diff options
| -rw-r--r-- | Year_2/OS/lookup-database.c | 346 |
1 files changed, 346 insertions, 0 deletions
diff --git a/Year_2/OS/lookup-database.c b/Year_2/OS/lookup-database.c new file mode 100644 index 0000000..d600898 --- /dev/null +++ b/Year_2/OS/lookup-database.c @@ -0,0 +1,346 @@ +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/ipc.h> +#include <sys/sem.h> +#include <sys/shm.h> +#include <sys/types.h> +#include <sys/wait.h> +#include <unistd.h> + +#define DIM_MSG 1024 + +typedef struct { + char name[256]; + int value; +} pairs; + +typedef struct { + int n; + long value; +} out_row; + +int +WAIT(int id_sem, int n) +{ + struct sembuf sops[1] = { { n, -1, 0 } }; + return semop(id_sem, sops, 1); +} + +int +SIGNAL(int id_sem, int n) +{ + struct sembuf sops[1] = { { n, 1, 0 } }; + return semop(id_sem, sops, 1); +} + +pairs* +find_row(char* name, pairs* rows, int n) +{ + for (int i = 0; i < n; ++i) { + if (strcmp(rows[i].name, name) == 0) + return &rows[i]; + } + + return NULL; +} + +void +parse_rows(FILE* f, pairs* rows) +{ + int i, ci; /* ci stands for character index */ + char* token; + char buf[1024]; + int pi; /* pi stands for pair index */ + i = ci = 0; + char ch; + + while ((ch = (char)fgetc(f)) != EOF) { + if (ch != '\n') { + buf[ci++] = ch; + } else { + buf[ci] = '\0'; + token = strtok(buf, ";"); + if (token == NULL) { + goto free_and_return; + } + + pi = 0; + while (token != NULL) { + if (pi == 0) { + strcpy(rows[i].name, token); + } else if (pi == 1) { + rows[i].value = atoi(token); + } else { + goto free_and_return; + } + pi++; + token = strtok(NULL, ";"); + } + + ci = 0; + i++; + } + } + + return; + +free_and_return: + perror("<db-file> has a bad format"); + free(rows); + exit(1); +} + +void +db(pairs* rows, char* db_path, int id_shm_db_in, int id_shm_db_out, int id_sem, int fin_n) +{ + FILE* f; + int n; /* It represents the number of lines of the file <db-file> */ + char ch; + char* msg; + char* msgout; + int count_newline; + char* token; + int in_n; + pairs* row; + + if ((f = fopen(db_path, "r")) == NULL) { + perror("fopen"); + exit(1); + } + + n = 0; + while ((ch = (char)fgetc(f)) != EOF) { + if (ch == '\n') + n++; + } + + fseek(f, 0, SEEK_SET); + rows = malloc(sizeof(pairs) * n); + parse_rows(f, rows); + fclose(f); + + printf("DB: letti n. %d record da file\n", n); + + if ((msg = (char*)shmat(id_shm_db_in, NULL, 0)) == (char*)-1) { + perror("shmat"); + exit(1); + } + + if ((msgout = (char*)shmat(id_shm_db_out, NULL, 0)) == (char*)-1) { + perror("shmat"); + exit(1); + } + + count_newline = 0; + while (count_newline < fin_n) { + WAIT(id_sem, 0); + if (strcmp(msg, "") == 0) { + count_newline++; + } else { + token = strtok(msg, ";"); + in_n = atoi(token); + token = strtok(NULL, ";"); + row = find_row(token, rows, n); + if (row == NULL) { + printf("DB: query '%s' da IN%d non trovata\n", token, in_n); + } else { + WAIT(id_sem, 3); + sprintf(msgout, "%d;%s;%d", in_n, row->name, row->value); + SIGNAL(id_sem, 2); + printf("DB: query '%s' da IN%d trovata con valore %d\n", token, in_n, row->value); + } + } + SIGNAL(id_sem, 1); + } + + WAIT(id_sem, 3); + strcpy(msgout, ""); + SIGNAL(id_sem, 2); +} + +void +out(int id_shm_db_out, int id_sem, int fin_n) +{ + char* msg; + out_row* processes; /* at i-index there is the data of process-i */ + char* token; + int* n = &fin_n; + int index; + int