diff options
Diffstat (limited to 'stacks/max25-bcpr/src/bcpr_lock.c')
| -rw-r--r-- | stacks/max25-bcpr/src/bcpr_lock.c | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/stacks/max25-bcpr/src/bcpr_lock.c b/stacks/max25-bcpr/src/bcpr_lock.c new file mode 100644 index 0000000..b179323 --- /dev/null +++ b/stacks/max25-bcpr/src/bcpr_lock.c @@ -0,0 +1,202 @@ +/* + * Exclusive lock on owned COM ports only (flock + optional setserial uart none). + * Pass real IRQ — refuse mismatch. See vault IRQ/lock contract. + */ +#define _GNU_SOURCE +#include "bcpr/bcpr_lock.h" + +#include <errno.h> +#include <fcntl.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/file.h> +#include <sys/stat.h> +#include <sys/types.h> +#include <unistd.h> + +static void tty_basename(const char *serial, char *out, size_t out_sz) +{ + const char *p = strrchr(serial, '/'); + p = p ? p + 1 : serial; + snprintf(out, out_sz, "%s", p); +} + +int bcpr_lock_verify_irq(const char *serial, unsigned expect_irq, + unsigned *got_irq, unsigned *got_io) +{ + char name[64]; + char path[128]; + char buf[64]; + FILE *f; + unsigned irq = 0; + unsigned io = 0; + + if (!serial || !serial[0]) { + return -1; + } + tty_basename(serial, name, sizeof(name)); + snprintf(path, sizeof(path), "/sys/class/tty/%s/irq", name); + f = fopen(path, "r"); + if (f) { + if (fgets(buf, sizeof(buf), f)) { + irq = (unsigned)strtoul(buf, NULL, 0); + } + fclose(f); + } else { + /* Fallback: setserial -g (best-effort). */ + char cmd[256]; + FILE *p; + snprintf(cmd, sizeof(cmd), "setserial -g %s 2>/dev/null", serial); + p = popen(cmd, "r"); + if (!p) { + return -1; + } + if (fgets(buf, sizeof(buf), p)) { + char *ip = strstr(buf, "IRQ: "); + char *pp = strstr(buf, "Port: "); + if (ip) { + irq = (unsigned)strtoul(ip + 5, NULL, 0); + } + if (pp) { + io = (unsigned)strtoul(pp + 6, NULL, 0); + } + } + pclose(p); + } + + snprintf(path, sizeof(path), "/sys/class/tty/%s/iomem_base", name); + f = fopen(path, "r"); + if (f) { + if (fgets(buf, sizeof(buf), f)) { + io = (unsigned)strtoul(buf, NULL, 0); + } + fclose(f); + } + + if (got_irq) { + *got_irq = irq; + } + if (got_io) { + *got_io = io; + } + if (expect_irq == 0) { + return -1; /* never invent; refuse zero when required */ + } + if (irq == 0 || irq != expect_irq) { + return -1; + } + return 0; +} + +static int make_lock_path(const bcpr_dev_config_t *dev, char *out, size_t sz) +{ + char name[64]; + const char *dir = "/var/run/max25-bcpr"; + tty_basename(dev->serial, name, sizeof(name)); + if (name[0] == '\0') { + return -1; + } + snprintf(out, sz, "%s/lock-%s", dir, name); + return 0; +} + +int bcpr_lock_acquire(bcpr_port_lock_t *lk, const bcpr_dev_config_t *dev, + int dry_run) +{ + char lockpath[192]; + unsigned got_irq = 0, got_io = 0; + + if (!lk || !dev) { + return -1; + } + memset(lk, 0, sizeof(*lk)); + snprintf(lk->serial, sizeof(lk->serial), "%s", dev->serial); + lk->iobase = dev->iobase; + lk->irq = dev->irq; + lk->lock_fd = -1; + lk->dry_run = dry_run ? 1 : 0; + + if (dry_run) { + return 0; + } + if (!dev->serial[0] || dev->irq == 0 || dev->iobase == 0) { + return -1; + } + if (bcpr_lock_verify_irq(dev->serial, dev->irq, &got_irq, &got_io) != 0) { +#if defined(__FreeBSD__) + /* + * No Linux sysfs/setserial — operator INI is SSoT for iobase/irq + * (see vault ExSys AM1 map). Skip hard fail when probe unavailable. + */ + got_irq = dev->irq; + got_io = dev->iobase; +#else + fprintf(stderr, + "bcpr: IRQ mismatch or unreadable for %s (expect %u got %u)\n", + dev->serial, dev->irq, got_irq); + return -1; +#endif + } + if (got_io && got_io != dev->iobase) { + fprintf(stderr, + "bcpr: iobase mismatch for %s (expect 0x%x got 0x%x)\n", + dev->serial, dev->iobase, got_io); + return -1; + } + + if (make_lock_path(dev, lockpath, sizeof(lockpath)) != 0) { + return -1; + } + (void)mkdir("/var/run/max25-bcpr", 0755); + lk->lock_fd = open(lockpath, O_RDWR | O_CREAT | O_CLOEXEC, 0644); + if (lk->lock_fd < 0) { + perror("bcpr lock open"); + return -1; + } + if (flock(lk->lock_fd, LOCK_EX | LOCK_NB) != 0) { + fprintf(stderr, "bcpr: port %s already locked\n", dev->serial); + close(lk->lock_fd); + lk->lock_fd = -1; + return -1; + } + + /* Release 8250 claim on this COM only so userspace can bit-bang. */ + { + char cmd[256]; + snprintf(cmd, sizeof(cmd), "setserial %s uart none 2>/dev/null", + dev->serial); + if (system(cmd) == 0) { + lk->uart_released = 1; + } + } + return 0; +} + +void bcpr_lock_release(bcpr_port_lock_t *lk) +{ + if (!lk) { + return; + } + if (lk->dry_run) { + memset(lk, 0, sizeof(*lk)); + lk->lock_fd = -1; + return; + } + if (lk->uart_released && lk->serial[0]) { + char cmd[256]; + /* Restore 16550A claim — best effort. */ + snprintf(cmd, sizeof(cmd), + "setserial %s uart 16550A port 0x%x irq %u 2>/dev/null", + lk->serial, lk->iobase, lk->irq); + (void)system(cmd); + lk->uart_released = 0; + } + if (lk->lock_fd >= 0) { + flock(lk->lock_fd, LOCK_UN); + close(lk->lock_fd); + lk->lock_fd = -1; + } + memset(lk, 0, sizeof(*lk)); + lk->lock_fd = -1; +} |