diff --git a/OSs/lab7/Makefile b/OSs/lab7/Makefile new file mode 100644 index 0000000..959d36a --- /dev/null +++ b/OSs/lab7/Makefile @@ -0,0 +1,15 @@ +targets = server client +all: $(targets) + +server: server.o + $(CC) -o $@ $^ $(CFLAGS) + +client: client.o + $(CC) -o $@ $^ $(CFLAGS) + +%.o: %.c + $(CC) -c $^ -o $@ $(CFLAGS) + +clean: + rm -f $(targets) + rm -f *.o diff --git a/OSs/lab7/client.c b/OSs/lab7/client.c new file mode 100644 index 0000000..081cfd8 --- /dev/null +++ b/OSs/lab7/client.c @@ -0,0 +1,65 @@ +#include "common.h" +#include +#include +#include +#include +#include +#include +#include +#include + +#define FAIL_TO_CLEANUP(cond, jmp_to) \ + if (cond) { \ + perror(#cond); \ + ret = EXIT_FAILURE; \ + goto jmp_to; \ + } + +int main(void) { + int ret = 0; + int shm_fd = -1; + void *shm_ptr = MAP_FAILED; + sem_t *sem_c2s = SEM_FAILED; + sem_t *sem_s2c = SEM_FAILED; + + FAIL_TO_CLEANUP((shm_fd = shm_open(SHM_NAME, O_RDWR, 0)) == -1, exit); + FAIL_TO_CLEANUP( + (shm_ptr = mmap(NULL, SHM_SIZE, + PROT_READ | PROT_WRITE, + MAP_SHARED, shm_fd, 0)) == MAP_FAILED, + unmap_shared_mem); + + FAIL_TO_CLEANUP((sem_c2s = sem_open(SEM_C2S_NAME, 0)) == SEM_FAILED, + close_sem_c2s); + FAIL_TO_CLEANUP((sem_s2c = sem_open(SEM_S2C_NAME, 0)) == SEM_FAILED, + close_sem_s2c); + + char filename[SHM_SIZE]; + FAIL_TO_CLEANUP(fgets(filename, sizeof(filename), stdin) == NULL, close_sem_s2c); + + size_t ln = strlen(filename); + if (ln > 0 && filename[ln - 1] == '\n') + filename[ln - 1] = '\0'; + + memset(shm_ptr, 0, SHM_SIZE); + strncpy((char *)shm_ptr, filename, SHM_SIZE - 1); + + FAIL_TO_CLEANUP(sem_post(sem_c2s) == -1, close_sem_s2c); + + FAIL_TO_CLEANUP(sem_wait(sem_s2c) == -1, close_sem_s2c); + + size_t len = strnlen((char *)shm_ptr, SHM_SIZE); + FAIL_TO_CLEANUP(fwrite(shm_ptr, sizeof(char), len, stdout) != len, close_sem_s2c); + fflush(stdout); // don't really care if fails + +close_sem_s2c: + sem_close(sem_s2c); +close_sem_c2s: + sem_close(sem_c2s); +unmap_shared_mem: + munmap(shm_ptr, SHM_SIZE); +close_shared_fd: + close(shm_fd); +exit: + return ret; +} diff --git a/OSs/lab7/common.h b/OSs/lab7/common.h new file mode 100644 index 0000000..36ca2dc --- /dev/null +++ b/OSs/lab7/common.h @@ -0,0 +1,12 @@ +#ifndef COMMON_H +#define COMMON_H + +#define SHM_NAME "/lab7_shm" +#define SEM_C2S_NAME "/sem_c2s_lab7" +#define SEM_S2C_NAME "/sem_s2c_lab7" +#define SHM_SIZE (64 * 1024) + +#define FAIL_ON(cond) if (cond) return EXIT_FAILURE + +#endif /* COMMON_H */ + diff --git a/OSs/lab7/server.c b/OSs/lab7/server.c new file mode 100644 index 0000000..7ee3114 --- /dev/null +++ b/OSs/lab7/server.c @@ -0,0 +1,136 @@ +#include +#include +#include +#include +#include +#include +#include +#include + +#include "common.h" + +#define FAIL_TO_CLEANUP(cond, jmp_to) \ + if (cond) { \ + perror(#cond); \ + ret = EXIT_FAILURE; \ + goto jmp_to; \ + } + +int main(void) { + int