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#ifndef _CRT_SECURE_NO_WARNINGS
# define _CRT_SECURE_NO_WARNINGS
#endif
#if defined(_MSC_VER) && _MSC_VER >= 1928
# pragma warning(disable : 5105) /* macro expansion warning in windows.h */
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX_MESSAGE_LENGTH 1023
#define USAGE "Usage: %s <output_file>\n"
// Extracts the jobserver details from the MAKEFLAGS environment variable.
//
// Returns a pointer to either a string of the form "R,W" where R and W are fds
// or "fifo:PATH".
//
// Returns NULL if MAKEFLAGS is not set or does not contain recognized
// jobserver flags.
char* jobserver_auth(char* message)
{
char const* jobserver_flags[3] = { "--jobserver-auth=", "--jobserver-fds=",
"-J" };
char* start = NULL;
char* end;
char* result;
size_t len;
int i;
char* makeflags = getenv("MAKEFLAGS");
if (makeflags == NULL) {
strncpy(message, "MAKEFLAGS not set", MAX_MESSAGE_LENGTH);
return NULL;
}
fprintf(stdout, "MAKEFLAGS: %s\n", makeflags);
for (i = 0; i < 3; i++) {
start = strstr(makeflags, jobserver_flags[i]);
if (start != NULL) {
start += strlen(jobserver_flags[i]);
break;
}
}
if (start == NULL) {
strncpy(message, "No jobserver flags found", MAX_MESSAGE_LENGTH);
return NULL;
}
// Skip leading white space
while (*start == ' ' || *start == '\t') {
start++;
}
end = strchr(start, ' ');
if (end == NULL) {
end = start + strlen(start);
}
len = (size_t)(end - start);
result = (char*)malloc(len + 1);
strncpy(result, start, len);
result[len] = '\0';
return result;
}
#if defined(_WIN32)
# include <windows.h>
int windows_semaphore(char const* semaphore, char* message)
{
// Open the semaphore
HANDLE hSemaphore = OpenSemaphoreA(SEMAPHORE_ALL_ACCESS, FALSE, semaphore);
if (hSemaphore == NULL) {
# if defined(_MSC_VER) && _MSC_VER < 1900
sprintf(message, "Error opening semaphore: %s (%ld)\n", semaphore,
GetLastError());
# else
snprintf(message, MAX_MESSAGE_LENGTH,
"Error opening semaphore: %s (%ld)\n", semaphore, GetLastError());
# endif
return 1;
}
strncpy(message, "Success", MAX_MESSAGE_LENGTH);
return 0;
}
#else
# include <errno.h>
# include <fcntl.h>
int test_fd(int read_fd, int write_fd, char* message)
{
// Detect if the file descriptors are valid
int read_good = fcntl(read_fd, F_GETFD) != -1;
int read_error = errno;
int write_good = fcntl(write_fd, F_GETFD) != -1;
int write_error = errno;
if (!read_good || !write_good) {
snprintf(message, MAX_MESSAGE_LENGTH,
"Error opening file descriptors: %d (%s), %d (%s)\n", read_fd,
strerror(read_error), write_fd, strerror(write_error));
return 1;
}
snprintf(message, MAX_MESSAGE_LENGTH, "Success\n");
return 0;
}
int posix(char const* jobserver, char* message)
{
int read_fd;
int write_fd;
// First try to parse as "R,W" file descriptors
if (sscanf(jobserver, "%d,%d", &read_fd, &write_fd) == 2) {
return test_fd(read_fd, write_fd, message);
}
// Then try to parse as "fifo:PATH"
if (strncmp(jobserver, "fifo:", 5) == 0) {
char const* path = jobserver + 5;
read_fd = open(path, O_RDONLY);
write_fd = open(path, O_WRONLY);
return test_fd(read_fd, write_fd, message);
}
// We don't understand the format
snprintf(message, MAX_MESSAGE_LENGTH, "Unrecognized jobserver format: %s\n",
jobserver);
return 1;
}
#endif
// Takes 1 argument: an outfile to write results to.
int main(int argc, char** argv)
{
char message[MAX_MESSAGE_LENGTH + 1];
char* output_file;
FILE* fp;
char* jobserver;
int result;
if (argc != 2) {
fprintf(stderr, USAGE, argv[0]);
return 2;
}
output_file = argv[1];
fp = fopen(output_file, "w");
if (fp == NULL) {
fprintf(stderr, "Error opening output file: %s\n", output_file);
return 2;
}
jobserver = jobserver_auth(message);
if (jobserver == NULL) {
fclose(fp);
fprintf(stderr, "%s\n", message);
return 1;
}
#if defined(_WIN32)
result = windows_semaphore(jobserver, message);
#else
result = posix(jobserver, message);
#endif
fclose(fp);
free(jobserver);
message[MAX_MESSAGE_LENGTH] = '\0';
return result;
}
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