i; + + processes = malloc(sizeof(out_row) * (*n)); + for (i = 0; i < *n; ++i) { + processes[i].n = 0; + processes[i].value = 0; + } + + if ((msg = (char*)shmat(id_shm_db_out, NULL, 0)) == (char*)-1) { + perror("shmat"); + exit(1); + } + + while (1) { + WAIT(id_sem, 2); + + if (strcmp(msg, "") == 0) + break; + + token = strtok(msg, ";"); + index = atoi(token); + strtok(NULL, ";"); /* Ignore the `name` param */ + token = strtok(NULL, ";"); + processes[index - 1].n++; + processes[index - 1].value += atol(token); + + SIGNAL(id_sem, 3); + } + + for (i = 0; i < *n; ++i) { + printf("OUT: ricevuti n.%d valori validi per IN%d con totale %lu\n", processes[i].n, i + 1, processes[i].value); + } + + free(processes); +} + +void +fn_in(int id_in, char* input_file, int id_shm_db_in, int id_sem) +{ + FILE* f; + char buf[DIM_MSG]; + char ch; + int ci; + char* msg; + int i; + char id_in_str[5]; /* Max process is 99999 */ + + sprintf(id_in_str, "%d", id_in); + + if ((f = fopen(input_file, "r")) == NULL) { + perror("fopen"); + exit(1); + } + + if ((msg = (char*)shmat(id_shm_db_in, NULL, 0)) == (char*)-1) { + perror("shmat"); + exit(1); + } + + ci = strlen(id_in_str) + 1; + for (i = 0; i < strlen(id_in_str); ++i) { + buf[i] = id_in_str[i]; + } + buf[i] = ';'; + + i = 1; + + while ((ch = fgetc(f)) != EOF) { + buf[ci++] = ch; + if (ch == '\n') { + buf[ci - 1] = '\0'; + + WAIT(id_sem, 1); + /* Write the `buf` into the shared memory buffer with db */ + strncpy(msg, buf, ci); + + printf("IN%d: inviata query n.%d '%s'\n", id_in, i, msg + strlen(id_in_str) + 1); + + ci = strlen(id_in_str) + 1; + SIGNAL(id_sem, 0); + i++; + } + } + WAIT(id_sem, 1); + strncpy(msg, "", 1); + SIGNAL(id_sem, 0); + + fclose(f); +} + +int +main(int argc, char** argv) +{ + int i; + int id_shm_db_in; + int id_shm_db_out; + int id_sem; + + pid_t pid_db; + pid_t pid_out; + pid_t pid_in[argc - 2]; + + pairs* rows; + rows = NULL; + + if (argc < 3) { + fprintf(stderr, "Usage: %s <db-file> <query-file-1> [<query-file-2>] .. [<query-file-n>]", argv[0]); + exit(1); + } + + /* Create the shared memory blocks */ + if ((id_shm_db_in = shmget(IPC_PRIVATE, DIM_MSG, IPC_CREAT | 0644)) == -1) { + perror("shmget"); + exit(1); + } + + if ((id_shm_db_out = shmget(IPC_PRIVATE, DIM_MSG, IPC_CREAT | 0644)) == -1) { + perror("shmget"); + exit(1); + } + + /* These are two semaphore used as mutexs */ + if ((id_sem = semget(IPC_PRIVATE, 4, IPC_CREAT | IPC_EXCL | 0644)) == -1) { + perror("semget"); + exit(1); + } + /* Set values to 0 */ + semctl(id_sem, 0, SETVAL, 0); + semctl(id_sem, 1, SETVAL, 1); + semctl(id_sem, 2, SETVAL, 0); + semctl(id_sem, 3, SETVAL, 1); + + pid_db = fork(); + if (pid_db == -1) { + perror("fork"); + exit(1); + } + + if (pid_db == 0) { + db(rows, argv[1], id_shm_db_in, id_shm_db_out, id_sem, argc - 2); + exit(0); + } + + pid_out = fork(); + if (pid_out == -1) { + perror("fork"); + exit(1); + } + + if (pid_out == 0) { + out(id_shm_db_out, id_sem, argc - 2); + exit(0); + } + + for (i = 0; i < argc - 2; ++i) { + pid_in[i] = fork(); + if (pid_in[i] == -1) { + perror("fork"); + exit(1); + } + + if (pid_in[i] == 0) { + fn_in(i + 1, argv[i + 2], id_shm_db_in, id_sem); + exit(0); + } + } + + for (i = 0; i < argc; ++i) + wait(NULL); + + shmctl(id_shm_db_in, IPC_RMID, 0); + shmctl(id_shm_db_out, IPC_RMID, 0); + semctl(id_sem, 4, IPC_RMID); + free(rows); + + return 0; +} |