ret; + int shm_fd = -1; + void *shm_ptr = MAP_FAILED; + sem_t *sem_c2s = SEM_FAILED; + sem_t *sem_s2c = SEM_FAILED; + + /* Create or open shared memory */ + FAIL_TO_CLEANUP((shm_fd = shm_open(SHM_NAME, O_CREAT | O_RDWR, 0600)), cleanup); + if (shm_fd == -1) { + perror("shm_open"); + goto cleanup; + } + if (ftruncate(shm_fd, SHM_SIZE) == -1) { + perror("ftruncate"); + goto cleanup; + } + + shm_ptr = mmap(NULL, SHM_SIZE, PROT_READ | PROT_WRITE, + MAP_SHARED, shm_fd, 0); + if (shm_ptr == MAP_FAILED) { + perror("mmap"); + goto cleanup; + } + + /* Create semaphores (initialize to 0) */ + sem_c2s = sem_open(SEM_C2S_NAME, O_CREAT, 0600, 0); + if (sem_c2s == SEM_FAILED) { + perror("sem_open c2s"); + goto cleanup; + } + sem_s2c = sem_open(SEM_S2C_NAME, O_CREAT, 0600, 0); + if (sem_s2c == SEM_FAILED) { + perror("sem_open s2c"); + goto cleanup; + } + + printf("Server: waiting for client...\n"); + + while (1) { + /* Wait for client to write filename */ + if (sem_wait(sem_c2s) == -1) { + perror("sem_wait c2s"); + break; + } + + /* Read filename from shared memory (ensure NUL) */ + char filename[SHM_SIZE]; + memset(filename, 0, sizeof(filename)); + memcpy(filename, shm_ptr, sizeof(filename) - 1); + + /* If client sent special "EXIT" filename, break loop and cleanup */ + if (strcmp(filename, "EXIT") == 0) { + /* Notify client and exit */ + const char *msg = "Server shutting down."; + size_t len = strlen(msg) + 1; + if (len > SHM_SIZE) + len = SHM_SIZE; + memcpy(shm_ptr, msg, len); + sem_post(sem_s2c); + break; + } + + /* Try open file */ + FILE *f = fopen(filename, "rb"); + if (!f) { + char errbuf[SHM_SIZE]; + snprintf(errbuf, sizeof(errbuf), "Error opening file '%s'\n", filename); + size_t len = strlen(errbuf) + 1; + if (len > SHM_SIZE) + len = SHM_SIZE; + memcpy(shm_ptr, errbuf, len); + sem_post(sem_s2c); + continue; + } + + /* Read file content and write to shared memory (truncate if too large) */ + size_t total = 0; + while (!feof(f) && total < SHM_SIZE - 1) { + size_t toread = SHM_SIZE - 1 - total; + size_t r = fread((char *)shm_ptr + total, 1, toread, f); + total += r; + if (r == 0) + break; + } + ((char *)shm_ptr)[total] = '\0'; /* ensure NUL */ + + if (!feof(f) && total == SHM_SIZE - 1) { + /* truncated */ + const char *note = + "\n[Output truncated: file larger than shared memory]\n"; + size_t note_len = strlen(note); + if (note_len + 1 < SHM_SIZE) { + size_t copy_pos = SHM_SIZE - 1 - note_len; + memcpy((char *)shm_ptr + copy_pos, note, note_len); + ((char *)shm_ptr)[SHM_SIZE - 1] = '\0'; + } + } + + fclose(f); + + /* Signal client that data is ready */ + if (sem_post(sem_s2c) == -1) { + perror("sem_post s2c"); + break; + } + } + +cleanup: + if (sem_c2s != SEM_FAILED) + sem_close(sem_c2s); + if (sem_s2c != SEM_FAILED) + sem_close(sem_s2c); + if (shm_ptr != MAP_FAILED) munmap(shm_ptr, SHM_SIZE); if (shm_fd != -1) + close(shm_fd); + + return 0; +}