpl_append_to_cmd(&iCom, &len, " '%s'", argv[i]);
     }
-
-    snprintf(baseCommand, sizeof(baseCommand), "salloc %s", iCom);
+    char* format = "salloc %s";
+    int baseCommandLen = strlen(format) + len + 1;
+    baseCommand = (char*)chpl_mem_allocMany(baseCommandLen, sizeof(char),
+                                            CHPL_RT_MD_COMMAND_BUFFER, -1, 0);
+    snprintf(baseCommand, baseCommandLen, format, iCom);
+    chpl_mem_free(iCom, 0, 0);
   }
 
   size = strlen(baseCommand) + 1;
 
-  command = chpl_mem_allocMany(size, sizeof(char), CHPL_RT_MD_COMMAND_BUFFER, -1, 0);
-
-  snprintf(command, size * sizeof(char), "%s", baseCommand);
+  command =
+      chpl_mem_allocMany(size, sizeof(char), CHPL_RT_MD_COMMAND_BUFFER, -1, 0);
 
+  snprintf(command, size, "%s", baseCommand);
+  chpl_mem_free(baseCommand, 0, 0);
   if (strlen(command)+1 > size) {
     chpl_internal_error("buffer overflow");
   }
@@ -385,6 +393,7 @@ int chpl_launch(int argc, char* argv[], int32_t numLocales,
                                           numLocales, numLocalesPerNode),
             argv[0]);
   chpl_launch_cleanup();
+  chpl_mem_free(slurmFilename, 0, 0);
   return retcode;
 }